h264: Split h264 slice decoding from nal decoding

1 files changed, 2384 insertions, 0 deletions

diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
new file mode 100644
index 0000000000..897c8ebdbb
--- /dev/null
+++ b/libavcodec/h264_slice.c
@@ -0,0 +1,2384 @@
+/*
+ * H.26L/H.264/AVC/JVT/14496-10/... decoder
+ * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * H.264 / AVC / MPEG4 part10 codec.
+ * @author Michael Niedermayer <michaelni@gmx.at>
+ */
+
+#include "libavutil/avassert.h"
+#include "libavutil/imgutils.h"
+#include "libavutil/timer.h"
+#include "internal.h"
+#include "cabac.h"
+#include "cabac_functions.h"
+#include "dsputil.h"
+#include "error_resilience.h"
+#include "avcodec.h"
+#include "h264.h"
+#include "h264data.h"
+#include "h264chroma.h"
+#include "h264_mvpred.h"
+#include "golomb.h"
+#include "mathops.h"
+#include "mpegutils.h"
+#include "rectangle.h"
+#include "thread.h"
+
+
+static const uint8_t rem6[QP_MAX_NUM + 1] = {
+    0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2,
+    3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5,
+    0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3,
+};
+
+static const uint8_t div6[QP_MAX_NUM + 1] = {
+    0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3,  3,  3,
+    3, 3, 3, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6,  6,  6,
+    7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10,
+};
+
+static const uint8_t field_scan[16] = {
+    0 + 0 * 4, 0 + 1 * 4, 1 + 0 * 4, 0 + 2 * 4,
+    0 + 3 * 4, 1 + 1 * 4, 1 + 2 * 4, 1 + 3 * 4,
+    2 + 0 * 4, 2 + 1 * 4, 2 + 2 * 4, 2 + 3 * 4,
+    3 + 0 * 4, 3 + 1 * 4, 3 + 2 * 4, 3 + 3 * 4,
+};
+
+static const uint8_t field_scan8x8[64] = {
+    0 + 0 * 8, 0 + 1 * 8, 0 + 2 * 8, 1 + 0 * 8,
+    1 + 1 * 8, 0 + 3 * 8, 0 + 4 * 8, 1 + 2 * 8,
+    2 + 0 * 8, 1 + 3 * 8, 0 + 5 * 8, 0 + 6 * 8,
+    0 + 7 * 8, 1 + 4 * 8, 2 + 1 * 8, 3 + 0 * 8,
+    2 + 2 * 8, 1 + 5 * 8, 1 + 6 * 8, 1 + 7 * 8,
+    2 + 3 * 8, 3 + 1 * 8, 4 + 0 * 8, 3 + 2 * 8,
+    2 + 4 * 8, 2 + 5 * 8, 2 + 6 * 8, 2 + 7 * 8,
+    3 + 3 * 8, 4 + 1 * 8, 5 + 0 * 8, 4 + 2 * 8,
+    3 + 4 * 8, 3 + 5 * 8, 3 + 6 * 8, 3 + 7 * 8,
+    4 + 3 * 8, 5 + 1 * 8, 6 + 0 * 8, 5 + 2 * 8,
+    4 + 4 * 8, 4 + 5 * 8, 4 + 6 * 8, 4 + 7 * 8,
+    5 + 3 * 8, 6 + 1 * 8, 6 + 2 * 8, 5 + 4 * 8,
+    5 + 5 * 8, 5 + 6 * 8, 5 + 7 * 8, 6 + 3 * 8,
+    7 + 0 * 8, 7 + 1 * 8, 6 + 4 * 8, 6 + 5 * 8,
+    6 + 6 * 8, 6 + 7 * 8, 7 + 2 * 8, 7 + 3 * 8,
+    7 + 4 * 8, 7 + 5 * 8, 7 + 6 * 8, 7 + 7 * 8,
+};
+
+static const uint8_t field_scan8x8_cavlc[64] = {
+    0 + 0 * 8, 1 + 1 * 8, 2 + 0 * 8, 0 + 7 * 8,
+    2 + 2 * 8, 2 + 3 * 8, 2 + 4 * 8, 3 + 3 * 8,
+    3 + 4 * 8, 4 + 3 * 8, 4 + 4 * 8, 5 + 3 * 8,
+    5 + 5 * 8, 7 + 0 * 8, 6 + 6 * 8, 7 + 4 * 8,
+    0 + 1 * 8, 0 + 3 * 8, 1 + 3 * 8, 1 + 4 * 8,
+    1 + 5 * 8, 3 + 1 * 8, 2 + 5 * 8, 4 + 1 * 8,
+    3 + 5 * 8, 5 + 1 * 8, 4 + 5 * 8, 6 + 1 * 8,
+    5 + 6 * 8, 7 + 1 * 8, 6 + 7 * 8, 7 + 5 * 8,
+    0 + 2 * 8, 0 + 4 * 8, 0 + 5 * 8, 2 + 1 * 8,
+    1 + 6 * 8, 4 + 0 * 8, 2 + 6 * 8, 5 + 0 * 8,
+    3 + 6 * 8, 6 + 0 * 8, 4 + 6 * 8, 6 + 2 * 8,
+    5 + 7 * 8, 6 + 4 * 8, 7 + 2 * 8, 7 + 6 * 8,
+    1 + 0 * 8, 1 + 2 * 8, 0 + 6 * 8, 3 + 0 * 8,
+    1 + 7 * 8, 3 + 2 * 8, 2 + 7 * 8, 4 + 2 * 8,
+    3 + 7 * 8, 5 + 2 * 8, 4 + 7 * 8, 5 + 4 * 8,
+    6 + 3 * 8, 6 + 5 * 8, 7 + 3 * 8, 7 + 7 * 8,
+};
+
+// zigzag_scan8x8_cavlc[i] = zigzag_scan8x8[(i/4) + 16*(i%4)]
+static const uint8_t zigzag_scan8x8_cavlc[64] = {
+    0 + 0 * 8, 1 + 1 * 8, 1 + 2 * 8, 2 + 2 * 8,
+    4 + 1 * 8, 0 + 5 * 8, 3 + 3 * 8, 7 + 0 * 8,
+    3 + 4 * 8, 1 + 7 * 8, 5 + 3 * 8, 6 + 3 * 8,
+    2 + 7 * 8, 6 + 4 * 8, 5 + 6 * 8, 7 + 5 * 8,
+    1 + 0 * 8, 2 + 0 * 8, 0 + 3 * 8, 3 + 1 * 8,
+    3 + 2 * 8, 0 + 6 * 8, 4 + 2 * 8, 6 + 1 * 8,
+    2 + 5 * 8, 2 + 6 * 8, 6 + 2 * 8, 5 + 4 * 8,
+    3 + 7 * 8, 7 + 3 * 8, 4 + 7 * 8, 7 + 6 * 8,
+    0 + 1 * 8, 3 + 0 * 8, 0 + 4 * 8, 4 + 0 * 8,
+    2 + 3 * 8, 1 + 5 * 8, 5 + 1 * 8, 5 + 2 * 8,
+    1 + 6 * 8, 3 + 5 * 8, 7 + 1 * 8, 4 + 5 * 8,
+    4 + 6 * 8, 7 + 4 * 8, 5 + 7 * 8, 6 + 7 * 8,
+    0 + 2 * 8, 2 + 1 * 8, 1 + 3 * 8, 5 + 0 * 8,
+    1 + 4 * 8, 2 + 4 * 8, 6 + 0 * 8, 4 + 3 * 8,
+    0 + 7 * 8, 4 + 4 * 8, 7 + 2 * 8, 3 + 6 * 8,
+    5 + 5 * 8, 6 + 5 * 8, 6 + 6 * 8, 7 + 7 * 8,
+};
+
+static const uint8_t dequant4_coeff_init[6][3] = {
+    { 10, 13, 16 },
+    { 11, 14, 18 },
+    { 13, 16, 20 },
+    { 14, 18, 23 },
+    { 16, 20, 25 },
+    { 18, 23, 29 },
+};
+
+static const uint8_t dequant8_coeff_init_scan[16] = {
+    0, 3, 4, 3, 3, 1, 5, 1, 4, 5, 2, 5, 3, 1, 5, 1
+};
+
+static const uint8_t dequant8_coeff_init[6][6] = {
+    { 20, 18, 32, 19, 25, 24 },
+    { 22, 19, 35, 21, 28, 26 },
+    { 26, 23, 42, 24, 33, 31 },
+    { 28, 25, 45, 26, 35, 33 },
+    { 32, 28, 51, 30, 40, 38 },
+    { 36, 32, 58, 34, 46, 43 },
+};
+
+static const enum AVPixelFormat h264_hwaccel_pixfmt_list_420[] = {
+#if CONFIG_H264_DXVA2_HWACCEL
+    AV_PIX_FMT_DXVA2_VLD,
+#endif
+#if CONFIG_H264_VAAPI_HWACCEL
+    AV_PIX_FMT_VAAPI_VLD,
+#endif
+#if CONFIG_H264_VDA_HWACCEL
+    AV_PIX_FMT_VDA_VLD,
+#endif
+#if CONFIG_H264_VDPAU_HWACCEL
+    AV_PIX_FMT_VDPAU,
+#endif
+    AV_PIX_FMT_YUV420P,
+    AV_PIX_FMT_NONE
+};
+
+static const enum AVPixelFormat h264_hwaccel_pixfmt_list_jpeg_420[] = {
+#if CONFIG_H264_DXVA2_HWACCEL
+    AV_PIX_FMT_DXVA2_VLD,
+#endif
+#if CONFIG_H264_VAAPI_HWACCEL
+    AV_PIX_FMT_VAAPI_VLD,
+#endif
+#if CONFIG_H264_VDA_HWACCEL
+    AV_PIX_FMT_VDA_VLD,
+#endif
+#if CONFIG_H264_VDPAU_HWACCEL
+    AV_PIX_FMT_VDPAU,
+#endif
+    AV_PIX_FMT_YUVJ420P,
+    AV_PIX_FMT_NONE
+};
+
+
+static void release_unused_pictures(H264Context *h, int remove_current)
+{
+    int i;
+
+    /* release non reference frames */
+    for (i = 0; i < H264_MAX_PICTURE_COUNT; i++) {
+        if (h->DPB[i].f.buf[0] && !h->DPB[i].reference &&
+            (remove_current || &h->DPB[i] != h->cur_pic_ptr)) {
+            ff_h264_unref_picture(h, &h->DPB[i]);
+        }
+    }
+}
+
+static int alloc_scratch_buffers(H264Context *h, int linesize)
+{
+    int alloc_size = FFALIGN(FFABS(linesize) + 32, 32);
+
+    if (h->bipred_scratchpad)
+        return 0;
+
+    h->bipred_scratchpad = av_malloc(16 * 6 * alloc_size);
+    // edge emu needs blocksize + filter length - 1
+    // (= 21x21 for  h264)
+    h->edge_emu_buffer = av_mallocz(alloc_size * 2 * 21);
+
+    if (!h->bipred_scratchpad || !h->edge_emu_buffer) {
+        av_freep(&h->bipred_scratchpad);
+        av_freep(&h->edge_emu_buffer);
+        return AVERROR(ENOMEM);
+    }
+
+    return 0;
+}
+
+static int init_table_pools(H264Context *h)
+{
+    const int big_mb_num    = h->mb_stride * (h->mb_height + 1) + 1;
+    const int mb_array_size = h->mb_stride * h->mb_height;
+    const int b4_stride     = h->mb_width * 4 + 1;
+    const int b4_array_size = b4_stride * h->mb_height * 4;
+
+    h->qscale_table_pool = av_buffer_pool_init(big_mb_num + h->mb_stride,
+                                               av_buffer_allocz);
+    h->mb_type_pool      = av_buffer_pool_init((big_mb_num + h->mb_stride) *
+                                               sizeof(uint32_t), av_buffer_allocz);
+    h->motion_val_pool = av_buffer_pool_init(2 * (b4_array_size + 4) *
+                                             sizeof(int16_t), av_buffer_allocz);
+    h->ref_index_pool  = av_buffer_pool_init(4 * mb_array_size, av_buffer_allocz);
+
+    if (!h->qscale_table_pool || !h->mb_type_pool || !h->motion_val_pool ||
+        !h->ref_index_pool) {
+        av_buffer_pool_uninit(&h->qscale_table_pool);
+        av_buffer_pool_uninit(&h->mb_type_pool);
+        av_buffer_pool_uninit(&h->motion_val_pool);
+        av_buffer_pool_uninit(&h->ref_index_pool);
+        return AVERROR(ENOMEM);
+    }
+
+    return 0;
+}
+
+static int alloc_picture(H264Context *h, H264Picture *pic)
+{
+    int i, ret = 0;
+
+    av_assert0(!pic->f.data[0]);
+
+    pic->tf.f = &pic->f;
+    ret = ff_thread_get_buffer(h->avctx, &pic->tf, pic->reference ?
+                                                   AV_GET_BUFFER_FLAG_REF : 0);
+    if (ret < 0)
+        goto fail;
+
+    h->linesize   = pic->f.linesize[0];
+    h->uvlinesize = pic->f.linesize[1];
+
+    if (h->avctx->hwaccel) {
+        const AVHWAccel *hwaccel = h->avctx->hwaccel;
+        av_assert0(!pic->hwaccel_picture_private);
+        if (hwaccel->priv_data_size) {
+            pic->hwaccel_priv_buf = av_buffer_allocz(hwaccel->priv_data_size);
+            if (!pic->hwaccel_priv_buf)
+                return AVERROR(ENOMEM);
+            pic->hwaccel_picture_private = pic->hwaccel_priv_buf->data;
+        }
+    }
+
+    if (!h->qscale_table_pool) {
+        ret = init_table_pools(h);
+        if (ret < 0)
+            goto fail;
+    }
+
+    pic->qscale_table_buf = av_buffer_pool_get(h->qscale_table_pool);
+    pic->mb_type_buf      = av_buffer_pool_get(h->mb_type_pool);
+    if (!pic->qscale_table_buf || !pic->mb_type_buf)
+        goto fail;
+
+    pic->mb_type      = (uint32_t*)pic->mb_type_buf->data + 2 * h->mb_stride + 1;
+    pic->qscale_table = pic->qscale_table_buf->data + 2 * h->mb_stride + 1;
+
+    for (i = 0; i < 2; i++) {
+        pic->motion_val_buf[i] = av_buffer_pool_get(h->motion_val_pool);
+        pic->ref_index_buf[i]  = av_buffer_pool_get(h->ref_index_pool);
+        if (!pic->motion_val_buf[i] || !pic->ref_index_buf[i])
+            goto fail;
+
+        pic->motion_val[i] = (int16_t (*)[2])pic->motion_val_buf[i]->data + 4;
+        pic->ref_index[i]  = pic->ref_index_buf[i]->data;
+    }
+
+    return 0;
+fail:
+    ff_h264_unref_picture(h, pic);
+    return (ret < 0) ? ret : AVERROR(ENOMEM);
+}
+
+static inline int pic_is_unused(H264Context *h, H264Picture *pic)
+{
+    if (!pic->f.buf[0])
+        return 1;
+    if (pic->needs_realloc && !(pic->reference & DELAYED_PIC_REF))
+        return 1;
+    return 0;
+}
+
+static int find_unused_picture(H264Context *h)
+{
+    int i;
+
+    for (i = 0; i < H264_MAX_PICTURE_COUNT; i++) {
+        if (pic_is_unused(h, &h->DPB[i]))
+            break;
+    }
+    if (i == H264_MAX_PICTURE_COUNT)
+        return AVERROR_INVALIDDATA;
+
+    if (h->DPB[i].needs_realloc) {
+        h->DPB[i].needs_realloc = 0;
+        ff_h264_unref_picture(h, &h->DPB[i]);
+    }
+
+    return i;
+}
+
+
+static void init_dequant8_coeff_table(H264Context *h)
+{
+    int i, j, q, x;
+    const int max_qp = 51 + 6 * (h->sps.bit_depth_luma - 8);
+
+    for (i = 0; i < 6; i++) {
+        h->dequant8_coeff[i] = h->dequant8_buffer[i];
+        for (j = 0; j < i; j++)
+            if (!memcmp(h->pps.scaling_matrix8[j], h->pps.scaling_matrix8[i],
+                        64 * sizeof(uint8_t))) {
+                h->dequant8_coeff[i] = h->dequant8_buffer[j];
+                break;
+            }
+        if (j < i)
+            continue;
+
+        for (q = 0; q < max_qp + 1; q++) {
+            int shift = div6[q];
+            int idx   = rem6[q];
+            for (x = 0; x < 64; x++)
+                h->dequant8_coeff[i][q][(x >> 3) | ((x & 7) << 3)] =
+                    ((uint32_t)dequant8_coeff_init[idx][dequant8_coeff_init_scan[((x >> 1) & 12) | (x & 3)]] *
+                     h->pps.scaling_matrix8[i][x]) << shift;
+        }
+    }
+}
+
+static void init_dequant4_coeff_table(H264Context *h)
+{
+    int i, j, q, x;
+    const int max_qp = 51 + 6 * (h->sps.bit_depth_luma - 8);
+    for (i = 0; i < 6; i++) {
+        h->dequant4_coeff[i] = h->dequant4_buffer[i];
+        for (j = 0; j < i; j++)
+            if (!memcmp(h->pps.scaling_matrix4[j], h->pps.scaling_matrix4[i],
+                        16 * sizeof(uint8_t))) {
+                h->dequant4_coeff[i] = h->dequant4_buffer[j];
+                break;
+            }
+        if (j < i)
+            continue;
+
+        for (q = 0; q < max_qp + 1; q++) {
+            int shift = div6[q] + 2;
+            int idx   = rem6[q];
+            for (x = 0; x < 16; x++)
+                h->dequant4_coeff[i][q][(x >> 2) | ((x << 2) & 0xF)] =
+                    ((uint32_t)dequant4_coeff_init[idx][(x & 1) + ((x >> 2) & 1)] *
+                     h->pps.scaling_matrix4[i][x]) << shift;
+        }
+    }
+}
+
+void h264_init_dequant_tables(H264Context *h)
+{
+    int i, x;
+    init_dequant4_coeff_table(h);
+    if (h->pps.transform_8x8_mode)
+        init_dequant8_coeff_table(h);
+    if (h->sps.transform_bypass) {
+        for (i = 0; i < 6; i++)
+            for (x = 0; x < 16; x++)
+                h->dequant4_coeff[i][0][x] = 1 << 6;
+        if (h->pps.transform_8x8_mode)
+            for (i = 0; i < 6; i++)
+                for (x = 0; x < 64; x++)
+                    h->dequant8_coeff[i][0][x] = 1 << 6;
+    }
+}
+
+/**
+ * Mimic alloc_tables(), but for every context thread.
+ */
+static void clone_tables(H264Context *dst, H264Context *src, int i)
+{
+    dst->intra4x4_pred_mode     = src->intra4x4_pred_mode + i * 8 * 2 * src->mb_stride;
+    dst->non_zero_count         = src->non_zero_count;
+    dst->slice_table            = src->slice_table;
+    dst->cbp_table              = src->cbp_table;
+    dst->mb2b_xy                = src->mb2b_xy;
+    dst->mb2br_xy               = src->mb2br_xy;
+    dst->chroma_pred_mode_table = src->chroma_pred_mode_table;
+    dst->mvd_table[0]           = src->mvd_table[0] + i * 8 * 2 * src->mb_stride;
+    dst->mvd_table[1]           = src->mvd_table[1] + i * 8 * 2 * src->mb_stride;
+    dst->direct_table           = src->direct_table;
+    dst->list_counts            = src->list_counts;
+    dst->DPB                    = src->DPB;
+    dst->cur_pic_ptr            = src->cur_pic_ptr;
+    dst->cur_pic                = src->cur_pic;
+    dst->bipred_scratchpad      = NULL;
+    dst->edge_emu_buffer        = NULL;
+    ff_h264_pred_init(&dst->hpc, src->avctx->codec_id, src->sps.bit_depth_luma,
+                      src->sps.chroma_format_idc);
+}
+
+#define IN_RANGE(a, b, size) (((a) >= (b)) && ((a) < ((b) + (size))))
+#undef REBASE_PICTURE
+#define REBASE_PICTURE(pic, new_ctx, old_ctx)             \
+    ((pic && pic >= old_ctx->DPB &&                       \
+      pic < old_ctx->DPB + H264_MAX_PICTURE_COUNT) ?          \
+     &new_ctx->DPB[pic - old_ctx->DPB] : NULL)
+
+static void copy_picture_range(H264Picture **to, H264Picture **from, int count,
+                               H264Context *new_base,
+                               H264Context *old_base)
+{
+    int i;
+
+    for (i = 0; i < count; i++) {
+        assert((IN_RANGE(from[i], old_base, sizeof(*old_base)) ||
+                IN_RANGE(from[i], old_base->DPB,
+                         sizeof(H264Picture) * H264_MAX_PICTURE_COUNT) ||
+                !from[i]));
+        to[i] = REBASE_PICTURE(from[i], new_base, old_base);
+    }
+}
+
+static int copy_parameter_set(void **to, void **from, int count, int size)
+{
+    int i;
+
+    for (i = 0; i < count; i++) {
+        if (to[i] && !from[i]) {
+            av_freep(&to[i]);
+        } else if (from[i] && !to[i]) {
+            to[i] = av_malloc(size);
+            if (!to[i])
+                return AVERROR(ENOMEM);
+        }
+
+        if (from[i])
+            memcpy(to[i], from[i], size);
+    }
+
+    return 0;
+}
+
+#define copy_fields(to, from, start_field, end_field)                   \
+    memcpy(&to->start_field, &from->start_field,                        \
+           (char *)&to->end_field - (char *)&to->start_field)
+
+static int h264_slice_header_init(H264Context *h, int reinit);
+
+int ff_h264_update_thread_context(AVCodecContext *dst,
+                                  const AVCodecContext *src)
+{
+    H264Context *h = dst->priv_data, *h1 = src->priv_data;
+    int inited = h->context_initialized, err = 0;
+    int context_reinitialized = 0;
+    int i, ret;
+
+    if (dst == src || !h1->context_initialized)
+        return 0;
+
+    if (inited &&
+        (h->width                 != h1->width                 ||
+         h->height                != h1->height                ||
+         h->mb_width              != h1->mb_width              ||
+         h->mb_height             != h1->mb_height             ||
+         h->sps.bit_depth_luma    != h1->sps.bit_depth_luma    ||
+         h->sps.chroma_format_idc != h1->sps.chroma_format_idc ||
+         h->sps.colorspace        != h1->sps.colorspace)) {
+
+        /* set bits_per_raw_sample to the previous value. the check for changed
+         * bit depth in h264_set_parameter_from_sps() uses it and sets it to
+         * the current value */
+        h->avctx->bits_per_raw_sample = h->sps.bit_depth_luma;
+
+        av_freep(&h->bipred_scratchpad);
+
+        h->width     = h1->width;
+        h->height    = h1->height;
+        h->mb_height = h1->mb_height;
+        h->mb_width  = h1->mb_width;
+        h->mb_num    = h1->mb_num;
+        h->mb_stride = h1->mb_stride;
+        h->b_stride  = h1->b_stride;
+
+        if ((err = h264_slice_header_init(h, 1)) < 0) {
+            av_log(h->avctx, AV_LOG_ERROR, "h264_slice_header_init() failed");
+            return err;
+        }
+        context_reinitialized = 1;
+
+        /* update linesize on resize. The decoder doesn't
+         * necessarily call h264_frame_start in the new thread */
+        h->linesize   = h1->linesize;
+        h->uvlinesize = h1->uvlinesize;
+
+        /* copy block_offset since frame_start may not be called */
+        memcpy(h->block_offset, h1->block_offset, sizeof(h->block_offset));
+    }
+
+    if (!inited) {
+        for (i = 0; i < MAX_SPS_COUNT; i++)
+            av_freep(h->sps_buffers + i);
+
+        for (i = 0; i < MAX_PPS_COUNT; i++)
+            av_freep(h->pps_buffers + i);
+
+        memcpy(h, h1, sizeof(*h1));
+        memset(h->sps_buffers, 0, sizeof(h->sps_buffers));
+        memset(h->pps_buffers, 0, sizeof(h->pps_buffers));
+        memset(&h->er, 0, sizeof(h->er));
+        memset(&h->mb, 0, sizeof(h->mb));
+        memset(&h->mb_luma_dc, 0, sizeof(h->mb_luma_dc));
+        memset(&h->mb_padding, 0, sizeof(h->mb_padding));
+        h->context_initialized = 0;
+
+        memset(&h->cur_pic, 0, sizeof(h->cur_pic));
+        av_frame_unref(&h->cur_pic.f);
+        h->cur_pic.tf.f = &h->cur_pic.f;
+
+        h->avctx             = dst;
+        h->DPB               = NULL;
+        h->qscale_table_pool = NULL;
+        h->mb_type_pool      = NULL;
+        h->ref_index_pool    = NULL;
+        h->motion_val_pool   = NULL;
+
+        ret = ff_h264_alloc_tables(h);
+        if (ret < 0) {
+            av_log(dst, AV_LOG_ERROR, "Could not allocate memory\n");
+            return ret;
+        }
+        ret = ff_h264_context_init(h);
+        if (ret < 0) {
+            av_log(dst, AV_LOG_ERROR, "context_init() failed.\n");
+            return ret;
+        }
+
+        for (i = 0; i < 2; i++) {
+            h->rbsp_buffer[i]      = NULL;
+            h->rbsp_buffer_size[i] = 0;
+        }
+        h->bipred_scratchpad = NULL;
+        h->edge_emu_buffer   = NULL;
+
+        h->thread_context[0] = h;
+
+        h->context_initialized = 1;
+    }
+
+    h->avctx->coded_height  = h1->avctx->coded_height;
+    h->avctx->coded_width   = h1->avctx->coded_width;
+    h->avctx->width         = h1->avctx->width;
+    h->avctx->height        = h1->avctx->height;
+    h->coded_picture_number = h1->coded_picture_number;
+    h->first_field          = h1->first_field;
+    h->picture_structure    = h1->picture_structure;
+    h->qscale               = h1->qscale;
+    h->droppable            = h1->droppable;
+    h->low_delay            = h1->low_delay;
+
+    for (i = 0; i < H264_MAX_PICTURE_COUNT; i++) {
+        ff_h264_unref_picture(h, &h->DPB[i]);
+        if (h1->DPB[i].f.buf[0] &&
+            (ret = ff_h264_ref_picture(h, &h->DPB[i], &h1->DPB[i])) < 0)
+            return ret;
+    }
+
+    h->cur_pic_ptr = REBASE_PICTURE(h1->cur_pic_ptr, h, h1);
+    ff_h264_unref_picture(h, &h->cur_pic);
+    if ((ret = ff_h264_ref_picture(h, &h->cur_pic, &h1->cur_pic)) < 0)
+        return ret;
+
+    h->workaround_bugs = h1->workaround_bugs;
+    h->low_delay       = h1->low_delay;
+    h->droppable       = h1->droppable;
+
+    /* frame_start may not be called for the next thread (if it's decoding
+     * a bottom field) so this has to be allocated here */
+    err = alloc_scratch_buffers(h, h1->linesize);
+    if (err < 0)
+        return err;
+
+    // extradata/NAL handling
+    h->is_avc = h1->is_avc;
+
+    // SPS/PPS
+    if ((ret = copy_parameter_set((void **)h->sps_buffers,
+                                  (void **)h1->sps_buffers,
+                                  MAX_SPS_COUNT, sizeof(SPS))) < 0)
+        return ret;
+    h->sps = h1->sps;
+    if ((ret = copy_parameter_set((void **)h->pps_buffers,
+                                  (void **)h1->pps_buffers,
+                                  MAX_PPS_COUNT, sizeof(PPS))) < 0)
+        return ret;
+    h->pps = h1->pps;
+
+    // Dequantization matrices
+    // FIXME these are big - can they be only copied when PPS changes?
+    copy_fields(h, h1, dequant4_buffer, dequant4_coeff);
+
+    for (i = 0; i < 6; i++)
+        h->dequant4_coeff[i] = h->dequant4_buffer[0] +
+                               (h1->dequant4_coeff[i] - h1->dequant4_buffer[0]);
+
+    for (i = 0; i < 6; i++)
+        h->dequant8_coeff[i] = h->dequant8_buffer[0] +
+                               (h1->dequant8_coeff[i] - h1->dequant8_buffer[0]);
+
+    h->dequant_coeff_pps = h1->dequant_coeff_pps;
+
+    // POC timing
+    copy_fields(h, h1, poc_lsb, redundant_pic_count);
+
+    // reference lists
+    copy_fields(h, h1, short_ref, cabac_init_idc);
+
+    copy_picture_range(h->short_ref, h1->short_ref, 32, h, h1);
+    copy_picture_range(h->long_ref, h1->long_ref, 32, h, h1);
+    copy_picture_range(h->delayed_pic, h1->delayed_pic,
+                       MAX_DELAYED_PIC_COUNT + 2, h, h1);
+
+    h->last_slice_type = h1->last_slice_type;
+
+    if (context_reinitialized)
+        ff_h264_set_parameter_from_sps(h);
+
+    if (!h->cur_pic_ptr)
+        return 0;
+
+    if (!h->droppable) {
+        err = ff_h264_execute_ref_pic_marking(h, h->mmco, h->mmco_index);
+        h->prev_poc_msb = h->poc_msb;
+        h->prev_poc_lsb = h->poc_lsb;
+    }
+    h->prev_frame_num_offset = h->frame_num_offset;
+    h->prev_frame_num        = h->frame_num;
+    h->outputed_poc          = h->next_outputed_poc;
+
+    h->recovery_frame        = h1->recovery_frame;
+    h->frame_recovered       = h1->frame_recovered;
+
+    return err;
+}
+
+static int h264_frame_start(H264Context *h)
+{
+    H264Picture *pic;
+    int i, ret;
+    const int pixel_shift = h->pixel_shift;
+
+    release_unused_pictures(h, 1);
+    h->cur_pic_ptr = NULL;
+
+    i = find_unused_picture(h);
+    if (i < 0) {
+        av_log(h->avctx, AV_LOG_ERROR, "no frame buffer available\n");
+        return i;
+    }
+    pic = &h->DPB[i];
+
+    pic->reference              = h->droppable ? 0 : h->picture_structure;
+    pic->f.coded_picture_number = h->coded_picture_number++;
+    pic->field_picture          = h->picture_structure != PICT_FRAME;
+    /*
+     * Zero key_frame here; IDR markings per slice in frame or fields are ORed
+     * in later.
+     * See decode_nal_units().
+     */
+    pic->f.key_frame = 0;
+    pic->mmco_reset  = 0;
+    pic->recovered   = 0;
+
+    if ((ret = alloc_picture(h, pic)) < 0)
+        return ret;
+
+    h->cur_pic_ptr = pic;
+    ff_h264_unref_picture(h, &h->cur_pic);
+    if ((ret = ff_h264_ref_picture(h, &h->cur_pic, h->cur_pic_ptr)) < 0)
+        return ret;
+
+    if (CONFIG_ERROR_RESILIENCE)
+        ff_er_frame_start(&h->er);
+
+    assert(h->linesize && h->uvlinesize);
+
+    for (i = 0; i < 16; i++) {
+        h->block_offset[i]           = (4 * ((scan8[i] - scan8[0]) & 7) << pixel_shift) + 4 * h->linesize * ((scan8[i] - scan8[0]) >> 3);
+        h->block_offset[48 + i]      = (4 * ((scan8[i] - scan8[0]) & 7) << pixel_shift) + 8 * h->linesize * ((scan8[i] - scan8[0]) >> 3);
+    }
+    for (i = 0; i < 16; i++) {
+        h->block_offset[16 + i]      =
+        h->block_offset[32 + i]      = (4 * ((scan8[i] - scan8[0]) & 7) << pixel_shift) + 4 * h->uvlinesize * ((scan8[i] - scan8[0]) >> 3);
+        h->block_offset[48 + 16 + i] =
+        h->block_offset[48 + 32 + i] = (4 * ((scan8[i] - scan8[0]) & 7) << pixel_shift) + 8 * h->uvlinesize * ((scan8[i] - scan8[0]) >> 3);
+    }
+
+    /* can't be in alloc_tables because linesize isn't known there.
+     * FIXME: redo bipred weight to not require extra buffer? */
+    for (i = 0; i < h->slice_context_count; i++)
+        if (h->thread_context[i]) {
+            ret = alloc_scratch_buffers(h->thread_context[i], h->linesize);
+            if (ret < 0)
+                return ret;
+        }
+
+    /* Some macroblocks can be accessed before they're available in case
+     * of lost slices, MBAFF or threading. */
+    memset(h->slice_table, -1,
+           (h->mb_height * h->mb_stride - 1) * sizeof(*h->slice_table));
+
+    // s->decode = (s->flags & CODEC_FLAG_PSNR) || !s->encoding ||
+    //             s->current_picture.f.reference /* || h->contains_intra */ || 1;
+
+    /* We mark the current picture as non-reference after allocating it, so
+     * that if we break out due to an error it can be released automatically
+     * in the next ff_MPV_frame_start().
+     */
+    h->cur_pic_ptr->reference = 0;
+
+    h->cur_pic_ptr->field_poc[0] = h->cur_pic_ptr->field_poc[1] = INT_MAX;
+
+    h->next_output_pic = NULL;
+
+    assert(h->cur_pic_ptr->long_ref == 0);
+
+    return 0;
+}
+
+static av_always_inline void backup_mb_border(H264Context *h, uint8_t *src_y,
+                                              uint8_t *src_cb, uint8_t *src_cr,
+                                              int linesize, int uvlinesize,
+                                              int simple)
+{
+    uint8_t *top_border;
+    int top_idx = 1;
+    const int pixel_shift = h->pixel_shift;
+    int chroma444 = CHROMA444(h);
+    int chroma422 = CHROMA422(h);
+
+    src_y  -= linesize;
+    src_cb -= uvlinesize;
+    src_cr -= uvlinesize;
+
+    if (!simple && FRAME_MBAFF(h)) {
+        if (h->mb_y & 1) {
+            if (!MB_MBAFF(h)) {
+                top_border = h->top_borders[0][h->mb_x];
+                AV_COPY128(top_border, src_y + 15 * linesize);
+                if (pixel_shift)
+                    AV_COPY128(top_border + 16, src_y + 15 * linesize + 16);
+                if (simple || !CONFIG_GRAY || !(h->flags & CODEC_FLAG_GRAY)) {
+                    if (chroma444) {
+                        if (pixel_shift) {
+                            AV_COPY128(top_border + 32, src_cb + 15 * uvlinesize);
+                            AV_COPY128(top_border + 48, src_cb + 15 * uvlinesize + 16);
+                            AV_COPY128(top_border + 64, src_cr + 15 * uvlinesize);
+                            AV_COPY128(top_border + 80, src_cr + 15 * uvlinesize + 16);
+                        } else {
+                            AV_COPY128(top_border + 16, src_cb + 15 * uvlinesize);
+                            AV_COPY128(top_border + 32, src_cr + 15 * uvlinesize);
+                        }
+                    } else if (chroma422) {
+                        if (pixel_shift) {
+                            AV_COPY128(top_border + 32, src_cb + 15 * uvlinesize);
+                            AV_COPY128(top_border + 48, src_cr + 15 * uvlinesize);
+                        } else {
+                            AV_COPY64(top_border + 16, src_cb + 15 * uvlinesize);
+                            AV_COPY64(top_border + 24, src_cr + 15 * uvlinesize);
+                        }
+                    } else {
+                        if (pixel_shift) {
+                            AV_COPY128(top_border + 32, src_cb + 7 * uvlinesize);
+                            AV_COPY128(top_border + 48, src_cr + 7 * uvlinesize);
+                        } else {
+                            AV_COPY64(top_border + 16, src_cb + 7 * uvlinesize);
+                            AV_COPY64(top_border + 24, src_cr + 7 * uvlinesize);
+                        }
+                    }
+                }
+            }
+        } else if (MB_MBAFF(h)) {
+            top_idx = 0;
+        } else
+            return;
+    }
+
+    top_border = h->top_borders[top_idx][h->mb_x];
+    /* There are two lines saved, the line above the top macroblock
+     * of a pair, and the line above the bottom macroblock. */
+    AV_COPY128(top_border, src_y + 16 * linesize);
+    if (pixel_shift)
+        AV_COPY128(top_border + 16, src_y + 16 * linesize + 16);
+
+    if (simple || !CONFIG_GRAY || !(h->flags & CODEC_FLAG_GRAY)) {
+        if (chroma444) {
+            if (pixel_shift) {
+                AV_COPY128(top_border + 32, src_cb + 16 * linesize);
+                AV_COPY128(top_border + 48, src_cb + 16 * linesize + 16);
+                AV_COPY128(top_border + 64, src_cr + 16 * linesize);
+                AV_COPY128(top_border + 80, src_cr + 16 * linesize + 16);
+            } else {
+                AV_COPY128(top_border + 16, src_cb + 16 * linesize);
+                AV_COPY128(top_border + 32, src_cr + 16 * linesize);
+            }
+        } else if (chroma422) {
+            if (pixel_shift) {
+                AV_COPY128(top_border + 32, src_cb + 16 * uvlinesize);
+                AV_COPY128(top_border + 48, src_cr + 16 * uvlinesize);
+            } else {
+                AV_COPY64(top_border + 16, src_cb + 16 * uvlinesize);
+                AV_COPY64(top_border + 24, src_cr + 16 * uvlinesize);
+            }
+        } else {
+            if (pixel_shift) {
+                AV_COPY128(top_border + 32, src_cb + 8 * uvlinesize);
+                AV_COPY128(top_border + 48, src_cr + 8 * uvlinesize);
+            } else {
+                AV_COPY64(top_border + 16, src_cb + 8 * uvlinesize);
+                AV_COPY64(top_border + 24, src_cr + 8 * uvlinesize);
+            }
+        }
+    }
+}
+
+/**
+ * Initialize implicit_weight table.
+ * @param field  0/1 initialize the weight for interlaced MBAFF
+ *                -1 initializes the rest
+ */
+static void implicit_weight_table(H264Context *h, int field)
+{
+    int ref0, ref1, i, cur_poc, ref_start, ref_count0, ref_count1;
+
+    for (i = 0; i < 2; i++) {
+        h->luma_weight_flag[i]   = 0;
+        h->chroma_weight_flag[i] = 0;
+    }
+
+    if (field < 0) {
+        if (h->picture_structure == PICT_FRAME) {
+            cur_poc = h->cur_pic_ptr->poc;
+        } else {
+            cur_poc = h->cur_pic_ptr->field_poc[h->picture_structure - 1];
+        }
+        if (h->ref_count[0] == 1 && h->ref_count[1] == 1 && !FRAME_MBAFF(h) &&
+            h->ref_list[0][0].poc + h->ref_list[1][0].poc == 2 * cur_poc) {
+            h->use_weight        = 0;
+            h->use_weight_chroma = 0;
+            return;
+        }
+        ref_start  = 0;
+        ref_count0 = h->ref_count[0];
+        ref_count1 = h->ref_count[1];
+    } else {
+        cur_poc    = h->cur_pic_ptr->field_poc[field];
+        ref_start  = 16;
+        ref_count0 = 16 + 2 * h->ref_count[0];
+        ref_count1 = 16 + 2 * h->ref_count[1];
+    }
+
+    h->use_weight               = 2;
+    h->use_weight_chroma        = 2;
+    h->luma_log2_weight_denom   = 5;
+    h->chroma_log2_weight_denom = 5;
+
+    for (ref0 = ref_start; ref0 < ref_count0; ref0++) {
+        int poc0 = h->ref_list[0][ref0].poc;
+        for (ref1 = ref_start; ref1 < ref_count1; ref1++) {
+            int w = 32;
+            if (!h->ref_list[0][ref0].long_ref && !h->ref_list[1][ref1].long_ref) {
+                int poc1 = h->ref_list[1][ref1].poc;
+                int td   = av_clip(poc1 - poc0, -128, 127);
+                if (td) {
+                    int tb = av_clip(cur_poc - poc0, -128, 127);
+                    int tx = (16384 + (FFABS(td) >> 1)) / td;
+                    int dist_scale_factor = (tb * tx + 32) >> 8;
+                    if (dist_scale_factor >= -64 && dist_scale_factor <= 128)
+                        w = 64 - dist_scale_factor;
+                }
+            }
+            if (field < 0) {
+                h->implicit_weight[ref0][ref1][0] =
+                h->implicit_weight[ref0][ref1][1] = w;
+            } else {
+                h->implicit_weight[ref0][ref1][field] = w;
+            }
+        }
+    }
+}
+
+/**
+ * initialize scan tables
+ */
+static void init_scan_tables(H264Context *h)
+{
+    int i;
+    for (i = 0; i < 16; i++) {
+#define TRANSPOSE(x) (x >> 2) | ((x << 2) & 0xF)
+        h->zigzag_scan[i] = TRANSPOSE(zigzag_scan[i]);
+        h->field_scan[i]  = TRANSPOSE(field_scan[i]);
+#undef TRANSPOSE
+    }
+    for (i = 0; i < 64; i++) {
+#define TRANSPOSE(x) (x >> 3) | ((x & 7) << 3)
+        h->zigzag_scan8x8[i]       = TRANSPOSE(ff_zigzag_direct[i]);
+        h->zigzag_scan8x8_cavlc[i] = TRANSPOSE(zigzag_scan8x8_cavlc[i]);
+        h->field_scan8x8[i]        = TRANSPOSE(field_scan8x8[i]);
+        h->field_scan8x8_cavlc[i]  = TRANSPOSE(field_scan8x8_cavlc[i]);
+#undef TRANSPOSE
+    }
+    if (h->sps.transform_bypass) { // FIXME same ugly
+        h->zigzag_scan_q0          = zigzag_scan;
+        h->zigzag_scan8x8_q0       = ff_zigzag_direct;
+        h->zigzag_scan8x8_cavlc_q0 = zigzag_scan8x8_cavlc;
+        h->field_scan_q0           = field_scan;
+        h->field_scan8x8_q0        = field_scan8x8;
+        h->field_scan8x8_cavlc_q0  = field_scan8x8_cavlc;
+    } else {
+        h->zigzag_scan_q0          = h->zigzag_scan;
+        h->zigzag_scan8x8_q0       = h->zigzag_scan8x8;
+        h->zigzag_scan8x8_cavlc_q0 = h->zigzag_scan8x8_cavlc;
+        h->field_scan_q0           = h->field_scan;
+        h->field_scan8x8_q0        = h->field_scan8x8;
+        h->field_scan8x8_cavlc_q0  = h->field_scan8x8_cavlc;
+    }
+}
+
+/**
+ * Replicate H264 "master" context to thread contexts.
+ */
+static int clone_slice(H264Context *dst, H264Context *src)
+{
+    memcpy(dst->block_offset, src->block_offset, sizeof(dst->block_offset));
+    dst->cur_pic_ptr = src->cur_pic_ptr;
+    dst->cur_pic     = src->cur_pic;
+    dst->linesize    = src->linesize;
+    dst->uvlinesize  = src->uvlinesize;
+    dst->first_field = src->first_field;
+
+    dst->prev_poc_msb          = src->prev_poc_msb;
+    dst->prev_poc_lsb          = src->prev_poc_lsb;
+    dst->prev_frame_num_offset = src->prev_frame_num_offset;
+    dst->prev_frame_num        = src->prev_frame_num;
+    dst->short_ref_count       = src->short_ref_count;
+
+    memcpy(dst->short_ref,        src->short_ref,        sizeof(dst->short_ref));
+    memcpy(dst->long_ref,         src->long_ref,         sizeof(dst->long_ref));
+    memcpy(dst->default_ref_list, src->default_ref_list, sizeof(dst->default_ref_list));
+
+    memcpy(dst->dequant4_coeff,   src->dequant4_coeff,   sizeof(src->dequant4_coeff));
+    memcpy(dst->dequant8_coeff,   src->dequant8_coeff,   sizeof(src->dequant8_coeff));
+
+    return 0;
+}
+
+static enum AVPixelFormat get_pixel_format(H264Context *h)
+{
+    switch (h->sps.bit_depth_luma) {
+    case 9:
+        if (CHROMA444(h)) {
+            if (h->avctx->colorspace == AVCOL_SPC_RGB) {
+                return AV_PIX_FMT_GBRP9;
+            } else
+                return AV_PIX_FMT_YUV444P9;
+        } else if (CHROMA422(h))
+            return AV_PIX_FMT_YUV422P9;
+        else
+            return AV_PIX_FMT_YUV420P9;
+        break;
+    case 10:
+        if (CHROMA444(h)) {
+            if (h->avctx->colorspace == AVCOL_SPC_RGB) {
+                return AV_PIX_FMT_GBRP10;
+            } else
+                return AV_PIX_FMT_YUV444P10;
+        } else if (CHROMA422(h))
+            return AV_PIX_FMT_YUV422P10;
+        else
+            return AV_PIX_FMT_YUV420P10;
+        break;
+    case 8:
+        if (CHROMA444(h)) {
+            if (h->avctx->colorspace == AVCOL_SPC_RGB) {
+                return AV_PIX_FMT_GBRP;
+            } else
+                return h->avctx->color_range == AVCOL_RANGE_JPEG ? AV_PIX_FMT_YUVJ444P
+                                                                 : AV_PIX_FMT_YUV444P;
+        } else if (CHROMA422(h)) {
+            return h->avctx->color_range == AVCOL_RANGE_JPEG ? AV_PIX_FMT_YUVJ422P
+                                                             : AV_PIX_FMT_YUV422P;
+        } else {
+            return h->avctx->get_format(h->avctx, h->avctx->codec->pix_fmts ?
+                                        h->avctx->codec->pix_fmts :
+                                        h->avctx->color_range == AVCOL_RANGE_JPEG ?
+                                        h264_hwaccel_pixfmt_list_jpeg_420 :
+                                        h264_hwaccel_pixfmt_list_420);
+        }
+        break;
+    default:
+        av_log(h->avctx, AV_LOG_ERROR,
+               "Unsupported bit depth %d\n", h->sps.bit_depth_luma);
+        return AVERROR_INVALIDDATA;
+    }
+}
+
+/* export coded and cropped frame dimensions to AVCodecContext */
+static int init_dimensions(H264Context *h)
+{
+    int width  = h->width  - (h->sps.crop_right + h->sps.crop_left);
+    int height = h->height - (h->sps.crop_top   + h->sps.crop_bottom);
+
+    /* handle container cropping */
+    if (!h->sps.crop &&
+        FFALIGN(h->avctx->width,  16) == h->width &&
+        FFALIGN(h->avctx->height, 16) == h->height) {
+        width  = h->avctx->width;
+        height = h->avctx->height;
+    }
+
+    if (width <= 0 || height <= 0) {
+        av_log(h->avctx, AV_LOG_ERROR, "Invalid cropped dimensions: %dx%d.\n",
+               width, height);
+        if (h->avctx->err_recognition & AV_EF_EXPLODE)
+            return AVERROR_INVALIDDATA;
+
+        av_log(h->avctx, AV_LOG_WARNING, "Ignoring cropping information.\n");
+        h->sps.crop_bottom = h->sps.crop_top = h->sps.crop_right = h->sps.crop_left = 0;
+        h->sps.crop        = 0;
+
+        width  = h->width;
+        height = h->height;
+    }
+
+    h->avctx->coded_width  = h->width;
+    h->avctx->coded_height = h->height;
+    h->avctx->width        = width;
+    h->avctx->height       = height;
+
+    return 0;
+}
+
+static int h264_slice_header_init(H264Context *h, int reinit)
+{
+    int nb_slices = (HAVE_THREADS &&
+                     h->avctx->active_thread_type & FF_THREAD_SLICE) ?
+                    h->avctx->thread_count : 1;
+    int i, ret;
+
+    h->avctx->sample_aspect_ratio = h->sps.sar;
+    av_assert0(h->avctx->sample_aspect_ratio.den);
+    av_pix_fmt_get_chroma_sub_sample(h->avctx->pix_fmt,
+                                     &h->chroma_x_shift, &h->chroma_y_shift);
+
+    if (h->sps.timing_info_present_flag) {
+        int64_t den = h->sps.time_scale;
+        if (h->x264_build < 44U)
+            den *= 2;
+        av_reduce(&h->avctx->time_base.num, &h->avctx->time_base.den,
+                  h->sps.num_units_in_tick, den, 1 << 30);
+    }
+
+    h->avctx->hwaccel = ff_find_hwaccel(h->avctx);
+
+    if (reinit)
+        ff_h264_free_tables(h, 0);
+    h->first_field           = 0;
+    h->prev_interlaced_frame = 1;
+
+    init_scan_tables(h);
+    ret = ff_h264_alloc_tables(h);
+    if (ret < 0) {
+        av_log(h->avctx, AV_LOG_ERROR, "Could not allocate memory\n");
+        return ret;
+    }
+
+    if (nb_slices > H264_MAX_THREADS || (nb_slices > h->mb_height && h->mb_height)) {
+        int max_slices;
+        if (h->mb_height)
+            max_slices = FFMIN(H264_MAX_THREADS, h->mb_height);
+        else
+            max_slices = H264_MAX_THREADS;
+        av_log(h->avctx, AV_LOG_WARNING, "too many threads/slices %d,"
+               " reducing to %d\n", nb_slices, max_slices);
+        nb_slices = max_slices;
+    }
+    h->slice_context_count = nb_slices;
+
+    if (!HAVE_THREADS || !(h->avctx->active_thread_type & FF_THREAD_SLICE)) {
+        ret = ff_h264_context_init(h);
+        if (ret < 0) {
+            av_log(h->avctx, AV_LOG_ERROR, "context_init() failed.\n");
+            return ret;
+        }
+    } else {
+        for (i = 1; i < h->slice_context_count; i++) {
+            H264Context *c;
+            c                    = h->thread_context[i] = av_mallocz(sizeof(H264Context));
+            if (!c)
+                return AVERROR(ENOMEM);
+            c->avctx             = h->avctx;
+            c->dsp               = h->dsp;
+            c->vdsp              = h->vdsp;
+            c->h264dsp           = h->h264dsp;
+            c->h264qpel          = h->h264qpel;
+            c->h264chroma        = h->h264chroma;
+            c->sps               = h->sps;
+            c->pps               = h->pps;
+            c->pixel_shift       = h->pixel_shift;
+            c->width             = h->width;
+            c->height            = h->height;
+            c->linesize          = h->linesize;
+            c->uvlinesize        = h->uvlinesize;
+            c->chroma_x_shift    = h->chroma_x_shift;
+            c->chroma_y_shift    = h->chroma_y_shift;
+            c->qscale            = h->qscale;
+            c->droppable         = h->droppable;
+            c->data_partitioning = h->data_partitioning;
+            c->low_delay         = h->low_delay;
+            c->mb_width          = h->mb_width;
+            c->mb_height         = h->mb_height;
+            c->mb_stride         = h->mb_stride;
+            c->mb_num            = h->mb_num;
+            c->flags             = h->flags;
+            c->workaround_bugs   = h->workaround_bugs;
+            c->pict_type         = h->pict_type;
+
+            init_scan_tables(c);
+            clone_tables(c, h, i);
+            c->context_initialized = 1;
+        }
+
+        for (i = 0; i < h->slice_context_count; i++)
+            if ((ret = ff_h264_context_init(h->thread_context[i])) < 0) {
+                av_log(h->avctx, AV_LOG_ERROR, "context_init() failed.\n");
+                return ret;
+            }
+    }
+
+    h->context_initialized = 1;
+
+    return 0;
+}
+
+/**
+ * Decode a slice header.
+ * This will (re)intialize the decoder and call h264_frame_start() as needed.
+ *
+ * @param h h264context
+ * @param h0 h264 master context (differs from 'h' when doing sliced based
+ *           parallel decoding)
+ *
+ * @return 0 if okay, <0 if an error occurred, 1 if decoding must not be multithreaded
+ */
+int ff_h264_decode_slice_header(H264Context *h, H264Context *h0)
+{
+    unsigned int first_mb_in_slice;
+    unsigned int pps_id;
+    int ret;
+    unsigned int slice_type, tmp, i, j;
+    int default_ref_list_done = 0;
+    int last_pic_structure, last_pic_droppable;
+    int needs_reinit = 0;
+    int field_pic_flag, bottom_field_flag;
+
+    h->qpel_put = h->h264qpel.put_h264_qpel_pixels_tab;
+    h->qpel_avg = h->h264qpel.avg_h264_qpel_pixels_tab;
+
+    first_mb_in_slice = get_ue_golomb(&h->gb);
+
+    if (first_mb_in_slice == 0) { // FIXME better field boundary detection
+        if (h0->current_slice && h->cur_pic_ptr && FIELD_PICTURE(h)) {
+            ff_h264_field_end(h, 1);
+        }
+
+        h0->current_slice = 0;
+        if (!h0->first_field) {
+            if (h->cur_pic_ptr && !h->droppable) {
+                ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX,
+                                          h->picture_structure == PICT_BOTTOM_FIELD);
+            }
+            h->cur_pic_ptr = NULL;
+        }
+    }
+
+    slice_type = get_ue_golomb_31(&h->gb);
+    if (slice_type > 9) {
+        av_log(h->avctx, AV_LOG_ERROR,
+               "slice type %d too large at %d %d\n",
+               slice_type, h->mb_x, h->mb_y);
+        return AVERROR_INVALIDDATA;
+    }
+    if (slice_type > 4) {
+        slice_type -= 5;
+        h->slice_type_fixed = 1;
+    } else
+        h->slice_type_fixed = 0;
+
+    slice_type = golomb_to_pict_type[slice_type];
+    if (slice_type == AV_PICTURE_TYPE_I ||
+        (h0->current_slice != 0 && slice_type == h0->last_slice_type)) {
+        default_ref_list_done = 1;
+    }
+    h->slice_type     = slice_type;
+    h->slice_type_nos = slice_type & 3;
+
+    if (h->nal_unit_type  == NAL_IDR_SLICE &&
+        h->slice_type_nos != AV_PICTURE_TYPE_I) {
+        av_log(h->avctx, AV_LOG_ERROR, "A non-intra slice in an IDR NAL unit.\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    // to make a few old functions happy, it's wrong though
+    h->pict_type = h->slice_type;
+
+    pps_id = get_ue_golomb(&h->gb);
+    if (pps_id >= MAX_PPS_COUNT) {
+        av_log(h->avctx, AV_LOG_ERROR, "pps_id %u out of range\n", pps_id);
+        return AVERROR_INVALIDDATA;
+    }
+    if (!h0->pps_buffers[pps_id]) {
+        av_log(h->avctx, AV_LOG_ERROR,
+               "non-existing PPS %u referenced\n",
+               pps_id);
+        return AVERROR_INVALIDDATA;
+    }
+    h->pps = *h0->pps_buffers[pps_id];
+
+    if (!h0->sps_buffers[h->pps.sps_id]) {
+        av_log(h->avctx, AV_LOG_ERROR,
+               "non-existing SPS %u referenced\n",
+               h->pps.sps_id);
+        return AVERROR_INVALIDDATA;
+    }
+
+    if (h->pps.sps_id != h->sps.sps_id ||
+        h0->sps_buffers[h->pps.sps_id]->new) {
+        h0->sps_buffers[h->pps.sps_id]->new = 0;
+
+        h->sps = *h0->sps_buffers[h->pps.sps_id];
+
+        if (h->bit_depth_luma    != h->sps.bit_depth_luma ||
+            h->chroma_format_idc != h->sps.chroma_format_idc) {
+            h->bit_depth_luma    = h->sps.bit_depth_luma;
+            h->chroma_format_idc = h->sps.chroma_format_idc;
+            needs_reinit         = 1;
+        }
+        if ((ret = ff_h264_set_parameter_from_sps(h)) < 0)
+            return ret;
+    }
+
+    h->avctx->profile = ff_h264_get_profile(&h->sps);
+    h->avctx->level   = h->sps.level_idc;
+    h->avctx->refs    = h->sps.ref_frame_count;
+
+    if (h->mb_width  != h->sps.mb_width ||
+        h->mb_height != h->sps.mb_height * (2 - h->sps.frame_mbs_only_flag))
+        needs_reinit = 1;
+
+    h->mb_width  = h->sps.mb_width;
+    h->mb_height = h->sps.mb_height * (2 - h->sps.frame_mbs_only_flag);
+    h->mb_num    = h->mb_width * h->mb_height;
+    h->mb_stride = h->mb_width + 1;
+
+    h->b_stride = h->mb_width * 4;
+
+    h->chroma_y_shift = h->sps.chroma_format_idc <= 1; // 400 uses yuv420p
+
+    h->width  = 16 * h->mb_width;
+    h->height = 16 * h->mb_height;
+
+    ret = init_dimensions(h);
+    if (ret < 0)
+        return ret;
+
+    if (h->sps.video_signal_type_present_flag) {
+        h->avctx->color_range = h->sps.full_range ? AVCOL_RANGE_JPEG
+                                                  : AVCOL_RANGE_MPEG;
+        if (h->sps.colour_description_present_flag) {
+            if (h->avctx->colorspace != h->sps.colorspace)
+                needs_reinit = 1;
+            h->avctx->color_primaries = h->sps.color_primaries;
+            h->avctx->color_trc       = h->sps.color_trc;
+            h->avctx->colorspace      = h->sps.colorspace;
+        }
+    }
+
+    if (h->context_initialized &&
+        (h->width  != h->avctx->coded_width   ||
+         h->height != h->avctx->coded_height  ||
+         needs_reinit)) {
+        if (h != h0) {
+            av_log(h->avctx, AV_LOG_ERROR,
+                   "changing width %d -> %d / height %d -> %d on "
+                   "slice %d\n",
+                   h->width, h->avctx->coded_width,
+                   h->height, h->avctx->coded_height,
+                   h0->current_slice + 1);
+            return AVERROR_INVALIDDATA;
+        }
+
+        ff_h264_flush_change(h);
+
+        if ((ret = get_pixel_format(h)) < 0)
+            return ret;
+        h->avctx->pix_fmt = ret;
+
+        av_log(h->avctx, AV_LOG_INFO, "Reinit context to %dx%d, "
+               "pix_fmt: %d\n", h->width, h->height, h->avctx->pix_fmt);
+
+        if ((ret = h264_slice_header_init(h, 1)) < 0) {
+            av_log(h->avctx, AV_LOG_ERROR,
+                   "h264_slice_header_init() failed\n");
+            return ret;
+        }
+    }
+    if (!h->context_initialized) {
+        if (h != h0) {
+            av_log(h->avctx, AV_LOG_ERROR,
+                   "Cannot (re-)initialize context during parallel decoding.\n");
+            return AVERROR_PATCHWELCOME;
+        }
+
+        if ((ret = get_pixel_format(h)) < 0)
+            return ret;
+        h->avctx->pix_fmt = ret;
+
+        if ((ret = h264_slice_header_init(h, 0)) < 0) {
+            av_log(h->avctx, AV_LOG_ERROR,
+                   "h264_slice_header_init() failed\n");
+            return ret;
+        }
+    }
+
+    if (h == h0 && h->dequant_coeff_pps != pps_id) {
+        h->dequant_coeff_pps = pps_id;
+        h264_init_dequant_tables(h);
+    }
+
+    h->frame_num = get_bits(&h->gb, h->sps.log2_max_frame_num);
+
+    h->mb_mbaff        = 0;
+    h->mb_aff_frame    = 0;
+    last_pic_structure = h0->picture_structure;
+    last_pic_droppable = h0->droppable;
+    h->droppable       = h->nal_ref_idc == 0;
+    if (h->sps.frame_mbs_only_flag) {
+        h->picture_structure = PICT_FRAME;
+    } else {
+        field_pic_flag = get_bits1(&h->gb);
+        if (field_pic_flag) {
+            bottom_field_flag = get_bits1(&h->gb);
+            h->picture_structure = PICT_TOP_FIELD + bottom_field_flag;
+        } else {
+            h->picture_structure = PICT_FRAME;
+            h->mb_aff_frame      = h->sps.mb_aff;
+        }
+    }
+    h->mb_field_decoding_flag = h->picture_structure != PICT_FRAME;
+
+    if (h0->current_slice != 0) {
+        if (last_pic_structure != h->picture_structure ||
+            last_pic_droppable != h->droppable) {
+            av_log(h->avctx, AV_LOG_ERROR,
+                   "Changing field mode (%d -> %d) between slices is not allowed\n",
+                   last_pic_structure, h->picture_structure);
+            h->picture_structure = last_pic_structure;
+            h->droppable         = last_pic_droppable;
+            return AVERROR_INVALIDDATA;
+        } else if (!h0->cur_pic_ptr) {
+            av_log(h->avctx, AV_LOG_ERROR,
+                   "unset cur_pic_ptr on slice %d\n",
+                   h0->current_slice + 1);
+            return AVERROR_INVALIDDATA;
+        }
+    } else {
+        /* Shorten frame num gaps so we don't have to allocate reference
+         * frames just to throw them away */
+        if (h->frame_num != h->prev_frame_num) {
+            int unwrap_prev_frame_num = h->prev_frame_num;
+            int max_frame_num         = 1 << h->sps.log2_max_frame_num;
+
+            if (unwrap_prev_frame_num > h->frame_num)
+                unwrap_prev_frame_num -= max_frame_num;
+
+            if ((h->frame_num - unwrap_prev_frame_num) > h->sps.ref_frame_count) {
+                unwrap_prev_frame_num = (h->frame_num - h->sps.ref_frame_count) - 1;
+                if (unwrap_prev_frame_num < 0)
+                    unwrap_prev_frame_num += max_frame_num;
+
+                h->prev_frame_num = unwrap_prev_frame_num;
+            }
+        }
+
+        /* See if we have a decoded first field looking for a pair...
+         * Here, we're using that to see if we should mark previously
+         * decode frames as "finished".
+         * We have to do that before the "dummy" in-between frame allocation,
+         * since that can modify s->current_picture_ptr. */
+        if (h0->first_field) {
+            assert(h0->cur_pic_ptr);
+            assert(h0->cur_pic_ptr->f.buf[0]);
+            assert(h0->cur_pic_ptr->reference != DELAYED_PIC_REF);
+
+            /* figure out if we have a complementary field pair */
+            if (!FIELD_PICTURE(h) || h->picture_structure == last_pic_structure) {
+                /* Previous field is unmatched. Don't display it, but let it
+                 * remain for reference if marked as such. */
+                if (!last_pic_droppable && last_pic_structure != PICT_FRAME) {
+                    ff_thread_report_progress(&h0->cur_pic_ptr->tf, INT_MAX,
+                                              last_pic_structure == PICT_TOP_FIELD);
+                }
+            } else {
+                if (h0->cur_pic_ptr->frame_num != h->frame_num) {
+                    /* This and previous field were reference, but had
+                     * different frame_nums. Consider this field first in
+                     * pair. Throw away previous field except for reference
+                     * purposes. */
+                    if (!last_pic_droppable && last_pic_structure != PICT_FRAME) {
+                        ff_thread_report_progress(&h0->cur_pic_ptr->tf, INT_MAX,
+                                                  last_pic_structure == PICT_TOP_FIELD);
+                    }
+                } else {
+                    /* Second field in complementary pair */
+                    if (!((last_pic_structure   == PICT_TOP_FIELD &&
+                           h->picture_structure == PICT_BOTTOM_FIELD) ||
+                          (last_pic_structure   == PICT_BOTTOM_FIELD &&
+                           h->picture_structure == PICT_TOP_FIELD))) {
+                        av_log(h->avctx, AV_LOG_ERROR,
+                               "Invalid field mode combination %d/%d\n",
+                               last_pic_structure, h->picture_structure);
+                        h->picture_structure = last_pic_structure;
+                        h->droppable         = last_pic_droppable;
+                        return AVERROR_INVALIDDATA;
+                    } else if (last_pic_droppable != h->droppable) {
+                        avpriv_request_sample(h->avctx,
+                                              "Found reference and non-reference fields in the same frame, which");
+                        h->picture_structure = last_pic_structure;
+                        h->droppable         = last_pic_droppable;
+                        return AVERROR_PATCHWELCOME;
+                    }
+                }
+            }
+        }
+
+        while (h->frame_num != h->prev_frame_num &&
+               h->frame_num != (h->prev_frame_num + 1) % (1 << h->sps.log2_max_frame_num)) {
+            H264Picture *prev = h->short_ref_count ? h->short_ref[0] : NULL;
+            av_log(h->avctx, AV_LOG_DEBUG, "Frame num gap %d %d\n",
+                   h->frame_num, h->prev_frame_num);
+            ret = h264_frame_start(h);
+            if (ret < 0) {
+                h0->first_field = 0;
+                return ret;
+            }
+
+            h->prev_frame_num++;
+            h->prev_frame_num        %= 1 << h->sps.log2_max_frame_num;
+            h->cur_pic_ptr->frame_num = h->prev_frame_num;
+            ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX, 0);
+            ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX, 1);
+            ret = ff_generate_sliding_window_mmcos(h, 1);
+            if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE))
+                return ret;
+            ret = ff_h264_execute_ref_pic_marking(h, h->mmco, h->mmco_index);
+            if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE))
+                return ret;
+            /* Error concealment: If a ref is missing, copy the previous ref
+             * in its place.
+             * FIXME: Avoiding a memcpy would be nice, but ref handling makes
+             * many assumptions about there being no actual duplicates.
+             * FIXME: This does not copy padding for out-of-frame motion
+             * vectors.  Given we are concealing a lost frame, this probably
+             * is not noticeable by comparison, but it should be fixed. */
+            if (h->short_ref_count) {
+                if (prev) {
+                    av_image_copy(h->short_ref[0]->f.data,
+                                  h->short_ref[0]->f.linesize,
+                                  (const uint8_t **)prev->f.data,
+                                  prev->f.linesize,
+                                  h->avctx->pix_fmt,
+                                  h->mb_width  * 16,
+                                  h->mb_height * 16);
+                    h->short_ref[0]->poc = prev->poc + 2;
+                }
+                h->short_ref[0]->frame_num = h->prev_frame_num;
+            }
+        }
+
+        /* See if we have a decoded first field looking for a pair...
+         * We're using that to see whether to continue decoding in that
+         * frame, or to allocate a new one. */
+        if (h0->first_field) {
+            assert(h0->cur_pic_ptr);
+            assert(h0->cur_pic_ptr->f.buf[0]);
+            assert(h0->cur_pic_ptr->reference != DELAYED_PIC_REF);
+
+            /* figure out if we have a complementary field pair */
+            if (!FIELD_PICTURE(h) || h->picture_structure == last_pic_structure) {
+                /* Previous field is unmatched. Don't display it, but let it
+                 * remain for reference if marked as such. */
+                h0->cur_pic_ptr = NULL;
+                h0->first_field = FIELD_PICTURE(h);
+            } else {
+                if (h0->cur_pic_ptr->frame_num != h->frame_num) {
+                    /* This and the previous field had different frame_nums.
+                     * Consider this field first in pair. Throw away previous
+                     * one except for reference purposes. */
+                    h0->first_field = 1;
+                    h0->cur_pic_ptr = NULL;
+                } else {
+                    /* Second field in complementary pair */
+                    h0->first_field = 0;
+                }
+            }
+        } else {
+            /* Frame or first field in a potentially complementary pair */
+            h0->first_field = FIELD_PICTURE(h);
+        }
+
+        if (!FIELD_PICTURE(h) || h0->first_field) {
+            if (h264_frame_start(h) < 0) {
+                h0->first_field = 0;
+                return AVERROR_INVALIDDATA;
+            }
+        } else {
+            release_unused_pictures(h, 0);
+        }
+    }
+    if (h != h0 && (ret = clone_slice(h, h0)) < 0)
+        return ret;
+
+    h->cur_pic_ptr->frame_num = h->frame_num; // FIXME frame_num cleanup
+
+    assert(h->mb_num == h->mb_width * h->mb_height);
+    if (first_mb_in_slice << FIELD_OR_MBAFF_PICTURE(h) >= h->mb_num ||
+        first_mb_in_slice >= h->mb_num) {
+        av_log(h->avctx, AV_LOG_ERROR, "first_mb_in_slice overflow\n");
+        return AVERROR_INVALIDDATA;
+    }
+    h->resync_mb_x = h->mb_x =  first_mb_in_slice % h->mb_width;
+    h->resync_mb_y = h->mb_y = (first_mb_in_slice / h->mb_width) <<
+                               FIELD_OR_MBAFF_PICTURE(h);
+    if (h->picture_structure == PICT_BOTTOM_FIELD)
+        h->resync_mb_y = h->mb_y = h->mb_y + 1;
+    assert(h->mb_y < h->mb_height);
+
+    if (h->picture_structure == PICT_FRAME) {
+        h->curr_pic_num = h->frame_num;
+        h->max_pic_num  = 1 << h->sps.log2_max_frame_num;
+    } else {
+        h->curr_pic_num = 2 * h->frame_num + 1;
+        h->max_pic_num  = 1 << (h->sps.log2_max_frame_num + 1);
+    }
+
+    if (h->nal_unit_type == NAL_IDR_SLICE)
+        get_ue_golomb(&h->gb); /* idr_pic_id */
+
+    if (h->sps.poc_type == 0) {
+        h->poc_lsb = get_bits(&h->gb, h->sps.log2_max_poc_lsb);
+
+        if (h->pps.pic_order_present == 1 && h->picture_structure == PICT_FRAME)
+            h->delta_poc_bottom = get_se_golomb(&h->gb);
+    }
+
+    if (h->sps.poc_type == 1 && !h->sps.delta_pic_order_always_zero_flag) {
+        h->delta_poc[0] = get_se_golomb(&h->gb);
+
+        if (h->pps.pic_order_present == 1 && h->picture_structure == PICT_FRAME)
+            h->delta_poc[1] = get_se_golomb(&h->gb);
+    }
+
+    ff_init_poc(h, h->cur_pic_ptr->field_poc, &h->cur_pic_ptr->poc);
+
+    if (h->pps.redundant_pic_cnt_present)
+        h->redundant_pic_count = get_ue_golomb(&h->gb);
+
+    ret = ff_set_ref_count(h);
+    if (ret < 0)
+        return ret;
+    else if (ret == 1)
+        default_ref_list_done = 0;
+
+    if (!default_ref_list_done)
+        ff_h264_fill_default_ref_list(h);
+
+    if (h->slice_type_nos != AV_PICTURE_TYPE_I) {
+       ret = ff_h264_decode_ref_pic_list_reordering(h);
+       if (ret < 0) {
+           h->ref_count[1] = h->ref_count[0] = 0;
+           return ret;
+       }
+    }
+
+    if ((h->pps.weighted_pred && h->slice_type_nos == AV_PICTURE_TYPE_P) ||
+        (h->pps.weighted_bipred_idc == 1 &&
+         h->slice_type_nos == AV_PICTURE_TYPE_B))
+        ff_pred_weight_table(h);
+    else if (h->pps.weighted_bipred_idc == 2 &&
+             h->slice_type_nos == AV_PICTURE_TYPE_B) {
+        implicit_weight_table(h, -1);
+    } else {
+        h->use_weight = 0;
+        for (i = 0; i < 2; i++) {
+            h->luma_weight_flag[i]   = 0;
+            h->chroma_weight_flag[i] = 0;
+        }
+    }
+
+    // If frame-mt is enabled, only update mmco tables for the first slice
+    // in a field. Subsequent slices can temporarily clobber h->mmco_index
+    // or h->mmco, which will cause ref list mix-ups and decoding errors
+    // further down the line. This may break decoding if the first slice is
+    // corrupt, thus we only do this if frame-mt is enabled.
+    if (h->nal_ref_idc) {
+        ret = ff_h264_decode_ref_pic_marking(h0, &h->gb,
+                                             !(h->avctx->active_thread_type & FF_THREAD_FRAME) ||
+                                             h0->current_slice == 0);
+        if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE))
+            return AVERROR_INVALIDDATA;
+    }
+
+    if (FRAME_MBAFF(h)) {
+        ff_h264_fill_mbaff_ref_list(h);
+
+        if (h->pps.weighted_bipred_idc == 2 && h->slice_type_nos == AV_PICTURE_TYPE_B) {
+            implicit_weight_table(h, 0);
+            implicit_weight_table(h, 1);
+        }
+    }
+
+    if (h->slice_type_nos == AV_PICTURE_TYPE_B && !h->direct_spatial_mv_pred)
+        ff_h264_direct_dist_scale_factor(h);
+    ff_h264_direct_ref_list_init(h);
+
+    if (h->slice_type_nos != AV_PICTURE_TYPE_I && h->pps.cabac) {
+        tmp = get_ue_golomb_31(&h->gb);
+        if (tmp > 2) {
+            av_log(h->avctx, AV_LOG_ERROR, "cabac_init_idc %u overflow\n", tmp);
+            return AVERROR_INVALIDDATA;
+        }
+        h->cabac_init_idc = tmp;
+    }
+
+    h->last_qscale_diff = 0;
+    tmp = h->pps.init_qp + get_se_golomb(&h->gb);
+    if (tmp > 51 + 6 * (h->sps.bit_depth_luma - 8)) {
+        av_log(h->avctx, AV_LOG_ERROR, "QP %u out of range\n", tmp);
+        return AVERROR_INVALIDDATA;
+    }
+    h->qscale       = tmp;
+    h->chroma_qp[0] = get_chroma_qp(h, 0, h->qscale);
+    h->chroma_qp[1] = get_chroma_qp(h, 1, h->qscale);
+    // FIXME qscale / qp ... stuff
+    if (h->slice_type == AV_PICTURE_TYPE_SP)
+        get_bits1(&h->gb); /* sp_for_switch_flag */
+    if (h->slice_type == AV_PICTURE_TYPE_SP ||
+        h->slice_type == AV_PICTURE_TYPE_SI)
+        get_se_golomb(&h->gb); /* slice_qs_delta */
+
+    h->deblocking_filter     = 1;
+    h->slice_alpha_c0_offset = 0;
+    h->slice_beta_offset     = 0;
+    if (h->pps.deblocking_filter_parameters_present) {
+        tmp = get_ue_golomb_31(&h->gb);
+        if (tmp > 2) {
+            av_log(h->avctx, AV_LOG_ERROR,
+                   "deblocking_filter_idc %u out of range\n", tmp);
+            return AVERROR_INVALIDDATA;
+        }
+        h->deblocking_filter = tmp;
+        if (h->deblocking_filter < 2)
+            h->deblocking_filter ^= 1;  // 1<->0
+
+        if (h->deblocking_filter) {
+            h->slice_alpha_c0_offset = get_se_golomb(&h->gb) * 2;
+            h->slice_beta_offset     = get_se_golomb(&h->gb) * 2;
+            if (h->slice_alpha_c0_offset >  12 ||
+                h->slice_alpha_c0_offset < -12 ||
+                h->slice_beta_offset >  12     ||
+                h->slice_beta_offset < -12) {
+                av_log(h->avctx, AV_LOG_ERROR,
+                       "deblocking filter parameters %d %d out of range\n",
+                       h->slice_alpha_c0_offset, h->slice_beta_offset);
+                return AVERROR_INVALIDDATA;
+            }
+        }
+    }
+
+    if (h->avctx->skip_loop_filter >= AVDISCARD_ALL ||
+        (h->avctx->skip_loop_filter >= AVDISCARD_NONKEY &&
+         h->slice_type_nos != AV_PICTURE_TYPE_I) ||
+        (h->avctx->skip_loop_filter >= AVDISCARD_BIDIR  &&
+         h->slice_type_nos == AV_PICTURE_TYPE_B) ||
+        (h->avctx->skip_loop_filter >= AVDISCARD_NONREF &&
+         h->nal_ref_idc == 0))
+        h->deblocking_filter = 0;
+
+    if (h->deblocking_filter == 1 && h0->max_contexts > 1) {
+        if (h->avctx->flags2 & CODEC_FLAG2_FAST) {
+            /* Cheat slightly for speed:
+             * Do not bother to deblock across slices. */
+            h->deblocking_filter = 2;
+        } else {
+            h0->max_contexts = 1;
+            if (!h0->single_decode_warning) {
+                av_log(h->avctx, AV_LOG_INFO,
+                       "Cannot parallelize deblocking type 1, decoding such frames in sequential order\n");
+                h0->single_decode_warning = 1;
+            }
+            if (h != h0) {
+                av_log(h->avctx, AV_LOG_ERROR,
+                       "Deblocking switched inside frame.\n");
+                return 1;
+            }
+        }
+    }
+    h->qp_thresh = 15 -
+                   FFMIN(h->slice_alpha_c0_offset, h->slice_beta_offset) -
+                   FFMAX3(0,
+                          h->pps.chroma_qp_index_offset[0],
+                          h->pps.chroma_qp_index_offset[1]) +
+                   6 * (h->sps.bit_depth_luma - 8);
+
+    h0->last_slice_type = slice_type;
+    h->slice_num        = ++h0->current_slice;
+    if (h->slice_num >= MAX_SLICES) {
+        av_log(h->avctx, AV_LOG_ERROR,
+               "Too many slices, increase MAX_SLICES and recompile\n");
+    }
+
+    for (j = 0; j < 2; j++) {
+        int id_list[16];
+        int *ref2frm = h->ref2frm[h->slice_num & (MAX_SLICES - 1)][j];
+        for (i = 0; i < 16; i++) {
+            id_list[i] = 60;
+            if (j < h->list_count && i < h->ref_count[j] &&
+                h->ref_list[j][i].f.buf[0]) {
+                int k;
+                AVBuffer *buf = h->ref_list[j][i].f.buf[0]->buffer;
+                for (k = 0; k < h->short_ref_count; k++)
+                    if (h->short_ref[k]->f.buf[0]->buffer == buf) {
+                        id_list[i] = k;
+                        break;
+                    }
+                for (k = 0; k < h->long_ref_count; k++)
+                    if (h->long_ref[k] && h->long_ref[k]->f.buf[0]->buffer == buf) {
+                        id_list[i] = h->short_ref_count + k;
+                        break;
+                    }
+            }
+        }
+
+        ref2frm[0] =
+        ref2frm[1] = -1;
+        for (i = 0; i < 16; i++)
+            ref2frm[i + 2] = 4 * id_list[i] + (h->ref_list[j][i].reference & 3);
+        ref2frm[18 + 0] =
+        ref2frm[18 + 1] = -1;
+        for (i = 16; i < 48; i++)
+            ref2frm[i + 4] = 4 * id_list[(i - 16) >> 1] +
+                             (h->ref_list[j][i].reference & 3);
+    }
+
+    if (h->avctx->debug & FF_DEBUG_PICT_INFO) {
+        av_log(h->avctx, AV_LOG_DEBUG,
+               "slice:%d %s mb:%d %c%s%s pps:%u frame:%d poc:%d/%d ref:%d/%d qp:%d loop:%d:%d:%d weight:%d%s %s\n",
+               h->slice_num,
+               (h->picture_structure == PICT_FRAME ? "F" : h->picture_structure == PICT_TOP_FIELD ? "T" : "B"),
+               first_mb_in_slice,
+               av_get_picture_type_char(h->slice_type),
+               h->slice_type_fixed ? " fix" : "",
+               h->nal_unit_type == NAL_IDR_SLICE ? " IDR" : "",
+               pps_id, h->frame_num,
+               h->cur_pic_ptr->field_poc[0],
+               h->cur_pic_ptr->field_poc[1],
+               h->ref_count[0], h->ref_count[1],
+               h->qscale,
+               h->deblocking_filter,
+               h->slice_alpha_c0_offset, h->slice_beta_offset,
+               h->use_weight,
+               h->use_weight == 1 && h->use_weight_chroma ? "c" : "",
+               h->slice_type == AV_PICTURE_TYPE_B ? (h->direct_spatial_mv_pred ? "SPAT" : "TEMP") : "");
+    }
+
+    return 0;
+}
+
+int ff_h264_get_slice_type(const H264Context *h)
+{
+    switch (h->slice_type) {
+    case AV_PICTURE_TYPE_P:
+        return 0;
+    case AV_PICTURE_TYPE_B:
+        return 1;
+    case AV_PICTURE_TYPE_I:
+        return 2;
+    case AV_PICTURE_TYPE_SP:
+        return 3;
+    case AV_PICTURE_TYPE_SI:
+        return 4;
+    default:
+        return AVERROR_INVALIDDATA;
+    }
+}
+
+static av_always_inline void fill_filter_caches_inter(H264Context *h,
+                                                      int mb_type, int top_xy,
+                                                      int left_xy[LEFT_MBS],
+                                                      int top_type,
+                                                      int left_type[LEFT_MBS],
+                                                      int mb_xy, int list)
+{
+    int b_stride = h->b_stride;
+    int16_t(*mv_dst)[2] = &h->mv_cache[list][scan8[0]];
+    int8_t *ref_cache = &h->ref_cache[list][scan8[0]];
+    if (IS_INTER(mb_type) || IS_DIRECT(mb_type)) {
+        if (USES_LIST(top_type, list)) {
+            const int b_xy  = h->mb2b_xy[top_xy] + 3 * b_stride;
+            const int b8_xy = 4 * top_xy + 2;
+            int (*ref2frm)[64] = h->ref2frm[h->slice_table[top_xy] & (MAX_SLICES - 1)][0] + (MB_MBAFF(h) ? 20 : 2);
+            AV_COPY128(mv_dst - 1 * 8, h->cur_pic.motion_val[list][b_xy + 0]);
+            ref_cache[0 - 1 * 8] =
+            ref_cache[1 - 1 * 8] = ref2frm[list][h->cur_pic.ref_index[list][b8_xy + 0]];
+            ref_cache[2 - 1 * 8] =
+            ref_cache[3 - 1 * 8] = ref2frm[list][h->cur_pic.ref_index[list][b8_xy + 1]];
+        } else {
+            AV_ZERO128(mv_dst - 1 * 8);
+            AV_WN32A(&ref_cache[0 - 1 * 8], ((LIST_NOT_USED) & 0xFF) * 0x01010101u);
+        }
+
+        if (!IS_INTERLACED(mb_type ^ left_type[LTOP])) {
+            if (USES_LIST(left_type[LTOP], list)) {
+                const int b_xy  = h->mb2b_xy[left_xy[LTOP]] + 3;
+                const int b8_xy = 4 * left_xy[LTOP] + 1;
+                int (*ref2frm)[64] = h->ref2frm[h->slice_table[left_xy[LTOP]] & (MAX_SLICES - 1)][0] + (MB_MBAFF(h) ? 20 : 2);
+                AV_COPY32(mv_dst - 1 +  0, h->cur_pic.motion_val[list][b_xy + b_stride * 0]);
+                AV_COPY32(mv_dst - 1 +  8, h->cur_pic.motion_val[list][b_xy + b_stride * 1]);
+                AV_COPY32(mv_dst - 1 + 16, h->cur_pic.motion_val[list][b_xy + b_stride * 2]);
+                AV_COPY32(mv_dst - 1 + 24, h->cur_pic.motion_val[list][b_xy + b_stride * 3]);
+                ref_cache[-1 +  0] =
+                ref_cache[-1 +  8] = ref2frm[list][h->cur_pic.ref_index[list][b8_xy + 2 * 0]];
+                ref_cache[-1 + 16] =
+                ref_cache[-1 + 24] = ref2frm[list][h->cur_pic.ref_index[list][b8_xy + 2 * 1]];
+            } else {
+                AV_ZERO32(mv_dst - 1 +  0);
+                AV_ZERO32(mv_dst - 1 +  8);
+                AV_ZERO32(mv_dst - 1 + 16);
+                AV_ZERO32(mv_dst - 1 + 24);
+                ref_cache[-1 +  0] =
+                ref_cache[-1 +  8] =
+                ref_cache[-1 + 16] =
+                ref_cache[-1 + 24] = LIST_NOT_USED;
+            }
+        }
+    }
+
+    if (!USES_LIST(mb_type, list)) {
+        fill_rectangle(mv_dst, 4, 4, 8, pack16to32(0, 0), 4);
+        AV_WN32A(&ref_cache[0 * 8], ((LIST_NOT_USED) & 0xFF) * 0x01010101u);
+        AV_WN32A(&ref_cache[1 * 8], ((LIST_NOT_USED) & 0xFF) * 0x01010101u);
+        AV_WN32A(&ref_cache[2 * 8], ((LIST_NOT_USED) & 0xFF) * 0x01010101u);
+        AV_WN32A(&ref_cache[3 * 8], ((LIST_NOT_USED) & 0xFF) * 0x01010101u);
+        return;
+    }
+
+    {
+        int8_t *ref = &h->cur_pic.ref_index[list][4 * mb_xy];
+        int (*ref2frm)[64] = h->ref2frm[h->slice_num & (MAX_SLICES - 1)][0] + (MB_MBAFF(h) ? 20 : 2);
+        uint32_t ref01 = (pack16to32(ref2frm[list][ref[0]], ref2frm[list][ref[1]]) & 0x00FF00FF) * 0x0101;
+        uint32_t ref23 = (pack16to32(ref2frm[list][ref[2]], ref2frm[list][ref[3]]) & 0x00FF00FF) * 0x0101;
+        AV_WN32A(&ref_cache[0 * 8], ref01);
+        AV_WN32A(&ref_cache[1 * 8], ref01);
+        AV_WN32A(&ref_cache[2 * 8], ref23);
+        AV_WN32A(&ref_cache[3 * 8], ref23);
+    }
+
+    {
+        int16_t(*mv_src)[2] = &h->cur_pic.motion_val[list][4 * h->mb_x + 4 * h->mb_y * b_stride];
+        AV_COPY128(mv_dst + 8 * 0, mv_src + 0 * b_stride);
+        AV_COPY128(mv_dst + 8 * 1, mv_src + 1 * b_stride);
+        AV_COPY128(mv_dst + 8 * 2, mv_src + 2 * b_stride);
+        AV_COPY128(mv_dst + 8 * 3, mv_src + 3 * b_stride);
+    }
+}
+
+/**
+ *
+ * @return non zero if the loop filter can be skipped
+ */
+static int fill_filter_caches(H264Context *h, int mb_type)
+{
+    const int mb_xy = h->mb_xy;
+    int top_xy, left_xy[LEFT_MBS];
+    int top_type, left_type[LEFT_MBS];
+    uint8_t *nnz;
+    uint8_t *nnz_cache;
+
+    top_xy = mb_xy - (h->mb_stride << MB_FIELD(h));
+
+    /* Wow, what a mess, why didn't they simplify the interlacing & intra
+     * stuff, I can't imagine that these complex rules are worth it. */
+
+    left_xy[LBOT] = left_xy[LTOP] = mb_xy - 1;
+    if (FRAME_MBAFF(h)) {
+        const int left_mb_field_flag = IS_INTERLACED(h->cur_pic.mb_type[mb_xy - 1]);
+        const int curr_mb_field_flag = IS_INTERLACED(mb_type);
+        if (h->mb_y & 1) {
+            if (left_mb_field_flag != curr_mb_field_flag)
+                left_xy[LTOP] -= h->mb_stride;
+        } else {
+            if (curr_mb_field_flag)
+                top_xy += h->mb_stride &
+                          (((h->cur_pic.mb_type[top_xy] >> 7) & 1) - 1);
+            if (left_mb_field_flag != curr_mb_field_flag)
+                left_xy[LBOT] += h->mb_stride;
+        }
+    }
+
+    h->top_mb_xy        = top_xy;
+    h->left_mb_xy[LTOP] = left_xy[LTOP];
+    h->left_mb_xy[LBOT] = left_xy[LBOT];
+    {
+        /* For sufficiently low qp, filtering wouldn't do anything.
+         * This is a conservative estimate: could also check beta_offset
+         * and more accurate chroma_qp. */
+        int qp_thresh = h->qp_thresh; // FIXME strictly we should store qp_thresh for each mb of a slice
+        int qp        = h->cur_pic.qscale_table[mb_xy];
+        if (qp <= qp_thresh &&
+            (left_xy[LTOP] < 0 ||
+             ((qp + h->cur_pic.qscale_table[left_xy[LTOP]] + 1) >> 1) <= qp_thresh) &&
+            (top_xy < 0 ||
+             ((qp + h->cur_pic.qscale_table[top_xy] + 1) >> 1) <= qp_thresh)) {
+            if (!FRAME_MBAFF(h))
+                return 1;
+            if ((left_xy[LTOP] < 0 ||
+                 ((qp + h->cur_pic.qscale_table[left_xy[LBOT]] + 1) >> 1) <= qp_thresh) &&
+                (top_xy < h->mb_stride ||
+                 ((qp + h->cur_pic.qscale_table[top_xy - h->mb_stride] + 1) >> 1) <= qp_thresh))
+                return 1;
+        }
+    }
+
+    top_type        = h->cur_pic.mb_type[top_xy];
+    left_type[LTOP] = h->cur_pic.mb_type[left_xy[LTOP]];
+    left_type[LBOT] = h->cur_pic.mb_type[left_xy[LBOT]];
+    if (h->deblocking_filter == 2) {
+        if (h->slice_table[top_xy] != h->slice_num)
+            top_type = 0;
+        if (h->slice_table[left_xy[LBOT]] != h->slice_num)
+            left_type[LTOP] = left_type[LBOT] = 0;
+    } else {
+        if (h->slice_table[top_xy] == 0xFFFF)
+            top_type = 0;
+        if (h->slice_table[left_xy[LBOT]] == 0xFFFF)
+            left_type[LTOP] = left_type[LBOT] = 0;
+    }
+    h->top_type        = top_type;
+    h->left_type[LTOP] = left_type[LTOP];
+    h->left_type[LBOT] = left_type[LBOT];
+
+    if (IS_INTRA(mb_type))
+        return 0;
+
+    fill_filter_caches_inter(h, mb_type, top_xy, left_xy,
+                             top_type, left_type, mb_xy, 0);
+    if (h->list_count == 2)
+        fill_filter_caches_inter(h, mb_type, top_xy, left_xy,
+                                 top_type, left_type, mb_xy, 1);
+
+    nnz       = h->non_zero_count[mb_xy];
+    nnz_cache = h->non_zero_count_cache;
+    AV_COPY32(&nnz_cache[4 + 8 * 1], &nnz[0]);
+    AV_COPY32(&nnz_cache[4 + 8 * 2], &nnz[4]);
+    AV_COPY32(&nnz_cache[4 + 8 * 3], &nnz[8]);
+    AV_COPY32(&nnz_cache[4 + 8 * 4], &nnz[12]);
+    h->cbp = h->cbp_table[mb_xy];
+
+    if (top_type) {
+        nnz = h->non_zero_count[top_xy];
+        AV_COPY32(&nnz_cache[4 + 8 * 0], &nnz[3 * 4]);
+    }
+
+    if (left_type[LTOP]) {
+        nnz = h->non_zero_count[left_xy[LTOP]];
+        nnz_cache[3 + 8 * 1] = nnz[3 + 0 * 4];
+        nnz_cache[3 + 8 * 2] = nnz[3 + 1 * 4];
+        nnz_cache[3 + 8 * 3] = nnz[3 + 2 * 4];
+        nnz_cache[3 + 8 * 4] = nnz[3 + 3 * 4];
+    }
+
+    /* CAVLC 8x8dct requires NNZ values for residual decoding that differ
+     * from what the loop filter needs */
+    if (!CABAC(h) && h->pps.transform_8x8_mode) {
+        if (IS_8x8DCT(top_type)) {
+            nnz_cache[4 + 8 * 0] =
+            nnz_cache[5 + 8 * 0] = (h->cbp_table[top_xy] & 0x4000) >> 12;
+            nnz_cache[6 + 8 * 0] =
+            nnz_cache[7 + 8 * 0] = (h->cbp_table[top_xy] & 0x8000) >> 12;
+        }
+        if (IS_8x8DCT(left_type[LTOP])) {
+            nnz_cache[3 + 8 * 1] =
+            nnz_cache[3 + 8 * 2] = (h->cbp_table[left_xy[LTOP]] & 0x2000) >> 12; // FIXME check MBAFF
+        }
+        if (IS_8x8DCT(left_type[LBOT])) {
+            nnz_cache[3 + 8 * 3] =
+            nnz_cache[3 + 8 * 4] = (h->cbp_table[left_xy[LBOT]] & 0x8000) >> 12; // FIXME check MBAFF
+        }
+
+        if (IS_8x8DCT(mb_type)) {
+            nnz_cache[scan8[0]] =
+            nnz_cache[scan8[1]] =
+            nnz_cache[scan8[2]] =
+            nnz_cache[scan8[3]] = (h->cbp & 0x1000) >> 12;
+
+            nnz_cache[scan8[0 + 4]] =
+            nnz_cache[scan8[1 + 4]] =
+            nnz_cache[scan8[2 + 4]] =
+            nnz_cache[scan8[3 + 4]] = (h->cbp & 0x2000) >> 12;
+
+            nnz_cache[scan8[0 + 8]] =
+            nnz_cache[scan8[1 + 8]] =
+            nnz_cache[scan8[2 + 8]] =
+            nnz_cache[scan8[3 + 8]] = (h->cbp & 0x4000) >> 12;
+
+            nnz_cache[scan8[0 + 12]] =
+            nnz_cache[scan8[1 + 12]] =
+            nnz_cache[scan8[2 + 12]] =
+            nnz_cache[scan8[3 + 12]] = (h->cbp & 0x8000) >> 12;
+        }
+    }
+
+    return 0;
+}
+
+static void loop_filter(H264Context *h, int start_x, int end_x)
+{
+    uint8_t *dest_y, *dest_cb, *dest_cr;
+    int linesize, uvlinesize, mb_x, mb_y;
+    const int end_mb_y       = h->mb_y + FRAME_MBAFF(h);
+    const int old_slice_type = h->slice_type;
+    const int pixel_shift    = h->pixel_shift;
+    const int block_h        = 16 >> h->chroma_y_shift;
+
+    if (h->deblocking_filter) {
+        for (mb_x = start_x; mb_x < end_x; mb_x++)
+            for (mb_y = end_mb_y - FRAME_MBAFF(h); mb_y <= end_mb_y; mb_y++) {
+                int mb_xy, mb_type;
+                mb_xy         = h->mb_xy = mb_x + mb_y * h->mb_stride;
+                h->slice_num  = h->slice_table[mb_xy];
+                mb_type       = h->cur_pic.mb_type[mb_xy];
+                h->list_count = h->list_counts[mb_xy];
+
+                if (FRAME_MBAFF(h))
+                    h->mb_mbaff               =
+                    h->mb_field_decoding_flag = !!IS_INTERLACED(mb_type);
+
+                h->mb_x = mb_x;
+                h->mb_y = mb_y;
+                dest_y  = h->cur_pic.f.data[0] +
+                          ((mb_x << pixel_shift) + mb_y * h->linesize) * 16;
+                dest_cb = h->cur_pic.f.data[1] +
+                          (mb_x << pixel_shift) * (8 << CHROMA444(h)) +
+                          mb_y * h->uvlinesize * block_h;
+                dest_cr = h->cur_pic.f.data[2] +
+                          (mb_x << pixel_shift) * (8 << CHROMA444(h)) +
+                          mb_y * h->uvlinesize * block_h;
+                // FIXME simplify above
+
+                if (MB_FIELD(h)) {
+                    linesize   = h->mb_linesize   = h->linesize   * 2;
+                    uvlinesize = h->mb_uvlinesize = h->uvlinesize * 2;
+                    if (mb_y & 1) { // FIXME move out of this function?
+                        dest_y  -= h->linesize   * 15;
+                        dest_cb -= h->uvlinesize * (block_h - 1);
+                        dest_cr -= h->uvlinesize * (block_h - 1);
+                    }
+                } else {
+                    linesize   = h->mb_linesize   = h->linesize;
+                    uvlinesize = h->mb_uvlinesize = h->uvlinesize;
+                }
+                backup_mb_border(h, dest_y, dest_cb, dest_cr, linesize,
+                                 uvlinesize, 0);
+                if (fill_filter_caches(h, mb_type))
+                    continue;
+                h->chroma_qp[0] = get_chroma_qp(h, 0, h->cur_pic.qscale_table[mb_xy]);
+                h->chroma_qp[1] = get_chroma_qp(h, 1, h->cur_pic.qscale_table[mb_xy]);
+
+                if (FRAME_MBAFF(h)) {
+                    ff_h264_filter_mb(h, mb_x, mb_y, dest_y, dest_cb, dest_cr,
+                                      linesize, uvlinesize);
+                } else {
+                    ff_h264_filter_mb_fast(h, mb_x, mb_y, dest_y, dest_cb,
+                                           dest_cr, linesize, uvlinesize);
+                }
+            }
+    }
+    h->slice_type   = old_slice_type;
+    h->mb_x         = end_x;
+    h->mb_y         = end_mb_y - FRAME_MBAFF(h);
+    h->chroma_qp[0] = get_chroma_qp(h, 0, h->qscale);
+    h->chroma_qp[1] = get_chroma_qp(h, 1, h->qscale);
+}
+
+static void predict_field_decoding_flag(H264Context *h)
+{
+    const int mb_xy = h->mb_x + h->mb_y * h->mb_stride;
+    int mb_type     = (h->slice_table[mb_xy - 1] == h->slice_num) ?
+                      h->cur_pic.mb_type[mb_xy - 1] :
+                      (h->slice_table[mb_xy - h->mb_stride] == h->slice_num) ?
+                      h->cur_pic.mb_type[mb_xy - h->mb_stride] : 0;
+    h->mb_mbaff     = h->mb_field_decoding_flag = IS_INTERLACED(mb_type) ? 1 : 0;
+}
+
+/**
+ * Draw edges and report progress for the last MB row.
+ */
+static void decode_finish_row(H264Context *h)
+{
+    int top            = 16 * (h->mb_y      >> FIELD_PICTURE(h));
+    int pic_height     = 16 *  h->mb_height >> FIELD_PICTURE(h);
+    int height         =  16      << FRAME_MBAFF(h);
+    int deblock_border = (16 + 4) << FRAME_MBAFF(h);
+
+    if (h->deblocking_filter) {
+        if ((top + height) >= pic_height)
+            height += deblock_border;
+        top -= deblock_border;
+    }
+
+    if (top >= pic_height || (top + height) < 0)
+        return;
+
+    height = FFMIN(height, pic_height - top);
+    if (top < 0) {
+        height = top + height;
+        top    = 0;
+    }
+
+    ff_h264_draw_horiz_band(h, top, height);
+
+    if (h->droppable)
+        return;
+
+    ff_thread_report_progress(&h->cur_pic_ptr->tf, top + height - 1,
+                              h->picture_structure == PICT_BOTTOM_FIELD);
+}
+
+static void er_add_slice(H264Context *h, int startx, int starty,
+                         int endx, int endy, int status)
+{
+#if CONFIG_ERROR_RESILIENCE
+    ERContext *er = &h->er;
+
+    er->ref_count = h->ref_count[0];
+    ff_er_add_slice(er, startx, starty, endx, endy, status);
+#endif
+}
+
+static int decode_slice(struct AVCodecContext *avctx, void *arg)
+{
+    H264Context *h = *(void **)arg;
+    int lf_x_start = h->mb_x;
+
+    h->mb_skip_run = -1;
+
+    h->is_complex = FRAME_MBAFF(h) || h->picture_structure != PICT_FRAME ||
+                    avctx->codec_id != AV_CODEC_ID_H264 ||
+                    (CONFIG_GRAY && (h->flags & CODEC_FLAG_GRAY));
+
+    if (h->pps.cabac) {
+        /* realign */
+        align_get_bits(&h->gb);
+
+        /* init cabac */
+        ff_init_cabac_decoder(&h->cabac,
+                              h->gb.buffer + get_bits_count(&h->gb) / 8,
+                              (get_bits_left(&h->gb) + 7) / 8);
+
+        ff_h264_init_cabac_states(h);
+
+        for (;;) {
+            // START_TIMER
+            int ret = ff_h264_decode_mb_cabac(h);
+            int eos;
+            // STOP_TIMER("decode_mb_cabac")
+
+            if (ret >= 0)
+                ff_h264_hl_decode_mb(h);
+
+            // FIXME optimal? or let mb_decode decode 16x32 ?
+            if (ret >= 0 && FRAME_MBAFF(h)) {
+                h->mb_y++;
+
+                ret = ff_h264_decode_mb_cabac(h);
+
+                if (ret >= 0)
+                    ff_h264_hl_decode_mb(h);
+                h->mb_y--;
+            }
+            eos = get_cabac_terminate(&h->cabac);
+
+            if ((h->workaround_bugs & FF_BUG_TRUNCATED) &&
+                h->cabac.bytestream > h->cabac.bytestream_end + 2) {
+                er_add_slice(h, h->resync_mb_x, h->resync_mb_y, h->mb_x - 1,
+                             h->mb_y, ER_MB_END);
+                if (h->mb_x >= lf_x_start)
+                    loop_filter(h, lf_x_start, h->mb_x + 1);
+                return 0;
+            }
+            if (ret < 0 || h->cabac.bytestream > h->cabac.bytestream_end + 2) {
+                av_log(h->avctx, AV_LOG_ERROR,
+                       "error while decoding MB %d %d, bytestream %td\n",
+                       h->mb_x, h->mb_y,
+                       h->cabac.bytestream_end - h->cabac.bytestream);
+                er_add_slice(h, h->resync_mb_x, h->resync_mb_y, h->mb_x,
+                             h->mb_y, ER_MB_ERROR);
+                return AVERROR_INVALIDDATA;
+            }
+
+            if (++h->mb_x >= h->mb_width) {
+                loop_filter(h, lf_x_start, h->mb_x);
+                h->mb_x = lf_x_start = 0;
+                decode_finish_row(h);
+                ++h->mb_y;
+                if (FIELD_OR_MBAFF_PICTURE(h)) {
+                    ++h->mb_y;
+                    if (FRAME_MBAFF(h) && h->mb_y < h->mb_height)
+                        predict_field_decoding_flag(h);
+                }
+            }
+
+            if (eos || h->mb_y >= h->mb_height) {
+                tprintf(h->avctx, "slice end %d %d\n",
+                        get_bits_count(&h->gb), h->gb.size_in_bits);
+                er_add_slice(h, h->resync_mb_x, h->resync_mb_y, h->mb_x - 1,
+                             h->mb_y, ER_MB_END);
+                if (h->mb_x > lf_x_start)
+                    loop_filter(h, lf_x_start, h->mb_x);
+                return 0;
+            }
+        }
+    } else {
+        for (;;) {
+            int ret = ff_h264_decode_mb_cavlc(h);
+
+            if (ret >= 0)
+                ff_h264_hl_decode_mb(h);
+
+            // FIXME optimal? or let mb_decode decode 16x32 ?
+            if (ret >= 0 && FRAME_MBAFF(h)) {
+                h->mb_y++;
+                ret = ff_h264_decode_mb_cavlc(h);
+
+                if (ret >= 0)
+                    ff_h264_hl_decode_mb(h);
+                h->mb_y--;
+            }
+
+            if (ret < 0) {
+                av_log(h->avctx, AV_LOG_ERROR,
+                       "error while decoding MB %d %d\n", h->mb_x, h->mb_y);
+                er_add_slice(h, h->resync_mb_x, h->resync_mb_y, h->mb_x,
+                             h->mb_y, ER_MB_ERROR);
+                return ret;
+            }
+
+            if (++h->mb_x >= h->mb_width) {
+                loop_filter(h, lf_x_start, h->mb_x);
+                h->mb_x = lf_x_start = 0;
+                decode_finish_row(h);
+                ++h->mb_y;
+                if (FIELD_OR_MBAFF_PICTURE(h)) {
+                    ++h->mb_y;
+                    if (FRAME_MBAFF(h) && h->mb_y < h->mb_height)
+                        predict_field_decoding_flag(h);
+                }
+                if (h->mb_y >= h->mb_height) {
+                    tprintf(h->avctx, "slice end %d %d\n",
+                            get_bits_count(&h->gb), h->gb.size_in_bits);
+
+                    if (get_bits_left(&h->gb) == 0) {
+                        er_add_slice(h, h->resync_mb_x, h->resync_mb_y,
+                                     h->mb_x - 1, h->mb_y,
+                                     ER_MB_END);
+
+                        return 0;
+                    } else {
+                        er_add_slice(h, h->resync_mb_x, h->resync_mb_y,
+                                     h->mb_x - 1, h->mb_y,
+                                     ER_MB_END);
+
+                        return AVERROR_INVALIDDATA;
+                    }
+                }
+            }
+
+            if (get_bits_left(&h->gb) <= 0 && h->mb_skip_run <= 0) {
+                tprintf(h->avctx, "slice end %d %d\n",
+                        get_bits_count(&h->gb), h->gb.size_in_bits);
+
+                if (get_bits_left(&h->gb) == 0) {
+                    er_add_slice(h, h->resync_mb_x, h->resync_mb_y,
+                                 h->mb_x - 1, h->mb_y,
+                                 ER_MB_END);
+                    if (h->mb_x > lf_x_start)
+                        loop_filter(h, lf_x_start, h->mb_x);
+
+                    return 0;
+                } else {
+                    er_add_slice(h, h->resync_mb_x, h->resync_mb_y, h->mb_x,
+                                 h->mb_y, ER_MB_ERROR);
+
+                    return AVERROR_INVALIDDATA;
+                }
+            }
+        }
+    }
+}
+
+/**
+ * Call decode_slice() for each context.
+ *
+ * @param h h264 master context
+ * @param context_count number of contexts to execute
+ */
+int ff_h264_execute_decode_slices(H264Context *h, unsigned context_count)
+{
+    AVCodecContext *const avctx = h->avctx;
+    H264Context *hx;
+    int i;
+
+    if (h->mb_y >= h->mb_height) {
+        av_log(h->avctx, AV_LOG_ERROR,
+               "Input contains more MB rows than the frame height.\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    if (h->avctx->hwaccel)
+        return 0;
+    if (context_count == 1) {
+        return decode_slice(avctx, &h);
+    } else {
+        for (i = 1; i < context_count; i++) {
+            hx                 = h->thread_context[i];
+            hx->er.error_count = 0;
+        }
+
+        avctx->execute(avctx, decode_slice, h->thread_context,
+                       NULL, context_count, sizeof(void *));
+
+        /* pull back stuff from slices to master context */
+        hx                   = h->thread_context[context_count - 1];
+        h->mb_x              = hx->mb_x;
+        h->mb_y              = hx->mb_y;
+        h->droppable         = hx->droppable;
+        h->picture_structure = hx->picture_structure;
+        for (i = 1; i < context_count; i++)
+            h->er.error_count += h->thread_context[i]->er.error_count;
+    }
+
+    return 0;
+}