Add an OpenH264 decoder wrapper

This is cherrypicked from libav, from commits
82b7525173f20702a8cbc26ebedbf4b69b8fecec and
d0b1e6049b06eeeeca146ece4d2f199c5dba1565.

Signed-off-by: Martin Storsjö <martin@martin.st>

1 files changed, 243 insertions, 0 deletions

diff --git a/libavcodec/libopenh264dec.c b/libavcodec/libopenh264dec.c
new file mode 100644
index 0000000000..f642082182
--- /dev/null
+++ b/libavcodec/libopenh264dec.c
@@ -0,0 +1,243 @@
+/*
+ * OpenH264 video decoder
+ * Copyright (C) 2016 Martin Storsjo
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <wels/codec_api.h>
+#include <wels/codec_ver.h>
+
+#include "libavutil/common.h"
+#include "libavutil/fifo.h"
+#include "libavutil/imgutils.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/mathematics.h"
+#include "libavutil/opt.h"
+
+#include "avcodec.h"
+#include "internal.h"
+#include "libopenh264.h"
+
+typedef struct SVCContext {
+    ISVCDecoder *decoder;
+    AVBSFContext *bsf;
+    AVFifoBuffer *packet_fifo;
+    AVPacket pkt_filtered;
+} SVCContext;
+
+static av_cold int svc_decode_close(AVCodecContext *avctx)
+{
+    SVCContext *s = avctx->priv_data;
+    AVPacket pkt;
+
+    if (s->decoder)
+        WelsDestroyDecoder(s->decoder);
+
+    while (s->packet_fifo && av_fifo_size(s->packet_fifo) >= sizeof(pkt)) {
+        av_fifo_generic_read(s->packet_fifo, &pkt, sizeof(pkt), NULL);
+        av_packet_unref(&pkt);
+    }
+
+    av_bsf_free(&s->bsf);
+    av_packet_unref(&s->pkt_filtered);
+    av_fifo_free(s->packet_fifo);
+
+    return 0;
+}
+
+static av_cold int svc_decode_init(AVCodecContext *avctx)
+{
+    SVCContext *s = avctx->priv_data;
+    SDecodingParam param = { 0 };
+    int err;
+    int log_level;
+    WelsTraceCallback callback_function;
+
+    if ((err = ff_libopenh264_check_version(avctx)) < 0)
+        return err;
+
+    s->packet_fifo = av_fifo_alloc(sizeof(AVPacket));
+    if (!s->packet_fifo) {
+        err = AVERROR(ENOMEM);
+        goto fail;
+    }
+
+    if (WelsCreateDecoder(&s->decoder)) {
+        av_log(avctx, AV_LOG_ERROR, "Unable to create decoder\n");
+        err = AVERROR_UNKNOWN;
+        goto fail;
+    }
+
+    // Pass all libopenh264 messages to our callback, to allow ourselves to filter them.
+    log_level = WELS_LOG_DETAIL;
+    callback_function = ff_libopenh264_trace_callback;
+    (*s->decoder)->SetOption(s->decoder, DECODER_OPTION_TRACE_LEVEL, &log_level);
+    (*s->decoder)->SetOption(s->decoder, DECODER_OPTION_TRACE_CALLBACK, (void *)&callback_function);
+    (*s->decoder)->SetOption(s->decoder, DECODER_OPTION_TRACE_CALLBACK_CONTEXT, (void *)&avctx);
+
+    param.eOutputColorFormat = videoFormatI420;
+    param.eEcActiveIdc       = ERROR_CON_DISABLE;
+    param.sVideoProperty.eVideoBsType = VIDEO_BITSTREAM_DEFAULT;
+
+    if ((*s->decoder)->Initialize(s->decoder, &param) != cmResultSuccess) {
+        av_log(avctx, AV_LOG_ERROR, "Initialize failed\n");
+        err = AVERROR_UNKNOWN;
+        goto fail;
+    }
+
+    avctx->pix_fmt = AV_PIX_FMT_YUV420P;
+
+fail:
+    return err;
+}
+
+static int init_bsf(AVCodecContext *avctx)
+{
+    SVCContext *s = avctx->priv_data;
+    const AVBitStreamFilter *filter;
+    int ret;
+
+    if (s->bsf)
+        return 0;
+
+    // If the input stream already is annex b, this BSF only passes the
+    // packets through unchanged.
+    filter = av_bsf_get_by_name("h264_mp4toannexb");
+    if (!filter)
+        return AVERROR_BUG;
+
+    ret = av_bsf_alloc(filter, &s->bsf);
+    if (ret < 0)
+        return ret;
+
+    ret = avcodec_parameters_from_context(s->bsf->par_in, avctx);
+    if (ret < 0)
+        return ret;
+
+    s->bsf->time_base_in = avctx->time_base;
+
+    ret = av_bsf_init(s->bsf);
+    if (ret < 0)
+        return ret;
+
+    return ret;
+}
+
+static int svc_decode_frame(AVCodecContext *avctx, void *data,
+                            int *got_frame, AVPacket *avpkt)
+{
+    SVCContext *s = avctx->priv_data;
+    SBufferInfo info = { 0 };
+    uint8_t* ptrs[3];
+    int linesize[3];
+    AVFrame *avframe = data;
+    int ret;
+    DECODING_STATE state;
+
+    if ((ret = init_bsf(avctx)) < 0)
+        return ret;
+
+    if (avpkt->size) {
+        AVPacket input_ref = { 0 };
+        if (av_fifo_space(s->packet_fifo) < sizeof(input_ref)) {
+            ret = av_fifo_realloc2(s->packet_fifo,
+                                   av_fifo_size(s->packet_fifo) + sizeof(input_ref));
+            if (ret < 0)
+                return ret;
+        }
+
+        ret = av_packet_ref(&input_ref, avpkt);
+        if (ret < 0)
+            return ret;
+        av_fifo_generic_write(s->packet_fifo, &input_ref, sizeof(input_ref), NULL);
+    }
+
+    while (!*got_frame) {
+        /* prepare the input data -- convert to Annex B if needed */
+        if (s->pkt_filtered.size <= 0) {
+            AVPacket input_ref;
+
+            /* no more data */
+            if (av_fifo_size(s->packet_fifo) < sizeof(AVPacket))
+                return avpkt->size ? avpkt->size : 0;
+
+            av_packet_unref(&s->pkt_filtered);
+
+            av_fifo_generic_read(s->packet_fifo, &input_ref, sizeof(input_ref), NULL);
+            ret = av_bsf_send_packet(s->bsf, &input_ref);
+            if (ret < 0) {
+                av_packet_unref(&input_ref);
+                return ret;
+            }
+
+            ret = av_bsf_receive_packet(s->bsf, &s->pkt_filtered);
+            if (ret < 0)
+                av_packet_move_ref(&s->pkt_filtered, &input_ref);
+            else
+                av_packet_unref(&input_ref);
+        }
+
+        state = (*s->decoder)->DecodeFrame2(s->decoder, s->pkt_filtered.data, s->pkt_filtered.size, ptrs, &info);
+        s->pkt_filtered.size = 0;
+        if (state != dsErrorFree) {
+            av_log(avctx, AV_LOG_ERROR, "DecodeFrame2 failed\n");
+            return AVERROR_UNKNOWN;
+        }
+        if (info.iBufferStatus != 1) {
+            av_log(avctx, AV_LOG_DEBUG, "No frame produced\n");
+            continue;
+        }
+
+        ret = ff_set_dimensions(avctx, info.UsrData.sSystemBuffer.iWidth, info.UsrData.sSystemBuffer.iHeight);
+        if (ret < 0)
+            return ret;
+        // The decoder doesn't (currently) support decoding into a user
+        // provided buffer, so do a copy instead.
+        if (ff_get_buffer(avctx, avframe, 0) < 0) {
+            av_log(avctx, AV_LOG_ERROR, "Unable to allocate buffer\n");
+            return AVERROR(ENOMEM);
+        }
+
+        linesize[0] = info.UsrData.sSystemBuffer.iStride[0];
+        linesize[1] = linesize[2] = info.UsrData.sSystemBuffer.iStride[1];
+        av_image_copy(avframe->data, avframe->linesize, (const uint8_t **) ptrs, linesize, avctx->pix_fmt, avctx->width, avctx->height);
+
+        avframe->pts     = s->pkt_filtered.pts;
+        avframe->pkt_dts = s->pkt_filtered.dts;
+        avframe->pkt_pts = s->pkt_filtered.pts;
+
+        *got_frame = 1;
+    }
+    return avpkt->size;
+}
+
+AVCodec ff_libopenh264_decoder = {
+    .name           = "libopenh264",
+    .long_name      = NULL_IF_CONFIG_SMALL("OpenH264 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10"),
+    .type           = AVMEDIA_TYPE_VIDEO,
+    .id             = AV_CODEC_ID_H264,
+    .priv_data_size = sizeof(SVCContext),
+    .init           = svc_decode_init,
+    .decode         = svc_decode_frame,
+    .close          = svc_decode_close,
+    // The decoder doesn't currently support B-frames, and the decoder's API
+    // doesn't support reordering/delay, but the BSF could incur delay.
+    .capabilities   = AV_CODEC_CAP_DELAY | AV_CODEC_CAP_DR1,
+    .caps_internal  = FF_CODEC_CAP_SETS_PKT_DTS | FF_CODEC_CAP_INIT_THREADSAFE |
+                      FF_CODEC_CAP_INIT_CLEANUP,
+};