avcodec/mpegvideo: Split ff_mpv_reconstruct_mb() into de/encoder part

This has the advantage of not having to check for whether
a given MpegEncContext is actually a decoder or an encoder
context at runtime.

To do so, mpv_reconstruct_mb_internal() is moved into a new
template file that is included by both mpegvideo_enc.c
and mpegvideo_dec.c; the decoder-only code (mainly lowres)
are also moved to mpegvideo_dec.c. The is_encoder checks are
changed to #if IS_ENCODER in order to avoid having to include
headers for decoder-only functions in mpegvideo_enc.c.

This approach also has the advantage that it is easy to adapt
mpv_reconstruct_mb_internal() to using different structures
for decoders and encoders (e.g. the check for whether
a macroblock should be processed for the encoder or not
uses MpegEncContext elements that make no sense for decoders
and should not be part of their context).

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

1 files changed, 300 insertions, 0 deletions

diff --git a/libavcodec/mpv_reconstruct_mb_template.c b/libavcodec/mpv_reconstruct_mb_template.c
new file mode 100644
index 0000000000..fd03d71985
--- /dev/null
+++ b/libavcodec/mpv_reconstruct_mb_template.c
@@ -0,0 +1,300 @@
+/*
+ * MPEG macroblock reconstruction
+ * Copyright (c) 2000,2001 Fabrice Bellard
+ * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * 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
+ */
+
+#define NOT_MPEG12        0
+#define MAY_BE_MPEG12     1
+#define DEFINITELY_MPEG12 2
+
+/* put block[] to dest[] */
+static inline void put_dct(MpegEncContext *s,
+                           int16_t *block, int i, uint8_t *dest, int line_size, int qscale)
+{
+    s->dct_unquantize_intra(s, block, i, qscale);
+    s->idsp.idct_put(dest, line_size, block);
+}
+
+static inline void add_dequant_dct(MpegEncContext *s,
+                           int16_t *block, int i, uint8_t *dest, int line_size, int qscale)
+{
+    if (s->block_last_index[i] >= 0) {
+        s->dct_unquantize_inter(s, block, i, qscale);
+
+        s->idsp.idct_add(dest, line_size, block);
+    }
+}
+
+/* generic function called after a macroblock has been parsed by the
+   decoder or after it has been encoded by the encoder.
+
+   Important variables used:
+   s->mb_intra : true if intra macroblock
+   s->mv_dir   : motion vector direction
+   s->mv_type  : motion vector type
+   s->mv       : motion vector
+   s->interlaced_dct : true if interlaced dct used (mpeg2)
+ */
+static av_always_inline
+void mpv_reconstruct_mb_internal(MpegEncContext *s, int16_t block[12][64],
+                                 int lowres_flag, int is_mpeg12)
+{
+#define IS_MPEG12(s) (is_mpeg12 == MAY_BE_MPEG12 ? ((s)->out_format == FMT_MPEG1) : is_mpeg12)
+    const int mb_xy = s->mb_y * s->mb_stride + s->mb_x;
+
+    s->current_picture.qscale_table[mb_xy] = s->qscale;
+
+    /* update DC predictors for P macroblocks */
+    if (!s->mb_intra) {
+        if (is_mpeg12 != DEFINITELY_MPEG12 && (s->h263_pred || s->h263_aic)) {
+            if (s->mbintra_table[mb_xy])
+                ff_clean_intra_table_entries(s);
+        } else {
+            s->last_dc[0] =
+            s->last_dc[1] =
+            s->last_dc[2] = 128 << s->intra_dc_precision;
+        }
+    } else if (is_mpeg12 != DEFINITELY_MPEG12 && (s->h263_pred || s->h263_aic))
+        s->mbintra_table[mb_xy] = 1;
+
+#if IS_ENCODER
+    if ((s->avctx->flags & AV_CODEC_FLAG_PSNR) || s->frame_skip_threshold || s->frame_skip_factor ||
+        !((s->intra_only || s->pict_type == AV_PICTURE_TYPE_B) &&
+          s->avctx->mb_decision != FF_MB_DECISION_RD))  // FIXME precalc
+#endif /* IS_ENCODER */
+    {
+        uint8_t *dest_y, *dest_cb, *dest_cr;
+        int dct_linesize, dct_offset;
+        const int linesize   = s->current_picture.f->linesize[0]; //not s->linesize as this would be wrong for field pics
+        const int uvlinesize = s->current_picture.f->linesize[1];
+        const int readable   = IS_ENCODER || lowres_flag || s->pict_type != AV_PICTURE_TYPE_B;
+        const int block_size = lowres_flag ? 8 >> s->avctx->lowres : 8;
+
+        /* avoid copy if macroblock skipped in last frame too */
+        /* skip only during decoding as we might trash the buffers during encoding a bit */
+        if (!IS_ENCODER) {
+            uint8_t *mbskip_ptr = &s->mbskip_table[mb_xy];
+
+            if (s->mb_skipped) {
+                s->mb_skipped = 0;
+                av_assert2(s->pict_type!=AV_PICTURE_TYPE_I);
+                *mbskip_ptr = 1;
+            } else if(!s->current_picture.reference) {
+                *mbskip_ptr = 1;
+            } else{
+                *mbskip_ptr = 0; /* not skipped */
+            }
+        }
+
+        dct_linesize = linesize << s->interlaced_dct;
+        dct_offset   = s->interlaced_dct ? linesize : linesize * block_size;
+
+        if (readable) {
+            dest_y  = s->dest[0];
+            dest_cb = s->dest[1];
+            dest_cr = s->dest[2];
+        } else {
+            dest_y  = s->sc.b_scratchpad;
+            dest_cb = s->sc.b_scratchpad + 16 * linesize;
+            dest_cr = s->sc.b_scratchpad + 32 * linesize;
+        }
+
+        if (!s->mb_intra) {
+            /* motion handling */
+            /* decoding or more than one mb_type (MC was already done otherwise) */
+
+#if !IS_ENCODER
+            if (HAVE_THREADS && s->avctx->active_thread_type & FF_THREAD_FRAME) {
+                if (s->mv_dir & MV_DIR_FORWARD) {
+                    ff_thread_await_progress(&s->last_picture_ptr->tf,
+                                             lowest_referenced_row(s, 0), 0);
+                }
+                if (s->mv_dir & MV_DIR_BACKWARD) {
+                    ff_thread_await_progress(&s->next_picture_ptr->tf,
+                                             lowest_referenced_row(s, 1), 0);
+                }
+            }
+
+            if (lowres_flag) {
+                const h264_chroma_mc_func *op_pix = s->h264chroma.put_h264_chroma_pixels_tab;
+
+                if (s->mv_dir & MV_DIR_FORWARD) {
+                    MPV_motion_lowres(s, dest_y, dest_cb, dest_cr, 0, s->last_picture.f->data, op_pix);
+                    op_pix = s->h264chroma.avg_h264_chroma_pixels_tab;
+                }
+                if (s->mv_dir & MV_DIR_BACKWARD) {
+                    MPV_motion_lowres(s, dest_y, dest_cb, dest_cr, 1, s->next_picture.f->data, op_pix);
+                }
+            } else {
+                op_pixels_func (*op_pix)[4];
+                qpel_mc_func (*op_qpix)[16] = s->me.qpel_put;
+
+                if ((is_mpeg12 == DEFINITELY_MPEG12 || !s->no_rounding) || s->pict_type == AV_PICTURE_TYPE_B) {
+                    op_pix = s->hdsp.put_pixels_tab;
+                } else {
+                    op_pix = s->hdsp.put_no_rnd_pixels_tab;
+                }
+                if (s->mv_dir & MV_DIR_FORWARD) {
+                    ff_mpv_motion(s, dest_y, dest_cb, dest_cr, 0, s->last_picture.f->data, op_pix, op_qpix);
+                    op_pix  = s->hdsp.avg_pixels_tab;
+                    op_qpix = s->me.qpel_avg;
+                }
+                if (s->mv_dir & MV_DIR_BACKWARD) {
+                    ff_mpv_motion(s, dest_y, dest_cb, dest_cr, 1, s->next_picture.f->data, op_pix, op_qpix);
+                }
+            }
+
+            /* skip dequant / idct if we are really late ;) */
+            if (s->avctx->skip_idct) {
+                if(  (s->avctx->skip_idct >= AVDISCARD_NONREF && s->pict_type == AV_PICTURE_TYPE_B)
+                   ||(s->avctx->skip_idct >= AVDISCARD_NONKEY && s->pict_type != AV_PICTURE_TYPE_I)
+                   || s->avctx->skip_idct >= AVDISCARD_ALL)
+                    goto skip_idct;
+            }
+
+            /* add dct residue */
+            if (!(IS_MPEG12(s) || s->msmpeg4_version ||
+                  (s->codec_id == AV_CODEC_ID_MPEG4 && !s->mpeg_quant)))
+#endif /* !IS_ENCODER */
+            {
+                add_dequant_dct(s, block[0], 0, dest_y                          , dct_linesize, s->qscale);
+                add_dequant_dct(s, block[1], 1, dest_y              + block_size, dct_linesize, s->qscale);
+                add_dequant_dct(s, block[2], 2, dest_y + dct_offset             , dct_linesize, s->qscale);
+                add_dequant_dct(s, block[3], 3, dest_y + dct_offset + block_size, dct_linesize, s->qscale);
+
+                if (!CONFIG_GRAY || !(s->avctx->flags & AV_CODEC_FLAG_GRAY)) {
+                    if (s->chroma_y_shift) {
+                        add_dequant_dct(s, block[4], 4, dest_cb, uvlinesize, s->chroma_qscale);
+                        add_dequant_dct(s, block[5], 5, dest_cr, uvlinesize, s->chroma_qscale);
+                    } else {
+                        dct_linesize >>= 1;
+                        dct_offset   >>= 1;
+                        add_dequant_dct(s, block[4], 4, dest_cb,              dct_linesize, s->chroma_qscale);
+                        add_dequant_dct(s, block[5], 5, dest_cr,              dct_linesize, s->chroma_qscale);
+                        add_dequant_dct(s, block[6], 6, dest_cb + dct_offset, dct_linesize, s->chroma_qscale);
+                        add_dequant_dct(s, block[7], 7, dest_cr + dct_offset, dct_linesize, s->chroma_qscale);
+                    }
+                }
+            }
+#if !IS_ENCODER
+              else if (is_mpeg12 == DEFINITELY_MPEG12 || (s->codec_id != AV_CODEC_ID_WMV2)) {
+                add_dct(s, block[0], 0, dest_y                          , dct_linesize);
+                add_dct(s, block[1], 1, dest_y              + block_size, dct_linesize);
+                add_dct(s, block[2], 2, dest_y + dct_offset             , dct_linesize);
+                add_dct(s, block[3], 3, dest_y + dct_offset + block_size, dct_linesize);
+
+                if (!CONFIG_GRAY || !(s->avctx->flags & AV_CODEC_FLAG_GRAY)) {
+                    if (s->chroma_y_shift) {//Chroma420
+                        add_dct(s, block[4], 4, dest_cb, uvlinesize);
+                        add_dct(s, block[5], 5, dest_cr, uvlinesize);
+                    } else {
+                        //chroma422
+                        dct_linesize = uvlinesize << s->interlaced_dct;
+                        dct_offset   = s->interlaced_dct ? uvlinesize : uvlinesize*block_size;
+
+                        add_dct(s, block[4], 4, dest_cb, dct_linesize);
+                        add_dct(s, block[5], 5, dest_cr, dct_linesize);
+                        add_dct(s, block[6], 6, dest_cb+dct_offset, dct_linesize);
+                        add_dct(s, block[7], 7, dest_cr+dct_offset, dct_linesize);
+                        if (!s->chroma_x_shift) {//Chroma444
+                            add_dct(s, block[8], 8, dest_cb+block_size, dct_linesize);
+                            add_dct(s, block[9], 9, dest_cr+block_size, dct_linesize);
+                            add_dct(s, block[10], 10, dest_cb+block_size+dct_offset, dct_linesize);
+                            add_dct(s, block[11], 11, dest_cr+block_size+dct_offset, dct_linesize);
+                        }
+                    }
+                } //fi gray
+            } else if (CONFIG_WMV2_DECODER) {
+                ff_wmv2_add_mb(s, block, dest_y, dest_cb, dest_cr);
+            }
+#endif /* !IS_ENCODER */
+        } else {
+#if !IS_ENCODER
+            /* Only MPEG-4 Simple Studio Profile is supported in > 8-bit mode.
+               TODO: Integrate 10-bit properly into mpegvideo.c so that ER works properly */
+            if (is_mpeg12 != DEFINITELY_MPEG12 && CONFIG_MPEG4_DECODER &&
+                /* s->codec_id == AV_CODEC_ID_MPEG4 && */
+                s->avctx->bits_per_raw_sample > 8) {
+                ff_mpeg4_decode_studio(s, dest_y, dest_cb, dest_cr, block_size,
+                                       uvlinesize, dct_linesize, dct_offset);
+            } else if (!IS_MPEG12(s))
+#endif /* !IS_ENCODER */
+            {
+                /* dct only in intra block */
+                put_dct(s, block[0], 0, dest_y                          , dct_linesize, s->qscale);
+                put_dct(s, block[1], 1, dest_y              + block_size, dct_linesize, s->qscale);
+                put_dct(s, block[2], 2, dest_y + dct_offset             , dct_linesize, s->qscale);
+                put_dct(s, block[3], 3, dest_y + dct_offset + block_size, dct_linesize, s->qscale);
+
+                if (!CONFIG_GRAY || !(s->avctx->flags & AV_CODEC_FLAG_GRAY)) {
+                    if (s->chroma_y_shift) {
+                        put_dct(s, block[4], 4, dest_cb, uvlinesize, s->chroma_qscale);
+                        put_dct(s, block[5], 5, dest_cr, uvlinesize, s->chroma_qscale);
+                    } else {
+                        dct_offset >>=1;
+                        dct_linesize >>=1;
+                        put_dct(s, block[4], 4, dest_cb,              dct_linesize, s->chroma_qscale);
+                        put_dct(s, block[5], 5, dest_cr,              dct_linesize, s->chroma_qscale);
+                        put_dct(s, block[6], 6, dest_cb + dct_offset, dct_linesize, s->chroma_qscale);
+                        put_dct(s, block[7], 7, dest_cr + dct_offset, dct_linesize, s->chroma_qscale);
+                    }
+                }
+            }
+#if !IS_ENCODER
+              else {
+                s->idsp.idct_put(dest_y,                           dct_linesize, block[0]);
+                s->idsp.idct_put(dest_y              + block_size, dct_linesize, block[1]);
+                s->idsp.idct_put(dest_y + dct_offset,              dct_linesize, block[2]);
+                s->idsp.idct_put(dest_y + dct_offset + block_size, dct_linesize, block[3]);
+
+                if (!CONFIG_GRAY || !(s->avctx->flags & AV_CODEC_FLAG_GRAY)) {
+                    if (s->chroma_y_shift) {
+                        s->idsp.idct_put(dest_cb, uvlinesize, block[4]);
+                        s->idsp.idct_put(dest_cr, uvlinesize, block[5]);
+                    } else {
+                        dct_linesize = uvlinesize << s->interlaced_dct;
+                        dct_offset   = s->interlaced_dct ? uvlinesize : uvlinesize*block_size;
+
+                        s->idsp.idct_put(dest_cb,              dct_linesize, block[4]);
+                        s->idsp.idct_put(dest_cr,              dct_linesize, block[5]);
+                        s->idsp.idct_put(dest_cb + dct_offset, dct_linesize, block[6]);
+                        s->idsp.idct_put(dest_cr + dct_offset, dct_linesize, block[7]);
+                        if (!s->chroma_x_shift) { //Chroma444
+                            s->idsp.idct_put(dest_cb + block_size,              dct_linesize, block[8]);
+                            s->idsp.idct_put(dest_cr + block_size,              dct_linesize, block[9]);
+                            s->idsp.idct_put(dest_cb + block_size + dct_offset, dct_linesize, block[10]);
+                            s->idsp.idct_put(dest_cr + block_size + dct_offset, dct_linesize, block[11]);
+                        }
+                    }
+                } //gray
+            }
+        }
+skip_idct:
+        if (!readable) {
+            s->hdsp.put_pixels_tab[0][0](s->dest[0], dest_y, linesize, 16);
+            if (!CONFIG_GRAY || !(s->avctx->flags & AV_CODEC_FLAG_GRAY)) {
+                s->hdsp.put_pixels_tab[s->chroma_x_shift][0](s->dest[1], dest_cb, uvlinesize, 16 >> s->chroma_y_shift);
+                s->hdsp.put_pixels_tab[s->chroma_x_shift][0](s->dest[2], dest_cr, uvlinesize, 16 >> s->chroma_y_shift);
+            }
+#endif /* !IS_ENCODER */
+        }
+    }
+}
+