avcodec/mpeg4videodec: Workaround interlaced mpeg4 edge MC bug

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/avcodec.h

@@ -2878,6 +2878,7 @@ typedef struct AVCodecContext {
 #define FF_BUG_DC_CLIP          4096
 #define FF_BUG_MS               8192 ///< Work around various bugs in Microsoft's broken decoders.
 #define FF_BUG_TRUNCATED       16384
+#define FF_BUG_IEDGE           32768
 
     /**
      * strictly follow the standard (MPEG-4, ...).

libavcodec/mpeg4videodec.c

@@ -2195,6 +2195,13 @@ int ff_mpeg4_workaround_bugs(AVCodecContext *avctx)
         if (ctx->lavc_build <= 4712U)
             s->workaround_bugs |= FF_BUG_DC_CLIP;
 
+        if ((ctx->lavc_build&0xFF) >= 100) {
+            if (ctx->lavc_build > 3621476 && ctx->lavc_build < 3752552 &&
+               (ctx->lavc_build < 3752037 || ctx->lavc_build > 3752191) // 3.2.1+
+            )
+                s->workaround_bugs |= FF_BUG_IEDGE;
+        }
+
         if (ctx->divx_version >= 0)
             s->workaround_bugs |= FF_BUG_DIRECT_BLOCKSIZE;
         if (ctx->divx_version == 501 && ctx->divx_build == 20020416)

libavcodec/mpegvideo.c

@@ -2117,6 +2117,8 @@ static av_always_inline void mpeg_motion_lowres(MpegEncContext *s,
         if (!CONFIG_GRAY || !(s->avctx->flags & AV_CODEC_FLAG_GRAY)) {
             uint8_t *ubuf = s->sc.edge_emu_buffer + 18 * s->linesize;
             uint8_t *vbuf =ubuf + 10 * s->uvlinesize;
+            if (s->workaround_bugs & FF_BUG_IEDGE)
+                vbuf -= s->uvlinesize;
             s->vdsp.emulated_edge_mc(ubuf,  ptr_cb,
                                      uvlinesize >> field_based, uvlinesize >> field_based,
                                      9, 9 + field_based,

libavcodec/mpegvideo_motion.c

@@ -327,6 +327,8 @@ void mpeg_motion_internal(MpegEncContext *s,
         if (!CONFIG_GRAY || !(s->avctx->flags & AV_CODEC_FLAG_GRAY)) {
             uint8_t *ubuf = s->sc.edge_emu_buffer + 18 * s->linesize;
             uint8_t *vbuf = ubuf + 10 * s->uvlinesize;
+            if (s->workaround_bugs & FF_BUG_IEDGE)
+                vbuf -= s->uvlinesize;
             uvsrc_y = (unsigned)uvsrc_y << field_based;
             s->vdsp.emulated_edge_mc(ubuf, ptr_cb,
                                      s->uvlinesize, s->uvlinesize,
@@ -550,6 +552,8 @@ static inline void qpel_motion(MpegEncContext *s,
         if (!CONFIG_GRAY || !(s->avctx->flags & AV_CODEC_FLAG_GRAY)) {
             uint8_t *ubuf = s->sc.edge_emu_buffer + 18 * s->linesize;
             uint8_t *vbuf = ubuf + 10 * s->uvlinesize;
+            if (s->workaround_bugs & FF_BUG_IEDGE)
+                vbuf -= s->uvlinesize;
             s->vdsp.emulated_edge_mc(ubuf, ptr_cb,
                                      s->uvlinesize, s->uvlinesize,
                                      9, 9 + field_based,

libavcodec/options_table.h

@@ -163,6 +163,7 @@ static const AVOption avcodec_options[] = {
 {"dc_clip", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = FF_BUG_DC_CLIP }, INT_MIN, INT_MAX, V|D, "bug"},
 {"ms", "work around various bugs in Microsoft's broken decoders", 0, AV_OPT_TYPE_CONST, {.i64 = FF_BUG_MS }, INT_MIN, INT_MAX, V|D, "bug"},
 {"trunc", "truncated frames", 0, AV_OPT_TYPE_CONST, {.i64 = FF_BUG_TRUNCATED}, INT_MIN, INT_MAX, V|D, "bug"},
+{"iedge", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = FF_BUG_IEDGE }, INT_MIN, INT_MAX, V|D, "bug"},
 {"strict", "how strictly to follow the standards", OFFSET(strict_std_compliance), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX, A|V|D|E, "strict"},
 {"very", "strictly conform to a older more strict version of the spec or reference software", 0, AV_OPT_TYPE_CONST, {.i64 = FF_COMPLIANCE_VERY_STRICT }, INT_MIN, INT_MAX, A|V|D|E, "strict"},
 {"strict", "strictly conform to all the things in the spec no matter what the consequences", 0, AV_OPT_TYPE_CONST, {.i64 = FF_COMPLIANCE_STRICT }, INT_MIN, INT_MAX, A|V|D|E, "strict"},