avcodec/mpeg4videodec: Fix nonsense warning

Since db772308941a2a338c7809f90d347219a6a93074 parsing of
mpeg4-extradata lead to a "Failed to parse extradata" warning, because
ff_mpeg4_decode_picture_header returns AVERROR_INVALIDDATA in case that
no VOP was found. This patch adds a parameter to signify whether a
header (where the absence of a VOP does not raise an error) or not is
parsed. The first mode is of course used for parsing headers.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@googlemail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

1 files changed, 7 insertions, 3 deletions

diff --git a/libavcodec/mpeg4videodec.c b/libavcodec/mpeg4videodec.c
index ecd028a87c..99b1e10620 100644
--- a/libavcodec/mpeg4videodec.c
+++ b/libavcodec/mpeg4videodec.c
@@ -3203,11 +3203,13 @@ static int decode_studio_vol_header(Mpeg4DecContext *ctx, GetBitContext *gb)
 
 /**
  * Decode MPEG-4 headers.
- * @return <0 if no VOP found (or a damaged one)
+ *
+ * @param  header If set the absence of a VOP is not treated as error; otherwise, it is treated as such.
+ * @return <0 if an error occured
  *         FRAME_SKIPPED if a not coded VOP is found
- *         0 if a VOP is found
+ *         0 else
  */
-int ff_mpeg4_decode_picture_header(Mpeg4DecContext *ctx, GetBitContext *gb)
+int ff_mpeg4_decode_picture_header(Mpeg4DecContext *ctx, GetBitContext *gb, int header)
 {
     MpegEncContext *s = &ctx->m;
     unsigned startcode, v;
@@ -3236,6 +3238,8 @@ int ff_mpeg4_decode_picture_header(Mpeg4DecContext *ctx, GetBitContext *gb)
                 (ctx->divx_version >= 0 || ctx->xvid_build >= 0) || s->codec_tag == AV_RL32("QMP4")) {
                 av_log(s->avctx, AV_LOG_VERBOSE, "frame skip %d\n", gb->size_in_bits);
                 return FRAME_SKIPPED;  // divx bug
+            } else if (header && get_bits_count(gb) == gb->size_in_bits) {
+                return 0; // ordinary return value for parsing of extradata
             } else
                 return AVERROR_INVALIDDATA;  // end of stream
         }