[FFmpeg-cvslog] avcodec/mpeg12dec: ignore picture start code in extradata for AVID mpeg2 files

[Marton Balint]

ffmpeg | branch: master | Marton Balint <cus at passwd.hu> | Sun Jun 25 20:38:32 2023 +0200| [4e27b485d7924dfa4600c978863b1d84f1fc317b] | committer: Marton Balint

avcodec/mpeg12dec: ignore picture start code in extradata for AVID mpeg2 files

AVID IMX MPEG2 files in MOV seems to have extradata like this:

00000000: 0000 0018 4143 4c52 4143 4c52 3030 3031  ....ACLRACLR0001
00000010: 0000 0001 0000 0000                      ........

Signed-off-by: Marton Balint <cus at passwd.hu>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4e27b485d7924dfa4600c978863b1d84f1fc317b
---

 libavcodec/mpeg12dec.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c
index 27c862ffb2..27b45c6fc4 100644
--- a/libavcodec/mpeg12dec.c
+++ b/libavcodec/mpeg12dec.c
@@ -2522,6 +2522,11 @@ static int decode_chunks(AVCodecContext *avctx, AVFrame *picture,
             }
             picture_start_code_seen = 1;
 
+            if (buf == avctx->extradata && avctx->codec_tag == AV_RL32("AVmp")) {
+                av_log(avctx, AV_LOG_WARNING, "ignoring picture start code in AVmp extradata\n");
+                break;
+            }
+
             if (s2->width <= 0 || s2->height <= 0) {
                 av_log(avctx, AV_LOG_ERROR, "Invalid frame dimensions %dx%d.\n",
                        s2->width, s2->height);