avcodec/mpeg4videodec: Clear interlaced_dct for studio profile

Fixes: Out of array access
Fixes: 13090/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEG4_fuzzer-5408668986638336
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Kieran Kunhya <kierank@obe.tv>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

diff --git a/libavcodec/mpeg4videodec.c b/libavcodec/mpeg4videodec.c
index f44ee76bd4194630882e6fe26630ae08618439e6..ecd028a87c7705295b6f9e61687977437430c50d 100644 (file)
--- a/libavcodec/mpeg4videodec.c
+++ b/libavcodec/mpeg4videodec.c
@@ -3057,6 +3057,7 @@ static int decode_studio_vop_header(Mpeg4DecContext *ctx, GetBitContext *gb)
         return 0;
 
     s->partitioned_frame = 0;
+    s->interlaced_dct = 0;
     s->decode_mb = mpeg4_decode_studio_mb;
 
     decode_smpte_tc(ctx, gb);