[FFmpeg-devel] [PATCH v4] avformat/mp3dec: Fixes misdetection of zYLx.wav

[Michael Niedermayer]

On Fri, Nov 08, 2019 at 12:16:22AM +0800, lance.lmwang at gmail.com wrote:
> From: Limin Wang <lance.lmwang at gmail.com>
> 
> Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> ---
> By Hendrik comments, I have proposal a more general fix for 
> more common case. 
> Now It's only tested with fate and all samples in:
> http://samples.ffmpeg.org/A-codecs/MP3-pro
> http://samples.ffmpeg.org/A-codecs/MP3
> 
>  libavformat/mp3dec.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/libavformat/mp3dec.c b/libavformat/mp3dec.c
> index 258f191..551aa56 100644
> --- a/libavformat/mp3dec.c
> +++ b/libavformat/mp3dec.c
> @@ -73,7 +73,8 @@ static int mp3_read_probe(const AVProbeData *p)
>      int frames, ret;
>      int framesizes, max_framesizes;
>      uint32_t header;
> -    const uint8_t *buf, *buf0, *buf2, *end;
> +    uint32_t next_sync;
> +    const uint8_t *buf, *buf0, *buf2, *buf3, *end;
>  
>      buf0 = p->buf;
>      end = p->buf + p->buf_size - sizeof(uint32_t);
> @@ -93,6 +94,16 @@ static int mp3_read_probe(const AVProbeData *p)
>              ret = avpriv_mpegaudio_decode_header(&h, header);
>              if (ret != 0)
>                  break;
> +
> +            buf3 = buf2 + 4;
> +            while (buf3 < end) {
> +                next_sync = AV_RB32(buf3);
> +                if ((next_sync & MP3_MASK) == (header & MP3_MASK))
> +                    break;
> +                buf3++;
> +            }
> +            if (buf3 - buf2 != h.frame_size)
> +                break;

iam not sure if a single occurance of the header should trigger rejection
of the frame, the failing sample has hundreads
ill post a modified version of this in a moment which is a bit simpler
and counts these cases

Thanks

[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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