[FFmpeg-devel] [PATCH] avformat/tta: only check for header and seek table crc if requested

[Michael Niedermayer]

On Wed, Feb 04, 2015 at 02:01:16AM -0300, James Almer wrote:
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
> I made it abort only if AV_EF_EXPLODE is also set like we do when decoding 
> audio frames, but maybe aborting if the header or seek table are damaged 
> should be the default behaviour. Chances are a file with a broken header is 
> unplayable after all.
> 
> Thoughts?
> 
>  libavformat/tta.c | 28 ++++++++++++++++++----------
>  1 file changed, 18 insertions(+), 10 deletions(-)
> 
> diff --git a/libavformat/tta.c b/libavformat/tta.c
> index 5789e5b..45dfee9 100644
> --- a/libavformat/tta.c
> +++ b/libavformat/tta.c
> @@ -64,7 +64,8 @@ static int tta_read_header(AVFormatContext *s)
>      start_offset = avio_tell(s->pb);
>      if (start_offset < 0)
>          return start_offset;
> -    ffio_init_checksum(s->pb, tta_check_crc, UINT32_MAX);
> +    if (s->error_recognition & AV_EF_CRCCHECK)
> +        ffio_init_checksum(s->pb, tta_check_crc, UINT32_MAX);
>      if (avio_rl32(s->pb) != AV_RL32("TTA1"))
>          return AVERROR_INVALIDDATA;
>  
> @@ -83,10 +84,13 @@ static int tta_read_header(AVFormatContext *s)
>          return AVERROR_INVALIDDATA;
>      }
>  
> -    crc = ffio_get_checksum(s->pb) ^ UINT32_MAX;
> -    if (crc != avio_rl32(s->pb)) {
> -        av_log(s, AV_LOG_ERROR, "Header CRC error\n");
> -        return AVERROR_INVALIDDATA;
> +    if (s->error_recognition & AV_EF_CRCCHECK) {
> +        crc = ffio_get_checksum(s->pb) ^ UINT32_MAX;
> +        if (crc != avio_rl32(s->pb)) {
> +            av_log(s, AV_LOG_ERROR, "Header CRC error\n");
> +            if (s->error_recognition & AV_EF_EXPLODE)
> +                return AVERROR_INVALIDDATA;
> +        }
>      }

this code would skip avio_rl32() and affect the filepos after it
same for the later hunk

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

it is not once nor twice but times without number that the same ideas make
their appearance in the world. -- Aristotle
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