[FFmpeg-devel] [PATCH]Improce auto-detection for cdata files

Reimar Döffinger Reimar.Doeffinger
Wed Dec 30 21:12:15 CET 2009


On Wed, Dec 30, 2009 at 08:54:15PM +0100, Carl Eugen Hoyos wrote:
> Hi!
> 
> Attached patch improves cdata auto-detection (and "fixes" issue 1634 by 
> not trying to decode the sample any more).
> Details from 
> http://wiki.multimedia.cx/index.php?title=EA_Command_And_Conquer_3_Audio_Codec
> 
> The new detection passes probetest, and I would like to raise the score to 
> 26, is that ok?
> 
> Please comment, Carl Eugen

> Index: libavformat/eacdata.c
> ===================================================================
> --- libavformat/eacdata.c	(revision 20959)
> +++ libavformat/eacdata.c	(working copy)
> @@ -39,7 +39,8 @@
>  {
>      const uint8_t *b = p->buf;
>  
> -    if (b[0] == 0x04 && (b[1] == 0x00 || b[1] == 0x04 || b[1] == 0x0C))
> +    if (b[0] == 0x04 && (b[1] == 0x00 || b[1] == 0x04 || b[1] == 0x0C) &&
> +        ((uint32_t *)b)[1] == ((uint32_t *)b)[3] && ((uint32_t *)b)[1])
>          return AVPROBE_SCORE_MAX/8;

You should check for a valid sample_rate (since that is essential for
decoding), and the new checks for "total samples" should only be used to
raise the score above AVPROBE_SCORE_MAX/4 (since those are non-essential
they should not be "required" by the probe if possible).
Also since speed does not matter, I think
AV_RB32(b + 4) == AV_RB32(b + 12)
etc. is more readable than the casts.



More information about the ffmpeg-devel mailing list