[MPlayer-dev-eng] WMA MAX_CODED_SUPERFRAME_SIZE too small
Diego Biurrun
diego at biurrun.de
Tue Jun 28 14:26:07 CEST 2005
On Mon, Jun 27, 2005 at 03:37:49PM +0100, Mark Weaver wrote:
> I have a few WMA file examples where there are superframes >4K. (These
> files were created with WMP 10, but playback ok with WMP 9/10). I have
> placed a short sample at http://www.blushingpenguin.com/mark/test.wma
> that exhibits the glitch. I chopped the file off at 128K but there is
> enough there to show the problem.
>
> On playback these frames are simply dropped causing audio glitches.
> During testing I have seen frames of about 8,900 bytes. The resolution
> is pretty straightforward -- just increasing the
> MAX_CODED_SUPERFRAME_SIZE fixes it. I picked 16K, but there's no real
> rationale behind that.
>
> The code is in libavcodec/wmadec.c, patch is simply:
>
> --- wmadec_org.c 2005-06-27 15:34:31.114852300 +0100
> +++ wmadec.c 2005-06-27 15:05:31.149199000 +0100
> @@ -47,7 +47,7 @@
> #define NB_LSP_COEFS 10
>
> /* XXX: is it a suitable value ? */
> -#define MAX_CODED_SUPERFRAME_SIZE 4096
> +#define MAX_CODED_SUPERFRAME_SIZE 16384
>
> #define MAX_CHANNELS 2
This does indeed fix playback of the above mentioned sample. The proper
place to discuss this is ffmpeg-devel, not mplayer-dev-eng since
wmadec.c is a file from the FFmpeg project, not from MPlayer.
It seems trivial enough, though, I have CCed ffmpeg-devel and uploaded
the sample to
http://mplayerhq.hu/MPlayer/samples/A-codecs/WMA/large_superframe.wma
Diego
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