[Ffmpeg-devel] [PATCH] xan_dpcm in MPlayer + libavformat

[Måns Rullgård]

Diego Biurrun <diego at biurrun.de> writes:

> On Sat, Nov 18, 2006 at 03:20:24AM +0100, Michael Niedermayer wrote:
>> 
>> On Fri, Nov 17, 2006 at 05:17:58PM -0800, Mike Melanson wrote:
>> > Diego Biurrun wrote:
>> > >IIUC MPlayer falls back on codec_id if codec_tag is not set.  The
>> > >problem is that these AVI files mark the xan_dpcm audio as 0x1 (or was
>> > >it FourCC Axan + TwoCC 0x1 Roberto?), which is PCM.  I don't think there
>> > >is a way to support this without hacks..
>> > 
>> > Right. The people (Origin) that developed this format never applied with 
>> > Microsoft for a specific codec ID; they didn't mean for these files to 
>> > be played in general media players. They have codec ID 0x0001 (usually 
>> > reserved for PCM). There is data elsewhere in the AVI file indicating 
>> > 'Axan'. All written up here:
>> 
>> AVCodecContext.stream_codec_tag i assume, and i would appreciate it if
>> someone would remove this dirty "if video is xan then audio is so too"
>> hack and instead add Axan to riff.c and check both stream_codec_id and
>> codec_id
>
> Dunno if I understood you correctly (probably not), but here is a patch
> that contains the hack a bit more based on your suggestion to check
> stream_codec_tag.  It's better than it was before at least.

What is the meaning of stream_codec_tag?  The official microsoft docs
are rather fuzzy on this topic.

-- 
M?ns Rullg?rd
mru at inprovide.com