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

[Diego Biurrun]

On Sat, Nov 18, 2006 at 01:45:28AM +0000, M?ns Rullg?rd wrote:
> Diego Biurrun <diego at biurrun.de> writes:
> 
> > On Sat, Nov 18, 2006 at 01:01:43AM +0000, M?ns Rullg?rd wrote:
> >> Diego Biurrun <diego at biurrun.de> writes:
> >> 
> >> > On Fri, Nov 17, 2006 at 04:34:45PM -0800, Mike Melanson wrote:
> >> >> Diego Biurrun wrote:
> >> >> >Attached patch is necessary to make xan_dpcm work in MPlayer with the
> >> >> >libavformat AVI demuxer.  Since it just adds another line to an already
> >> >> >present hack I hope it's acceptable...
> >> >> 
> >> >> Seems reasonable. I guess the API changed enough that this is necessary?
> >> >
> >> > Without this the audio gets misdetected as PCM since the codec_tag is 1
> >> > in the AVI header.
> >> 
> >> I wonder how they plan on storing xan dpcm in nut...
> >
> > FourCC Axan?  Where is the problem?
> 
> You said yourself that xan dpcm audio is stored in avi with a codec
> tag of 0x0001, and audio codecs don't have a fourcc at all.  The xan
> video uses a fourcc of Xxan, so what is this Axan you're talking
> about?

Mike describes the gory technical details in the Wiki:

http://wiki.multimedia.cx/index.php?title=Xan_DPCM

In short: xan_dpcm uses codec tag 0x0001, but has the FourCC Axan
somewhere else in the AVI header.

Diego