[MPlayer-users] Re: H264/AAC in MKV: Wrong channel mapping [Was: Quicktime sound atom v2: Wrong audio channel mapping]

Frank Aurich fa859178 at inf.tu-dresden.de
Sun May 28 15:12:31 CEST 2006


Corey Hickey wrote:
> Frank Aurich wrote:
>>> Yes, you are right. When I dug deeper, I found that the channel mapping 
>>> was coming from the AAC decoder rather than from the MOV demuxer.
>>>
>>> The problem isn't really a problem like a bug; it is evidence of a lack 
>>> of foresight on the part of whoever designed the audio formats. There 
>>> are many, many different types of multichannel audio and no standard for 
>>> how to order the channels. Consequently, AAC is different from AC3 and 
>>> other formats are probably different still.
>>>
>>> Since MPlayer's channel ordering is designed around AC3, it doesn't 
>>> handle AAC correctly. I wrote a proof of concept patch quite a while ago:
>>>
>>> http://mplayerhq.hu/pipermail/mplayer-dev-eng/2006-February/040764.html
>>>
>>> Please test it. I'll try to find some time later to re-do the patch 
>>> properly and commit something. Don't hold your breath, though; I'm very 
>>> busy these days.
>>>
>>> -Corey
>> Thanks Corey,
>>
>> with the mentioned patch (the link seems to be wrong but I found it 
>> anyway) it works fine with the matroska files.
> 
> The mailing lists got moved to the new server and old URLs got mixed up.
> http://www.mplayerhq.hu/pipermail/mplayer-dev-eng/2006-February/040805.html
> 
>> I discovered though that for Quicktime files the patch for demux_mov.c 
>> has to be applied as well, otherwise the mapping is incorrect.
> 
> Which patch? I don't remember such a patch, though it's possible I wrote
> it and forgot about it or somebody else wrote it and I forgot about it.
> 
> -Corey

Nevermind, I had confused something. I was referring to a patch you 
wrote in december 2005 so MPlayer could pars QT files using atom v2. 
This one has been committed to the repository already, so everything's fine.

Thanks again,

Frank




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