[FFmpeg-user] .avi audio question

Rick C. rickcorteza at gmail.com
Wed Jan 18 12:16:46 CET 2012

On Jan 18, 2012, at 11:00 AM, Carl Eugen Hoyos wrote:

> Rick C. <rickcorteza <at> gmail.com> writes:
>> When creating an .avi I know that using mp3 audio codec can only give 2
>> channels.
> That is correct.
> (There is MPEG surround and multichannel MPEG but both are not supported by
> FFmpeg and both are not widely supported at all.)
>> And I know if the source video has let's say 6 channels that the conversion 
>> can sometimes fail.
> Could you elaborate? I don't think downmixing to stereo fails (anymore).
>> So what is the common alternative to use instead of mp3?  I was thinking
>> either aac or ac3?
> Both are possible, aac in avi is unusual, multichannel ac-3 has the disadvantage
> that while it works with WMP (because FFmpeg conforms to Microsoft's avi
> specification), there have been rumours that some (famous) open source media
> players expects multichannel ac-3 audio to not confirm to the specification and
> playback therefore fails. (Works fine with MPlayer.)
>> I thought aac actually but I had a problem getting the sound
>> to play back with VLC even using -vtag DX50, so I thought I'd ask.
> The "v"tag part of this sentence makes no sense at all with respect to audio.
> Carl Eugen

Thanks Carl for the reply.  I don't have a current example of downmixing failing, it was more a comment based on the past.  If it doesn't happen anymore that's great!  If aac in .avi is not common then I guess I'll go with ac-3.  And with the vtag yes it's not audio related, I just meant if I create a DivX compatible .avi using -vtag DX50 what would be the best audio.  Thanks again!


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