[Libav-user] avcodec_open2 is changing the channels and channel_layout... why?

Carl Eugen Hoyos cehoyos at ag.or.at
Fri Oct 12 00:49:26 CEST 2012

Michael Bradshaw <mbradshaw at ...> writes:

> > While I cannot really answer the question, I wonder
> > what you expect when the number of channels really change:
> > At least for AC-3 and AAC, this is not only allowed,
> > but happens regularly (for example on DVB).
> Really? That's useful to know. I suppose I should rely on
> AVFrame.channels, correct?
> While that's useful to know, I don't think it this 
> AAC stream changes channels.

I did not want to imply that what happens cannot be a bug, 
I just wanted to make sure you know that channel count 
(and channel layout) may change.

Did you verify if the problem is not that container and 
stream have different opinions about the number of channels?

(What does QuickTime say about the number of channels?)

Carl Eugen

More information about the Libav-user mailing list