[mythtv-users] trandcoding messes up 6 channel audio slow audio playback

Jean-Yves Avenard jyavenard at gmail.com
Fri Dec 31 09:34:42 UTC 2010


Hi

On 31 December 2010 18:03, Gavin Hurlbut <gjhurlbu at gmail.com> wrote:
> I can confirm that this is the case in all my testing.  Any time
> mythtranscode (particularly when using the --fifo mode) is sourced 5.1
> AC3 audio, it spits out 6 channels of 48kHz 16-bit PCM.  In nuvexport,
> I use sox to downmix that to stereo, but if we can get the mythtv
> internal downmixer working in that case, that would be so much nicer.

So you're saying that it does work ? (properly write 6 channels audio) ?

>
> What we could have is:  if you are using --fifodir, always downmix to
> stereo PCM for output *unless* the user says --fifo-passthru or
> something, in which case, you just pass the audio stream out the fifo
> unmolested?  This would be nice for archiving with the AC3 (or AAC in
> some cases) in place.

There are many ways we can write 5.1 audio.

Can do passthrough (of any format), or even if the original audio was
16bits PCM re-encode it either as AAC or AC3

Isn't there an option in the transcode setup on what audio you want in the end?

sorry if I don't know, I haven't tried transcoding in years..
JY


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