[mythtv-users] how to tell if 5.1 audio channels mapped correctly?
Dan Christensen
jdc at uwo.ca
Fri Nov 5 18:57:18 UTC 2010
Dan Christensen <jdc at uwo.ca> writes:
> Jean-Yves Avenard <jyavenard at gmail.com> writes:
>
>> A great deal of time was spent getting the channel ordering right in
>> mythtv.
>
> That's good. I've only found a few test files that also had video, but
> they all worked right for me in myth except for one, and I think that
> one was made incorrectly.
Well, there's good news and bad news. The good news is that I now see
the pattern. Whenever I get digital passthrough to work with a piece
of software (myth AC3/DTS, mplayer DTS and xine DTS), the playback is
correct. But whenever I don't use digital passthrough, the playback
is wrong, including with mythtv! For example, with
http://www.avenard.org/files/media/videotest/audiotest/idch_AviaSurroundTest-DTS.mkv
played back in myth without digital passthrough, the center and left
surround channels are swapped, and it sounds like the LFE and right
surround channels are swapped too (but I don't have a subwoofer, so
it's harder to tell).
So now it looks like I have a systematic problem with channel mappings.
Could it be because the version of alsa I'm running is older than yours?
I'm running Debian lenny with these alsa versions
alsa-base 1.0.23+dfsg-2 ALSA driver configuration files
alsa-source 1.0.23+dfsg-2 ALSA driver sources
alsa-utils 1.0.23-3 Utilities for configuring and using ALSA
alsaplayer-alsa 0.99.80-3 PCM player designed for ALSA (ALSA output module)
alsaplayer-common 0.99.80-3 PCM player designed for ALSA (common files)
and kernel 2.6.32-5-686. Maybe next week I'll try upgrading to
testing/squeeze to see if that fixes anything, but that's a major
upgrade that I'm hesitant to do if it's not necessary...
What happens for you with that clip without digital passthrough? What
does "speaker-test -twav -c6" do?
Thanks for all of the help!
Dan
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