[mythtv-users] Calling for testers...

Jean-Yves Avenard jyavenard at gmail.com
Wed May 12 16:13:09 UTC 2010

Hi there..

You may or may not be aware of some of the new features planned for 0.24

One of them is a new audio architecture...

I'll pass on the details on what exactly changed from a technical
point of view, instead only focusing on what's new from a user point
of view..

Obviously new:
-High-Def audio support (that is > 16 bits), including in mythmusic
-7.1 speak configuration
-multichannel LPCM support (for 5.1 and 7.1)
-Multichannel audio properly plays on stereo system (Dolby PLII compatible)
-7.1 and 5.1 HD audio can be streamed as 5.1 AC3 when your amplifier
doesn't support it (real-time transcoding)
-Full PulseAudio support

Several fixes:
-Improved AVSync
-Hopefully no more buffer (or far less) buffer underrun errors
-dozens more

For multi-channels analog users, you'll need to go in the Setup ->
General -> Audio, and check the "PCM support".

For people using HDMI digital and with a receiver supporting
multichannel LPCM, same as above, check "PCM support".
5.1 and 7.1 Audio will be transmitted as LPCM instead of being
re-encoded to AC3.

This is unfortunately required as there's no way to tell if an audio
output is digital or analog, nor can we detect the capabilities of
your audio receiver.

Note for PulseAudio users: we haven't been able to fully identified
where exactly the problem is, but there are times you get static.
It seems linked to some bugs in the pulseaudio default resampler. You
can configure which resampler pulseaudio will use, if you experience
static, try with a different resampler.
Other option is to change the default sampling rate pulse is using
from 44.1kHz to 48kHz.
(check /etc/pulse/daemon.conf default-sample-rate = 48000)

How to get it:
svn co http://svn.mythtv.org/svn/branches/mythtv-hdaudio

This branch closely follows trunk...

Report bugs in trac, make sure you select the "Mythtv - Audio Output" componet.

Thanks in advance

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