[mythtv-users] Raspberry Pi - Audio Passthrough

[ted.thom at yahoo.com]

Hi all!

I have been playing around with the latest MythTV version for a week or so and I am enjoying the Raspberry Pi support :-) Thank you to all the people that were/are involved in bringing this support to the MythTV project, I am a big fan of yours! :-D

I have mainly been playing with Peter's MythTV Light package and with the package compiled on my own Pi via the packaging scripts (fixes/0.28).

The video quality is awesome and pretty much flawless and I am able to get good sound and video with both packages (video playback is slightly better with Peter's package) using:
Audio: "ALSA:hw:CARD=ALSA,DEV=1" (direct hardware device without any conversions) and with Dolby Digital and DTS UNchecked.
Video: OpenMAX Normal, openmax decoder, openmax video renderer, Advance deinterlacer, etc. (and MPEG2 license activated, although it works pretty much flawlessly without it)

Where I am hitting a bit of a challenge is when it comes to audio passthrough. I don't seem to be able to get it to work properly (with both MythTV Light from Peter and fixes/0.28 compiled with the packaging scripts).
I am able to have the audio passed through by choosing the audio Output device "OpenMAX:hdmi" (checking Dolby Digital and DTS), but the result is hiccups during playback. I am not sure what is the right word in English to describe what it does: the frame rate drops every second (the frame rate is not smooth anymore, it goes up and down) [would that be called stuttering?] and sometimes the sound drops for half a second.
If I choose another device like "ALSA:hw:CARD=ALSA,DEV=1" and checks Dolby Digital and DTS, I just get static.

I am wondering if I am the only one to get this behavior (I already read the "static sound" problem is happening for others) and if somebody have been able to work around it or if somebody is able to have passthrough via some other way? I am especially wondering what is the reason why using the OpenMAX:hdmi audio output device is causing the video playback issue.

Thank you for your help!

Teddy