[mythtv-users] finding right alsa device for eeebox PC (ION2) and HDMI

[Brian J. Murrell]

On 13-02-11 05:05 PM, Jean-Yves Avenard wrote:
> 
> can you plug the eeepc directly to the receiver and test that DD/DTS work ?

I can't.  The receiver doesn't have HDMI, just optical and coaxial
digital inputs.  The eeepc only has HDMI out.

> If you are using a recent version of alsa (>= 1.0.25)

Check.

> and mythtv 0.26;

Ahhh.  Not so check.  Unfortunately, I can't upgrade this system to 0.26
yet due to being held back by Mythbuntu's lack of 0.26 support on Ubuntu
11.04/Natty.  I have a FE machine that refuses to run stably on anything
newer than the 2.6.38 natty kernel.  And I can't simply upgrade the
userspace to (say) 12.04/Precise and hold the kernel back due to
incompatibilities between the Xorg ABI in 12.04 and the newest Nvidia
binary drivers that will run on the 2.6.38 kernel.  It's a #$%^!$% mess.

> then the audio settings page will tell you which device to use. You
> simply need to go through the list, and it will show you if it detects
> a device and what it supports.

I did notice something similar to that on 0.25.  On the bottom-ish left
there is a description such as:

HDA NVidia, HDMI 0
HDMI Audio Output (No connection detected)
Device supports up to 7.1 (guessing: LPCM, AC3, DTS)

I guess you are saying 0.26 provides even better information?

> My guess is that you're running a more recent version of ALSA on that
> eeePC,

1.0.25+dfsg-0ubuntu1.  On the machine that does work in this
configuration alsa is 1.0.24+dfsg-0ubuntu1.

> one that check the EDID sent by the TV. The TV is reporting as
> not supporting DD/DTS and as such, myth doesn't attempt to send
> DD/DTS.

So, saying the EDID is lying.  Certainly not unbelievable.  I wonder if
alsa has a knob one can turn to disable believing the TV.

> Sometimes when that's the case, the order into which you start the
> appliances is important: amp , followed by TV, then start the PC

Interesting.  For the PC, do you mean a full, cold start or just
starting Myth would be sufficient?

> Start mythfrontend with -v audio,playback
> then go into the audio settings. exit (don't do anything, just enter / leave)
> 
> then go and play something.
> 
> Post the entire output of the log here.

Perhaps not necessary.  I can send if you like in any case, however,
going through the procedure you outline above, (turn on amp, then TV,
then PC) I was able to get DD/DTS output on the amp.

Interestingly the connection information changed slightly also:

HDA NVidia, HDMI 0
HDMI Audio Output (LG TV connected to HDMI)
Device supports up to 2.0 (LPCM)

Despite the "2.0" I am able to get 5.1 on the amp in DD/DTS.

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