[mythtv-users] rPi3 3.5mm audio out - HDMI
barry3martin at gmail.com
Sun Oct 22 20:41:30 UTC 2017
Peter and David:
> This amplification will likely not work with HDMI audio, or you may have
> to change some settings to get it to work.
> In my experience, HDMI audio is digital and volume controls either in
> mythtv or in Linux have no effect on volume. If you are seeing [ and ]
> having an effect you may have something set up wrongly.
> Some suggestions -
> - Run alsamixer before starting mythtv and make sure your volume is set
> to maximum on all devices shown.
Verified at 100%/maximum
> - use raspi-config to force HDMI audio
Found the utility; didn't see anything to configure audio. In
Preferences there is an Audio Device Settings option (a few above the
Raspberry Pi Configuration option) and it has a Sound Card selection, of
which the only option is "bcm2835 ALSA (Alsa mixer) (Default)" All
options turned on and set to 100%.
(Please note not trying to be a 'smart-rump': I've got Ubuntu computers
here which one will have an option and another will not and they were
configured from the same ISO.)
> - try the digital audio with ALSA instructions, see
This reference was very helpful!
> I can't test it right now to give the exact instructions, but
> somewhere in the MythTV audio setup, there is an option for software
> volume control. When that is enabled and the output audio is digital,
> MythTV will decode the audio, adjust the volume in software and then
> re-encode the audio before sending it out. Now, this requires some
> level of CPU power to do this, but I believe most current CPUs,
> including the RPi, should be able to do it.
What I found out is both you you were right, depending on the
configuration in Setup > Audio. If (page 1) Audio Output Device is set
for "ALSA:sysdefault:CARD=ALSA" and (page 2) "Use internal volume
controls" is ticked and 'Mixer device' is set to 'ALSA:default" then the
[ and ] keys will control the volume, which is handy as the monitor does
not have a volume control.
If I set to (page 1) to 'ALSA:pluhw:CARD=ALSA,DEV=0' or 'DEV=1' then I
loose the keyboard control.
Also experimented with the OpenMAX options; didn't seem to make any
difference and the webpage indicated ALSA was better on the RPi
experimented more with the ALSA.
So I guess unless we can figure how to increase above 100% (and no
distortion!) I'll leave things as-is.
Thanks for the assistance!
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the mythtv-users