[mythtv-users] No audio after upgrading video card

Barry Martin barry3martin at gmail.com
Fri Dec 10 17:01:27 UTC 2021

Hi DryHeat122!

> I had to replace my AV receiver because the old one crapped out. It would
> not take the VGA signal coming from my Myth Box, so I had to replace its
> video card with one that has HDMI out. I did so and it is working fine.
> When I test the speakers in settings, they work.  However when I try to
> play something in Myth there is no audio.
> When I go to frontend settings, it shows several ALSA output devices, a
> default, two ALSA:dmix CARD=Intel, DEV=0 or 1 (builtin audio), and four
> ALSA:dmix CARD=Nvidia, DEV=3,7,8,9.  Why are there four devices for one
> card?  What happened to 4,5,6?  Regardless, no sound when I select any of
> the Nvidia devices.
> Another odd thing is that when I select one of the Nvidia devices it says
> Nvidia HDMI0 at the bottom.  But in settings the device is listed as
> HDMI/Display port 2.
> How to fix?

I have one Frontend (connected to a TV) where I really have to shove the 
HDMI cable into the port.  It seems like the connection is made because 
the TV displays video but has no audio until that little extra shove.

As for the four devices for one card, only one will work. Easiest/surest 
way I've found is the next couple of paragraphs:

At Terminal "aplay -l"  (the letter, not the number) might give you a 
narrowed-down selection.   Also at Terminal speaker-test -c2 -twav 
-Dplughw:1,0   might be less fustrating and time-consuming than 
switching in and out of MythTV -- figure out what the system wants and 
then plug that into MythTV.   "-c2" is two channels (stereo), "-twav" 
will have a female voice chanting something like "left front, right 
front".  The -D switch is your options from aplay.

Also at Terminal "alsamixer" will pop-up a slider GUI.  Make sure none 
of the (needed) inputs are muted (MM) - you can ignore 'mic', etc.  Also 
make sure the volumes are cranked up -- 100% is fine. Reminds me: in 
Ubuntu check the speaker icon at the top right is at 100%.

One last thing, and I don't think this applies to you but I'll stick it 
in for anyone else troubleshooting and reading this thread.  By default 
the Raspberry Pi will turn off the HDMI port if nothing is detected at 
the other end.  "Oddly" this means it turns off HDMI if there's an HDMI 
switch or if the TV is off (as with a cron job to reboot nightly).  
Uncommenting two lines in /boot/config.txt fixes.


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