@john_carter No, it's is when I enable the VMS video driver and then the audio fails to work under HDMI. I haven't seen any other reports of this.
It's a common issue, since the HDMI audio is handled by the KMS driver automatically. It's been widely reported - in fact when the KMS driver for Pi4 was announced, it was one of the changes included (see this forum post). Here in the foruns - see this topic.
There is some configuration that can be done by modifying the ALSA configuration file ($HOME/.asoundrc), but looks complicated and there's no 'one-size-fits-all' solution (depends on the devices present on the system).
You could try installing PulseAudio and configure the module-combine for simultaneous output.
@mitu Thank you for your ongoing support to the community, much appreciated. I just learned that you do not support 3rd party images, which I fully understand. And honestly I have not created this setup on my own, as my knowledge is very limited. However, when I try a fresh install, everything works as you described.
Those solutions are not good enough for my project.
I simply want to read two buttons, if Button 1 is pressed, the PI should switch the Display Rotation to 0, if Button 2 is pressed, it should be 180degree.
Not SplitScreen, just rotating.
There must be a simple Solution with Python i think.
All have the same problem on soundbar systems (and likely also on surround receivers).
I just don't get why these particular games generate hdmi sound that gets wrecked by so many setups, one would think there was a way to fix this at the source - the generation of sound on the pi/other device.
Just my 0.02 here, the world of modern TVs and home theater/surround sound devices is needlessly complicated for these simple old tasks we are trying to recreate here with simple digital signals (ironically that are emulations of old analog signals).
What I would try to see if it helps:
Many TVs have a "game mode" that is intended to reduce or eliminate "signal processing" to enable a more pure, delay free signal and timings. Many surround sound receivers have something similar, although it is usually called Pure Audio or Direct Sound mode. You might see if your receiver has this option and try it to see if it eliminates audio hitches.
For what it's worth, I have an Onkyo receiver at home and even with modern consoles I have noticed that something in the HDMI convergence where all video inputs are routed to a single HDMI output to the TV will cause a 'gap' in sounds sometimes. (After a dead silence of any kind, the first sound made is either dropped entirely or gets cut so I only hear part of it before normal audio resumes. Sort of like the audio stream has to buffer up before it becomes stable again.)
EDIT: Hit the submit button too soon and wasn't done typing.
Thank you Mitu, but for me, a power-user at best, thats going to be like looking for the proverbial needle. Before I spend hours trying to troubleshoot this Ill just save my roms and do a fresh install.
#uncomment if you get no picture on HDMI for a default "safe" mode
#uncomment this if your display has a black border of unused pixels visible
#and your display can output without overscan
#uncomment the following to adjust overscan. Use positive numbers if console
#goes off screen, and negative if there is too much border
#uncomment to force a console size. By default it will be display's size minus
#uncomment if hdmi display is not detected and composite is being output
#uncomment to force a specific HDMI mode (this will force VGA)
#uncomment to increase signal to HDMI, if you have interference, blanking, or
#uncomment for composite PAL
#uncomment to overclock the arm. 700 MHz is the default.
#Uncomment some or all of these to enable the optional hardware interfaces
#Uncomment this to enable infrared communication.
#Additional overlays and parameters are documented /boot/overlays/README