Fri Jul 29, 2022 9:38 am
While it is true that HDMI can carry compressed digital audio (typically in one of the Dolby formats, AC3, Dolby Digital/DTS, etc.), I somewhat doubt that is related to the problem you are seeing as I don't think the ATEM switchers have any support for Dolby audio decoding or encoding. So you likely wouldn't get any audio at all in that case.
It's more common for cameras to send uncompressed (PCM) audio over their HDMI outputs and this is also what the ATEM works with (in the case of the ATEMs it is 24-bit audio at 48 kHz). If you were sending HDMI audio in a slightly different format (say 44.1 kHz), then some kind of sample rate conversion would likely be required, which in theory could affect the audio.
But I would also double check the settings of the ATEM Audio Mixer (using the ATEM software) to make sure that you don't have any of the more advanced audio processing enabled (compressor, EQ, etc.) as this could definitely affect the resulting audio signal out of the ATEM in a significant way.
And you could also try switching to a different HDMI input to see if that makes a difference (although from your description it sounds like the HDMI audio into the ATEM may be ok).