Originally Posted by DaverJ
I'm pretty sure this is a Microsoft thing. My Windows 10 PC also seems to arbitrarily switch audio output from Dolby Atmos for Home Theater to 7.1 for no reason.
This is good news! Last time, I hated Dolby Atmos for Home Theatre as it will always stick to Dolby Atmos even if I am playing other non-Dolby let alone, Atmos content.
This time, the Dolby Atmos for Home Theatre has gotten smarter.
Whenever I am at my Desktop or I am playing any AAC based videos like Youtube videos, my AVR shows that it is receiving PCM which is great. Other than that, video content is the same as when I set Windows 10 to 7.1 PCM on Sound Settings. It can still pass through any bitstream including Dolby Atmos and DTS-X for 4K Movie playback. So no differences there between using PCM 7.1 output and DAfHT.
The difference however is that
1a) PCM allows me to send as high a bitrate as I want which I set in Advanced Settings to my AVR in this case, a Marantz. I set it to 24-bit 48,000Hz (Studio Quality) under advanced.
1b) In Dolby Atmos for Home Theatre, this option is not available. It seems to be sending 16-bit 48,000Hz if it follows the same pattern as how DAfHT does on Windows 10 last time as well. You can hear the difference though it is subtle and depending on how good your speakers are that they can pick up the difference in Audio quality going from 16-bit to 24-bit. I wouldn't want to downgrade my audio quality just because I am playing my usual content and not gaming.
2a) In PCM 7.1, Modern Warfare 2019 game doesn't send Dolby Atmos to the AVR. Just sends in 7.1 PCM. (Remember to set Audio to Studio Reference in the game)
2B) In Dolby Atmos for Home Theatre, Modern Warfare 2019 will send Dolby Atmos to the AVR.
3a) When PCM 7.1 is set in Sound Settings in Windows 10, not only can you increase the bitrate to what your AVR is capable of, but you won't suffer from the dreaded silence at the start of any video or music as a result of the AVR trying to handshake with the PC to determine what audio it is playing and then playing with the right codec. So there will be no Audio cutouts at the beginning of every content that you play.
3b) In Dolby Atmos for Home Theatre though, even with PCM 7.1, you will notice that any video/music that you play, the audio at the beginning will be cutout while the AVR is handshaking on which codec to run even though you are using PCM all the way from desktop to the video and this happens every time you play the next video or when you stop (instead of pause) and play the video again.
The differences in 1 and 3 is what made me kind of dislike using Dolby Atmos for Home Theatre still as a result of the audio cut outs when playing any sort of content even if they do not have any bitstreams. So I will stick to PCM 7.1 as I won't get those issues and the 4K contents can still send the Dolby and DTS Bitstreams including Atmos and DTS:X so I will save using Dolby Atmos for Home Theatre exclusively for gaming as that is the only time the games it won't automatically switch to bitstream while sound output is in PCM 7.1.