Question Surround Sound Issues after clean install of Windows 10 ?

[rajthampi]

Hello, greetings from Kuwait!
I've been using a 10 + years old box with Windows 10 and Nvidia GTX 700 Series display card for last many years and recently was forced to do a clean installation of the OS. Here is how my setup is

Sony 65" Android TV.
AVR (Onkyo 5.1-Channel Home Theater System (HT-S3800)
HDMI connection from the graphics card to Sony TV HDMI port 2
HDMI port 3 ARC to AVR

After the clean installation of the OS, I noticed the following. AC-3 and Dolby Digital 5.1 streams are working perfectly when the media is played from the computer. However, AAC, AAC LC and FLAC encoded videos only have stereo output. I've bought Dolby Access from Microsoft store years back and the trailers that are played from the Access program play all the channels when the same demos downloaded from Dolby atmos trailers page (AAC 6 channel) are played as stereo. As it looked more like codec related issues, I download K-Lite standard codec package and setup LAV, enabling HDMI passthrough, did the same with VLC player. Yet, these sample files and couple of videos that have AAC, AAC LC or FLAC multichannel are stubborn and output is only stereo.
Prior the clean install, these whole played perfectly and I am failing to remember what I did years back to get it working. I need help to understand what could have gone wrong and to correct them.
Thanks in advance!

 

[Lutfij]

I've been using a 10 + years old box with Windows 10 and Nvidia GTX 700 Series display card for last many years and recently was forced to do a clean installation of the OS.
Did you recreate your bootable USB installer prior to installing the OS? Speaking of installing, did you install said OS in offline mode, to later manually install all the latest drivers inclusive of your audio drivers in an elevated command, i.e, Right click installer>Run as Administrator?

If the connection from your GPU to the AVR to the TV hasn't changed since you set it up a decade+ ago, then it's your drivers. Using Sound Manager, see what your default audio device is and what it's properties are set to.

On your TV, is your audio set to ARC?

 

[rajthampi]

Thank you ) It feels nice to be hear after long time. I've done an offline installation of the OS and the default audio device is Sony TV (as earlier). I've always kept all the drivers up to date, especially for the graphics card. I nearly never made a bootable USB installer & didn't expect this "issue" which is bugging me for few audio formats. As I mentioned with my initial post, the surround issue is specific to AAC and FLAC.

For the audio, I have tried setting up the speaker both sterio and 5.1 channel and all the players did route the audio to 5.1 channel as long as the audio encoded were AC-3 and Dolby digital regardless the speaker channel selection. To my surprise, even Windows Movies & TV routes the audio to 5.1 channels while the speaker settings are kept as stereo. I running out of guesses now.

 

[dwd999]

I had some problems where my system would get out of sync. I found I could solve it by cycling the computer and sound equipment through a Mute - Unmute cycle once or twice.

 

[rajthampi]

@dwd999 did it multiple times and even reset the AVR. As it worked earlier, it looks more like either a codec issue or Nvidia HD audio driver issue. Thanks for our suggestion )