Windows 10 20h2 breaks AC3 playback

After upgrading to v17.1.1 I had issues with my Sony Camcorder files, not being able to hear any audio (AC3 5.1). Initially I thought it was because of the new version. I was wrong.

I started on a different pc with a fresh install of Windows 10, 1909.
- Installed DaVinci Resolve v16.2.8: AC3 audio was playing fine.
- Upgraded DaVinci Resolve to v17.1.1: AC3 audio was playing fine!

Next I upgraded Windows 10 to 20h2.
- Still on DaVinci Resolve to v17.1.1: AC3 audio was NOT playing any more!

I hope these details are useful for the developers. I noticed a reference somewhere that DaVinci Resolve is using Windows installed codecs, so I tried also if the files would play well in Windows Media Player and they did (Windows 10 20h2). So the codecs still exist.

Update on the message above:

On my test PC (with DaVinci Resolve 17.1.1 still installed). I downgraded Windows back to 1909.
And as expected, AC3 (5.1) sound worked again.

Clearly something in the 20h2 version breaks DaVinci Resolve his ability to play AC3 (5.1) audio.

I looked back and found some files from 2005 from my old Sony SR7 5.1 audio and can confirm they do not work. They do work in EDIUS X and EDIUS 9 on the same PC though. So it has something to do with Resolve and Windows. Win 10 Pro 20H2 up to date today.

[Shrinivas Ramani]

Hi Klaas, Ron

Can you add shareable links to some clip samples we can test?

Please also add the Windows version and some info on your audio device and driver for reference.

Thanks
Shrinivas

This short video https://www.dropbox.com/s/afyvalx5f2c1q ... .m2ts?dl=0

Works in players and EDIUS but not in Resolve or Vegas. Output is IP4K to preview monitor over HDMI or system speakers . Neither work for Resolve or Vegas but all do for EDIUS or players on system.

WIN 10 Pro 20H2, OS build 19042.964, Feature pack 120.2212.2020.0

I will share a link with a couple of clips via a PM.

System + OS Details:

Code: Select all

         Operating System: Windows 10 Pro 64-bit (10.0, Build 19042) (19041.vb_release.191206-1406)
      System Manufacturer: Gigabyte Technology Co., Ltd.
             System Model: X470 AORUS ULTRA GAMING
                     BIOS: F51 (type: UEFI)
                Processor: AMD Ryzen 7 2700X Eight-Core Processor          (16 CPUs), ~3.7GHz
                   Memory: 32768MB RAM

Thanks for looking into this issue!

[Shrinivas Ramani]

Hi all

Can you try Resolve 17.2 with the latest Windows update please?

Thanks
Shrinivas

Yes it now works. Latest Windows update today and latest NVIDIA Studio driver from yesterday.

With the 17.2 update it also indicated a Speed Editor update which I also performed. That needed to be connected by USB C cable to perform and with both the Windows and Speed Editor update it was no longer connected to Resolve with Bluetooth. I had seen this before so removed pairing from Windows and re-paired and now all is well. Much faster loading of Resolve and also Speed Editor gets linked almost immediately.

Will play some more but so far update looks good.

I am very happy as well. I can confirm that also for me the 17.2 update fixed the problem.
Great support!! My compliments.