Seemingly real-time is not real-time playback?

I keep seeing stupid playback bug. It starts playing, its 60p (h.265, .mov), no drop is detected, or at least it shows that it keeps giving me all frames real-time playback, then suddenly the audio slips an the audio is behind the image. Resolve still shows me 60p with green dot, meaning it believes it plays back in real-time. As I hit space twice to restart the playback it gets back, the audio and video is synced again. Then this starts un-sync effect happening again.

What can be the issue here? It is extremely annoying.

My config:
I use Resolve 18.6 on Windows 11
PC: i9-13900K
GTX 1080 - latest nVidia driver
32 GB DDR4 3200 Mhz RAM
4 TB WD M.2 x4 SSD - SSD Western Digital Black SN850X 4TB PCI Express 4.0 x4 M.2 2280 WDS400T2X0E
ProArt B760-CREATOR D4 - with latest BIOS update

What are your sources? Camera, smartphone, or games?

What are your sources? Camera, smartphone, or games?

X AVC S .mp4 files from camera and .mov files from Topaz.

+ lots of Render In Place h.265 .mov clips, too.

Try to set your timeline to HD. Better?
The 1080 is not that much of a strong card any more these days.

I know it's not quite the same, but here's XAVC Intra 50fps 4k running very happily on my machine with a GTX 1060 in a 4k timeline.

In the menu for the Timeline Viewer, check the option to Show All Video Frames. (I believe this is off by default.)

If it's an audio sync drift issue, checking "show all video frames" is likely to make it worse. If it's currently checked, uncheck it and see what happens.

Otherwise, reduce timeline resolution for editing purposes and see if that helps.

Checking the option will give an accurate read on that green dot. Unchecked, it can give a false read on "real time" playback.

It's a good test to find out if the system is sufficiently capable.

I think his first priority is sync playback. And the green indicator is unreliable regardless of the setting.

Jim Simon, the problem is that the indicator shows green while it becomes unsync.

That option unchecked has the goal of real time audio. The playback sync issue could well be related to the skipped video frames. Checking that option will keep it all in sync, to the point of slowing down the audio if necessary.

If you checks the option, and don't get real time (green dot) playback, we've found the culprit.

I think his first priority is sync playback. And the green indicator is unreliable regardless of the setting.

yes

That option unchecked has the goal of real time audio. The playback sync issue could well be related to the skipped video frames. Checking that option will keep it all in sync, to the point of slowing down the audio if necessary.

If you checks the option, and don't get real time (green dot) playback, we've found the culprit.

It is selected to Show all Video frames and the dot is green. Interesting that as I restart the playback it jumps back to sync again.

I was trying to find out what the problem could be.

I disabled the iGPU and hardware accelerations for nVidia and Intel for h.265 files. I removed 2 screens that were connected with HDMI and I left only the DCI connected to the PC. One of the HDMI connected display had 75hz as its default refresh rate and the other had 60hz.

I think there is a problem with playback when there are monitors connected with HDMI too with different refresh rates.

I will try to re-enable the iGPU to see if the problem comes back but I believe there was an issue firstly because of the 2 older HDMI connected screens and with the one with a 75hz refresh rate.

[Peter Chamberlain]

Can u make all 3 the same rate?

I enabled back the iGPU and it's okay.

Resolve doesn't like HDMI displays with different refresh rates with a DCI display.

Can u make all 3 the same rate?

No, two supports 60hz and the oldest screen doesn't.

I tried to connect the one with HDMI with 60hz with the main 4K DCI 60hz but I saw the same playback issue. I think the HDMI itself is the problem.

Here is a screenshot about what the oldest supports. It is connected with a VGA to HDMI adaptor. It's good to see more from the user interface sometimes.

I will be using mostly the DCI 4K screen only from now.

[SOLVED]

I use the DCI 4K 60hz screen only.

I decided to turn back the h.265 hardware acceleration to see if there is any difference, here are my results: The playback smooth in both cases but with the hardware acceleration off it's better, a little bit less latency as I can notice.


With Hardware acceleration ON only the nVidia was active, like 30 to 42% - iGPU was 0%
With Hardware acceleration OFF the nVidia is still active, around 12% usage, and the i9 has 10% usage.

I will stick with the With Hardware acceleration OFF with the HDMI screens disconnected.