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Maniphest T78247

VSE Preview window performance degrading
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Description

System Information
Operating system: Linux-4.9.0-12-amd64-x86_64-with-debian-9.12 64 Bits
Graphics card: Gallium 0.4 on AMD KAVERI (DRM 2.49.0 / 4.9.0-12-amd64, LLVM 3.9.1) X.Org 4.3 (Core Profile) Mesa 13.0.6

Blender Version
Broken: version: 2.83.0, branch: master, commit date: 2020-06-03 14:38, hash: rB211b6c29f771
Worked: Blender 2.79

Short description of error
In VSE Preview window playback fps rate goes down when zoom out in the sequencer so strips would be visible in full length. Preview fps goes back up when zooming in the sequencer so only small part of a strip is visible.

Exact steps for others to reproduce the error

  1. Add two 1920x1080 2-hour video files to the sequencer.
  2. Zoom out in the sequencer window to the maximum so both movie strips would be visible.
  3. Play the video and watch fps in the preview window being 2-4 times smaller than the original. The level of performance degrading correlates with the sequencer window's zooming level.
  4. Zoom in the sequencer so only small part of the strip is visible and watch fps going back to normal.

Event Timeline

Alex (mklex) created this task.Jun 25 2020, 10:38 AM
Alex (mklex) added a project: Video Sequencer.Jun 25 2020, 10:55 AM
Alex (mklex) updated the task description. (Show Details)
Alex (mklex) updated the task description. (Show Details)Jun 25 2020, 11:08 AM
Richard Antalik (ISS) changed the task status from Needs Triage to Needs Information from User.Jun 25 2020, 11:17 AM
Richard Antalik (ISS) added a subscriber: Richard Antalik (ISS).

I have trouble reproducing reliably, but I have seen some issues. One thing I know of is grid drawing, which is quite slow at this zoom levels. But it's not 5 times slower playback slow.

Does this happen with 2hr long color strip? Can you share .blend file, so I can test with exactly same settings, just to be sure?

Alex (mklex) added a comment.Jun 25 2020, 12:08 PM

Does this happen with 2hr long color strip? Can you share .blend file, so I can test with exactly same settings, just to be sure?

Yep, 2hr long color strip produces the same bug. Attached the .blend file{F8643316}

Richard Antalik (ISS) added a comment.Jun 25 2020, 12:32 PM

I will have to check if grid drawing is disabled at some point, make changes possibly, commit and check with you it that helped. I can happily play at 120FPS at that zoom level, but that can be up to difference our machines.

Could you upload screenshot of VSE layout just to confirm if grid is visible? You can also try to disable Timeline > View > Show Cache > Show Cache but this shouldn't have great effect now.
Also checking that 2.90 is somehow almost 2x faster than 2.83 with same file...

Alex (mklex) added a comment.Jun 25 2020, 2:26 PM

Could you upload screenshot of VSE layout just to confirm if grid is visible? You can also try to disable Timeline > View > Show Cache > Show Cache but this shouldn't have great effect now.
Also checking that 2.90 is somehow almost 2x faster than 2.83 with same file...

Disabling "Show Cache" didn't bring any improvement. Attached the screenshot.

You can see 6 fps while the file's original is 25.
Okay, I just tried 2.90.0 alpha and the bug is not there. The fps is normal. The only fps drop I noticed was while actually zooming in/out in the sequencer. Maybe that's the remnant of the problem? But uninterrupted playback seems to be fine.
I thought maybe it is just some of my settings in 2.83 messing Blender and reset to "factory". That didn't help. Also I tried and found the bug in 2.80. So apparently the bug had been there from 2.80 to 2.83 and was somehow fixed in 2.90. Also tested 2.79 - no bug at all, even while zooming in/out, everything is very fast.
I hope 2.90 is stable enough to use with VSE. I definitely can't use 2.83. That fps drop is too annoying.
If you need me to do some additional tests or provide more info, please let me know. VSE is one of my favorite features in Blender and I plan to use it extensively.
Thank you for your help!

Richard Antalik (ISS) closed this task as Archived.Jun 25 2020, 3:11 PM
Richard Antalik (ISS) claimed this task.

It should be OK to use latest builds with VSE, there are mostly bugfixes getting committed.

I will close this report even though I am not sure what commit specifically fixed the issue. If you find any regression, please report again.