Maniphest T48439

Video Editing: Preview window shows the wrong frame
Closed, Archived
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Assigned To
Bastien Montagne (mont29)
Authored By
forceengine
May 15 2016, 5:15 PM
Tags
  • BF Blender
Subscribers
Bastien Montagne (mont29)
Campbell Barton (campbellbarton)
forceengine

Description

System Information
OS: Win 7, 64 bit

Blender Version
Broken: 2.77a Hash: abf6f08

Short description of error
I'm using blender to soft-cut (K) an existing video ( Size: 1920x1080, Container: mp4, Codec: H.264, FPS: 25, Format: Planar 4:2:0 YUV) into it's scenes.
When the curso is over a frame where you want to make a cut, because the scene changes it not the frame the change really is in. Instead it's one frame prior. The cursor shows the switch one frame too late (in both directions).
So if the scene changes in eg frame 15, the preview window will not show that until you reached frame 16. When you go back and check again, the scene will not change until frame 14. If you cut it on frame 15 then blender shows the correct change.
Sometimes this behaviour resets after a cut or if you position or the cursor with your mouse, but it does show up again.

The video is a random video downloaded from YouTube. The bug showed up with two seperate videos.

Event Timeline

forceengine created this task.May 15 2016, 5:15 PM
forceengine raised the priority of this task from to 90.
forceengine updated the task description.
forceengine added a project: BF Blender.
forceengine edited a custom field.
forceengine added a subscriber: forceengine.
Campbell Barton (campbellbarton) lowered the priority of this task from 90 to 30.May 16 2016, 1:48 PM
Campbell Barton (campbellbarton) added a subscriber: Campbell Barton (campbellbarton).

Please help us by creating a reproducible test case.

  • Does this happen with all videos?
  • Does this only happen with video strips?

Can you create a test-scene to redo the issue?

forceengine added a comment.May 20 2016, 6:53 PM
In T48439#374652, @Campbell Barton (campbellbarton) wrote:

Please help us by creating a reproducible test case.

  • Does this happen with all videos?
  • Does this only happen with video strips?

Can you create a test-scene to redo the issue?

This happens to every video I tried so far. Eg:
I downloaded the most viewed video from YouTube. Then I opened blender, switched to the Video editor and then inserted the video.
After blender changed the fps to the video fps, I changed the render size to 100% and moved the cursor with the arrow keys on my keyboard. Once I see a cut in the video I go back so that I can cut the new scene into a new stripe. When I go back to check where the cut is I have to go one frame past the the actual change so blender displays the change.

It doesn't matter if I use the arrow keys or Alt + Mousewheel.

I used blender to cut videos, no animation or other rendering things.

Bastien Montagne (mont29) changed the task status from Unknown Status to Archived.Jun 1 2016, 4:08 PM
Bastien Montagne (mont29) claimed this task.
Bastien Montagne (mont29) added a subscriber: Bastien Montagne (mont29).

Please generate/use timecodes (https://www.blender.org/manual/editors/sequencer/strips/properties/proxy_timecode.html, https://wiki.blender.org/index.php/User:Nazg-gul/ProxyAndTimecode), videos using advanced compressions like mp4 cannot be reliably edited without those.

If problems were to persist once you are using timecodes, then please report here with a minimal .blend file (and video file) demonstrating the issue.

forceengine added a comment.Jun 5 2016, 4:03 PM
In T48439#376673, @Bastien Montagne (mont29) wrote:

Please generate/use timecodes (https://www.blender.org/manual/editors/sequencer/strips/properties/proxy_timecode.html, https://wiki.blender.org/index.php/User:Nazg-gul/ProxyAndTimecode), videos using advanced compressions like mp4 cannot be reliably edited without those.

If problems were to persist once you are using timecodes, then please report here with a minimal .blend file (and video file) demonstrating the issue.

I will have a look into that and edit this entry later on...