No preview image in video sequence editor

Support Basics & Interface
21

hmm…I’ve been getting this problem too, though it seems to be inconsistent. sometimes it works with a certain video format, then I try the same video again --> White Screen of Frustration :wink: it’s also been giving me problems in the Background Image department…though that was probably because I was using either WMV or MP4 :o

anyway, it very probably has to do with 2 things - a bug in the Video Editor and/or my crappy GFX card (integrated Intel Express Chipset on a Toshiba Satellite)

22

I just saw this commit:

Commit by jhk :: r32638 /trunk/blender/ (4 files in 4 dirs): (link)
Temporary fix for sequencer bugs #22925, #21429, #21783, #24165

  • This fix is really only a bandage, as the underlying issue is that sequencer preview render doesn’t yet use the job system.
  • The sequencer preview can start a full render of the scene, and this can collide with other preview/actual renders in many cases.
  • Drawing the sequencer preview is now disabled when an other render is in progress, but the sequence preview rendering could have already been started before the other render, so this doesn’t really fix anything.
  • For now only OpenGL rendering can be used for the sequencer preview reliably until it’s reimplemented using the job system.
  • Using the job system in the future can handle the clashes between different renders properly and will give users a nice progress bar to indicate something is happening while the preview is recalculated.

Did this fix this issue?

23

It’s nice to see this glitch is getting some attention from others.
Thanks

24

I finally found the still open bug report for this bug and the revision above didn’t close it. It’s 22081

https://projects.blender.org/tracker/index.php?func=detail&aid=22081&group_id=9&atid=498

25

Did this commit fix it?

Commit by schlaile :: r33223 /trunk/blender/ (8 files in 6 dirs): (link)
== Sequencer ==

  • documented and rewrote the render interface of the sequencer. (now, the geometry / render_type / etc. settings are stored within a seperate structure called SeqRenderData that is passed within the code.)
  • that fixes * cache problems, since the caching system didn’t keep track of proxy files vs. final renders. * is a necessary step, to bring back frame blending in speed effect (the SeqRenderData structure elements are already there) * will make motion blur render options available within the sequencer!
  • this patch also fixes: * “easy retiming” using speed effects. (in Blender 2.49, you could add a speed effect and resize the source track to retime it to that length) * adds labels for the Original dimensions for Image + Movie tracks (worked in 2.49, too)
    Also this note was put in the bug tracker:

Date: 2010-11-16 18:47Sender: Janne KarhuPlease check if changing the render resolution to a power oftwo (for example 512x512) “fixes” the problem. If sothen this is a know issue, and can be closed as a duplicate of#24656.

Unfortunately I do not have a machine that has this bug anymore, but am trying to hound it for my brother who teaches a class on blender and all of the machines in his lab do it. If any of you could check it for me I’d appreciate it. Otherwise I’ll have my brother check these out in the coming week.

26

new post:

Date: 2010-11-29 06:50Sender: loop duplicateI tried again today to reproduce this bug and to try the testsCampbell and Janne suggested.On Ubuntu 10.10 64bit everything works nicely.On Windows XP 32bit the bug is still there.I can’t render the 3d viewport with OpenGL because of the “failedto create OpenGL offscreen buffer” error.The problem is “fixed” by setting the render resolutionto 512x512.

27

Yeah You Are Right. I have the same problem on Windows.
On Windows “failedto create OpenGL offscreen buffer” error
But it works on Ubuntu.Weird?

For the Video Sequence Editor issue, none works Blender 2.54

28

So Ton closed the issue without resolution and put it on the todo:

· : 2010-12-07 19:43
· Sender: Ton Roosendaal
· The 2.4x method was just doing a full render, which caused you to wait for the entire render cycle to finish. That’s not very useful either.
The best thing I can think of is to add a warning in Blender when off-screen buffers fail… but that can also be annoying. Maybe draw a stamp-text in the buffer? That would give more info. :slight_smile:

The issue has been added to our todo for later investigation.
http://wiki.blender.org/index.php/Dev:2.5/Source/Development/Todo/Editors#Video_Sequencer
Thanks for all the feedback!

29

I’m just a user so I can’t comment on many of the specifics. Nice to see the problem is at least still on a “to do list”. I think.
When you say Ton closed the issue, is this a “swept under the rug” thing?
I’m using r33594 and still have the same issue.
Thanks

30

Just curious if this was still active. I’ve got the 2.56 release and still get nothing but a white preview in the video editor.
Is this a question for Ton?
Thanks

31

I have been working around the issue by setting the render output to 512x512 while using the sequencer. Time to get some new video cards I guess.

32

Hey guys have you also noticed a problem playing back audio? That is with a strip that was working, when you copy and paste elsewhere on the timeline the strip stops playing audio.

33

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34

I’m getting the same problem. Video preview showing only a white screen. I’ll try the 512x512 fix.

35

I’ve tried some of the suggestions but still just a white preview up to the recent builds. It’s seems it’s a problem that most likely won’t be resolved. Must be the new python stuff and older video cards because 2.49 works fine. Too bad, but I guess it’s the sacrifice for some of the cool new features. I still hope for a patch someday though…

36

TRock what card or video chipset is giving problems? I haven’t seen this issue for a while now (on new builds) but I was thinking of blowing the dust off my old XP laptop and trying to trip it up there.

37

I’m using a generic old computer with generic Intel graphic chips.
But setting the output to 512x512 is a kludge that works for me.
I get a postage stamp preview which I can enlarge with the mouse wheel,
so thanks to the person who found that fix.

38

I just tried that trick (512x512) on a Win XP machine that only showed white. It works well. It stuffs up all the aspect ratio however :frowning: but its a good workaround if you can’t get anything else.

It would be great to save it as a display preset too. Can you define your own dimensions, like DV or HD etc?

39

Hey TRock,

Do you really think this issue will not be resolved, ever? cause that would be sad …

regards

Hewi

40

Thanks for the great tip. The 512 x 512 trick worked for my old XP 32 bit machine. It’s also possible, I found, to use 512 for the X render value and to use a lessor value for the Y to set up the proper aspect ratio. Ex: 512 x 288 == 16:9 ratio. I hope this bug gets fixed soon, but for this ancient machine, it’s good enough for a preview. :slight_smile: