I have some exr sequences in the VSE, but they won't playback at 25fps. Some parts play fine (random), but then it feels like it is caching again at 6fps or something. No matter how often the loop is running it always gets these hickups.

The 'cache memory limit' is set to 16000, but that doesn't help. Is there a way to see if/how much of the cache memory is used, or is there anything else I can do about it?



While you're playing your sequence, you should see a little fps counter in one corner of the preview. If it's red and below your frame rate you set beforehand, than your computer can't handle the preview rendering in real time. This can be related to memory, but (at least from my experience) it more likely depend on your CPU.

What you can do to improve the playback, is setting up proxy files. They're typically smaller so playback is easier.

  • $\begingroup$ Well, but what is the point of caching then? I can playback 1920x1080 jpegs just fine, but the same sequence as exr fails. Isn't caching the process of converting into displayable format (e.g remove bit-depth overhead) and store into memory? Basically it shouldn't make a difference if I want to playback jpeg or exr (except the caching takes longer on exr). Or do I get it wrong? $\endgroup$ – knekke Mar 20 '15 at 13:47
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    $\begingroup$ @knekke OpenEXR files are much larger than jpegs, with a higher bit depth (16bit but can be 32bit), usually uncompressed, and oftentimes with several layers. It's a format designed to keep the highest picture quality, not the fastest datarate. It's very unlikely you'd be able to edit OpenEXR files in realtime without a very powerful computer with lots of RAM and an RAID. On the other hand Blender's VSE is a nice tool but don't expect the performance of a dedicated video editing application. $\endgroup$ – user1853 Mar 20 '15 at 14:24
  • $\begingroup$ Also it seems to me, that the preview and rendering from the VSE are not really good in terms of performance. At least not yet. If I bake a proxy file, it uses most of my CPU cores at a high load, while the final rendering barely scratches 20% load. Blender has a nice video editor but is a 3D tool after all. :) $\endgroup$ – Felix Mar 20 '15 at 14:30
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    $\begingroup$ @cegaton: That's exactly why I want the cache to work! I am fully aware that exrs take longer to load and process, but once it is cached it doesn't matter anymore. A cached exr ist exactly the same as a cached jpeg, or at least it should be. I am looking for the 'timeline gets green' effect that you find in After-Effects, Nuke, Djv-View,...... $\endgroup$ – knekke Mar 20 '15 at 14:33
  • $\begingroup$ @knekke blender's VSE is not there yet. $\endgroup$ – user1853 Mar 20 '15 at 14:57

While in video editor mode: For people who do not see video playback -

I found under the lower bar, "Timeline Playback" Click on Playback and check-mark "Clip Editors". My video would not play until this was done.

Yes, insure your cache is high too.


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