What I know about blender's V.S.E. is that it can cache a certain amount of frames before dropping frames(Related). But, on my Ipod I have video editors like Imovie, and Cute Cut and there is never a delay with the videos, even with different FPS. (maybe because Cute Cut and Imovie have a MCFI?) So what method do they use, or does Blender just use an out-dated version of Caching? Also my Ipod has much smaller RAM so it wouldn't be able to Cache much. Then when I'm finally done making a video why do have to I render it? With other Video editors, like lightworks or Filmora or Imovie or CuteCut or WindowsMovie maker or pretty much everything else, I export it. So is Blender's VSE outdated- or the opposite, it's so good that normal pc's can't handle it? Which begs the question, why not have a dumbed down version for normal pcs?

Wow, ok that's a lot a questions, sorry, but to narrow it down to one(two) question(s):
How does Blenders VSE work, what makes it so slow?

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    $\begingroup$ Look at this video youtube.com/… , there are the answers for your question . $\endgroup$
    – Greg
    Commented Aug 7, 2016 at 22:15
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    $\begingroup$ Comparing blender to dedicated video editors is like a comparing apples and oranges. Blender is primarily a 3D app. With a video editor added on to it. $\endgroup$
    – user1853
    Commented Aug 7, 2016 at 22:53
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    $\begingroup$ @cegaton I see your point, but Blender is an apple, orange, kiwi, and banana smashed into one big fruit blob and I want to compare the orange part to a normal orange because obviously there are some comparable differences because they are still both video editors $\endgroup$ Commented Aug 7, 2016 at 23:00
  • $\begingroup$ How well do Cute Cut or Windows Movie maker or imovie deal with textures, meshes and armatures? $\endgroup$
    – user1853
    Commented Aug 7, 2016 at 23:28
  • $\begingroup$ @cegaton I can't honestly say they handle them well. $\endgroup$ Commented Aug 7, 2016 at 23:33

2 Answers 2


Short answer:

  1. There is no “rendered” cache.
  2. Not all codecs are equal.

As to the first point, every single operation, including shifting resolutions from your source file to destination, alpha overs, etc. are all done in real-time. This means that if you stack twenty strips with Alpha Over, every one is calculated on the fly.

As to the second point, codecs are designed with different design goals. Some are to compress the data size, some are for streams, some are for other nuanced things. These codecs can put more or less demand on a system depending how they were designed.

Typically, you shouldn't be doing manipulations and effects work in an NLE anyways, so it isn't much of an issue; use an NLE to get your beats, but use other tools for your grading or effects work in a non-realtime environment.

To maximize the VSE's ability to perform, you might want to try a few things:

  • Keep your rendering output dimensions precisely the same as the dimensions of your input file. Some DSLRs for example shoot 1920x1088, and using 1920x1080 will result in a costly scale every frame.
  • Use temporary simple effects strips to block in your complex work. Worry about keeping the frame rate high instead of how it looks. You can do the heavy work later in a compositor.
  • Don't bother grading or adding more processing. Again, save that for when you are finished so you can grade it more precisely in a proper tool, at proper deeper bit depths.
  • Keep dissolves and overs to an absolute minimum. The VSE can keep up if you avoid stacking many together.
  • Use a codec designed for quick seeking and decoding. A non Group Of Pictures (GOP) codec that stores all I frames is ideal.

As someone who decided to try and take a piece to broadcast with Blender, I can tell you that it can be used effectively, albeit with some effort and planning.

Hope that helps you along...


To add to the answer above...

The Sequencer only uses 1 CPU core

Blender's Sequencer doesn't use all the available power on your computer. The video engine roughly uses one CPU core, and that's it.

Note: I'm talking about video, image strips... scene strips are different as you directly render a 3d scene using the engine of your choice.

Blender's Sequencer was developed decades ago, and it seems its renderer wasn't re-written since then. Other professional video editing program will likely uses all CPU cores together with the GPU to provide faster preview and renders.

It's not as bad as it seems

In my experience, rendering performances are mostly an issue for real-time preview. Regardless of the codec, Blender will likely struggle with HD and certainly with 4k video. But you can edit comfortably with proxies: smaller resolution videos that use the right codec. See Mikeycal's proxy tutorial on Youtube for more info.

Rendering will often take a while. But as Blender keeps your other CPU cores free, you can keep working while it exports your video in the background. I edited over 200 videos with Blender so far, mostly tutorials, and actually appreciate that it doesn't lock your computer up. Also that it doesn't crash!

  • $\begingroup$ In the tutorial, he clicks on "Blender rebuild proxy and timecode indices using the job system". He doesn't say what it does but this may be it. I'd suggest using other software, such as Filmora as it's doesn't require a proxy. $\endgroup$
    – Rudy
    Commented Apr 5, 2019 at 8:36

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