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I just started yesterday with Blender, so this is maybe a basic question. I have already seen how to speed it a whole video using "effect strip - speed control". The problem I am trying is when I try to speed it up only a portion of a video, or when trying to speed up a whole video which has different portions. At the moment my project looks like this

At the moment my project looks like this

As you can see my video has five sequences. Each sequence uses 2 videos which I am putting side to side (one uses 50% of the screen left, the other 50% right). That's why I have those transforms, and then the alpha over, and then the text just to add some caption. I don't know if there is a better way to do this. This video runs at real-time, and it produces what I expected to get. The problem is when I try to speed it up, like by a factor of 4.

Now here is how I try to speed up the whole video:

enter image description here

I chose individually each alpha overlay and added the speed control. Then I moved on top the text, and when I click render animation, it looks fine, but I have some problems with the output video. Using the workflow from above, it produces a video where each segment has everything sped up in the first 15s, and then the following 45s are a static image of the last frame.

I also tried lowering the total frames of the video from 9000 to 2250 (that should be the frames when it is speed x4), but that basically produces a video of 15s first video speed up, then 45s static image, then 15s of the following video, and then it stops.

So my problem is that I don't really know how to speed it parts of a video, or a video as a whole which is composed by parts. When dealing with only 1 video, using speed control I know how to do it. But when working with parts, I dont.

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  • $\begingroup$ I have seen that I can select all and do a meta strip, and then use a speed control for all of it. that works. what I don't know how to do is to speed up some of the parts, but not the others. I have seen some stuff about "strech to input strip length", but I don't know how to use it $\endgroup$ – Dr Sokoban Nov 25 '16 at 15:19
  • $\begingroup$ If you want to speed it up 4 x then select the metastrip with speed effect applied (in stretch to input length) then go to the strip properties panel N-key. Find the strip length or duration and click in that value. You can then perform a math function to that value. i.e. if the length is 440 frames then type 440/4 and press enter. This will result in 110 frames length and the speed effect will shrink to fit. Although you may have to move to another frame for it to take effect. $\endgroup$ – 3pointedit Nov 30 '16 at 22:54
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The video gets sped up as you see but it does not affect the length of the strip. I do not know a way to automate the process but you need to shrink the length of each strip that you are speeding up. In your case, you are speeding it up by a factor of 4 so you need to make each strip 1/4 of the original length.

Then you need to move all the strips together so there is no space between them.

I did a search on Youtube using this - blender vse video speed up

and found this video: https://www.youtube.com/watch?v=NrX1sK_ZQqs

I hope that helps.

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