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How to save only every 2nd or 3rd or 50th frame when exporting a very large video ?


Wim
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Hello, I have a very large video (27 GB) with a high resolution (4096x3286) from a microscopic experiment with slowly moving events, so the number of recorded frames is way higher than the speed of the event that we want to observe.

I would like to import the .AVI file in Videopad Video Editor, lower the resolution and at the same time save only every 2nd, 3rd or even 50th frame, and then save it again.

I browsed through the forum and found many topics on setting a constant frame rate, or cutting and trimming clips, but not about only saving every x-th frame in an easy way. Maybe I searched for the wrong keywords (skip frames, drop frames, etc.), but I could not find it.

For example, in VirtualDub software, you can just set a counter to decimate by 2, 3 or more frames, but VirtualDub cannot deal with the very high resolution of the images (4096x3286) and the file size (more than 27 GB).

So I would like to read in the .AVI file, reduce the resolution 4-5 times and at the same time, save only every 50th frame, and then export the video again (and potentially change the frame rate again, to see the event happening much faster).

Are there any suggestions how to do this efficiently ?

Best regards, Wim

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Hi

It is possible and I repied to a similar question some years ago.:)

It went something like this if I remember correctly... You will have to do some maths....

As an example...  

Suppose your project was 10 minutes long and was exported at 30 fps. This means a total of 30 x 60 x 10  =  18000 frames.  If you export this as an Image Sequence you will end up with 18000 images in your selected folder...i.e. Every frame.

If you want to export every second frame (9000 images) then you need to 1/2 the duration of the project (speed it up to double speed) and then export it as an image sequence.

Every 5th frame means making the duration 1/5 of the original (speeding it up to 5x the speed) and so on. (Every 50 frames means increasing the speed by 50x)  

So, depending on your requirements Increase the speed of the project  200% ; or 500% or 5000% etc. and then export the Image Sequence. (If VP won't accept very high values in one go, do 2 speed changes.) I would create a specific folder for the jpgs.

Once exported you can now reconstitute the project by loading all the images back in order. They will now play at the Still Image Duration set in Options/Media .e.g. 1 second...each image will display giving a stop motion effect. This is not the same a speeding the project to make the action quicker.

Nat

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