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I tried reversing the video and then increasing the speed, but it did not help. Instead the clip went missing. Can anyone tell me what I should do?

Also the rendering process takes a lot of time if I start rendering it assuming "the clip is just not visible but its present in the project".

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  • If you need to find the clip again - assuming it's on disk (and not in a DB) - then do on the command line find / -name "$name_of_the_file_of_your_clip_with_extension" – Tomáš Pospíšek Dec 12 '17 at 7:40
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I’ve just run into this and it seems like a bug. When you apply the speed effect the ‘reversed’ clip shrinks to a tiny size on the timeline and you can only delete effects and the clip from the timeline (if you can find it).

You can easily reverse clips, but I think the reversal is actually just another saved job, so what you can do with that ‘reversed’ clip is severely limited. E.g. the clip I’m dealing with is 195 MB, but the .mlt reversed version shows as 3.4 KB.

The solution is to render an actual reversed version of the clip.

Kdenlive

Either….

  • save your project with a new name and clear the timeline (easy way to keep same project settings)
  • add a new track and disable all the others (tedious!)
  • create a new project with the same settings, add the source clip & ‘reverse’ it

…then…

  • drag your ‘reversed’ clip to a (new) track
  • render it

ffmpeg

ffmpeg -i source-clip -vf reverse -af reverse reversed-clip

or, to only reverse the video…

ffmpeg -i source-clip -vf reverse reversed-clip

Note that this may not practical for large clips as I’ve read elsewhere that the entire file is buffered, so it is very memory-dependant.

Although this was a lot quicker, for me it also seemed to reduce the quality of the reversed clip, which was unexpected.

Source: 9,880 kb/s, AVC (Baseline@L3.1)(1 Ref Frames) 195.4 MB
Reversed: 371 kb/s, AVC (High@L3)(CABAC / 4 Ref Frames) 8.2 MB

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