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Trimming/clipping, rotating, and extracting videos with FFmpeg
Sunday, December 25, 2011
FFmpeg is an amazing tool, but I find myself searching Google and StackOverflow to do what seem like extremely basic things...
Extract a video clip of length x starting at y seconds
For example, to produce a 5-second video from the 10s mark to the 15s mark of the input video:
$ ffmpeg -i input.avi -ss 10 -t 5 output.avi
Often you can do the above operation (and some others) without re-encoding. This results in output of the highest quality and also is very fast, but doesn't always work:
$ ffmpeg -i input.avi -ss 10 -t 5 -acodec copy -vcodec copy output.avi
Rotate video 90 degrees
There are some pages out there that say to use -vf rotate=90 or -vfilter rotate=90, but that just gives me an error. Here's how:
$ ffmpeg -i input.avi -vf transpose=1 output.avi
The options are:
- 0: rotate 90 degrees counterclockwise + vertical flip
- 1: rotate 90 degrees clockwise
- 2: rotate 90 degrees counterclockwise
- 3: rotate 90 degrees clockwise + vertical flip
Rotate video 180 degrees
It doesn't look like transpose has an option to rotate 180 degrees, so chain together vflip and hflip:
$ ffmpeg -i input.avi -vf 'vflip [a]; [a] hflip' output.avi
Extract video frames
This creates files named output1.png, output2.png, ...
$ ffmpeg -i input.avi -f image2 -an output%d.png
Converting video to animated GIF
I used this for an iPhone screencast; tweaking some of the options may be beneficial for other types of videos.
$ ffmpeg -i input.mov -vf "fps=10,scale=320:-1:flags=lanczos,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse" output.gif
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