I'd like to rotate video (mp4) by 180 degrees, but not flip. Is it possible to do it with avconv?
5 Answers
It is possible using the transpose video filter. You cannot rotate by 180 degrees, but you can rotate by 90 degrees and chain the filter.
avconv -i video.mp4 -vf transpose=1,transpose=1 out.mkv
See transpose in the avconv manpage:
http://manpages.ubuntu.com/manpages/quantal/en/man1/avconv.1.html
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Yes, but you'll need to add some additional options to your command for it to work properly. Transpose and vflip/hflip should do the trick, but if you don't tell avconv more detail about what you want, you'll likely get very low quality output try:
avconv -i original.mp4 -vf "hflip,vflip" -codec:v libx264 -preset slow -crf 20 -codec:a copy flipped.mp4
Notice the -crf option. That sets the output quality. It goes from 0 (lossless) upwards logarithmically. You'll probably want a value between 19 and 25 in most cases. -preset sets the speed of the encoding, either "slow", "medium", or "fast". Slow should get you smaller file sizes with an obvious tradeoff. You should adjust -codec:v to match the original. If you don't set these options you'll get the defaults, which don't work well when flipping iphone video.
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I did this:
avconv -i invertedOne.mp4 -c:a copy -vf "hflip,vflip" rightOne.mp4
Full HD video, great results with non perceivable quality loss
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For avconv or ffmpeg Under 14.04 or later
There have been some changes to the libav documentation since @phoibos quality answer to this question. You can rotate a video 180 degrees avoiding flipping entirely by chaining 2 90 degree commands together (separated by a comma) I accomplished this with the command
avconv -i inputfile -vf transpose=clock,transpose=clock outputfile
for clockwise rotation.
in ffmpeg the syntax is the same.
ffmpeg -i inputfile -vf transpose=clock,transpose=clock outputfile
where inputfile is your supported input video file and outputfile is your desired output file.
For counter clockwise rotation replace clock with cclock
Sources:
https://libav.org/avconv.html#transpose
Testing on Ubuntu 14.04.5 and 16.04 LTS
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