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Convert directory of videos to MP4 in parallel

 $ for INPUT in *.avi ; do echo "${INPUT%.avi}" ; done | xargs -i -P9  HandBrakeCLI -i "{}".avi -o "{}".mp4

— by shavenwarthog on Aug. 13, 2013, 5:10 a.m.

Explanation

This oneliner uses the wonderful Handbrake program to convert videos. We convert a directory of AVIs at a time, in parallel.

The first three bits ("for INPUT...done |") lists the AVI files in the current directory, then uses a Bash function to strip off the suffix. It then sends each video file name to the next part.

The next part of the command (| xargs ...) runs our converter in parallel. The "-i" flag says take each input (video file name) and stick it in the "{}" parts of the xargs command. The parallel option lets us run up to 9 commands at the same time ("-P9").

The last part (HandBrakeCLI -i "{}".avi -o "{}".mp4) converts a single video to MP4 format. The two open-close curly braces are replaced with xargs, once per input video file. The first run through will be "HandBrakeCLI -i "input1".avi -o "input1".mp4", next will be "HandBrakeCLI -i "input2".avi -o "input2".mp4", etc.

Enjoy!

Another version of this writeup is on my blog: http://johntellsall.blogspot.com/2013/08/converting-video-for-media-player.html

Limitations

Converting videos in parallel is confusing as Handbrake overwrites the status for every file -- ignore the screen.

install Handbrake from http://handbrake.fr/

It also has a pretty GUI for those who don't like the terminal :)