Video related useful unix commands

Finding out what codecs are used in all your MKV files

find . -iname "*.mkv" -exec mkvinfo "{}" \; |grep -i "codec id"

Converting MKV (h264/aac) to MP4 in FreeBSD

mkvextract tracks source.mkv 1:video.264 2:audio.aac 3:subtitles.ass
mp4box -add video.264 -add audio.aac new.mp4

Converting MKV (h264/ac3) to MP4 in FreeBSD

#/bin/sh
# usage: makemp4 <mkv filename> <framerate, e.g. 23.976>
BASENAME=`echo $1|sed s/.mkv$//`
mkvextract tracks "$1" 1:video.264 2:audio.ac3 3:"$BASENAME.ass" 4:"$BASENAME-b.ass"
mplayer audio.ac3 -af channels=2 -ao pcm:fast:waveheader:file=audio.wav -channels 2 -novideo 2>&1
normalize --clipping --peak audio.wav
faac -q 133 audio.wav audio.aac
rm "$BASENAME.mp4"
mp4box "$BASENAME.mp4" -fps $2 -add video.264
rm video.264 audio.wav audio.ac3
mp4box "$BASENAME.mp4" -add audio.aac
rm audio.aac