Bash script to conform between NTSC and PAL.
Conforming is either speeding up or slowing down the duration to match the desired output framerate. This is generally how films and TV shows are converted between standards.
The alternative is repeating or dropping frames to change the frame rate, and that's bad.
No. For the video this is done losslessly without re-encoding. The duration will be longer moving from PAL to NTSC and vice-versa.
Yes. For the audio it is changing the tempo. This means the pitch is adjusted accordingly to match the new speed. In other words, there should be little perceptible difference in pitch between the original and the conformed one. This is a lossy process.
The audio is re-encoded with Opus at 48000Hz/128K. This is actually very good quality for an Opus file.
Part of the mkvtoolnix package usually. Used to change the video framerate.
Both usually come with ffmpeg. Uses ffprobe to get the framerate of the input file and ffmpeg to convert the audio while maintaining pitch.
Part of mplayer-tools. I couldn't even find a package for this in Arch! So since it's a simple Perl script it's just included. Used to convert the frame rate for SRT subtitles.
Provide the folder where your MKV videos to be converted are followed by the framerate to conform to. Valid framerates are 23.976, 24, and 25.
It should not overwrite your originals, however it may be safest to make a backup copy!
The first embedded subtitle will be used, otherwise if there's an SRT subtitle of the same name next to the video file it will use that.
bash fps_conform.sh [folder] [framerate]
This will output the finished files in a converted folder in the same directory as the script.