Useful FFmpeg and mkvmerge commands

Burning subtitles

The output file could be in another format.

In a .srt file:

ffmpeg -i video.avi -vf subtitles=subtitle.srt out.avi

From a video:

ffmpeg -i video.mkv -vf subtitles=video.mkv out.avi

ffmpeg -i video.avi -vf "ass=subtitle.ass" out.avi

The output file could be in another format.

Extract the first track:

ffmpeg -i input.avi -codec copy -map 0:a:0 -metadata TITLE="title" out.mp3

The input file could be in another format.

ffmpeg -i input_video.avi -f matroska -vcodec libx264 -acodec aac output_video.mkv

The input and output files could be in another format. Increase from the speed at 23.976fps to 25fps:

ffmpeg -i test.mkv -filter:a "atempo=1.0427083333333333" -vn output.aac

mkvmerge -o out.mkv -A -S --default-duration '0:25fps' --fix-bitstream-timing-information 0 input.mkv