ffmpeg convert video to mp4 code example

Example 1: ffmpeg video to mp3

ffmpeg -i "file.mkv" -vn -ar 44100 -ac 2 -ab 128k -f mp3 "file.mp3"

Example 2: ffmpeg webm to mp4

ffmpeg -i "01 - file.webm" -crf 23 "file.mp4"

Example 3: how to transcode a video in python using ffmpeg

ffmpeg -i input.mkv -c:a copy -s hd720 output.mkv
This modifies the video to 1280x720 in the output, but you can set the width and height manually if you want:

ffmpeg -i input.mkv -c:a copy -s 1280x720 output.mkv
This produces the exact same output as the earlier command. If you want to set custom sizes in FFmpeg, please remember that the width parameter (1280) comes before height (720).