The simplest tool to reduce the file size of MPEG-4 multimedia format video is
ffmpeg. The most common process to shrink the file size is to use
ffmpeg and reduce bitrate. Before we begin let’s first get some statistics about our sample mp4 video file
$ ffmpeg -i foo.mp4 ... 17015 kb/s, 29.99 fps, 30 tbr, 90k tbn, 180k tbc (default) ...
The current file size is 22MB:
$ ls -hl foo.mp4 -rw-rw-r--. 1 lubos lubos 22M Jul 23 10:56 foo.mp4
The current bitrate of our mp4 video file is 17015 kb/s.
The following linux command will reduce the bit rate of the above MP4 video file by approximately half and save the output as
$ ffmpeg -i foo.mp4 -b 8507k out.mp4
The new size of our mp4 file is:
$ ls -hl out.mp4 -rw-rw-r--. 1 lubos lubos 12M Jul 23 11:14 out.mp4