FFmpeg examples

FFmpeg is very popular Video and Audio conversion utility. Here I will show few examples I found useful

To simply convert AVI to MP4 with default codec and settings try:

ffmpeg -i video.avi output.mp4

Using deinterlace filter:

• If your source is interlaced (for example MiniDV camera) you have to deinterlace it, because unlike classic TV today devices can't play it properly
• it is done with filter - I prefer yadif (Yet Another DeInterlace filter). Please see https://github.com/kfrn/ffmpeg-things/blob/master/deinterlacing.md for discussion on this topic.

ffmpeg -i video.avi -vf yadif output.mp4

Concat and deinterlace

• I use great WinDV from https://www.videohelp.com/software/WinDV to capture video from MiniDV camera to PC over FireWire. This tool splits video files on every scene and over specified number of frames (22500 frames = 15minutes in PAL format - 25fps).
• here is FFmpeg a bit confusing, because there are two concat blocks and we use so called concat demuxer, see https://trac.ffmpeg.org/wiki/Concatenate#demuxer.

1. You have to prepare list of files files.txt that looks like:

   file 'input.23-02-11_10-48.00.avi'
   file 'input.23-02-11_11-03.00.avi'
   file 'input.23-02-11_11-18.00.avi'
   

2. now you have to prepend these two parameters: -f concat -i files.txt to FFmpeg command.

Here is full example - concating input AVI files, deinterlace and produce MP4 on output:

ffmpeg.exe -f concat -i files.txt ^
   -vf yadif output.mp4

Please notice that because of using -f concat demuxer the input is NOT AVI file but text-file with list(!).

Handling Mono input:

• when capturing video it is often in mono format
• in my case only left audio channel has sound
• you have to use this audio-filter: -af "pan=mono|c0=FL" from https://superuser.com/questions/1063185/how-to-select-the-left-audio-channel-with-ffmpeg-and-downmix-to-mono
• to convert stereo with left channel to mono

Full example:

ffmpeg.exe -f concat -i files.txt ^
   -vf yadif -af "pan=mono|c0=FL" ^
   output.mp4

NOTE: For example contents of files.txt see above text.