A brief introduction to video file related concepts and formats.I will also explain general concepts of media handling, like containers and encoding formats. This post will give a glimpse of the tools that FFmpeg provides, showing how easy it is to perform the video/audio conversion, with extra processing. Therefore, this was a good occasion to exercise the FFmpeg conversion and processing capabilities. The player was very old, and couldn’t handle the video file (a modern MP4). For example you can use mp3 or aac with an mp4 file (container), but not with webm files.During my last vacation, I wanted to watch some very old cartoons, during the daily break, on the digital media player that the apartment provided. ) and for each format there is a set of audio/video codecs accepted. Notice that there is a set of formats (containers) accepted by browsers (most admit mp4, some also webm. $ ffmpeg -i INPUT -s 320x240 -c:a copy -c:v vp9 OUT.webm Vp9 will provide nearly 50% extra bandwidth saving, but only for supported browsers (Firefox/Chrome), and the encoding will much slower compared to libx264 (that itself is much slower that v:c copy): $ ffmpeg -i INPUT -s 320x240 -threads 4 -c:a copy -c:v libx264 OUT.mp4

The libx264 is recommended if you want compatibility with all browsers. Notice that once you start decoding-filtering-encoding (i.e., no copy) the process will be much slower (x100 time slower or even more). Video copy will ignore the video filter chain of ffmpeg, so no scaling is available (man ffmpeg is a great source of information that you will not find on Google).

Ffmpeg scale