wiki:

Null


Version 6 (modified by rogerdpack, 3 years ago) (diff)

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There are several ways to "output to null" in FFmpeg (like a null sink). This can be helpful for benchmarking purposes, for instance testing encoding speeds (without having to worry about the cost of disk writes) etc.

There is the null muxer, use it like this:

   ffmpeg -i INPUT -f null out.null # file out.null will not be created, decoding will occur, no encoding will occur

or just output to /dev/null (or the reserved filename NUL in windows) for your file to just disappear, if you want to perform encoding but not create a file

   ffmpeg -i INPUT -f mpeg4 -f mp4 -y /dev/null # no file is created, encoding and placing in container occur

See also the "-benchmark" parameter.

There is also a null video sink, however its description says "Pass the source unchanged to the output" so it is basically unrelated to the aboves.