Since*
0.7
Damages the contents of packets without damaging the container. Can be used for fuzzing or testing error resilience/concealment.
Parameters: A numeral string, whose value is related to how often output bytes will be modified. Therefore, values below or equal to 0 are forbidden, and the lower the more frequent bytes will be modified, with 1 meaning every byte is modified.
ffmpeg -i INPUT -c copy -bsf noise[=1] output.mkv
applies the modification to every byte.