sox

Halveren snelheid audio mp3 voor ongedaan maken cassette high speed dubbing

sox ipv ffmpeg

sox input.mp3 output.mp3 --show-progress speed 0.5

show progress

--show-progress

remove silence at the end of an mp3

sox input.mp3 output.mp3 reverse silence 1 0.1 0.1% reverse

split mp3 based on silence

sox input.mp3 output-.mp3  silence 1 0.5 1% 1 5.0 1% : newfile : restart