How can I change the Tone frequency. This Example only pitches it by keeping the old tone frequency and only decrease the length of File.
For Example, I have a constant 100 Herz tone (as mp3) and I want it to change 90 Herz
ffmpeg -i 100h.mp3 -af atempo=100/90 90h.mp3
This Example doesn't work for me, it sounds the same
finally, by combining the asetrate
and resample
from Gyan, with atempo
, the following works and preserves also the audio length
for example: use 0.9 for 90% of the frequenz
ffmpeg -i test.mp3 -af asetrate=44100*0.9,aresample=44100,atempo=1/0.9 output.mp3