Incrementar velocidad subir volumen con ffmpeg

ffmpeg -i input.m4a -filter:a "volume=4.0,atempo=1.5" output.m4a

• volume=2.0 → doubles the volume (you can use e.g. 1.5 = +50%, 3.0 = triple).
• atempo=1.5 → speeds up the audio to 1.5×.
• You can chain filters with a comma: "volume=...,atempo=...".

⚠️ Note:

• atempo only accepts values from 0.5 to 2.0.
• If you need faster than 2×, you must chain multiple atempo filters, e.g.:

ffmpeg -i input.mp3 -filter:a "atempo=2.0,atempo=1.5" output.mp3

(this would give 3× speed).