[FFmpeg-user] Possible to change pitch of audio in a downloaded mp4 file?

[Bo Berglund]

On Wed, 28 Apr 2021 23:43:51 +0200, Nicolas George <george at nsup.org> wrote:

>You changed the speed of the audio and not the video, what did you
>expect? FFmpeg does what you tell it to do, it cannot read your mind.

I did NOT want to change the *speed* of neither the audio nor the video!
What I wanted was to change the *pitch* of the audio while retaining the
playback speed!
So the playback time of the video should be the same as before and the audio
pitch changed without losing lip sync.

It is not like having an audio tape recorder and then increase the speed of the
tape feed motor, that only produces a faster playback (shorter time of the
playback) with a higher pitch audio (like in Donald Duck comics).

What I am after is what VLC can do, namely speed up or down the video playback
while *retaining* the pitch of the audio without losing lip sync. If VLC can do
it so should ffmpeg be able to (since I believe VLC uses ffmpeg in the
background).

No mind reading needed here.

But I have no knowledge on *how* VLC does this only that it is used in my own
video player/editor when speeding up the playback for instance.
It uses API:s from VLC, but cannot save to a video file, just display the
video...


-- 
Bo Berglund
Developer in Sweden