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

[Bo Berglund]

On Wed, 28 Apr 2021 11:35:47 +0200, Michael Koch <astroelectronic at t-online.de>
wrote:

>> I had tested this (which I found by googling) before I posted:
>>
>> ffmpeg -i input20.mp4 -filter:a "atempo=1.25" -vn output20.mp4
>>
>> There were no errors displayed but the resulting file *ONLY* contains the audio
>> part, I neeed both and the audio change must not change the length or lipsync of
>> the file.
>
>Sure, that's because -vn means "no video output". Just remove this 
>option and then your output file will contain audio and video.

OK, that included the video...
But now there is no lip-sync at all. Seems to drift longer apart during the
video playing. Audio and video running at different speeds.

I think I will abandon this experimental test. It was just an idea on how to
possibly improve a bad video.


-- 
Bo Berglund
Developer in Sweden