[FFmpeg-user] Weird crackling sound when muxing with an existing WAV file

[Michael Heuberger]

Hello guys

It's me Michael again, having another ffmpeg problem. Since I am Deaf I
cannot fine tune nor adjust audio stuff very well and would appreciate
your help a lot.

It's for the cool www.videomail.io app where Deaf people can exchange
stuff in sign language. But the sound part needs improvement. It works
but there is a nasty crackling sound my hearing friends say. Feel free
to test it yourself on that site.

Here's an example ffmpeg command how I mux a WAV file + encode the video
based on images on server side at the same time. With a long output, all
on this Gist:
https://gist.github.com/binarykitchen/fc6c73aca72881f76376fb274d82cd70

The WAV file itself is assembled on server side from PCM files sent from
the client (during recording). Plus stretched with Rubberband before it
is being muxed with the video file. You see, it's pretty sophisticated
and works well. Just the crackling sound is a problem.

Any advice, tips or even criticism would be very very welcome

Many thanks
Michael

-- 

Binary Kitchen
Michael Heuberger
1/33 Parrish Road
Sandringham
Auckland 1025
(New Zealand)

Mobile (text only) ...  +64 21 261 89 81
Email ................  michael at binarykitchen.com
Website ..............  http://www.binarykitchen.com