[FFmpeg-user] Distorted audio in screencast

Cecil Westerhof Cecil at decebal.nl
Thu Apr 17 19:42:10 CEST 2014

I have a problem with a zooming sound:

I did not have this in the past as far as I know. But this can also be
because in the past I only used the microphone of the web-cam (and on
another computer). Which is a Logitech, Inc. Webcam Pro 9000.

The command I use is:
ffmpeg -async 1                         \
       -f alsa                          \
       -i "plughw:1"                    \
       -f x11grab -s "800x600"          \
       -r 25                            \
       -i :0.0                          \
       -acodec libmp3lame               \
       -ac 1                            \
       -ar 22050                        \
       -ab 64k                          \
       -qscale:video 4                  \

Also sometimes the audio is a little out of sync and there are sometimes
sharp sounds. What should I change?

The version of ffmpeg I use is:
    ffmpeg version 2.1.1 Copyright (c) 2000-2013 the FFmpeg developers

Until recently I used a camera to make my video's, but I changed to a
screencast for two reasons:
- My camera does not have an external microphone connection
- I need pictures in my video and do not know how to replace video with
  a picture

Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof

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