[FFmpeg-user] Can't combine 2 pulse input streams in screencast

Andrew Stevanus hoot893 at gmail.com
Thu Aug 18 03:59:15 CEST 2011

Hi. I'm trying to record a screencast with ffmpeg and record my pc audio, and 
my microphone. Recording only one stream works fine, but when I try to record 
with two pulse inputs, I get no audio in the resulting video (I changed one of 
the pulse inputs with pavucontrol to use the pc audio instead of the 
microphone). Here's the command that I use:
ffmpeg -f x11grab -r 15 -s 1366x768 -i :0.0 -f alsa -ac 2 -i pulse -f alsa -ac 
1 -i pulse -vcodec libx264 -acodec pcm_s16le -vpre lossless_ultrafast -threads 
2 output.mp4

I should also say that whenever I use the input hw:0,0 or something similar, 
when I play back the resulting video, the audio seems to get gradually out of 
sync. Can anyone help?

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