High quality screen capture with Ffmpeg

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Revision as of 21:31, 1 March 2011 by Alex (Talk | contribs)

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Capture without audio:

 ffmpeg -f x11grab -r 25 -s 1280x720 -i :0.0+0,48 -vcodec libx264 -vpre lossless_ultrafast -threads 0 video.mkv

Compress and convert to MP4 format (Youtube ready):

 ffmpeg -i video.mkv -vcodec libx264 -vpre hq -crf 22 -threads 0 video.mov

Lower -crf gives higher quality.

For including audio:

 ffmpeg -f alsa -ac 2 -i pulse -f x11grab -r 30 -s 1024x768 -i :0.0 -acodec pcm_s16le 
   -vcodec libx264 -vpre lossless_ultrafast -threads 0 output.mkv

In order to make ffmpeg capture audio from other applications:

  1. Start the ffmpeg capture (it just has to run)
  2. Start pavucontrol
  3. In the Recording tab, ffmpeg should be visible and here we can choose between input and monitor

The settings will be remembered until we change them back.

Note: This does not work with Java running in firefox.

TODO:
The audio output can also be captured with gstreamer:

 gst-launch -e pulsesrc device="alsa_output.pci-0000_00_1b.0.analog-stereo.monitor" ! audioconvert ! \
               lamemp3enc target=1 bitrate=128 cbr=true ! filesink location=output.mp3

where the device name is the one returned by

 pactl list | grep -A2 'Source #' | grep 'Name: ' | cut -d" " -f2

Can we use this device name in ffmpeg recording?


References