Screen Capture with FFMpeg with Audio

Found it useful to capture the Linux desktop using FFMpeg, most useful with audio. Accomplished it using the following command:

$ ffmpeg -y -f alsa -i pulse -f x11grab -r 25 -s 1366x768 -i :0.0 -qscale 1 -s 1024x768  screenCap.mpg

First dimension specified is the resolution of the desktop, the second dimension is the desired resized video dimension. Cheers.

Capturing Radio Broadcast Streams with Mplayer

My wife and I took our honeymoon in Australia and I can admit that there are numerous occasions where I hunger for a bit of Aussie. I recently explored how to capture an audio stream to play back on my MP3 player (since our office frowns on streaming).

This is how I've been capturing Triple-J streams for fun;

$ mplayer http://202.6.74.107:8060/triplej.mp3 -dumpstream -dumpfile /tmp/audio.mp3

Screen Capture with FFmpeg

Sometimes it's useful to capture the display output as a means of archiving a procedure or to demonstrate a user experience. The following command will capture the display region 1680x1050 at 30fps for 90 seconds and shrink it to a 640x480 video at near raw resolution (fixed quantizer scale of 1).

The important thing is to confirm your ffmpeg format supports x11grab, otherwise you'll get the following error:

Unknown input or output format: x11grab

ffmpeg -y -f x11grab -r 30 -s 1680x1050 -i :0.0 -t 90 -qscale 1 -s 640x480 out.mpg

As you can imagine, capturing 30fps adds significant resource loading, if you so choose you can down-sample the frame rate but you may need to use an alternative encoder for non-compliant frame rates of some codecs.

The MJPEG encoder seems to work well enough for slow frame rates, like 1 Hz.

ffmpeg -y -f x11grab -r 1/1 -s 1680x1050 -i :0.0 -t 90 -qscale 1 -s 640x480 -vcodec mjpeg out.avi