Record your desktop audio and video

09 Jan 2016

This comes handy when you were not allowed to download a video from a website but allowed to play.

Libav is the library which is going to help us in such situations.

Libav is a set of tools which contains following:

Avplay - A video/audio player like VLC.
Avconv - A multimedia converter plus a video & audio recorder from different sources.
Avprobe - A tool that connects to the multimedia file stream and returns many useful information and statistics about it.
Libavfilter - A filtering API for different Libav tools.

sudo apt-get update
sudo apt-get install libav-tools

avconv -f x11grab -r 25 -s 1366x768 -i :0.0 -vcodec libx264 -threads 4 $HOME/output.avi

Explanation of above command:

avconv -f x11grab is the default command to capture video from the X server.
-r 25 is the frame rate you want, you may change it if you like.
-s 1920×1080 is your system’s screen resolution, change it to your current system resolution, it’s very important to do this.
-i :0.0 is where we want to set our recording start point, leave it like this.
-vcodec libx264 is the video codec that we’re using to record the desktop.
-threads 4 is the number of threads, you may change it as well if you like.
$HOME/output is the destination path where you want to save the file.
.avi is the video format, you may change it to “flv”, “mp4”, “wmv”, “mov”, “mkv”.

Ctrl+c will terminate the command and save the output file. open the output using VLC or avplay

To record both audio and video we should know the hardware address of our output hardware(speaker)

arecord -l

The above command will list the available output hardware. Now start the recording using

avconv -f alsa -i hw:0 -f x11grab -r 25 -s 1366x768 -i :0.0 -vcodec libx264 -threads 4 output-file2.avi

Explanation:

-f alsa is an option to capture the sound from the alsa device.
-i hw:1 is an option to take the audio input source from the “hw:1” device which is the first – and the only – input sound device in my computer.

Jayanth