Re: HOWTO: Proper Screencasting on Linux
Originally Posted by
mocha
Verb3k,
There's a minor problem with the order of command line options in the first post which causes ffmpeg to only "see" 1 audio channel on the incoming side. The proper syntax order for 2 channel capture is therefore:
Code:
ffmpeg -f alsa -ac 2 -ab 128k -i pulse -acodec pcm_s16le -f x11grab -r 30 -s 1280x1024 -i :0.0 -aspect 4:3 -vcodec libx264 -vpre lossless_ultrafast -threads 0 SCREENCAST.mkv
You can also specify an audio bitrate after the "-ac 2" part as I've shown, but if you don't it just defaults to 64 kbps. This method always captures to MP2 audio and I'm not sure why. I experimented with AAC audio capture and MPEG4 and AVI containers, but they don't work very well.
Thanks for making this tutorial! I'll never touch recordmydesktop again!
You don't need to specify a bitrate when you capture raw PCM. Also, since the input is usually a mic, so there is no difference whether you record with -ac 2 or not. It will have the same audio on 2 channels once you encode your compressed version.
I'm glad you found the tutorial useful
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