On 12/11/14 04:06, Jonathan Wilkes via Pd-list wrote:
Sure... what do people use in Debian/Ubuntu to do screencast + audio?
With Jack I use someting like this:
ffmpeg -f jack -ac 2 -i ffmpeg -f x11grab -r 25 -s 1366x768
-i :0.0 -acodec pcm_s16le -threads 0 output.mkv
Notice that:
- ffmpeg in my case is the 'original' one compiled by hand.
Unfortunately debian now seems to only package avconv and that has always crashed on me with jack as audio input. However ffmpeg is relatively easy to compile on debian following this guide:
https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu
You should play with the -s and -i parameters to suit your needs.
Pulseaudio will be automatically suspended when you run jack (I was
forced to install it to use skype with, alas, I'm forced to use for work).
- Clearly when screen-casting it'll be difficult to get Chuck Norris low
latencies without some xruns.
- The output with that ffmpeg command will be a very good quality mkv
video however it will also be very (very!) big and you'll have to factor in the extra time for re-compressing (it's possible to encode on the fly -but I prefer to have a good quality 'original') For encoding I've had rather nice results with using webem, for example (YMMV):
ffmpeg -y -i "$INFILE" -threads 8 -f webm -vcodec libvpx -g 120
-level 216 -profile 0 -qmax 42 -qmin 10 -rc_buf_aggressivity 0.95
-vb 2M -acodec libvorbis -aq 90 -ac 2 $OUTFILE
Hope this helps. Lorenzo.