Hi Leigh, you wrote: >> - What toolchain did you use? Was it the Xephyr/jack_capture/ffmpeg >> package that others (AutoStatic?) had mentioned here or in other places? > >Yep, I used AutoStatic's Xephyr and ffmpeg setup for capturing the >video. For the audio, I recorded straight in to Ardour -- that let me I tinkered around with Xephyr for a while today, and had some problems with what was described on http://www.rncbc.org/drupal/node/219#comment-3859 - specificly, starting your X session with simply "/etc/X11/Xsession &" did not work for me - the harddisk started rattling for a while, but nothing happened. I'd think that it is trying to "start too much" of the services, some of which are perhaps already running through my initial login. What I instead did now was to: - Enable XDMCP on my PC (via /etc/gdm/custom.conf) -> for Ubuntu Karmic, see http://www.peppertop.com/blog/?p=690 - Start Xephyr like this: Xephyr :2 -query 127.0.0.1 -once -screen 1280x1024 - Log in as usual, set up applications and continue from there - Start jack_capture&ffmpeg from outside Xephyr as described by you below. I also noticed that if I log in as some other user (one with a "default" Ubuntu desktop, perhaps better for screencasts), I need to allow the "host" to read the XDisplay of the "guest" by issuing a "xhost localhost" before I can start ffmpeg. However, this means that if I run QJackCtl/jackd as that other user, I cannot get at its audio stream with any JACK client - not even as root. I assume that is a safety mechanism in JACK. But there are ways to overcome this, like with sudo. > I used ffmpeg's default MPEG-4 compression, but with a very high maximum > bitrate -- that gave me high quality, a manageable (large, but not too > large) file size, and relatively low CPU usage. Here's the command I > used: > > ffmpeg -an -f x11grab -s 1280x720 -r 30 -i :2.0 -vb 10000000 tute1.avi > > > - Did you experience any audio/video out-of-sync problems which you had to > > compensate for by e.g. time-stretching the video? > > Nope, the audio I exported from Ardour lined up perfectly with the video > from ffmpeg. To make it easier to line them up in Kdenlive during the > edit, I started the video by hitting the "send test note" button in > XSynth; I was then able to line up the button press in the video track > with the sound of the note being played by XSynth in the audio track. Ah, ok - a "manual initial sync". As long as video is correctly recorded thereafter (no framedrops?), this should be fine. Thanks a lot for these explanations - this is all most useful to me. Greetings, Frank _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
