At the risk of breaking our forum rules for doubleposting, I thought I would post this ‘solution’ in one more place … 
On the subject of screen video capture, but NOT using xvidcap, I had pointed out in a Fedora thread that I was subscribed to, a very neat way of obtain a high quality screen capture with the ffmpeg command. I did NOT get the freeze noted in the initial post of Beli0135, although I recorded for only a minute or two in my testing.
Beli0135, how long did you record before you had the freeze using ffmpeg ?
Lets say one has a screen with a resolution of 1920x1200 (such as my screen). Lets say one has a KDE4 desktop and one wants to capture a video of an application in the desktop that only files PART of the desktop screen, say of 1440x900 resolution in the desktop screen. Then what one needs to do is move the application to the upper left hand corner of one’s KDE4 desktop. Set the application window size to exactly 1440x900. One can do this by clicking on the ‘menu’ icon in the very upper left corner of the window on the application title bar at window top, and select "advanced > special window settings > geometry > size " and type 1440,900. Select ‘apply now’ from the drop down menu.
This will then size the window to be exactly 1440x900 resolution. Ensure the window is in the upper left corner. And then send this ffmpeg command:
ffmpeg -f alsa -ac 2 -i hw:1,0 -f x11grab -r 30 -s 1440x900 -i :0.0 -acodec pcm_s16le -vcodec libx264 -vpre lossless_ultrafast -threads 0 output.avi
where the output video will be ‘output.avi’. One can stop the recording by pressing .
The only tricky part for me (on my openSUSE-11.3) was to select the mic in ffmpeg with the " -i … " option. If one has pulse audio enabled one can likely use " -i pulse " instead of the " -i hw:1,0 " that I used.
In my case I first ran :
arecord -l
which gave me:
oldcpu@core-i7:~> arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: Intel [HDA Intel], device 0: AD198x Analog [AD198x Analog]
Subdevices: 3/3
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
**card 1: U0x46d0x821 [USB Device 0x46d:0x821], device 0: USB Audio [USB Audio]**
Subdevices: 1/1
Subdevice #**0**: subdevice #0
and determined my USB (webcam) mic was HW:1,0 (ie card-1, subdevice 0). Since I wanted to use the mic in my webcam to record, I input hw:1,0 in the ffmpeg command.
I think the rest is intuitively obvious ?
Anyway, there is an excellent reference here: How to do Proper Screencasts on Linux Using FFmpeg � Hopefully Useful
