[PLUG] avconv -f x11grab tool question

website reader website.reader3 at gmail.com
Fri Mar 22 00:21:12 UTC 2013


I am attempting to create mpg or avi movies directly from a window on
my Ubuntu 12.04 LTS system.  The display monitor is a 1920x1080p
digital unit and the output from geomview of the rotating spherical
polygon and unit sphere look 3d when viewing the monitor.

However when I use "avconv -f x11grab -b 500k -s vga -r 30 -i
:0,0+738,98 out.mpg" to capture this window, the video capture ends up
with poor quality, and has distracting jerky green rectangular
blotches flashing in the movie.  The video itself has poor definition,
like viewing through frosted glass and slightly out of focus.

If we know exactly where the frame buffer is, for the window (which
xwininfo does provide) why cannot we get the exact video memory
capture of this window??

What can I do to improve the video quality?  It seems peculiar that
using a digital display that such a poor quality mpg resulted.  Is the
video codec the problem?  It wants to use the yuv420p video codec, not
the bgra.

I also rename the output file to out.mkv and that has improved the
quality of the video capture, but it still is out of focus and moire
effects are visible.  Searching the avconv documentation about yuv420p
doesn't turn up much.

Thanks for your suggestions.

Randall



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