[gst-devel] Summer Coding: Screen Recording on the Free Desktop

David Schleef ds at schleef.org
Tue Mar 25 21:46:02 CET 2008


On Tue, Mar 25, 2008 at 02:08:52AM -0700, cellenro cellenro wrote:
> Ogg Theora is not the best codec for screen recording
> because even at higher resolutions it is hard to see
> text clearly. Part of the project will be to evaluate
> the feasibility of using Driac as the codec for
> recording and editing.

Schroedinger isn't really optimal for screencasting, either.  Fixing
this would make a great GSoC project, so I just added it to the
Dirac/Schroedinger ideas page
(http://www.diracvideo.org/wiki/GSoC2008Ideas).  Mainly, someone needs
to add an "encode screencast" mode to schroedinger, and have it make
encoding decisions based on this information.  Some of the intelligence
it needs is:

 - text is not noise that should be filtered out

 - 99% of pictures are nearly identical to the previous frame, or have
   large changes (e.g., a new window)

 - the noise level in pictures is 0.

 - detect picture sequences that look like normal video (say, someone
   screencasting totem playing a video) and fall back to normal
   encoding.

In most cases, a good encoder should be able to encode a screencast
(nearly) losslessly without creating a giant file.  This is not currently
true.



dave...





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