[mythtv] PATCH: Commercial detection/skip using blank frames

Chris Pinkham cpinkham at bc2va.org
Sat Feb 22 17:23:29 EST 2003

>  > I just did some tests earlier and on my system (Athlon 700, recording 
> mpeg4
>  > at 352x480 resolution), I can decode at 194 frames per second.  That

> So you reread the file after recording? And for all the disk
> I/O, decode, and sampling it only took about 1/10 realtime?

I posted a small patch earlier that would scan through the file instead of
playing it if you had a certain environment variable set.  I used that
code and added a "cout" at the bottom to print total time used, total frames,
and fps.  I tried changing a few things but couldn't get it to get more
than 194fps.  At my 352x480 resolution, that's about 50 Megabytes of
just raw video data being passed around per second not counting the other
stuff going on like reading the compressed data, checking 200 pixels from
each frame to see if it's blank, etc..

> Excellent. You could also solve the Simpsons Eyes problem
> by ignoring long blank clusters that are not surrounded by
> other commercial blanking.

This is what the Karin sofware does, it's described pretty good on the

> When you do your flagging, did you intend to use the existing
> cutlist format? I haven't really used this myself but it might
> make sense so that the viewer could use edit mode to fix up
> recordings she intends to keep.

I haven't even given stuff much thought but would want to maintain
the most compatiblity.


** Chris Pinkham                  Linux v2.2.18, Sane v1.0.4, Cajun v3.0-8 **
** cpinkham at bc2va.org                          http://www.bc2va.org/chris/ **

More information about the mythtv-dev mailing list