[mythtv-users] Real time commflagging of 1080i material from hdpvr

[Tom Lichti]

On Tue, Apr 27, 2010 at 4:12 PM, Kevin Ross <kevin at familyross.net> wrote:
>> The flagger does have some code in it to try to optimize things so
>> that 1920x1080 doesn't take 27 times longer than 320x240 video
>> (ie, 2073600 pixels vs 76800).  For instance, the blank frame detection
>> short-circuits when it finds non-blank data.  The scene change code
>> doesn't look at every pixel, it uses a variable sized grid of points
>> in the frame.  It looks like I only change the grid spacing from every
>> 8 pixels to every 10 pixels when going from 1280x720 to 1920x1080.
>> If you want to try a test, you could edit 2 lines in the code and see
>> what kind of speedup you can get on 1080 material.
>>
>> Edit mythtv/programs/ClassicCommDetector.cpp and search for the
>> following:
>>
>>     if ((width * height) > 1000000)
>>     {
>>         horizSpacing = 10;
>>         vertSpacing = 10;
>>     }
>>     else if ((width * height) > 800000)
>>     {
>>         horizSpacing = 8;
>>         vertSpacing = 8;
>>     }
>>
>> Try changing the two 10's up there to 12 or 16.  That should speed up
>> detection a little.  That whole section of logic could probably be
>> cleaned up a bit to be hand-tuned to standard video sizes.  Patches
>> are welcome if they give good results. :)
>
> I build from source, so trying this won't be a problem at all.  I'll give it
> a try tonight and report back.

I'm going to test it out as well. I think you meant
mythtv/programs/mythcommflag/ClassicCommDetector.cpp though... :)

Tom