On Sun, 2004-05-23 at 16:09, Steven M. Schultz wrote: > What's a good metric for determining the "brightness" of a frame? > Compute a histogram of the Y' values and see if there's a big cluster > below a specified threshold (such as 32)? For example, this is a > histogram of Y' for a frame that's supposedly pure black (after Y=32 > it's all 0): > > Y 0 0 > Y 1 0 > Y 2 0 > Y 3 0 > Y 4 0 > Y 5 1 > Y 6 2 > Y 7 11 > Y 8 14 > Y 9 37 > Y 10 96 > Y 11 266 > Y 12 734 > Y 13 2223 > Y 14 5806 > Y 15 11904 > Y 16 19854 > Y 17 28770 > Y 18 41353 > Y 19 54259 > Y 20 58347 > Y 21 47760 > Y 22 32121 > Y 23 19341 > Y 24 9487 > Y 25 3593 > Y 26 1285 > Y 27 406 > Y 28 170 > Y 29 48 > Y 30 16 > Y 31 12 > Y 32 1
> Any statistics or signal processing folks care to chime in with ideas, > suggestions, or even better working code? :) :) > > Cheers, > Steven Schultz Well, no working code (yet), but.... If everything lower than 32 is black, could we clamp Y' to 32? It might not help the splotchiness, but seems that it should help the bitrate on "black" scenes. Jim ------------------------------------------------------- This SF.Net email is sponsored by: Oracle 10g Get certified on the hottest thing ever to hit the market... Oracle 10g. Take an Oracle 10g class now, and we'll give you the exam FREE. http://ads.osdn.com/?ad_id=3149&alloc_id=8166&op=click _______________________________________________ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
