> As far as the commercial flagging taking 8hours, the machine is a > Celeron 300, which came with the tiny 128k cache. I can only assume > that has something to do with the slow commerical flagging time.
This probably has a HUGE impact. :) If you figure that at 320x240, you're frame has 76800 pixels, but at 720x480, you're up to 345600. Commercial flagging usually only looks at the Y part of the YUV data, so that would be 345KB per frame, which is a lot more than the amount of data that can be cached. 1920x1088 is over 2MB, so flagging those shows would be slow even on CPUs with larger cache. I currently don't scan every pixel, as the resolution gets higher, the pixel spacing that I use for most things gets higher in order to try to keep the speed up. I plan on consolidating some of the methods so that the flagging process doesn't have to scan a frame more than once, but this is a little ways off. Since the various detection methods were independently created, the current code scans the frame multiple twice (once for blank-frame detection and once for scene-change). It also partially scans a third time for the logo. > (as an aside, damn commercial flagging takes a long time on HD > content... my flag times on my main flagger went up 4x when I started > recording HD content) I've never profiled the code, but a huge amount of the flagging time is spent decoding the video, so if HD content takes 4x the CPU to decode, you could expect it to take 4x the CPU to flag. :) -- Chris
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