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Issues with multiply composite mode and compressor
Hey
First issue. Making a video track for a song which is mostly graphics. Had a guy draw some pictures for it (black & white) which we scanned in at 600dpi so we could blow up the pictures without having them pixelate. As they all have white backgrounds, for some of the song we wanted to remove the background so we could put something else behind the pictures. Setting their composite mode to multiply removes the white, but leaves black lines around the edges of the pictures as well, which cropping doesn’t remove. Is this something that you can work around or do I need to put them into photoshop and convert the white background to an alpha channel?
Second is when encoding these clips to mpeg2 in compressor. The settings I’ve used are:
One pass VBR Best
Average bit rate: 6.1mbps
Maximum bit rate: 7.2mbps
Motion Estimation: bestThey’re all PAL clips, 720/576.
When I play back these files, SOME of the scanned in pictures do a lot of glitching, yet others are fine.
Should I be encoding these with a CBR instead of a VBR, or are my bit rates set too high for it to be able to handle true black and white?
Thanks a bundle of honey.
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1 Reply
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[EdgeInt] “Setting their composite mode to multiply removes the white, but leaves black lines around the edges of the pictures as well”
If you want to lift the background of something that you shot against a white screen, go to Video Effects Effects> Matte> Extract.
Multiply is not a method to pull a key. When you apply multiply mode you are multiplying the Y” value of each pixel for the Y’ value of the underneath pixel. Only when you have a pure white pixel (Y’=1) you really get what you get in the layer below.
You should have a look to the FC manual about the composite modes.
RafaelPPC G5 2x2Gh 4GbRAM/BlackMagic SD/PMBP 17″Core2Duo 4GbRAM
JVC DTV-17″/FCS2/AE CS3/COMBUSTION/SHAKE
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