Compression for Great Video and Audio, 2nd Edition

CHAPTER 6 Preprocessing

Preprocessing encompasses everything done to the original source between the time it’s handed to you and the time you hand it off to a codec in its final color space. Typical preprocessing operations include cropping, scaling, deinterlacing, aspect ratio correction, noise reduction, image level adjustment, and audio normalization. It’s during preprocessing that whatever the source is becomes optimized for its delivery target.

Some projects don’t need preprocessing at all; if the source is already 640 × 480 4:2:0, and that’s what it’ll be encoded to, there’s nothing that needs to be done. Other times the preprocessing is implicit in the process; converting from DV to DVD requires a conversion from 4:1:1 to 4:2:2, but that’s ...