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webp-src/src/dec/vp8i.h  view on Meta::CPAN

//
//   .+------   <- only 1 pixel high
//   .|yyyyt.
//   .|yyyyt.
//   .|yyyyt.
//   .|yyyy..
//   .+--.+--   <- only 1 pixel high
//   .|uu.|vv
//   .|uu.|vv
//
// Every character is a 4x4 block, with legend:
//  '.' = unused
//  'y' = y-samples   'u' = u-samples     'v' = u-samples
//  '|' = left sample,   '-' = top sample,    '+' = top-left sample
//  't' = extra top-right sample for 4x4 modes
// With this layout, BPS (=Bytes Per Scan-line) is one cacheline size.
#define BPS       32    // this is the common stride used by yuv[]
#define YUV_SIZE (BPS * 17 + BPS * 9)
#define Y_SIZE   (BPS * 17)
#define Y_OFF    (BPS * 1 + 8)
#define U_OFF    (Y_OFF + BPS * 16 + BPS)