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| author | Vittorio Giovara <vittorio.giovara@gmail.com> | 2016-01-19 17:10:59 -0500 |
|---|---|---|
| committer | Vittorio Giovara <vittorio.giovara@gmail.com> | 2016-01-20 11:18:31 -0500 |
| commit | e9175634ec96e36873929637491189150cfce9ec (patch) | |
| tree | ca299890eb991c6ceba42c78bb148233d493fd5b | |
| parent | 472d488ebcc53bea4cdb124edb94558e72d8f23f (diff) | |
| download | ffmpeg-e9175634ec96e36873929637491189150cfce9ec.tar.gz | |
yuv2rgb: Document the color space coefficients
Based on the original documentation found in mpeg2dec (1995).
Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
| -rw-r--r-- | libswscale/yuv2rgb.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/libswscale/yuv2rgb.c b/libswscale/yuv2rgb.c index a4f7a1178e..fca324299d 100644 --- a/libswscale/yuv2rgb.c +++ b/libswscale/yuv2rgb.c @@ -35,6 +35,17 @@ #include "swscale.h" #include "swscale_internal.h" +/* Color space conversion coefficients for YCbCr -> RGB mapping. + * + * Entries are {crv, cbu, cgu, cgv} + * + * crv = (255 / 224) * 65536 * (1 - cr) / 0.5 + * cbu = (255 / 224) * 65536 * (1 - cb) / 0.5 + * cgu = (255 / 224) * 65536 * (cb / cg) * (1 - cb) / 0.5 + * cgv = (255 / 224) * 65536 * (cr / cg) * (1 - cr) / 0.5 + * + * where Y = cr * R + cg * G + cb * B and cr + cg + cb = 1. + */ const int32_t ff_yuv2rgb_coeffs[8][4] = { { 117504, 138453, 13954, 34903 }, /* no sequence_display_extension */ { 117504, 138453, 13954, 34903 }, /* ITU-R Rec. 709 (1990) */ |