[FFmpeg-devel] [PATCH] swscale: add bt2020 yuv2rgb coefficients.

[Ronald S. Bultje]

Also fix the bt709 ones. They seem derived from incorrect values
cr=0.2125 (should be cr=0.2126) and cb=0.0721 (should be cb=0.0722).
---
 libswscale/swscale.h |  1 +
 libswscale/yuv2rgb.c | 13 ++++++++-----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/libswscale/swscale.h b/libswscale/swscale.h
index da9dd2e..6b8b926 100644
--- a/libswscale/swscale.h
+++ b/libswscale/swscale.h
@@ -91,6 +91,7 @@ const char *swscale_license(void);
 #define SWS_CS_SMPTE170M      5
 #define SWS_CS_SMPTE240M      7
 #define SWS_CS_DEFAULT        5
+#define SWS_CS_BT2020         9
 
 /**
  * Return a pointer to yuv<->rgb coefficients for the given colorspace
diff --git a/libswscale/yuv2rgb.c b/libswscale/yuv2rgb.c
index 62abb7d..1fe5abe 100644
--- a/libswscale/yuv2rgb.c
+++ b/libswscale/yuv2rgb.c
@@ -46,20 +46,23 @@
  *
  * 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) */
+const int32_t ff_yuv2rgb_coeffs[11][4] = {
+    { 117489, 138438, 13975, 34925 }, /* no sequence_display_extension */
+    { 117489, 138438, 13975, 34925 }, /* ITU-R Rec. 709 (1990) */
     { 104597, 132201, 25675, 53279 }, /* unspecified */
     { 104597, 132201, 25675, 53279 }, /* reserved */
     { 104448, 132798, 24759, 53109 }, /* FCC */
     { 104597, 132201, 25675, 53279 }, /* ITU-R Rec. 624-4 System B, G */
     { 104597, 132201, 25675, 53279 }, /* SMPTE 170M */
-    { 117579, 136230, 16907, 35559 }  /* SMPTE 240M (1987) */
+    { 117579, 136230, 16907, 35559 }, /* SMPTE 240M (1987) */
+    {      0                       }, /* YCgCo */
+    { 110013, 140363, 12277, 42626 }, /* Bt-2020-NCL */
+    { 110013, 140363, 12277, 42626 }, /* Bt-2020-CL */
 };
 
 const int *sws_getCoefficients(int colorspace)
 {
-    if (colorspace > 7 || colorspace < 0)
+    if (colorspace > 10 || colorspace < 0 || colorspace == 8)
         colorspace = SWS_CS_DEFAULT;
     return ff_yuv2rgb_coeffs[colorspace];
 }
-- 
2.1.2