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

[Clément Bœsch]

On Thu, Mar 31, 2016 at 02:29:12PM -0400, Ronald S. Bultje wrote:
> 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).

Can you split?

> ---
>  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
>  

probably requires micro or minor bump in version.h

>  /**
>   * 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) */

no FATE change? oO

>      { 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 */

why the empty entry?

> +    { 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];
>  }

-- 
Clément B.
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