[x265] [PATCH] primitives: added C primitives to compute SSIM

[Steve Borho]

On Tue, Oct 8, 2013 at 6:43 AM, Aarthi Thirumalai <
aarthi at multicorewareinc.com> wrote:

> # HG changeset patch
> # User Aarthi Thirumalai
> # Date 1381232217 -19800
> #      Tue Oct 08 17:06:57 2013 +0530
> # Node ID 47286888d5a293234340153112810ce2a4f81546
> # Parent  9b3a427a1009d1853bbdc30abe1fd891864e6b38
> primitives: added C primitives to compute SSIM
>
> diff -r 9b3a427a1009 -r 47286888d5a2 source/common/pixel.cpp
> --- a/source/common/pixel.cpp   Tue Oct 08 11:12:12 2013 +0530
> +++ b/source/common/pixel.cpp   Tue Oct 08 17:06:57 2013 +0530
> @@ -653,6 +653,58 @@
>      }
>  }
>
> +/* structural similarity metric */
> +void ssim_4x4x2_core(const pixel *pix1, intptr_t stride1, const pixel
> *pix2, intptr_t stride2, ssim_t sums[2][4])
> +{
> +    for (int z = 0; z < 2; z++)
> +    {
> +        ssim_t s1 = 0, s2 = 0, ss = 0, s12 = 0;
> +        for (int y = 0; y < 4; y++)
> +        {
> +            for (int x = 0; x < 4; x++)
> +            {
> +                ssim_t a = pix1[x + y * stride1];
> +                ssim_t b = pix2[x + y * stride2];
> +                s1 += a;
> +                s2 += b;
> +                ss += a * a;
> +                ss += b * b;
> +                s12 += a * b;
> +            }
> +        }
> +        sums[z][0] = s1;
> +        sums[z][1] = s2;
> +        sums[z][2] = ss;
> +        sums[z][3] = s12;
> +        pix1 += 4;
> +        pix2 += 4;
> +    }
> +}
> +
> +float ssim_end_1(ssim_t s1, ssim_t s2, ssim_t ss, ssim_t s12)
> +{
> +    static const uint32_t pixelMax = (1 << X265_DEPTH) - 1;
> +    static const ssim_t ssim_c1 = (ssim_t)(.01 * .01 * pixelMax *
> pixelMax * 64 + .5);
> +    static const ssim_t ssim_c2 = (ssim_t)(.03 * .03 * pixelMax *
> pixelMax * 64 * 63 + .5);
> +    ssim_t vars = ss * 64 - s1 * s1 - s2 * s2;
> +    ssim_t covar = s12 * 64 - s1 * s2;
> +    return (float)(2 * s1 * s2 + ssim_c1) * (float)(2 * covar + ssim_c2)
> +           / ((float)(s1 * s1 + s2 * s2 + ssim_c1) * (float)(vars +
> ssim_c2));
> +}
> +
> +float ssim_end_4(ssim_t sum0[5][4], ssim_t sum1[5][4], int width)
> +{
> +    float ssim = 0.0;
> +
> +    for (int i = 0; i < width; i++)
> +    {
> +        ssim += ssim_end_1(sum0[i][0] + sum0[i + 1][0] + sum1[i][0] +
> sum1[i + 1][0],
> +                           sum0[i][1] + sum0[i + 1][1] + sum1[i][1] +
> sum1[i + 1][1],
> +                           sum0[i][2] + sum0[i + 1][2] + sum1[i][2] +
> sum1[i + 1][2],
> +                           sum0[i][3] + sum0[i + 1][3] + sum1[i][3] +
> sum1[i + 1][3]);
> +    }
> +    return ssim;
> +}
>  }  // end anonymous namespace
>
>  namespace x265 {
> @@ -870,5 +922,7 @@
>      p.scale1D_128to64 = scale1D_128to64;
>      p.scale2D_64to32 = scale2D_64to32;
>      p.frame_init_lowres_core = frame_init_lowres_core;
> +    p.ssim_4x4x2_core = ssim_4x4x2_core;
> +    p.ssim_end_4 = ssim_end_4;
>  }
>  }
> diff -r 9b3a427a1009 -r 47286888d5a2 source/common/primitives.h
> --- a/source/common/primitives.h        Tue Oct 08 11:12:12 2013 +0530
> +++ b/source/common/primitives.h        Tue Oct 08 17:06:57 2013 +0530
> @@ -64,11 +64,13 @@
>  typedef uint32_t sum_t;
>  typedef uint64_t sum2_t;
>  typedef uint64_t pixel4;
> +typedef int64_t ssim_t;
>  #else
>  typedef uint8_t pixel;
>  typedef uint16_t sum_t;
>  typedef uint32_t sum2_t;
>  typedef uint32_t pixel4;
> +typedef int32_t ssim_t;
>  #endif // if HIGH_BIT_DEPTH
>
>  namespace x265 {
> @@ -200,6 +202,8 @@
>  typedef void (*downscale_t)(pixel *src0, pixel *dstf, pixel *dsth, pixel
> *dstv, pixel *dstc,
>                              intptr_t src_stride, intptr_t dst_stride, int
> width, int height);
>  typedef void (*extendCURowBorder_t)(pixel* txt, intptr_t stride, int
> width, int height, int marginX);
> +typedef void (*ssim_4x4x2_core_t)(const pixel *pix1, intptr_t stride1,
> const pixel *pix2, intptr_t stride2, ssim_t sums[2][4]);
> +typedef float (*ssim_end4_t)(ssim_t sum0[5][4], ssim_t sum1[5][4], int
> width);
>
>  /* Define a structure containing function pointers to optimized encoder
>   * primitives.  Each pointer can reference either an assembly routine,
> @@ -259,6 +263,8 @@
>      scale_t         scale1D_128to64;
>      scale_t         scale2D_64to32;
>      downscale_t     frame_init_lowres_core;
> +    ssim_4x4x2_core_t ssim_4x4x2_core;
> +    ssim_end4_t       ssim_end_4;
>  };
>

The next logical step is to hookup x264's assembly functions for this
primitive pointer in asm-primitives.cpp

-- 
Steve Borho
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