FFmpeg: tests/tiny_ssim.c Source File

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tiny_ssim.c

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1 /*

3 *

4 * This program is free software; you can redistribute it and/or modify

5 * it under the terms of the GNU General Public License as published by

6 * the Free Software Foundation; either version 2 of the License, or

7 * (at your option) any later version.

8 *

9 * This program is distributed in the hope that it will be useful,

10 * but WITHOUT ANY WARRANTY; without even the implied warranty of

11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

12 * GNU General Public License for more details.

13 *

14 * You should have received a copy of the GNU General Public License

15 * along with this program; if not, write to the Free Software

16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110 USA

17 */

18 /*

19 * tiny_ssim.c

20 * Computes the Structural Similarity Metric between two rawYV12 video files.

21 * original algorithm:

22 * Z. Wang, A. C. Bovik, H. R. Sheikh and E. P. Simoncelli,

23 * "Image quality assessment: From error visibility to structural similarity,"

24 * IEEE Transactions on Image Processing, vol. 13, no. 4, pp. 600-612, Apr. 2004.

25 *

26 * To improve speed, this implementation uses the standard approximation of

27 * overlapped 8x8 block sums, rather than the original gaussian weights.

28 */

30 #include "config.h"

31 #include <inttypes.h>

32 #include <limits.h>

33 #include <math.h>

34 #include <stdio.h>

35 #include <stdlib.h>

37 #define FFSWAP(type,a,b) do{type SWAP_tmp= b; b= a; a= SWAP_tmp;}while(0)

38 #define FFMIN(a,b) ((a) > (b) ? (b) : (a))

40 #define BIT_DEPTH 8

41 #define PIXEL_MAX ((1 << BIT_DEPTH)-1)

42 typedef uint8_t pixel;

44 /****************************************************************************

45 * structural similarity metric

46 ****************************************************************************/

47 static void ssim_4x4x2_core( const pixel *pix1, intptr_t stride1,

48 const pixel *pix2, intptr_t stride2,

49 int sums[2][4] )

50 {

51 int x,y,z;

53 for( z = 0; z < 2; z++ )

54 {

55 uint32_t s1 = 0, s2 = 0, ss = 0, s12 = 0;

56 for( y = 0; y < 4; y++ )

57 for( x = 0; x < 4; x++ )

58 {

59 int a = pix1[x+y*stride1];

60 int b = pix2[x+y*stride2];

61 s1 += a;

62 s2 += b;

63 ss += a*a;

64 ss += b*b;

65 s12 += a*b;

66 }

67 sums[z][0] = s1;

68 sums[z][1] = s2;

69 sums[z][2] = ss;

70 sums[z][3] = s12;

71 pix1 += 4;

72 pix2 += 4;

73 }

74 }

76 static float ssim_end1( int s1, int s2, int ss, int s12 )

77 {

78 /* Maximum value for 10-bit is: ss*64 = (2^10-1)^2*16*4*64 = 4286582784, which will overflow in some cases.

79 * s1*s1, s2*s2, and s1*s2 also obtain this value for edge cases: ((2^10-1)*16*4)^2 = 4286582784.

80 * Maximum value for 9-bit is: ss*64 = (2^9-1)^2*16*4*64 = 1069551616, which will not overflow. */

81 #if BIT_DEPTH > 9

82 #define type float

83 static const float ssim_c1 = .01*.01*PIXEL_MAX*PIXEL_MAX*64;

84 static const float ssim_c2 = .03*.03*PIXEL_MAX*PIXEL_MAX*64*63;

85 #else

86 #define type int

87 static const int ssim_c1 = (int)(.01*.01*PIXEL_MAX*PIXEL_MAX*64 + .5);

88 static const int ssim_c2 = (int)(.03*.03*PIXEL_MAX*PIXEL_MAX*64*63 + .5);

89 #endif

90 type fs1 = s1;

91 type fs2 = s2;

92 type fss = ss;

93 type fs12 = s12;

94 type vars = fss*64 - fs1*fs1 - fs2*fs2;

95 type covar = fs12*64 - fs1*fs2;

96 return (float)(2*fs1*fs2 + ssim_c1) * (float)(2*covar + ssim_c2)

97 / ((float)(fs1*fs1 + fs2*fs2 + ssim_c1) * (float)(vars + ssim_c2));

98 #undef type

99 }

100

101 static float ssim_end4( int sum0[5][4], int sum1[5][4], int width )

102 {

103 float ssim = 0.0;

104 int i;

105

106 for( i = 0; i < width; i++ )

107 ssim += ssim_end1( sum0[i][0] + sum0[i+1][0] + sum1[i][0] + sum1[i+1][0],

108 sum0[i][1] + sum0[i+1][1] + sum1[i][1] + sum1[i+1][1],

109 sum0[i][2] + sum0[i+1][2] + sum1[i][2] + sum1[i+1][2],

110 sum0[i][3] + sum0[i+1][3] + sum1[i][3] + sum1[i+1][3] );

111 return ssim;

112 }

113

114 float ssim_plane(

115 pixel *pix1, intptr_t stride1,

116 pixel *pix2, intptr_t stride2,

117 int width, int height, void *buf, int *cnt )

118 {

119 int z = 0;

120 int x, y;

121 float ssim = 0.0;

122 int (*sum0)[4] = buf;

123 int (*sum1)[4] = sum0 + (width >> 2) + 3;

124 width >>= 2;

125 height >>= 2;

126 for( y = 1; y < height; y++ )

127 {

128 for( ; z <= y; z++ )

129 {

130 FFSWAP( void*, sum0, sum1 );

131 for( x = 0; x < width; x+=2 )

132 ssim_4x4x2_core( &pix1[4*(x+z*stride1)], stride1, &pix2[4*(x+z*stride2)], stride2, &sum0[x] );

133 }

134 for( x = 0; x < width-1; x += 4 )

135 ssim += ssim_end4( sum0+x, sum1+x, FFMIN(4,width-x-1) );

136 }

137 // *cnt = (height-1) * (width-1);

138 return ssim / ((height-1) * (width-1));

139 }

140

141

142 uint64_t ssd_plane( const uint8_t *pix1, const uint8_t *pix2, int size )

143 {

144 uint64_t ssd = 0;

145 int i;

146 for( i=0; i<size; i++ )

147 {

148 int d = pix1[i] - pix2[i];

149 ssd += d*d;

150 }

151 return ssd;

152 }

153

154 static double ssd_to_psnr( uint64_t ssd, uint64_t denom )

155 {

156 return -10*log((double)ssd/(denom*255*255))/log(10);

157 }

158

159 static double ssim_db( double ssim, double weight )

160 {

161 return 10*(log(weight)/log(10)-log(weight-ssim)/log(10));

162 }

163

164 static void print_results(uint64_t ssd[3], double ssim[3], int frames, int w, int h)

165 {

166 printf( "PSNR Y:%.3f U:%.3f V:%.3f All:%.3f | ",

167 ssd_to_psnr( ssd[0], (uint64_t)frames*w*h ),

168 ssd_to_psnr( ssd[1], (uint64_t)frames*w*h/4 ),

169 ssd_to_psnr( ssd[2], (uint64_t)frames*w*h/4 ),

170 ssd_to_psnr( ssd[0] + ssd[1] + ssd[2], (uint64_t)frames*w*h*3/2 ) );

171 printf( "SSIM Y:%.5f U:%.5f V:%.5f All:%.5f (%.5f)",

172 ssim[0] / frames,

173 ssim[1] / frames,

174 ssim[2] / frames,

175 (ssim[0]*4 + ssim[1] + ssim[2]) / (frames*6),

176 ssim_db(ssim[0] * 4 + ssim[1] + ssim[2], frames*6));

177 }

178

179 int main(int argc, char* argv[])

180 {

181 FILE *f[2];

182 uint8_t *buf[2], *plane[2][3];

183 int *temp;

184 uint64_t ssd[3] = {0,0,0};

185 double ssim[3] = {0,0,0};

186 int frame_size, w, h;

187 int frames, seek;

188 int i;

189

190 if( argc<4 || 2 != sscanf(argv[3], "%dx%d", &w, &h) )

191 {

192 printf("tiny_ssim <file1.yuv> <file2.yuv> <width>x<height> [<seek>]\n");

193 return -1;

194 }

195

196 f[0] = fopen(argv[1], "rb");

197 f[1] = fopen(argv[2], "rb");

198 sscanf(argv[3], "%dx%d", &w, &h);

199

200 if (w<=0 || h<=0 || w*(int64_t)h >= INT_MAX/3 || 2LL*w+12 >= INT_MAX / sizeof(*temp)) {

201 fprintf(stderr, "Dimensions are too large, or invalid\n");

202 return -2;

203 }

204

205 frame_size = w*h*3LL/2;

206 for( i=0; i<2; i++ )

207 {

208 buf[i] = malloc(frame_size);

209 plane[i][0] = buf[i];

210 plane[i][1] = plane[i][0] + w*h;

211 plane[i][2] = plane[i][1] + w*h/4;

212 }

213 temp = malloc((2*w+12)*sizeof(*temp));

214 seek = argc<5 ? 0 : atoi(argv[4]);

215 fseek(f[seek<0], seek < 0 ? -seek : seek, SEEK_SET);

216

217 for( frames=0;; frames++ )

218 {

219 uint64_t ssd_one[3];

220 double ssim_one[3];

221 if( fread(buf[0], frame_size, 1, f[0]) != 1) break;

222 if( fread(buf[1], frame_size, 1, f[1]) != 1) break;

223 for( i=0; i<3; i++ )

224 {

225 ssd_one[i] = ssd_plane ( plane[0][i], plane[1][i], w*h>>2*!!i );

226 ssim_one[i] = ssim_plane( plane[0][i], w>>!!i,

227 plane[1][i], w>>!!i,

228 w>>!!i, h>>!!i, temp, NULL );

229 ssd[i] += ssd_one[i];

230 ssim[i] += ssim_one[i];

231 }

232

233 printf("Frame %d | ", frames);

234 print_results(ssd_one, ssim_one, 1, w, h);

235 printf(" \r");

236 fflush(stdout);

237 }

238

239 if( !frames ) return 0;

240

241 printf("Total %d frames | ", frames);

242 print_results(ssd, ssim, frames, w, h);

243 printf("\n");

244

245 return 0;

246 }

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