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author | Jörg Frings-Fürst <debian@jff-webhosting.net> | 2015-11-06 05:38:49 +0100 |
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committer | Jörg Frings-Fürst <debian@jff-webhosting.net> | 2015-11-06 05:38:49 +0100 |
commit | 9491825ddff7a294d1f49061bae7044e426aeb2e (patch) | |
tree | 06e651099f87140ec534ae47fb8ce1ac6ec7976d /tiff/tools/ycbcr.c | |
parent | fa756339d4204bff7f2820067f58214d32780d17 (diff) |
Imported Upstream version 1.8.3
Diffstat (limited to 'tiff/tools/ycbcr.c')
-rwxr-xr-x | tiff/tools/ycbcr.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/tiff/tools/ycbcr.c b/tiff/tools/ycbcr.c new file mode 100755 index 0000000..8f72447 --- /dev/null +++ b/tiff/tools/ycbcr.c @@ -0,0 +1,168 @@ +float ycbcrCoeffs[3] = { .299, .587, .114 }; +/* default coding range is CCIR Rec 601-1 with no headroom/footroom */ +unsigned long refBlackWhite[6] = { 0, 255, 128, 255, 128, 255 }; + +#define LumaRed ycbcrCoeffs[0] +#define LumaGreen ycbcrCoeffs[1] +#define LumaBlue ycbcrCoeffs[2] + +long eRtotal = 0; +long eGtotal = 0; +long eBtotal = 0; +long preveRtotal = 0; +long preveGtotal = 0; +long preveBtotal = 0; +unsigned long AbseRtotal = 0; +unsigned long AbseGtotal = 0; +unsigned long AbseBtotal = 0; +unsigned long eCodes = 0; +unsigned long preveCodes = 0; +unsigned long eBits = 0; +unsigned long preveBits = 0; + +static void setupLumaTables(); +static int abs(int v) { return (v < 0 ? -v : v); } +static double pct(int v,double range) { return (v*100. / range); } +static void check(int R, int G, int B); + +float D1, D2; +float D3, D4; +float D5, D6; + +int +main(int argc, char** argv) +{ + int R, G, B; + + if (argc > 1) { + refBlackWhite[0] = 16; + refBlackWhite[1] = 235; + refBlackWhite[2] = 128; + refBlackWhite[3] = 240; + refBlackWhite[4] = 128; + refBlackWhite[5] = 240; + } + D3 = 2 - 2*LumaRed; + D4 = 2 - 2*LumaBlue; + D1 = 1. / D3; + D2 = 1. / D4; + D5 = D3*LumaRed / LumaGreen; + D6 = D4*LumaBlue / LumaGreen; + setupLumaTables(); + for (R = 0; R < 256; R++) { + for (G = 0; G < 256; G++) + for (B = 0; B < 256; B++) + check(R, G, B); + printf("[%3u] c %u/%u b %u/%u (R %u/%d/%u G %u/%d/%u B %u/%d/%u)\n" + , R + , eCodes - preveCodes, eCodes + , eBits - preveBits, eBits + , abs(AbseRtotal - preveRtotal), eRtotal , AbseRtotal + , abs(AbseGtotal - preveGtotal), eGtotal , AbseGtotal + , abs(AbseBtotal - preveBtotal), eBtotal , AbseBtotal + ); + preveRtotal = AbseRtotal; + preveGtotal = AbseGtotal; + preveBtotal = AbseBtotal; + preveCodes = eCodes; + preveBits = eBits; + } + printf("%u total codes\n", 256*256*256); + printf("total error: %u codes %u bits (R %d/%u G %d/%u B %d/%u)\n" + , eCodes + , eBits + , eRtotal , AbseRtotal + , eGtotal , AbseGtotal + , eBtotal , AbseBtotal + ); + return (0); +} + +float *lumaRed; +float *lumaGreen; +float *lumaBlue; + +static float* +setupLuma(float c) +{ + float *v = (float *)_TIFFmalloc(256 * sizeof (float)); + int i; + for (i = 0; i < 256; i++) + v[i] = c * i; + return (v); +} + +static void +setupLumaTables(void) +{ + lumaRed = setupLuma(LumaRed); + lumaGreen = setupLuma(LumaGreen); + lumaBlue = setupLuma(LumaBlue); +} + +static unsigned +V2Code(float f, unsigned long RB, unsigned long RW, int CR) +{ + unsigned int c = (unsigned int)((((f)*(RW-RB)/CR)+RB)+.5); + return (c > 255 ? 255 : c); +} + +#define Code2V(c, RB, RW, CR) ((((c)-(int)RB)*(float)CR)/(float)(RW-RB)) + +#define CLAMP(f,min,max) \ + (int)((f)+.5 < (min) ? (min) : (f)+.5 > (max) ? (max) : (f)+.5) + +static +void +check(int R, int G, int B) +{ + float Y, Cb, Cr; + int iY, iCb, iCr; + float rY, rCb, rCr; + float rR, rG, rB; + int eR, eG, eB; + + Y = lumaRed[R] + lumaGreen[G] + lumaBlue[B]; + Cb = (B - Y)*D2; + Cr = (R - Y)*D1; + iY = V2Code(Y, refBlackWhite[0], refBlackWhite[1], 255); + iCb = V2Code(Cb, refBlackWhite[2], refBlackWhite[3], 127); + iCr = V2Code(Cr, refBlackWhite[4], refBlackWhite[5], 127); + rCb = Code2V(iCb, refBlackWhite[2], refBlackWhite[3], 127); + rCr = Code2V(iCr, refBlackWhite[4], refBlackWhite[5], 127); + rY = Code2V(iY, refBlackWhite[0], refBlackWhite[1], 255); + rR = rY + rCr*D3; + rB = rY + rCb*D4; + rG = rY - rCb*D6 - rCr*D5; + eR = R - CLAMP(rR,0,255); + eG = G - CLAMP(rG,0,255); + eB = B - CLAMP(rB,0,255); + if (abs(eR) > 1 || abs(eG) > 1 || abs(eB) > 1) { + printf("R %u G %u B %u", R, G, B); + printf(" Y %g Cb %g Cr %g", Y, Cb, Cr); + printf(" iY %u iCb %u iCr %u", iY, iCb, iCr); + printf("\n -> Y %g Cb %g Cr %g", rY, rCb, rCr); + printf(" R %g (%u) G %g (%u) B %g (%u) E=[%d %d %d])\n" + , rR, CLAMP(rR,0,255) + , rG, CLAMP(rG,0,255) + , rB, CLAMP(rB,0,255) + , eR, eG, eB + ); + } + eRtotal += eR; + eGtotal += eG; + eBtotal += eB; + AbseRtotal += abs(eR); + AbseGtotal += abs(eG); + AbseBtotal += abs(eB); + if (eR | eG | eB) + eCodes++; + eBits += abs(eR) + abs(eG) + abs(eB); +} +/* + * Local Variables: + * mode: c + * c-basic-offset: 8 + * fill-column: 78 + * End: + */ |