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Improve accuracy of J422 color space using higher precission fixed point and bias.

Browse Source 
BUG=414
TESTED=TestFullYUVJ
R=tpsiaki@google.com

Review URL: https://webrtc-codereview.appspot.com/44679004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@1327 16f28f9a-4ce2-e073-06de-1de4eb20be90
This commit is contained in:
fbarchard@google.com 2015-03-16 18:08:12 +00:00
parent ca5b1bd58b
commit e408a3759f
1 changed files with 56 additions and 40 deletions
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96
source/row_common.cc
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@ -994,30 +994,34 @@ void I400ToARGBRow_C(const uint8* src_y, uint8* dst_argb, int width) {
}
}
// YUV to RGB conversion constants.
// BT.601 YUV to RGB reference
// R = (Y - 16) * 1.164 - V * -1.596
// G = (Y - 16) * 1.164 - U * 0.391 - V * 0.813
// B = (Y - 16) * 1.164 - U * -2.018
// Y contribution to R,G,B. Scale and bias.
// TODO(fbarchard): Consider moving constants into a common header.
#define YG 18997 /* round(1.164 * 64 * 256 * 256 / 257) */
#define YGB 1160 /* 1.164 * 64 * 16 - adjusted for even error distribution */
#define YGB -1160 /* 1.164 * 64 * -16 + 64 / 2 */
// U and V contributions to R,G,B.
#define UB -128 /* -min(128, round(2.018 * 64)) */
#define UG 25 /* -round(-0.391 * 64) */
#define VG 52 /* -round(-0.813 * 64) */
#define VR -102 /* -round(1.596 * 64) */
#define UB -128 /* max(-128, round(-2.018 * 64)) */
#define UG 25 /* round(0.391 * 64) */
#define VG 52 /* round(0.813 * 64) */
#define VR -102 /* round(-1.596 * 64) */
// Bias values to subtract 16 from Y and 128 from U and V.
#define BB (UB * 128 - YGB)
#define BG (UG * 128 + VG * 128 - YGB)
#define BR (VR * 128 - YGB)
#define BB (UB * 128 + YGB)
#define BG (UG * 128 + VG * 128 + YGB)
#define BR (VR * 128 + YGB)
// C reference code that mimics the YUV assembly.
static __inline void YuvPixel(uint8 y, uint8 u, uint8 v,
uint8* b, uint8* g, uint8* r) {
uint32 y1 = (uint32)(y * 0x0101 * YG) >> 16;
*b = Clamp((int32)(BB - ( u * UB) + y1) >> 6);
*g = Clamp((int32)(BG - (v * VG + u * UG) + y1) >> 6);
*r = Clamp((int32)(BR - (v * VR ) + y1) >> 6);
*b = Clamp((int32)(-( u * UB) + y1 + BB) >> 6);
*g = Clamp((int32)(-(v * VG + u * UG) + y1 + BG) >> 6);
*r = Clamp((int32)(-(v * VR ) + y1 + BR) >> 6);
}
// C reference code that mimics the YUV assembly.
@ -1038,6 +1042,46 @@ static __inline void YPixel(uint8 y, uint8* b, uint8* g, uint8* r) {
#undef BG
#undef BR
// JPEG YUV to RGB reference
// * R = Y - V * -1.40200
// * G = Y - U * 0.34414 - V * 0.71414
// * B = Y - U * -1.77200
// Y contribution to R,G,B. Scale and bias.
// TODO(fbarchard): Consider moving constants into a common header.
#define YGJ 16320 /* round(1.000 * 64 * 256 * 256 / 257) */
#define YGBJ 32 /* 64 / 2 */
// U and V contributions to R,G,B.
#define UBJ -113 /* round(-1.77200 * 64) */
#define UGJ 22 /* round(0.34414 * 64) */
#define VGJ 46 /* round(0.71414 * 64) */
#define VRJ -90 /* round(-1.40200 * 64) */
// Bias values to subtract 16 from Y and 128 from U and V.
#define BBJ (UBJ * 128 + YGBJ)
#define BGJ (UGJ * 128 + VGJ * 128 + YGBJ)
#define BRJ (VRJ * 128 + YGBJ)
// C reference code that mimics the YUV assembly.
static __inline void YuvJPixel(uint8 y, uint8 u, uint8 v,
uint8* b, uint8* g, uint8* r) {
uint32 y1 = (uint32)(y * 0x0101 * YGJ) >> 16;
*b = Clamp((int32)(-( u * UBJ) + y1 + BBJ) >> 6);
*g = Clamp((int32)(-(v * VGJ + u * UGJ) + y1 + BGJ) >> 6);
*r = Clamp((int32)(-(v * VRJ ) + y1 + BRJ) >> 6);
}
#undef YGJ
#undef YGBJ
#undef UBJ
#undef UGJ
#undef VGJ
#undef VRJ
#undef BBJ
#undef BGJ
#undef BRJ
#if !defined(LIBYUV_DISABLE_NEON) && \
(defined(__ARM_NEON__) || defined(__aarch64__) || defined(LIBYUV_NEON))
// C mimic assembly.
@ -1110,34 +1154,6 @@ void I422ToARGBRow_C(const uint8* src_y,
}
}
// C reference code that mimics the YUV assembly.
// * R = Y + 1.40200 * Cr
// * G = Y - 0.34414 * Cb - 0.71414 * Cr
// * B = Y + 1.77200 * Cb
#define YGJ 64 /* (int8)round(1.000 * 64) */
#define UBJ 113 /* (int8)round(1.772 * 64) */
#define UGJ -22 /* (int8)round(-0.34414 * 64) */
#define URJ 0
#define VBJ 0
#define VGJ -46 /* (int8)round(-0.71414 * 64) */
#define VRJ 90 /* (int8)round(1.402 * 64) */
// Bias
#define BBJ (UBJ * 128 + VBJ * 128)
#define BGJ (UGJ * 128 + VGJ * 128)
#define BRJ (URJ * 128 + VRJ * 128)
static __inline void YuvJPixel(uint8 y, uint8 u, uint8 v,
uint8* b, uint8* g, uint8* r) {
uint32 y1 = (uint32)(y * YGJ);
*b = Clamp((int32)(u * UBJ + v * VBJ + y1 - BBJ) >> 6);
*g = Clamp((int32)(u * UGJ + v * VGJ + y1 - BGJ) >> 6);
*r = Clamp((int32)(u * URJ + v * VRJ + y1 - BRJ) >> 6);
}
void J422ToARGBRow_C(const uint8* src_y,
const uint8* src_u,
const uint8* src_v,