blind

commit 2b646382a5745b65d32e6bc66b9cf41149673c8c
parent 233e70bd856bb1b90844b51b0e7b3534e804c4ef
Author: Mattias Andrée <maandree@kth.se>
Date:   Sat, 23 Sep 2017 19:14:42 +0200

Fix conversion of Y value

Signed-off-by: Mattias Andrée <maandree@kth.se>

Diffstat:
M
TODO
 | 
3
+--
M
src/blind-convert.c
 | 
36
++++++++++++++++++------------------
M
src/blind-from-video.c
 | 
14
+++++++-------
M
src/blind-to-video.c
 | 
12
++++++------
M
src/util/colour.h
 | 
12
++++++------

5 files changed, 38 insertions(+), 39 deletions(-)
diff --git a/TODO b/TODO
@@ -1,5 +1,4 @@
-Why does blind-from-video produce darker images than blind-from-image and
-why does blind-to-video produce brighter images than blind-to-image?
+Conversion either from or to video changes the brightness of the primitives (but not greys)
 
 blind-transform		affine transformation by matrix multiplication, -[xy] for tiling, -s for
 				improve quality on downscaling (pixels' neighbours must not change)
diff --git a/src/blind-convert.c b/src/blind-convert.c
@@ -47,12 +47,12 @@ static size_t
 remove_alpha_u16(uint16_t *buf, size_t n)
 {
 	size_t i, j;
-	long int a, max = (long int)UINT16_MAX;
+	long int a, max = (long int)UINT16_MAX, ymax = 0xDAF4L;
 	for (i = j = 0; i < n; i += 4, j += 3) {
 		a = (long int)(buf[i + 3]);
-		buf[j + 0] = (uint16_t)(((long int)(buf[i + 0]) -  16L * 256L) * a / max +  16L * 256L);
-		buf[j + 1] = (uint16_t)(((long int)(buf[i + 1]) - 128L * 256L) * a / max + 128L * 256L);
-		buf[j + 2] = (uint16_t)(((long int)(buf[i + 2]) - 128L * 256L) * a / max + 128L * 256L);
+		buf[j + 0] = (uint16_t)(((long int)(buf[i + 0]) - 0x1001L) * a / ymax + 0x1001L);
+		buf[j + 1] = (uint16_t)(((long int)(buf[i + 1]) - 0x8000L) * a /  max + 0x8000L);
+		buf[j + 2] = (uint16_t)(((long int)(buf[i + 2]) - 0x8000L) * a /  max + 0x8000L);
 	}
 	return j;
 }
@@ -108,12 +108,12 @@ raw1_to_raw0(uint16_t *buf, size_t n)
 #define RAW2_TO_RAW3(TYPE, WITH_ALPHA)\
 	do {\
 		size_t i;\
-		TYPE max = (TYPE)UINT16_MAX;\
+		TYPE max = (TYPE)UINT16_MAX, ymax = (TYPE)0xDAF4;\
 		if (sizeof(*in) > sizeof(*out)) {\
 			for (i = 0; i < n; i += 3 + WITH_ALPHA) {\
-				out[i + 0] = (TYPE)((long int)(in[i + 0]) -  16L * 256L) / max;\
-				out[i + 1] = (TYPE)((long int)(in[i + 1]) - 128L * 256L) / max;\
-				out[i + 2] = (TYPE)((long int)(in[i + 2]) - 128L * 256L) / max;\
+				out[i + 0] = (TYPE)((long int)(in[i + 0]) - 0x1001L) / ymax;\
+				out[i + 1] = (TYPE)((long int)(in[i + 1]) - 0x8000L) /  max;\
+				out[i + 2] = (TYPE)((long int)(in[i + 2]) - 0x8000L) /  max;\
 				if (WITH_ALPHA)\
 					out[i + 3] = (TYPE)(in[i + 3]) / max;\
 			}\
@@ -121,9 +121,9 @@ raw1_to_raw0(uint16_t *buf, size_t n)
 			for (i = n; i; i -= 3 + WITH_ALPHA) {\
 				if (WITH_ALPHA)\
 					out[i - 1] = (TYPE)(in[i - 1]) / max;\
-				out[i - 1 - WITH_ALPHA] = (TYPE)((long int)(in[i - 1 - WITH_ALPHA]) - 128L * 256L) / max;\
-				out[i - 2 - WITH_ALPHA] = (TYPE)((long int)(in[i - 2 - WITH_ALPHA]) - 128L * 256L) / max;\
-				out[i - 3 - WITH_ALPHA] = (TYPE)((long int)(in[i - 3 - WITH_ALPHA]) -  16L * 256L) / max;\
+				out[i - 1 - WITH_ALPHA] = (TYPE)((long int)(in[i - 1 - WITH_ALPHA]) - 0x8000L) /  max;\
+				out[i - 2 - WITH_ALPHA] = (TYPE)((long int)(in[i - 2 - WITH_ALPHA]) - 0x8000L) /  max;\
+				out[i - 3 - WITH_ALPHA] = (TYPE)((long int)(in[i - 3 - WITH_ALPHA]) - 0x1001L) / ymax;\
 			}\
 		}\
 	} while (0)
@@ -136,13 +136,13 @@ static void raw2a_to_raw3a_f (uint16_t *in, float  *out, size_t n) { RAW2_TO_RAW
 #define RAW3_TO_RAW2(TYPE, WITH_ALPHA)\
 	do {\
 		size_t i;\
-		TYPE max = (TYPE)UINT16_MAX;\
+		TYPE max = (TYPE)UINT16_MAX, ymax = (TYPE)0xDAF4;\
 		long int y, u, v;\
 		if (sizeof(*in) > sizeof(*out)) {\
 			for (i = 0; i < n; i += 3 + WITH_ALPHA) {\
-				y = (long int)(in[i + 0] * max) +  16L * 256L;\
-				u = (long int)(in[i + 1] * max) + 128L * 256L;\
-				v = (long int)(in[i + 2] * max) + 128L * 256L;\
+				y = (long int)(in[i + 0] * ymax) + 0x1001L;\
+				u = (long int)(in[i + 1] *  max) + 0x8000L;\
+				v = (long int)(in[i + 2] *  max) + 0x8000L;\
 				out[i + 0] = (uint16_t)CLIP(0, y, 0xFFFFL);\
 				out[i + 1] = (uint16_t)CLIP(0, u, 0xFFFFL);\
 				out[i + 2] = (uint16_t)CLIP(0, v, 0xFFFFL);\
@@ -157,9 +157,9 @@ static void raw2a_to_raw3a_f (uint16_t *in, float  *out, size_t n) { RAW2_TO_RAW
 					v = (long int)(in[i - 1] * max);\
 					out[i - 1] = (uint16_t)CLIP(0, v, 0xFFFFL); \
 				}\
-				v = (long int)(in[i - 1 - WITH_ALPHA] * max) + 128L * 256L;\
-				u = (long int)(in[i - 2 - WITH_ALPHA] * max) + 128L * 256L;\
-				y = (long int)(in[i - 3 - WITH_ALPHA] * max) +  16L * 256L;\
+				v = (long int)(in[i - 1 - WITH_ALPHA] *  max) + 0x8000L;\
+				u = (long int)(in[i - 2 - WITH_ALPHA] *  max) + 0x8000L;\
+				y = (long int)(in[i - 3 - WITH_ALPHA] * ymax) + 0x1001L;\
 				out[i - 1 - WITH_ALPHA] = (uint16_t)CLIP(0, v, 0xFFFFL);\
 				out[i - 2 - WITH_ALPHA] = (uint16_t)CLIP(0, u, 0xFFFFL);\
 				out[i - 3 - WITH_ALPHA] = (uint16_t)CLIP(0, y, 0xFFFFL);\
diff --git a/src/blind-from-video.c b/src/blind-from-video.c
@@ -75,7 +75,7 @@ get_metadata(char *file, size_t *width, size_t *height)
 	do {\
 		typedef TYPE pixel_t[4];\
 		size_t i, ptr;\
-		TYPE y, u, v, max = (TYPE)UINT16_MAX;\
+		TYPE y, u, v, max = (TYPE)UINT16_MAX, ymax = (TYPE)0xDAF4;\
 		TYPE r, g, b;\
 		pixel_t pixels[1024];\
 		uint16_t *pix;\
@@ -83,9 +83,9 @@ get_metadata(char *file, size_t *width, size_t *height)
 			for (ptr = i = 0; ptr < n; ptr += 8) {\
 				pix = (uint16_t *)(buf + ptr);\
 				pixels[i][3] = 1;\
-				y = (TYPE)((long int)(le16toh(pix[1])) -  16L * 256L);\
-				u = (TYPE)((long int)(le16toh(pix[2])) - 128L * 256L);\
-				v = (TYPE)((long int)(le16toh(pix[3])) - 128L * 256L);\
+				y = (TYPE)((long int)(le16toh(pix[1])) - 0x1001L);\
+				u = (TYPE)((long int)(le16toh(pix[2])) - 0x8000L);\
+				v = (TYPE)((long int)(le16toh(pix[3])) - 0x8000L);\
 				scaled_yuv_to_ciexyz(y, u, v, pixels[i] + 0,\
 						     pixels[i] + 1, pixels[i] + 2);\
 				if (++i == 1024) {\
@@ -97,9 +97,9 @@ get_metadata(char *file, size_t *width, size_t *height)
 			for (ptr = i = 0; ptr < n; ptr += 8) {\
 				pix = (uint16_t *)(buf + ptr);\
 				pixels[i][3] = le16toh(pix[0]) / max;\
-				y = (TYPE)((long int)le16toh(pix[1]) -  16L * 256L) / max;\
-				u = (TYPE)((long int)le16toh(pix[2]) - 128L * 256L) / max;\
-				v = (TYPE)((long int)le16toh(pix[3]) - 128L * 256L) / max;\
+				y = (TYPE)((long int)le16toh(pix[1]) - 0x1001L) / ymax;\
+				u = (TYPE)((long int)le16toh(pix[2]) - 0x8000L) / max;\
+				v = (TYPE)((long int)le16toh(pix[3]) - 0x8000L) / max;\
 				yuv_to_srgb(y, u, v, &r, &g, &b);\
 				r = srgb_decode(r);\
 				g = srgb_decode(g);\
diff --git a/src/blind-to-video.c b/src/blind-to-video.c
@@ -99,9 +99,9 @@ PROCESS(struct stream *stream, size_t n)
 		for (ptr = 0; ptr < n; ptr += 4 * sizeof(TYPE)) {
 			pixel = (TYPE *)(buf + ptr);
 			ciexyz_to_scaled_yuv(pixel[0], pixel[1], pixel[2], &r, &g, &b);
-			y = (long int)r +  16L * 256L;
-			u = (long int)g + 128L * 256L;
-			v = (long int)b + 128L * 256L;
+			y = (long int)r + 0x1001L;
+			u = (long int)g + 0x8000L;
+			v = (long int)b + 0x8000L;
 			*pixels++ = 0xFFFFU;
 			*pixels++ = htole((uint16_t)CLIP(0, y, 0xFFFFL));
 			*pixels++ = htole((uint16_t)CLIP(0, u, 0xFFFFL));
@@ -118,9 +118,9 @@ PROCESS(struct stream *stream, size_t n)
 			g = srgb_encode(g);
 			b = srgb_encode(b);
 			srgb_to_yuv(r, g, b, pixel + 0, pixel + 1, pixel + 2);
-			y = (long int)(pixel[0] * 0xFFFFL) +  16L * 256L;
-			u = (long int)(pixel[1] * 0xFFFFL) + 128L * 256L;
-			v = (long int)(pixel[2] * 0xFFFFL) + 128L * 256L;
+			y = (long int)(pixel[0] * 0xDAF4L) + 0x1001L;
+			u = (long int)(pixel[1] * 0xFFFFL) + 0x8000L;
+			v = (long int)(pixel[2] * 0xFFFFL) + 0x8000L;
 			*pixels++ = htole((uint16_t)CLIP(0, a, 0xFFFFL));
 			*pixels++ = htole((uint16_t)CLIP(0, y, 0xFFFFL));
 			*pixels++ = htole((uint16_t)CLIP(0, u, 0xFFFFL));
diff --git a/src/util/colour.h b/src/util/colour.h
@@ -99,20 +99,20 @@ MATRIX_MULTIPLY_FUNCTIONS(srgb_to_ciexyz,
                           0.950302838552371742508739771438)
 
 MATRIX_MULTIPLY_FUNCTIONS(scaled_yuv_to_ciexyz,
-                           0.00001450325106667098632156481796684488472237717360,
+                           0.00001450325106667098632156481796684488472237717360 / 0.8552986953536278,
                            0.00000345586790639342739093228633329157872822179343,
                            0.00000400923398630552893485111398685916128670214675,
-                           0.00001525902189669641837040624243737596543724066578,
+                           0.00001525902189669641837040624243737596543724066578 / 0.8552986953536278,
                           -0.00000207722814409390653614547427030512238843584782,
                           -0.00000263898607692305410302407824019166326934282552,
-                           0.00001661446153041708825425643025752719950105529279,
+                           0.00001661446153041708825425643025752719950105529279 / 0.8552986953536278,
                            0.00002885925752619118069149627137104374696718878113,
                           -0.00000071781086875769179526501342566979779746816348)
 
 MATRIX_MULTIPLY_FUNCTIONS(ciexyz_to_scaled_yuv,
-                            26625.38231027395886485464870929718017578125,
-                            40524.0090949436053051613271236419677734375,
-                             -271.5313105642117079696618020534515380859375,
+                            26625.38231027395886485464870929718017578125   * 0.8552986953536278,
+                            40524.0090949436053051613271236419677734375    * 0.8552986953536278,
+                             -271.5313105642117079696618020534515380859375 * 0.8552986953536278,
                            -11278.3751445417292416095733642578125,
                            -26409.91773157499847002327442169189453125,
                             34100.5706543184860493056476116180419921875,