commit 4154609e5de76bc8858d3f86e0af09ba2700c488
parent 2b646382a5745b65d32e6bc66b9cf41149673c8c
Author: Mattias Andrée <maandree@kth.se>
Date: Sat, 23 Sep 2017 21:57:45 +0200
Fix colour distortion
This matrices are not convert to or from the proper YUV colour space both
rather the ones used in videos. srgb_to_yuv was created by converting the
image [sRGB(100%, 0, 0); sRGB(0, 100%, 0); sRGB(0, 0, 100%)] to YUV with
FFmpeg and transposing the matrix. yuv_to_srgb is the inversion of that
matrix, the values in the first column should all be 1 but are not due to
rounding/truncation error.
Signed-off-by: Mattias Andrée <maandree@kth.se>
Diffstat:
5 files changed, 49 insertions(+), 44 deletions(-)
diff --git a/TODO b/TODO
@@ -1,5 +1,3 @@
-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)
blind-apply-map remap pixels (distortion) using the X and Y values, -[xy] for tiling, -s for
diff --git a/src/blind-convert.c b/src/blind-convert.c
@@ -47,7 +47,7 @@ static size_t
remove_alpha_u16(uint16_t *buf, size_t n)
{
size_t i, j;
- long int a, max = (long int)UINT16_MAX, ymax = 0xDAF4L;
+ long int a, max = (long int)0xFF00L, 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]) - 0x1001L) * a / ymax + 0x1001L);
@@ -108,19 +108,23 @@ 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, ymax = (TYPE)0xDAF4;\
+ TYPE max = (TYPE)0xFF00L, ymax = (TYPE)0xDAF4L;\
if (sizeof(*in) > sizeof(*out)) {\
for (i = 0; i < n; i += 3 + WITH_ALPHA) {\
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)\
+ if (WITH_ALPHA) {\
out[i + 3] = (TYPE)(in[i + 3]) / max;\
+ out[i + 3] = CLIP(0, out[i + 3], 1);\
+ }\
}\
} else {\
for (i = n; i; i -= 3 + WITH_ALPHA) {\
- if (WITH_ALPHA)\
+ if (WITH_ALPHA) {\
out[i - 1] = (TYPE)(in[i - 1]) / max;\
+ out[i - 1] = CLIP(0, out[i - 1], 1);\
+ }\
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;\
@@ -136,7 +140,7 @@ 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, ymax = (TYPE)0xDAF4;\
+ TYPE max = (TYPE)0xFF00L, ymax = (TYPE)0xDAF4L;\
long int y, u, v;\
if (sizeof(*in) > sizeof(*out)) {\
for (i = 0; i < n; i += 3 + WITH_ALPHA) {\
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, ymax = (TYPE)0xDAF4;\
+ TYPE y, u, v, max = (TYPE)0xFF00L, ymax = (TYPE)0xDAF4L;\
TYPE r, g, b;\
pixel_t pixels[1024];\
uint16_t *pix;\
@@ -97,6 +97,7 @@ 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;\
+ pixels[i][3] = CLIP(0, pixels[i][3], 1);\
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;\
diff --git a/src/blind-to-video.c b/src/blind-to-video.c
@@ -119,8 +119,8 @@ PROCESS(struct stream *stream, size_t n)
b = srgb_encode(b);
srgb_to_yuv(r, g, b, pixel + 0, pixel + 1, pixel + 2);
y = (long int)(pixel[0] * 0xDAF4L) + 0x1001L;
- u = (long int)(pixel[1] * 0xFFFFL) + 0x8000L;
- v = (long int)(pixel[2] * 0xFFFFL) + 0x8000L;
+ u = (long int)(pixel[1] * 0xFF00L) + 0x8000L;
+ v = (long int)(pixel[2] * 0xFF00L) + 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
@@ -57,24 +57,26 @@ SRGB_DECODE(float, _f, f)
MATRIX_MULTIPLY_FUNCTION(FUNCTION_BASE##_f, float, __VA_ARGS__)
MATRIX_MULTIPLY_FUNCTIONS(yuv_to_srgb,
- 1,
- 0.00028328010485821202317155420580263580632163211703,
- 1.14070449590558520291949662350816652178764343261719,
- 1,
- -0.39630886669497211727275498560629785060882568359375,
- -0.58107364288228224857846271333983168005943298339844,
- 1,
- 2.03990003507541306504435851820744574069976806640625,
- 0.00017179031692307700847528739718228507626918144524)
+ 0.99983946058747896756813133833929896354675292968750,
+ -0.00111314629257774910797706979792565107345581054688,
+ 1.59561960249794831945280293439282104372978210449219,
+ 0.99983946058762285247212275862693786621093750000000,
+ -0.39124374513994553126394748687744140625000000000000,
+ -0.81304201036561862814266987697919830679893493652344,
+ 0.99983946058757433572594663928612135350704193115234,
+ 2.01741786772377817982260239659808576107025146484375,
+ 0.00115819721926166407932612401054939255118370056152)
MATRIX_MULTIPLY_FUNCTIONS(srgb_to_yuv,
- 0.299, 0.587, 0.114,
- -0.14662756598240470062854967636667424812912940979004,
- -0.28771586836102963635752871596196200698614120483398,
- 0.43434343434343436474165400795754976570606231689453,
- 0.61456892577224520035628074765554629266262054443359,
- -0.51452282157676354490405401520547457039356231689453,
- -0.10004610419548178035231700278018251992762088775635)
+ 0.29906158567044888174635275390755850821733474731445,
+ 0.58707985442089483107963587826816365122795104980469,
+ 0.11401912509812317519930502385250292718410491943359,
+ -0.14846813725490196067546833091910229995846748352051,
+ -0.29074754901960786490633381617954000830650329589844,
+ 0.43921568627450979782622653146972879767417907714844,
+ 0.43921568627450979782622653146972879767417907714844,
+ -0.36807598039215688734415721228288020938634872436523,
+ -0.07113970588235293823764493481576209887862205505371)
MATRIX_MULTIPLY_FUNCTIONS(ciexyz_to_srgb,
3.240446254647737500675930277794,
@@ -99,26 +101,26 @@ MATRIX_MULTIPLY_FUNCTIONS(srgb_to_ciexyz,
0.950302838552371742508739771438)
MATRIX_MULTIPLY_FUNCTIONS(scaled_yuv_to_ciexyz,
- 0.00001450325106667098632156481796684488472237717360 / 0.8552986953536278,
- 0.00000345586790639342739093228633329157872822179343,
- 0.00000400923398630552893485111398685916128670214675,
- 0.00001525902189669641837040624243737596543724066578 / 0.8552986953536278,
- -0.00000207722814409390653614547427030512238843584782,
- -0.00000263898607692305410302407824019166326934282552,
- 0.00001661446153041708825425643025752719950105529279 / 0.8552986953536278,
- 0.00002885925752619118069149627137104374696718878113,
- -0.00000071781086875769179526501342566979779746816348)
+ 0.00001450092272326647052454150210731853576362482272 / 0.8552986953536278,
+ 0.00000341281577174185336742326911385614351956974133,
+ 0.00000560936853511406815494611324823814868523186306,
+ 0.00001525657222228693664302541510569000138275441714 / 0.8552986953536278,
+ -0.00000205124661398017884712786061685019234346327721,
+ -0.00000369297336083484072815404791745308443751127925,
+ 0.00001661179425452522781048517175328527173405745998 / 0.8552986953536278,
+ 0.00002854205077959434113873959937279778387164697051,
+ -0.00000099119265445913120730111588868593841539222922)
MATRIX_MULTIPLY_FUNCTIONS(ciexyz_to_scaled_yuv,
- 26625.38231027395886485464870929718017578125 * 0.8552986953536278,
- 40524.0090949436053051613271236419677734375 * 0.8552986953536278,
- -271.5313105642117079696618020534515380859375 * 0.8552986953536278,
- -11278.3751445417292416095733642578125,
- -26409.91773157499847002327442169189453125,
- 34100.5706543184860493056476116180419921875,
- 162829.60100012840121053159236907958984375,
- -123829.313212639070115983486175537109375,
- -28411.65702312920984695665538311004638671875)
+ 26633.45812403910895227454602718353271484375 * 0.8552986953536278,
+ 40527.367131481194519437849521636962890625 * 0.8552986953536278,
+ -272.0008243176007454167120158672332763671875 * 0.8552986953536278,
+ -11458.90154486896426533348858356475830078125,
+ -26662.3801805758339469321072101593017578125,
+ 34490.0235254608633113093674182891845703125,
+ 116394.099928013441967777907848358154296875,
+ -88546.58492295184987597167491912841796875,
+ -20281.0410136536011123098433017730712890625)
#undef MATRIX_MULTIPLY_FUNCTIONS
#undef MATRIX_MULTIPLY_FUNCTION
