When looking at the full range matrices, it becomes obvious that the difference
between the standard matrices and the full range matrices is that column 0
is multiplied by 1.164 and columns 1 and 2 are muliplied by 1.138. This can
be accomplished by multiplying the contrast with 1.164 and the saturation with
1.138/1.164. Removes the need to specify separate full range matrices.
We can also incorporate the ybias in the brightness simplifying the
calculation somewhat.
Signed-off-by: Thomas Hellstrom <thellst...@vmware.com>
---
src/gallium/auxiliary/vl/vl_csc.c | 50 ++++++++++-----------------------------
1 file changed, 12 insertions(+), 38 deletions(-)
diff --git a/src/gallium/auxiliary/vl/vl_csc.c
b/src/gallium/auxiliary/vl/vl_csc.c
index fc11f73..bb2cc58 100644
--- a/src/gallium/auxiliary/vl/vl_csc.c
+++ b/src/gallium/auxiliary/vl/vl_csc.c
@@ -108,18 +108,6 @@ static const vl_csc_matrix bt_601 =
};
/*
- * Converts ITU-R BT.601 YCbCr pixels to RGB pixels where:
- * Y is in [16,235], Cb and Cr are in [16,240]
- * R, G, and B are in [0,255]
- */
-static const vl_csc_matrix bt_601_full =
-{
- { 1.164f, 0.0f, 1.596f, 0.0f, },
- { 1.164f, -0.391f, -0.813f, 0.0f, },
- { 1.164f, 2.018f, 0.0f, 0.0f, }
-};
-
-/*
* Converts ITU-R BT.709 YCbCr pixels to RGB pixels where:
* Y is in [16,235], Cb and Cr are in [16,240]
* R, G, and B are in [16,235]
@@ -131,18 +119,6 @@ static const vl_csc_matrix bt_709 =
{ 1.0f, 1.816f, 0.0f, 0.0f, }
};
-/*
- * Converts ITU-R BT.709 YCbCr pixels to RGB pixels where:
- * Y is in [16,235], Cb and Cr are in [16,240]
- * R, G, and B are in [0,255]
- */
-static const vl_csc_matrix bt_709_full =
-{
- { 1.164f, 0.0f, 1.793f, 0.0f, },
- { 1.164f, -0.213f, -0.534f, 0.0f, },
- { 1.164f, 2.115f, 0.0f, 0.0f, }
-};
-
static const vl_csc_matrix smpte240m =
{
{ 1.0f, 0.0f, 1.582f, 0.0f, },
@@ -150,13 +126,6 @@ static const vl_csc_matrix smpte240m =
{ 1.0f, 1.833f, 0.0f, 0.0f, }
};
-static const vl_csc_matrix smpte240m_full =
-{
- { 1.164f, 0.0f, 1.794f, 0.0f, },
- { 1.164f, -0.258f, -0.543f, 0.0f, },
- { 1.164f, 2.079f, 0.0f, 0.0f, }
-};
-
static const vl_csc_matrix identity =
{
{ 1.0f, 0.0f, 0.0f, 0.0f, },
@@ -176,7 +145,6 @@ void vl_csc_get_matrix(enum VL_CSC_COLOR_STANDARD cs,
bool full_range,
vl_csc_matrix *matrix)
{
- float ybias = full_range ? -16.0f/255.0f : 0.0f;
float cbbias = -128.0f/255.0f;
float crbias = -128.0f/255.0f;
@@ -188,17 +156,23 @@ void vl_csc_get_matrix(enum VL_CSC_COLOR_STANDARD cs,
const vl_csc_matrix *cstd;
+ if (full_range) {
+ b -= -16.0f/255.0f; /* Adjust for the y bias */
+ c *= 1.164f; /* Adjust for the y range */
+ s *= 1.138f/1.164f; /* Adjust for the chroma range */
+ }
+
assert(matrix);
switch (cs) {
case VL_CSC_COLOR_STANDARD_BT_601:
- cstd = full_range ? &bt_601_full : &bt_601;
+ cstd = &bt_601;
break;
case VL_CSC_COLOR_STANDARD_BT_709:
- cstd = full_range ? &bt_709_full : &bt_709;
+ cstd = &bt_709;
break;
case VL_CSC_COLOR_STANDARD_SMPTE_240M:
- cstd = full_range ? &smpte240m_full : &smpte240m;
+ cstd = &smpte240m;
break;
case VL_CSC_COLOR_STANDARD_IDENTITY:
default:
@@ -210,21 +184,21 @@ void vl_csc_get_matrix(enum VL_CSC_COLOR_STANDARD cs,
(*matrix)[0][0] = c * (*cstd)[0][0];
(*matrix)[0][1] = c * (*cstd)[0][1] * s * cosf(h) - c * (*cstd)[0][2] * s *
sinf(h);
(*matrix)[0][2] = c * (*cstd)[0][2] * s * cosf(h) + c * (*cstd)[0][1] * s *
sinf(h);
- (*matrix)[0][3] = (*cstd)[0][3] + (*cstd)[0][0] * c * (b + ybias) +
+ (*matrix)[0][3] = (*cstd)[0][3] + (*cstd)[0][0] * c * b +
(*cstd)[0][1] * (c * cbbias * s * cosf(h) + c * crbias *
s * sinf(h)) +
(*cstd)[0][2] * (c * crbias * s * cosf(h) - c * cbbias *
s * sinf(h));
(*matrix)[1][0] = c * (*cstd)[1][0];
(*matrix)[1][1] = c * (*cstd)[1][1] * s * cosf(h) - c * (*cstd)[1][2] * s *
sinf(h);
(*matrix)[1][2] = c * (*cstd)[1][2] * s * cosf(h) + c * (*cstd)[1][1] * s *
sinf(h);
- (*matrix)[1][3] = (*cstd)[1][3] + (*cstd)[1][0] * c * (b + ybias) +
+ (*matrix)[1][3] = (*cstd)[1][3] + (*cstd)[1][0] * c * b +
(*cstd)[1][1] * (c * cbbias * s * cosf(h) + c * crbias *
s * sinf(h)) +
(*cstd)[1][2] * (c * crbias * s * cosf(h) - c * cbbias *
s * sinf(h));
(*matrix)[2][0] = c * (*cstd)[2][0];
(*matrix)[2][1] = c * (*cstd)[2][1] * s * cosf(h) - c * (*cstd)[2][2] * s *
sinf(h);
(*matrix)[2][2] = c * (*cstd)[2][2] * s * cosf(h) + c * (*cstd)[2][1] * s *
sinf(h);
- (*matrix)[2][3] = (*cstd)[2][3] + (*cstd)[2][0] * c * (b + ybias) +
+ (*matrix)[2][3] = (*cstd)[2][3] + (*cstd)[2][0] * c * b +
(*cstd)[2][1] * (c * cbbias * s * cosf(h) + c * crbias *
s * sinf(h)) +
(*cstd)[2][2] * (c * crbias * s * cosf(h) - c * cbbias *
s * sinf(h));
}
--
2.5.0
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