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authorNiklas Haas <git@haasn.xyz>2020-05-29 21:39:05 +0200
committerNiklas Haas <git@haasn.xyz>2020-06-15 01:24:09 +0200
commitc9f6c458ea54f595127684a3bcd94f578ec42b1f (patch)
tree12a145ef85a83821926af0e9e18a67a9be5413d1
parentef6bc8504a945eb6492b8ed46fd5a1afaaf32182 (diff)
downloadmpv-ref_white.tar.bz2
mpv-ref_white.tar.xz
vo_gpu: add BT.2390 tone-mappingref_white
Implementation copy/pasted from: https://code.videolan.org/videolan/libplacebo/-/commit/f793fc0480f This brings mpv's tone mapping more in line with industry standard practices, for a hopefully more consistent result across the board. Note that we ignore the black point adjustment of the tone mapping entirely. In theory we could revisit this, if we ever make black point compensation part of the mpv rendering pipeline.
-rw-r--r--DOCS/man/options.rst3
-rw-r--r--video/out/gpu/video.c5
-rw-r--r--video/out/gpu/video.h1
-rw-r--r--video/out/gpu/video_shaders.c59
4 files changed, 61 insertions, 7 deletions
diff --git a/DOCS/man/options.rst b/DOCS/man/options.rst
index 4850439a8a..209b857850 100644
--- a/DOCS/man/options.rst
+++ b/DOCS/man/options.rst
@@ -6058,6 +6058,9 @@ The following video options are currently all specific to ``--vo=gpu`` and
color/brightness accuracy. This is roughly equivalent to
``--tone-mapping=reinhard --tone-mapping-param=0.24``. If possible,
you should also enable ``--hdr-compute-peak`` for the best results.
+ bt.2390
+ Perceptual tone mapping curve (EETF) specified in ITU-R Report BT.2390.
+ This is the recommended curve to use for typical HDR-mastered content.
(Default)
gamma
Fits a logarithmic transfer between the tone curves.
diff --git a/video/out/gpu/video.c b/video/out/gpu/video.c
index 500ec6af22..dedeed7001 100644
--- a/video/out/gpu/video.c
+++ b/video/out/gpu/video.c
@@ -322,7 +322,7 @@ static const struct gl_video_opts gl_video_opts_def = {
.background = {0, 0, 0, 255},
.gamma = 1.0f,
.tone_map = {
- .curve = TONE_MAPPING_HABLE,
+ .curve = TONE_MAPPING_BT_2390,
.curve_param = NAN,
.max_boost = 1.0,
.decay_rate = 100.0,
@@ -382,7 +382,8 @@ const struct m_sub_options gl_video_conf = {
{"reinhard", TONE_MAPPING_REINHARD},
{"hable", TONE_MAPPING_HABLE},
{"gamma", TONE_MAPPING_GAMMA},
- {"linear", TONE_MAPPING_LINEAR})},
+ {"linear", TONE_MAPPING_LINEAR},
+ {"bt.2390", TONE_MAPPING_BT_2390})},
{"hdr-compute-peak", OPT_CHOICE(tone_map.compute_peak,
{"auto", 0},
{"yes", 1},
diff --git a/video/out/gpu/video.h b/video/out/gpu/video.h
index 4c079d463c..4e442a5e6d 100644
--- a/video/out/gpu/video.h
+++ b/video/out/gpu/video.h
@@ -94,6 +94,7 @@ enum tone_mapping {
TONE_MAPPING_HABLE,
TONE_MAPPING_GAMMA,
TONE_MAPPING_LINEAR,
+ TONE_MAPPING_BT_2390,
};
struct gl_tone_map_opts {
diff --git a/video/out/gpu/video_shaders.c b/video/out/gpu/video_shaders.c
index ba7caeaeec..5bc32dcd3b 100644
--- a/video/out/gpu/video_shaders.c
+++ b/video/out/gpu/video_shaders.c
@@ -649,6 +649,15 @@ static void hdr_update_peak(struct gl_shader_cache *sc,
GLSL(})
}
+static inline float pq_delinearize(float x)
+{
+ x *= MP_REF_WHITE / 10000.0;
+ x = powf(x, PQ_M1);
+ x = (PQ_C1 + PQ_C2 * x) / (1.0 + PQ_C3 * x);
+ x = pow(x, PQ_M2);
+ return x;
+}
+
// Tone map from a known peak brightness to the range [0,1]. If ref_peak
// is 0, we will use peak detection instead
static void pass_tone_map(struct gl_shader_cache *sc,
@@ -672,12 +681,18 @@ static void pass_tone_map(struct gl_shader_cache *sc,
GLSLF("vec3 sig = color.rgb;\n");
+ // This function always operates on an absolute scale, so ignore the
+ // dst_peak normalization for it
+ float dst_scale = dst_peak;
+ if (opts->curve == TONE_MAPPING_BT_2390)
+ dst_scale = 1.0;
+
// Rescale the variables in order to bring it into a representation where
// 1.0 represents the dst_peak. This is because all of the tone mapping
// algorithms are defined in such a way that they map to the range [0.0, 1.0].
- if (dst_peak > 1.0) {
- GLSLF("sig *= 1.0/%f;\n", dst_peak);
- GLSLF("sig_peak *= 1.0/%f;\n", dst_peak);
+ if (dst_scale > 1.0) {
+ GLSLF("sig *= 1.0/%f;\n", dst_scale);
+ GLSLF("sig_peak *= 1.0/%f;\n", dst_scale);
}
GLSL(float sig_orig = sig[sig_idx];)
@@ -744,6 +759,40 @@ static void pass_tone_map(struct gl_shader_cache *sc,
break;
}
+ case TONE_MAPPING_BT_2390:
+ // We first need to encode both sig and sig_peak into PQ space
+ GLSLF("vec4 sig_pq = vec4(sig.rgb, sig_peak); \n"
+ "sig_pq *= vec4(1.0/%f); \n"
+ "sig_pq = pow(sig_pq, vec4(%f)); \n"
+ "sig_pq = (vec4(%f) + vec4(%f) * sig_pq) \n"
+ " / (vec4(1.0) + vec4(%f) * sig_pq); \n"
+ "sig_pq = pow(sig_pq, vec4(%f)); \n",
+ 10000.0 / MP_REF_WHITE, PQ_M1, PQ_C1, PQ_C2, PQ_C3, PQ_M2);
+ // Encode both the signal and the target brightness to be relative to
+ // the source peak brightness, and figure out the target peak in this space
+ GLSLF("float scale = 1.0 / sig_pq.a; \n"
+ "sig_pq.rgb *= vec3(scale); \n"
+ "float maxLum = %f * scale; \n",
+ pq_delinearize(dst_peak));
+ // Apply piece-wise hermite spline
+ GLSLF("float ks = 1.5 * maxLum - 0.5; \n"
+ "vec3 tb = (sig_pq.rgb - vec3(ks)) / vec3(1.0 - ks); \n"
+ "vec3 tb2 = tb * tb; \n"
+ "vec3 tb3 = tb2 * tb; \n"
+ "vec3 pb = (2.0 * tb3 - 3.0 * tb2 + vec3(1.0)) * vec3(ks) + \n"
+ " (tb3 - 2.0 * tb2 + tb) * vec3(1.0 - ks) + \n"
+ " (-2.0 * tb3 + 3.0 * tb2) * vec3(maxLum); \n"
+ "sig = mix(pb, sig_pq.rgb, lessThan(sig_pq.rgb, vec3(ks))); \n");
+ // Convert back from PQ space to linear light
+ GLSLF("sig *= vec3(sig_pq.a); \n"
+ "sig = pow(sig, vec3(1.0/%f)); \n"
+ "sig = max(sig - vec3(%f), 0.0) / \n"
+ " (vec3(%f) - vec3(%f) * sig); \n"
+ "sig = pow(sig, vec3(1.0/%f)); \n"
+ "sig *= vec3(%f); \n",
+ PQ_M2, PQ_C1, PQ_C2, PQ_C3, PQ_M1, 10000.0 / MP_REF_WHITE);
+ break;
+
default:
abort();
}
@@ -754,11 +803,11 @@ static void pass_tone_map(struct gl_shader_cache *sc,
// Mix between the per-channel tone mapped and the linear tone mapped
// signal based on the desaturation strength
if (opts->desat > 0) {
- float base = 0.18 * dst_peak;
+ float base = 0.18 * dst_scale;
GLSLF("float coeff = max(sig[sig_idx] - %f, 1e-6) / "
" max(sig[sig_idx], 1.0);\n", base);
GLSLF("coeff = %f * pow(coeff, %f);\n", opts->desat, opts->desat_exp);
- GLSLF("color.rgb = mix(sig_lin, %f * sig, coeff);\n", dst_peak);
+ GLSLF("color.rgb = mix(sig_lin, %f * sig, coeff);\n", dst_scale);
} else {
GLSL(color.rgb = sig_lin;)
}