This adds the actual usage and allows for command lines similar to this:
ffmpeg -apply_trc bt709 -i linear.exr bt709.png
ffmpeg -apply_trc smpte2084 -i linear.exr smpte2084.png
ffmpeg -apply_trc iec61966_2_1 -i linear.exr sRGB.png
Which assuming the correct primaries in the linear OpenEXR file will
generate the appropriate file.
Kevin
From 25aedae9dc873abcba3a6db3dff503c64cd9e066 Mon Sep 17 00:00:00 2001
From: Kevin Wheatley <kevin.j.wheat...@gmail.com>
Date: Tue, 1 Sep 2015 11:02:53 +0100
Subject: [PATCH 5/5] Add support for applying a transfer characteristic curve to OpenEXR inputs.
Signed-off-by: Kevin Wheatley <kevin.j.wheat...@gmail.com>
---
libavcodec/exr.c | 123 ++++++++++++++++++++++++++++++++++++++++++------------
1 files changed, 96 insertions(+), 27 deletions(-)
diff --git a/libavcodec/exr.c b/libavcodec/exr.c
index b9de7c1..8794da5 100644
--- a/libavcodec/exr.c
+++ b/libavcodec/exr.c
@@ -37,6 +37,7 @@
#include "libavutil/imgutils.h"
#include "libavutil/intfloat.h"
#include "libavutil/opt.h"
+#include "libavutil/color_utils.h"
#include "avcodec.h"
#include "bytestream.h"
@@ -110,6 +111,7 @@ typedef struct EXRContext {
const char *layer;
+ enum AVColorTransferCharacteristic apply_trc_type;
float gamma;
uint16_t gamma_table[65536];
} EXRContext;
@@ -842,6 +844,7 @@ static int decode_block(AVCodecContext *avctx, void *tdata,
int bxmin = s->xmin * 2 * s->desc->nb_components;
int i, x, buf_size = s->buf_size;
float one_gamma = 1.0f / s->gamma;
+ avpriv_trc_function trc_func = avpriv_get_trc_function_from_trc(s->apply_trc_type);
int ret;
line_offset = AV_RL64(s->gb.buffer + jobnr * 8);
@@ -921,24 +924,43 @@ static int decode_block(AVCodecContext *avctx, void *tdata,
ptr_x += s->xmin * s->desc->nb_components;
if (s->pixel_type == EXR_FLOAT) {
// 32-bit
- for (x = 0; x < xdelta; x++) {
- union av_intfloat32 t;
- t.i = bytestream_get_le32(&r);
- if (t.f > 0.0f) /* avoid negative values */
- t.f = powf(t.f, one_gamma);
- *ptr_x++ = exr_flt2uint(t.i);
-
- t.i = bytestream_get_le32(&g);
- if (t.f > 0.0f)
- t.f = powf(t.f, one_gamma);
- *ptr_x++ = exr_flt2uint(t.i);
-
- t.i = bytestream_get_le32(&b);
- if (t.f > 0.0f)
- t.f = powf(t.f, one_gamma);
- *ptr_x++ = exr_flt2uint(t.i);
- if (channel_buffer[3])
- *ptr_x++ = exr_flt2uint(bytestream_get_le32(&a));
+ if (trc_func) {
+ for (x = 0; x < xdelta; x++) {
+ union av_intfloat32 t;
+ t.i = bytestream_get_le32(&r);
+ t.f = trc_func(t.f);
+ *ptr_x++ = exr_flt2uint(t.i);
+
+ t.i = bytestream_get_le32(&g);
+ t.f = trc_func(t.f);
+ *ptr_x++ = exr_flt2uint(t.i);
+
+ t.i = bytestream_get_le32(&b);
+ t.f = trc_func(t.f);
+ *ptr_x++ = exr_flt2uint(t.i);
+ if (channel_buffer[3])
+ *ptr_x++ = exr_flt2uint(bytestream_get_le32(&a));
+ }
+ } else {
+ for (x = 0; x < xdelta; x++) {
+ union av_intfloat32 t;
+ t.i = bytestream_get_le32(&r);
+ if (t.f > 0.0f) /* avoid negative values */
+ t.f = powf(t.f, one_gamma);
+ *ptr_x++ = exr_flt2uint(t.i);
+
+ t.i = bytestream_get_le32(&g);
+ if (t.f > 0.0f)
+ t.f = powf(t.f, one_gamma);
+ *ptr_x++ = exr_flt2uint(t.i);
+
+ t.i = bytestream_get_le32(&b);
+ if (t.f > 0.0f)
+ t.f = powf(t.f, one_gamma);
+ *ptr_x++ = exr_flt2uint(t.i);
+ if (channel_buffer[3])
+ *ptr_x++ = exr_flt2uint(bytestream_get_le32(&a));
+ }
}
} else {
// 16-bit
@@ -1364,21 +1386,31 @@ static av_cold int decode_init(AVCodecContext *avctx)
uint32_t i;
union av_intfloat32 t;
float one_gamma = 1.0f / s->gamma;
+ avpriv_trc_function trc_func = NULL;
s->avctx = avctx;
- if (one_gamma > 0.9999f && one_gamma < 1.0001f) {
- for (i = 0; i < 65536; ++i)
- s->gamma_table[i] = exr_halflt2uint(i);
- } else {
+ trc_func = avpriv_get_trc_function_from_trc(s->apply_trc_type);
+ if (trc_func) {
for (i = 0; i < 65536; ++i) {
t = exr_half2float(i);
- /* If negative value we reuse half value */
- if (t.f <= 0.0f) {
+ t.f = trc_func(t.f);
+ s->gamma_table[i] = exr_flt2uint(t.i);
+ }
+ } else {
+ if (one_gamma > 0.9999f && one_gamma < 1.0001f) {
+ for (i = 0; i < 65536; ++i)
s->gamma_table[i] = exr_halflt2uint(i);
- } else {
- t.f = powf(t.f, one_gamma);
- s->gamma_table[i] = exr_flt2uint(t.i);
+ } else {
+ for (i = 0; i < 65536; ++i) {
+ t = exr_half2float(i);
+ /* If negative value we reuse half value */
+ if (t.f <= 0.0f) {
+ s->gamma_table[i] = exr_halflt2uint(i);
+ } else {
+ t.f = powf(t.f, one_gamma);
+ s->gamma_table[i] = exr_flt2uint(t.i);
+ }
}
}
}
@@ -1427,6 +1459,43 @@ static const AVOption options[] = {
AV_OPT_TYPE_STRING, { .str = "" }, 0, 0, VD },
{ "gamma", "Set the float gamma value when decoding", OFFSET(gamma),
AV_OPT_TYPE_FLOAT, { .dbl = 1.0f }, 0.001, FLT_MAX, VD },
+
+ // XXX: Note the abuse of the enum using AVCOL_TRC_UNSPECIFIED to subsume the existing gamma option
+ { "apply_trc", "color transfer characteristics to apply to EXR linear input", OFFSET(apply_trc_type),
+ AV_OPT_TYPE_INT, {.i64 = AVCOL_TRC_UNSPECIFIED }, 1, AVCOL_TRC_NB-1, VD, "apply_trc_type"},
+ { "bt709", "BT.709", 0,
+ AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_BT709 }, INT_MIN, INT_MAX, VD, "apply_trc_type"},
+ { "gamma", "gamma", 0,
+ AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_UNSPECIFIED }, INT_MIN, INT_MAX, VD, "apply_trc_type"},
+ { "gamma22", "BT.470 M", 0,
+ AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_GAMMA22 }, INT_MIN, INT_MAX, VD, "apply_trc_type"},
+ { "gamma28", "BT.470 BG", 0,
+ AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_GAMMA28 }, INT_MIN, INT_MAX, VD, "apply_trc_type"},
+ { "smpte170m", "SMPTE 170 M", 0,
+ AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_SMPTE170M }, INT_MIN, INT_MAX, VD, "apply_trc_type"},
+ { "smpte240m", "SMPTE 240 M", 0,
+ AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_SMPTE240M }, INT_MIN, INT_MAX, VD, "apply_trc_type"},
+ { "linear", "Linear", 0,
+ AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_LINEAR }, INT_MIN, INT_MAX, VD, "apply_trc_type"},
+ { "log", "Log", 0,
+ AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_LOG }, INT_MIN, INT_MAX, VD, "apply_trc_type"},
+ { "log_sqrt", "Log square root", 0,
+ AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_LOG_SQRT }, INT_MIN, INT_MAX, VD, "apply_trc_type"},
+ { "iec61966_2_4", "IEC 61966-2-4", 0,
+ AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_IEC61966_2_4 }, INT_MIN, INT_MAX, VD, "apply_trc_type"},
+ { "bt1361", "BT.1361", 0,
+ AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_BT1361_ECG }, INT_MIN, INT_MAX, VD, "apply_trc_type"},
+ { "iec61966_2_1", "IEC 61966-2-1", 0,
+ AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_IEC61966_2_1 }, INT_MIN, INT_MAX, VD, "apply_trc_type"},
+ { "bt2020_10bit", "BT.2020 - 10 bit", 0,
+ AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_BT2020_10 }, INT_MIN, INT_MAX, VD, "apply_trc_type"},
+ { "bt2020_12bit", "BT.2020 - 12 bit", 0,
+ AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_BT2020_12 }, INT_MIN, INT_MAX, VD, "apply_trc_type"},
+ { "smpte2084", "SMPTE ST 2084", 0,
+ AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_SMPTEST2084 }, INT_MIN, INT_MAX, VD, "apply_trc_type"},
+ { "smpte428_1", "SMPTE ST 428-1", 0,
+ AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_SMPTEST428_1 }, INT_MIN, INT_MAX, VD, "apply_trc_type"},
+
{ NULL },
};
--
1.7.1
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