avcodec/exr: Add support for applying a transfer characteristic curve to OpenEXR inputs.

Signed-off-by: Kevin Wheatley <kevin.j.wheatley@gmail.com>

1 files changed, 96 insertions, 27 deletions

diff --git a/libavcodec/exr.c b/libavcodec/exr.c
index b9de7c1c0a..d97cdc7cb9 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 },
 };