[FFmpeg-devel] [PATCH] avcodec/exr: deprecate gamma and apply_trc options

[James Almer <jamrial@gmail.com>]

Decoders should not modify sample values, as that's the job of a library like swscale.

Signed-off-by: James Almer <jamrial@gmail.com>
---
 libavcodec/exr.c           | 38 ++++++++++++++++++++++++++------------
 libavcodec/version_major.h |  1 +
 2 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/libavcodec/exr.c b/libavcodec/exr.c
index e1e05902c6..0bd9ce9ebe 100644
--- a/libavcodec/exr.c
+++ b/libavcodec/exr.c
@@ -189,15 +189,17 @@ typedef struct EXRContext {
     const char *layer;
     int selected_part;
 
-    enum AVColorTransferCharacteristic apply_trc_type;
-    float gamma;
 
     uint8_t *offset_table;
 
+#if FF_API_EXR_GAMMA
+    enum AVColorTransferCharacteristic apply_trc_type;
+    float gamma;
     uint16_t gamma_table[65536];
+    Float2HalfTables f2h_tables;
+#endif
 
     Half2FloatTables h2f_tables;
-    Float2HalfTables f2h_tables;
 } EXRContext;
 
 static int zip_uncompress(const EXRContext *s, const uint8_t *src, int compressed_size,
@@ -1194,8 +1196,10 @@ static int decode_block(AVCodecContext *avctx, void *tdata,
     int data_xoffset, data_yoffset, data_window_offset, xsize, ysize;
     int i, x, buf_size = s->buf_size;
     int c, rgb_channel_count;
+#if FF_API_EXR_GAMMA
     float one_gamma = 1.0f / s->gamma;
     av_csp_trc_function trc_func = av_csp_trc_func_from_id(s->apply_trc_type);
+#endif
     int ret;
 
     line_offset = AV_RL64(s->gb.buffer + jobnr * 8);
@@ -1387,6 +1391,7 @@ static int decode_block(AVCodecContext *avctx, void *tdata,
                     s->compression == EXR_DWAA ||
                     s->compression == EXR_DWAB) {
                     // 32-bit
+#if FF_API_EXR_GAMMA
                     if (trc_func && (!c || (c < 3 && s->desc->flags & AV_PIX_FMT_FLAG_PLANAR))) {
                         for (int x = 0; x < xsize; x++, ptr_x += step) {
                             float f = av_int2float(bytestream_get_le32(&src));
@@ -1399,19 +1404,20 @@ static int decode_block(AVCodecContext *avctx, void *tdata,
                                 f = powf(f, one_gamma);
                             AV_WN32A(ptr_x, av_float2int(f));
                         }
-                    } else {
+                    } else
+#endif
                         for (int x = 0; x < xsize; x++, ptr_x += step)
                             AV_WN32A(ptr_x, bytestream_get_le32(&src));
-                    }
                 } else if (s->pixel_type == EXR_HALF) {
                     // 16-bit
+#if FF_API_EXR_GAMMA
                     if (one_gamma != 1.f || (trc_func && (!c || (c < 3 && s->desc->flags & AV_PIX_FMT_FLAG_PLANAR)))) {
                         for (int x = 0; x < xsize; x++, ptr_x += step)
                             AV_WN16A(ptr_x, s->gamma_table[bytestream_get_le16(&src)]);
-                    } else {
+                    } else
+#endif
                         for (int x = 0; x < xsize; x++, ptr_x += step)
                             AV_WN16A(ptr_x, bytestream_get_le16(&src));
-                    }
                 }
 
                 // Zero out the end if xmax+1 is not w
@@ -2093,10 +2099,12 @@ static int decode_frame(AVCodecContext *avctx, AVFrame *picture,
         return AVERROR_INVALIDDATA;
     }
 
+#if FF_API_EXR_GAMMA
     if (s->apply_trc_type != AVCOL_TRC_UNSPECIFIED)
         avctx->color_trc = s->apply_trc_type;
     else if (s->gamma > 0.9999f && s->gamma < 1.0001f)
         avctx->color_trc = AVCOL_TRC_LINEAR;
+#endif
 
     switch (s->compression) {
     case EXR_RAW:
@@ -2221,13 +2229,15 @@ static int decode_frame(AVCodecContext *avctx, AVFrame *picture,
 static av_cold int decode_init(AVCodecContext *avctx)
 {
     EXRContext *s = avctx->priv_data;
+#if FF_API_EXR_GAMMA
     uint32_t i;
     union av_intfloat32 t;
     float one_gamma = 1.0f / s->gamma;
     av_csp_trc_function trc_func = NULL;
+    ff_init_float2half_tables(&s->f2h_tables);
+#endif
 
     ff_init_half2float_tables(&s->h2f_tables);
-    ff_init_float2half_tables(&s->f2h_tables);
 
     s->avctx              = avctx;
 
@@ -2237,6 +2247,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
     ff_bswapdsp_init(&s->bbdsp);
 #endif
 
+#if FF_API_EXR_GAMMA
     trc_func = av_csp_trc_func_from_id(s->apply_trc_type);
     if (trc_func) {
         for (i = 0; i < 65536; ++i) {
@@ -2256,6 +2267,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
             }
         }
     }
+#endif
 
     // allocate thread data, used for non EXR_RAW compression types
     s->thread_data = av_calloc(avctx->thread_count, sizeof(*s->thread_data));
@@ -2298,12 +2310,13 @@ static const AVOption options[] = {
         AV_OPT_TYPE_STRING, { .str = "" }, 0, 0, VD },
     { "part",  "Set the decoding part", OFFSET(selected_part),
         AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, VD },
-    { "gamma", "Set the float gamma value when decoding", OFFSET(gamma),
-        AV_OPT_TYPE_FLOAT, { .dbl = 1.0f }, 0.001, FLT_MAX, VD },
+#if FF_API_EXR_GAMMA
+    { "gamma", "Set the float gamma value when decoding (deprecated, use a scaler)", OFFSET(gamma),
+        AV_OPT_TYPE_FLOAT, { .dbl = 1.0f }, 0.001, FLT_MAX, VD | AV_OPT_FLAG_DEPRECATED },
 
     // 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, .unit = "apply_trc_type"},
+    { "apply_trc", "color transfer characteristics to apply to EXR linear input (deprecated, use a scaler)", OFFSET(apply_trc_type),
+        AV_OPT_TYPE_INT, {.i64 = AVCOL_TRC_UNSPECIFIED }, 1, AVCOL_TRC_NB-1, VD | AV_OPT_FLAG_DEPRECATED, .unit = "apply_trc_type"},
     { "bt709",        "BT.709",           0,
         AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_BT709 },        INT_MIN, INT_MAX, VD, .unit = "apply_trc_type"},
     { "gamma",        "gamma",            0,
@@ -2336,6 +2349,7 @@ static const AVOption options[] = {
         AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_SMPTEST2084 },  INT_MIN, INT_MAX, VD, .unit = "apply_trc_type"},
     { "smpte428_1",   "SMPTE ST 428-1",   0,
         AV_OPT_TYPE_CONST, {.i64 = AVCOL_TRC_SMPTEST428_1 }, INT_MIN, INT_MAX, VD, .unit = "apply_trc_type"},
+#endif
 
     { NULL },
 };
diff --git a/libavcodec/version_major.h b/libavcodec/version_major.h
index 35df5eb779..55e79d5505 100644
--- a/libavcodec/version_major.h
+++ b/libavcodec/version_major.h
@@ -50,6 +50,7 @@
 #define FF_API_QUALITY_FACTOR      (LIBAVCODEC_VERSION_MAJOR < 62)
 #define FF_API_V408_CODECID        (LIBAVCODEC_VERSION_MAJOR < 62)
 #define FF_API_CODEC_PROPS         (LIBAVCODEC_VERSION_MAJOR < 63)
+#define FF_API_EXR_GAMMA           (LIBAVCODEC_VERSION_MAJOR < 63)
 
 // reminder to remove the OMX encoder on next major bump
 #define FF_CODEC_OMX               (LIBAVCODEC_VERSION_MAJOR < 62)
-- 
2.48.1

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