avcodec: add API for automatic handling of icc profiles

This functionally already exists, but as pointed out in #9672 and #9673,
requiring users to manually include filters is clumsy, error-prone and
hard to use together with tools like ffplay.

To streamline ICC profile support, add a new AVCodecContext flag to
globally enable reading and writing ICC profiles, automatically, for all
appropriate media types.

Note that this commit only includes the new API. The implementation is
split off to separate commits for readability.

Signed-off-by: Niklas Haas <git@haasn.dev>

doc/APIchanges

@@ -14,6 +14,11 @@ libavutil:     2021-04-27
 
 API changes, most recent first:
 
+2022-07-xx - xxxxxxxxx - lavc 59.40.100 - avcodec.h
+  Add the AV_CODEC_FLAG2_ICC_PROFILES flag to AVCodecContext, to enable
+  automatic reading and writing of embedded ICC profiles in image files.
+  The "flags2" option now supports the corresponding flag "icc_profiles".
+
 2022-07-xx - xxxxxxxxxx - lavu 57.30.100 - frame.h
   Add AVFrame.duration, deprecate AVFrame.pkt_duration.
 

doc/codecs.texi

@@ -644,6 +644,8 @@ for codecs that support it. See also @file{doc/examples/export_mvs.c}.
 Do not skip samples and export skip information as frame side data.
 @item ass_ro_flush_noop
 Do not reset ASS ReadOrder field on flush.
+@item icc_profiles
+Generate/parse embedded ICC profiles from/to colorimetry tags.
 @end table
 
 @item export_side_data @var{flags} (@emph{decoding/encoding,audio,video,subtitles})

libavcodec/avcodec.h

@@ -331,6 +331,12 @@ typedef struct RcOverride{
  * Do not reset ASS ReadOrder field on flush (subtitles decoding)
  */
 #define AV_CODEC_FLAG2_RO_FLUSH_NOOP  (1 << 30)
+/**
+ * Generate/parse ICC profiles on encode/decode, as appropriate for the type of
+ * file. No effect on codecs which cannot contain embedded ICC profiles, or
+ * when compiled without support for lcms2.
+ */
+#define AV_CODEC_FLAG2_ICC_PROFILES   (1U << 31)
 
 /* Unsupported options :
  *              Syntax Arithmetic coding (SAC)

libavcodec/options_table.h

@@ -83,6 +83,7 @@ static const AVOption avcodec_options[] = {
 {"export_mvs", "export motion vectors through frame side data", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG2_EXPORT_MVS}, INT_MIN, INT_MAX, V|D, "flags2"},
 {"skip_manual", "do not skip samples and export skip information as frame side data", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG2_SKIP_MANUAL}, INT_MIN, INT_MAX, A|D, "flags2"},
 {"ass_ro_flush_noop", "do not reset ASS ReadOrder field on flush", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG2_RO_FLUSH_NOOP}, INT_MIN, INT_MAX, S|D, "flags2"},
+{"icc_profiles", "generate/parse embedded ICC profiles from/to colorimetry tags", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_FLAG2_ICC_PROFILES}, INT_MIN, INT_MAX, S|D, "flags2"},
 {"export_side_data", "Export metadata as side data", OFFSET(export_side_data), AV_OPT_TYPE_FLAGS, {.i64 = DEFAULT}, 0, UINT_MAX, A|V|S|D|E, "export_side_data"},
 {"mvs", "export motion vectors through frame side data", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_EXPORT_DATA_MVS}, INT_MIN, INT_MAX, V|D, "export_side_data"},
 {"prft", "export Producer Reference Time through packet side data", 0, AV_OPT_TYPE_CONST, {.i64 = AV_CODEC_EXPORT_DATA_PRFT}, INT_MIN, INT_MAX, A|V|S|E, "export_side_data"},

libavcodec/version.h

@@ -29,7 +29,7 @@
 
 #include "version_major.h"
 
-#define LIBAVCODEC_VERSION_MINOR  39
+#define LIBAVCODEC_VERSION_MINOR  40
 #define LIBAVCODEC_VERSION_MICRO 100
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \