vo_opengl: implement ARIB STD-B68 (HLG) HDR TRC

This HDR function is unique in that it's still display-referred, it just
allows for values above the reference peak (super-highlights). The
official standard doesn't actually document this very well, but the
nominal peak turns out to be exactly 12.0 - so we normalize to this
value internally in mpv. (This lets us preserve the property that the
textures are encoded in the range [0,1], preventing clipping and making
the best use of an integer texture's range)

This was grouped together with SMPTE ST2084 when checking libavutil
compatibility since they were added in the same release window, in a
similar timeframe.

1 files changed, 4 insertions, 3 deletions

diff --git a/wscript b/wscript
index 1915f7cd67..e29d1ab403 100644
--- a/wscript
+++ b/wscript
@@ -498,10 +498,11 @@ FFmpeg/Libav libraries. You need at least {0}. Aborting.".format(libav_versions_
                                 '(void)offsetof(AVFrame, hw_frames_ctx)',
                                 use='libav'),
     }, {
-        'name': 'avutil-st2084',
-        'desc': 'libavutil AVCOL_TRC_SMPTEST2084',
+        'name': 'avutil-hdr',
+        'desc': 'libavutil HDR TRCs',
         'func': check_statement('libavutil/pixfmt.h',
-                                'AVCOL_TRC_SMPTEST2084',
+                                'AVCOL_TRC_SMPTEST2084,'
+                                'AVCOL_TRC_ARIB_STD_B67',
                                 use='libav'),
     }
 ]