PR #20690 opened by Kacper Michajłow (kasper93) URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20690 Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20690.patch
The previously used gamma value of 1.961 was derived from the BT.709 OETF, which does not define an EOTF. The proper EOTF was later specified in BT.1886. This patch updates the approximation to match the BT.1886 EOTF assuming a perfect black level, which corresponds to a pure power gamma of 2.4. Fixes: https://github.com/mpv-player/mpv/issues/13438 From 6c6cb15777ae5d4005d2397fb088bffce899ee41 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Kacper=20Michaj=C5=82ow?= <[email protected]> Date: Sun, 3 Aug 2025 20:15:21 +0200 Subject: [PATCH] avutil/csp: correct gamma approximation to match BT.1886 EOTF The previously used gamma value of 1.961 was derived from the BT.709 OETF, which does not define an EOTF. The proper EOTF was later specified in BT.1886. This patch updates the approximation to match the BT.1886 EOTF assuming a perfect black level, which corresponds to a pure power gamma of 2.4. Fixes: https://github.com/mpv-player/mpv/issues/13438 --- libavutil/csp.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/libavutil/csp.c b/libavutil/csp.c index 75ac871616..52a8f01ab1 100644 --- a/libavutil/csp.c +++ b/libavutil/csp.c @@ -133,12 +133,12 @@ enum AVColorPrimaries av_csp_primaries_id_from_desc(const AVColorPrimariesDesc * } static const double approximate_gamma[AVCOL_TRC_NB] = { - [AVCOL_TRC_BT709] = 1.961, - [AVCOL_TRC_SMPTE170M] = 1.961, - [AVCOL_TRC_SMPTE240M] = 1.961, - [AVCOL_TRC_BT1361_ECG] = 1.961, - [AVCOL_TRC_BT2020_10] = 1.961, - [AVCOL_TRC_BT2020_12] = 1.961, + [AVCOL_TRC_BT709] = 2.4, + [AVCOL_TRC_SMPTE170M] = 2.4, + [AVCOL_TRC_SMPTE240M] = 2.4, + [AVCOL_TRC_BT1361_ECG] = 2.4, + [AVCOL_TRC_BT2020_10] = 2.4, + [AVCOL_TRC_BT2020_12] = 2.4, [AVCOL_TRC_GAMMA22] = 2.2, [AVCOL_TRC_IEC61966_2_1] = 2.2, [AVCOL_TRC_GAMMA28] = 2.8, -- 2.49.1 _______________________________________________ ffmpeg-devel mailing list -- [email protected] To unsubscribe send an email to [email protected]
