[FFmpeg-devel] [PATCH] avcodec/libjxldec: fix gamma22 and gamma28 recognization

From: Leo Izen <leo.izen@gmail.com>
To: ffmpeg-devel@ffmpeg.org
Cc: Leo Izen <leo.izen@gmail.com>
Subject: [FFmpeg-devel] [PATCH] avcodec/libjxldec: fix gamma22 and gamma28 recognization
Date: Wed, 18 Jan 2023 09:24:05 -0500
Message-ID: <20230118142405.23568-1-leo.izen@gmail.com> (raw)

Gamma 2.2 and Gamma 2.8 are tagged in the file as 0.45455 and 0.35714,
respectively (i.e. 1/2.2 and 1/2.8). Trying to identify them as 2.2 and
2.8 instead of these values will cause the transfer function to not
properly be recognized. This patch fixes this.
---
 libavcodec/libjxldec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/libjxldec.c b/libavcodec/libjxldec.c
index 55c7366f61..0009af9615 100644
--- a/libavcodec/libjxldec.c
+++ b/libavcodec/libjxldec.c
@@ -167,9 +167,9 @@ static enum AVColorTransferCharacteristic libjxl_get_trc(void *avctx, const JxlC
     case JXL_TRANSFER_FUNCTION_DCI: return AVCOL_TRC_SMPTE428;
     case JXL_TRANSFER_FUNCTION_HLG: return AVCOL_TRC_ARIB_STD_B67;
     case JXL_TRANSFER_FUNCTION_GAMMA:
-        if (jxl_color->gamma > 2.199 && jxl_color->gamma < 2.201)
+        if (jxl_color->gamma > 0.45355 && jxl_color->gamma < 0.45555)
             return AVCOL_TRC_GAMMA22;
-        else if (jxl_color->gamma > 2.799 && jxl_color->gamma < 2.801)
+        else if (jxl_color->gamma > 0.35614 && jxl_color->gamma < 0.35814)
             return AVCOL_TRC_GAMMA28;
         else
             av_log(avctx, AV_LOG_WARNING, "Unsupported gamma transfer: %f\n", jxl_color->gamma);
-- 
2.39.0

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