[FFmpeg-devel] [PATCH 1/2] avcodec/libjxldec: properly tag output colorspace

Leo Izen leo.izen at gmail.com
Tue May 3 18:44:02 EEST 2022


Whether an ICC profile is present or not, the decoder
should now properly tag the colorspace of pixel data
received by the decoder.
---
 libavcodec/libjxl.h    |   9 +++
 libavcodec/libjxldec.c | 121 ++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 127 insertions(+), 3 deletions(-)

diff --git a/libavcodec/libjxl.h b/libavcodec/libjxl.h
index 5387c438fd..2b388dc45d 100644
--- a/libavcodec/libjxl.h
+++ b/libavcodec/libjxl.h
@@ -27,8 +27,17 @@
 #ifndef AVCODEC_LIBJXL_H
 #define AVCODEC_LIBJXL_H
 
+#include "libavutil/rational.h"
+
 #include <jxl/memory_manager.h>
 
+#define FF_JXL_WP_D65_X av_make_q(3127, 10000)
+#define FF_JXL_WP_D65_Y av_make_q(3290, 10000)
+#define FF_JXL_WP_E_X av_make_q(1, 3)
+#define FF_JXL_WP_E_Y av_make_q(1, 3)
+#define FF_JXL_WP_DCI_X av_make_q(314, 1000)
+#define FF_JXL_WP_DCI_Y av_make_q(351, 1000)
+
 /**
  * Transform threadcount in ffmpeg to one used by libjxl.
  *
diff --git a/libavcodec/libjxldec.c b/libavcodec/libjxldec.c
index cd4bca3343..bd308590ab 100644
--- a/libavcodec/libjxldec.c
+++ b/libavcodec/libjxldec.c
@@ -28,9 +28,11 @@
 #include "libavutil/buffer.h"
 #include "libavutil/common.h"
 #include "libavutil/error.h"
+#include "libavutil/mastering_display_metadata.h"
 #include "libavutil/mem.h"
 #include "libavutil/pixdesc.h"
 #include "libavutil/pixfmt.h"
+#include "libavutil/rational.h"
 #include "libavutil/frame.h"
 
 #include "avcodec.h"
@@ -189,16 +191,129 @@ static int libjxl_decode_frame(AVCodecContext *avctx, AVFrame *frame, int *got_f
             continue;
         case JXL_DEC_COLOR_ENCODING:
             av_log(avctx, AV_LOG_DEBUG, "COLOR_ENCODING event emitted\n");
-            jret = JxlDecoderGetICCProfileSize(ctx->decoder, &ctx->jxl_pixfmt, JXL_COLOR_PROFILE_TARGET_ORIGINAL, &iccp_len);
+            jret = JxlDecoderGetICCProfileSize(ctx->decoder, &ctx->jxl_pixfmt, JXL_COLOR_PROFILE_TARGET_DATA, &iccp_len);
             if (jret == JXL_DEC_SUCCESS && iccp_len > 0) {
                 av_buffer_unref(&ctx->iccp);
                 ctx->iccp = av_buffer_alloc(iccp_len);
                 if (!ctx->iccp)
                     return AVERROR(ENOMEM);
-                jret = JxlDecoderGetColorAsICCProfile(ctx->decoder, &ctx->jxl_pixfmt, JXL_COLOR_PROFILE_TARGET_ORIGINAL, ctx->iccp->data, iccp_len);
-                if (jret != JXL_DEC_SUCCESS)
+                jret = JxlDecoderGetColorAsICCProfile(ctx->decoder, &ctx->jxl_pixfmt, JXL_COLOR_PROFILE_TARGET_DATA, ctx->iccp->data, iccp_len);
+                if (jret != JXL_DEC_SUCCESS) {
+                    av_log(avctx, AV_LOG_WARNING, "Unable to obtain ICCP from header\n");
                     av_buffer_unref(&ctx->iccp);
+                }
             }
+            avctx->color_range = frame->color_range = AVCOL_RANGE_JPEG;
+            if (ctx->iccp) {
+                /* if the ICCP is present, libjxl outputs sRGB */
+                if (ctx->jxl_pixfmt.num_channels >= 3)
+                    avctx->color_primaries = AVCOL_PRI_BT709;
+                /* linear sRGB if float values, standard sRGB if int values */
+                avctx->color_trc = ctx->jxl_pixfmt.data_type == JXL_TYPE_FLOAT ? AVCOL_TRC_LINEAR : AVCOL_TRC_IEC61966_2_1;
+            } else {
+                JxlColorEncoding jxl_encoding;
+                jret = JxlDecoderGetColorAsEncodedProfile(ctx->decoder, &ctx->jxl_pixfmt, JXL_COLOR_PROFILE_TARGET_DATA, &jxl_encoding);
+                if (jret != JXL_DEC_SUCCESS) {
+                    av_log(avctx, AV_LOG_WARNING, "Unable to obtain color encoding from header\n");
+                    continue;
+                }
+
+                if (ctx->jxl_pixfmt.num_channels >= 3) {
+                    AVMasteringDisplayMetadata *mdm = NULL;
+
+                    avctx->colorspace = frame->colorspace = AVCOL_SPC_RGB;
+
+                    /* dont set MDM if D65 white point is used */
+                    /* unless the custom primaries are set */
+                    if (jxl_encoding.primaries == JXL_PRIMARIES_CUSTOM ||
+                        jxl_encoding.white_point != JXL_WHITE_POINT_D65) {
+                        mdm = av_mastering_display_metadata_create_side_data(frame);
+                        if (!mdm)
+                            return AVERROR(ENOMEM);
+                    }
+
+                    switch (jxl_encoding.primaries) {
+                    case JXL_PRIMARIES_SRGB:
+                        avctx->color_primaries = AVCOL_PRI_BT709;
+                        break;
+                    case JXL_PRIMARIES_2100:
+                        avctx->color_primaries = AVCOL_PRI_BT2020;
+                        break;
+                    case JXL_PRIMARIES_P3:
+                        avctx->color_primaries = AVCOL_PRI_SMPTE431;
+                        break;
+                    case JXL_PRIMARIES_CUSTOM:
+                        mdm->display_primaries[0][0] = av_d2q(jxl_encoding.primaries_red_xy[0], 100000);
+                        mdm->display_primaries[0][1] = av_d2q(jxl_encoding.primaries_red_xy[1], 100000);
+                        mdm->display_primaries[1][0] = av_d2q(jxl_encoding.primaries_green_xy[0], 100000);
+                        mdm->display_primaries[1][1] = av_d2q(jxl_encoding.primaries_green_xy[1], 100000);
+                        mdm->display_primaries[2][0] = av_d2q(jxl_encoding.primaries_blue_xy[0], 100000);
+                        mdm->display_primaries[2][1] = av_d2q(jxl_encoding.primaries_blue_xy[1], 100000);
+                        mdm->has_primaries = 1;
+                        break;
+                    default:
+                        av_log(avctx, AV_LOG_WARNING, "Unknown JXL color primaries: %d\n", jxl_encoding.primaries);
+                        avctx->color_primaries = AVCOL_PRI_UNSPECIFIED;
+                    }
+
+                    switch (jxl_encoding.white_point) {
+                    case JXL_WHITE_POINT_D65:
+                        if (mdm) {
+                            mdm->white_point[0] = FF_JXL_WP_D65_X;
+                            mdm->white_point[1] = FF_JXL_WP_D65_Y;
+                        }
+                        break;
+                    case JXL_WHITE_POINT_E:
+                        mdm->white_point[0] = FF_JXL_WP_E_X;
+                        mdm->white_point[1] = FF_JXL_WP_E_Y;
+                        break;
+                    case JXL_WHITE_POINT_DCI:
+                        mdm->white_point[0] = FF_JXL_WP_DCI_X;
+                        mdm->white_point[1] = FF_JXL_WP_DCI_Y;
+                        break;
+                    case JXL_WHITE_POINT_CUSTOM:
+                        mdm->white_point[0] = av_d2q(jxl_encoding.white_point_xy[0], 100000);
+                        mdm->white_point[1] = av_d2q(jxl_encoding.white_point_xy[1], 100000);
+                        break;
+                    default:
+                        av_log(avctx, AV_LOG_WARNING, "Unknown JXL white point: %d\n", jxl_encoding.white_point);
+                    }
+                }
+
+                switch (jxl_encoding.transfer_function) {
+                case JXL_TRANSFER_FUNCTION_709:
+                    avctx->color_trc = AVCOL_TRC_BT709;
+                    break;
+                case JXL_TRANSFER_FUNCTION_LINEAR:
+                    avctx->color_trc = AVCOL_TRC_LINEAR;
+                    break;
+                case JXL_TRANSFER_FUNCTION_SRGB:
+                    avctx->color_trc = AVCOL_TRC_IEC61966_2_1;
+                    break;
+                case JXL_TRANSFER_FUNCTION_PQ:
+                case JXL_TRANSFER_FUNCTION_DCI:
+                    avctx->color_trc = AVCOL_TRC_SMPTE428;
+                    break;
+                case JXL_TRANSFER_FUNCTION_HLG:
+                    avctx->color_trc = AVCOL_TRC_ARIB_STD_B67;
+                    break;
+                case JXL_TRANSFER_FUNCTION_GAMMA:
+                    if (jxl_encoding.gamma == 2.2) {
+                        avctx->color_trc = AVCOL_TRC_GAMMA22;
+                    } else if (jxl_encoding.gamma == 2.8) {
+                        avctx->color_trc = AVCOL_TRC_GAMMA28;
+                    } else {
+                        av_log(avctx, AV_LOG_WARNING, "Unsupported gamma transfer: %f\n", jxl_encoding.gamma);
+                        avctx->color_trc = AVCOL_TRC_UNSPECIFIED;
+                    }
+                    break;
+                default:
+                    av_log(avctx, AV_LOG_WARNING, "Unknown transfer function: %d\n", jxl_encoding.transfer_function);
+                    avctx->color_trc = AVCOL_TRC_UNSPECIFIED;
+                }
+            }
+            frame->color_trc = avctx->color_trc;
+            frame->color_primaries = avctx->color_primaries;
             continue;
         case JXL_DEC_NEED_IMAGE_OUT_BUFFER:
             av_log(avctx, AV_LOG_DEBUG, "NEED_IMAGE_OUT_BUFFER event emitted\n");
-- 
2.36.0



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