johncf · April 9, 2025 07:24 · Oct 9, 2024 · Oct 9, 2024 · Oct 9, 2024 · Oct 8, 2024
diff --git a/avifenc-hdr.md b/avifenc-hdr.md
@@ -104,3 +104,4 @@ Pillow-HEIF
 - Does `heif_image_handle_get_preferred_decoding_colorspace` or `heif_image_handle_get_nclx_color_profile` work on a handle of an auxiliary image? ([relevant source](https://github.com/strukturag/libheif/blob/88568e07a55627420338bee9685470da4dda34b9/libheif/api/libheif/heif.h#L1181-L1188))
 - pyheif ref: https://github.com/carsales/pyheif/blob/master/pyheif/reader.py#L222-L248
 - https://pillow-heif.readthedocs.io/en/latest/installation.html ([windows requirements](https://stackoverflow.com/questions/40018405/cannot-open-include-file-io-h-no-such-file-or-directory#50210015))
+- https://nokiatech.github.io/heif/examples.html
diff --git a/avifenc-hdr.md b/avifenc-hdr.md
@@ -97,6 +97,7 @@ HDR Gain map
 - https://github.com/colour-science/colour/blob/develop/colour/models/rgb/transfer_functions/itur_bt_709.py#L39
 - https://stackoverflow.com/a/57034526
 - https://github.com/exiftool/exiftool/blob/405674e/lib/Image/ExifTool/Apple.pm#L175 (0x0021 = 33, 0x0030 = 48)
+- https://exiftool.org/forum/index.php?topic=14786.0
 
 Pillow-HEIF
 - https://github.com/strukturag/libheif/blob/88568e07a55627420338bee9685470da4dda34b9/examples/heif_dec.cc#L604

diff --git a/avifenc-hdr.md b/avifenc-hdr.md
@@ -94,6 +94,9 @@ HDR Gain map
 - https://github.com/m13253/heif-hdrgainmap-decode/blob/master/heif-hdrgainmap-decode-y4m.py
 - https://developer.apple.com/documentation/appkit/images_and_pdf/applying_apple_hdr_effect_to_your_photos
 - https://en.wikipedia.org/wiki/Transfer_functions_in_imaging
+- https://github.com/colour-science/colour/blob/develop/colour/models/rgb/transfer_functions/itur_bt_709.py#L39
+- https://stackoverflow.com/a/57034526
+- https://github.com/exiftool/exiftool/blob/405674e/lib/Image/ExifTool/Apple.pm#L175 (0x0021 = 33, 0x0030 = 48)
 
 Pillow-HEIF
 - https://github.com/strukturag/libheif/blob/88568e07a55627420338bee9685470da4dda34b9/examples/heif_dec.cc#L604

diff --git a/avifenc-hdr.md b/avifenc-hdr.md
@@ -98,4 +98,5 @@ HDR Gain map
 Pillow-HEIF
 - https://github.com/strukturag/libheif/blob/88568e07a55627420338bee9685470da4dda34b9/examples/heif_dec.cc#L604
 - Does `heif_image_handle_get_preferred_decoding_colorspace` or `heif_image_handle_get_nclx_color_profile` work on a handle of an auxiliary image? ([relevant source](https://github.com/strukturag/libheif/blob/88568e07a55627420338bee9685470da4dda34b9/libheif/api/libheif/heif.h#L1181-L1188))
+- pyheif ref: https://github.com/carsales/pyheif/blob/master/pyheif/reader.py#L222-L248
 - https://pillow-heif.readthedocs.io/en/latest/installation.html ([windows requirements](https://stackoverflow.com/questions/40018405/cannot-open-include-file-io-h-no-such-file-or-directory#50210015))
diff --git a/avifenc-hdr.md b/avifenc-hdr.md
@@ -85,5 +85,17 @@ Sources:
 
 ## Misc: HDR-merging and Tone-mapping using OpenCV
 
-https://learnopencv.com/high-dynamic-range-hdr-imaging-using-opencv-cpp-python/
-https://docs.opencv.org/3.4/d2/df0/tutorial_py_hdr.html
+- https://learnopencv.com/high-dynamic-range-hdr-imaging-using-opencv-cpp-python/
+- https://docs.opencv.org/3.4/d2/df0/tutorial_py_hdr.html
+
+## Misc: Notes on HDR Gain Map and HEIF-Pillow
+
+HDR Gain map
+- https://github.com/m13253/heif-hdrgainmap-decode/blob/master/heif-hdrgainmap-decode-y4m.py
+- https://developer.apple.com/documentation/appkit/images_and_pdf/applying_apple_hdr_effect_to_your_photos
+- https://en.wikipedia.org/wiki/Transfer_functions_in_imaging
+
+Pillow-HEIF
+- https://github.com/strukturag/libheif/blob/88568e07a55627420338bee9685470da4dda34b9/examples/heif_dec.cc#L604
+- Does `heif_image_handle_get_preferred_decoding_colorspace` or `heif_image_handle_get_nclx_color_profile` work on a handle of an auxiliary image? ([relevant source](https://github.com/strukturag/libheif/blob/88568e07a55627420338bee9685470da4dda34b9/libheif/api/libheif/heif.h#L1181-L1188))
+- https://pillow-heif.readthedocs.io/en/latest/installation.html ([windows requirements](https://stackoverflow.com/questions/40018405/cannot-open-include-file-io-h-no-such-file-or-directory#50210015))
diff --git a/avifenc-hdr.md b/avifenc-hdr.md
@@ -83,7 +83,7 @@ Sources:
 - https://wiki.x266.mov/docs/colorimetry/transfer#14-bt2020-10-bit
 - https://gist.github.com/kiding/fa4876ab4ddc797e3f18c71b3c2eeb3a?permalink_comment_id=4754146#gistcomment-4754146
 
-### Misc: HDR-merging and Tone-mapping using OpenCV
+## Misc: HDR-merging and Tone-mapping using OpenCV
 
 https://learnopencv.com/high-dynamic-range-hdr-imaging-using-opencv-cpp-python/
 https://docs.opencv.org/3.4/d2/df0/tutorial_py_hdr.html
diff --git a/avifenc-hdr.md b/avifenc-hdr.md
@@ -82,3 +82,8 @@ Sources:
 - https://trac.ffmpeg.org/wiki/colorspace
 - https://wiki.x266.mov/docs/colorimetry/transfer#14-bt2020-10-bit
 - https://gist.github.com/kiding/fa4876ab4ddc797e3f18c71b3c2eeb3a?permalink_comment_id=4754146#gistcomment-4754146
+
+### Misc: HDR-merging and Tone-mapping using OpenCV
+
+https://learnopencv.com/high-dynamic-range-hdr-imaging-using-opencv-cpp-python/
+https://docs.opencv.org/3.4/d2/df0/tutorial_py_hdr.html
diff --git a/avifenc-hdr.md b/avifenc-hdr.md
@@ -39,7 +39,7 @@ Generate a look-up table (LUT) with [hlg-tools](https://github.com/wswartzendrub
 hlg-tools/pq2hlg -r 203 -s 128 pq2hlg.cube
 ```
 
-Note: there are three "popular" reference white points in use: 100 nits, 203 nits, and 300 nits. But 203 nits seems to be becoming the standard in photography.
+Note: popular reference white points in use are: 80 nits, 100 nits, 203 nits, and 300 nits. But 203 nits seems to be becoming the standard in photography.
 
 Map the pixel values with FFMPEG using the above generated LUT (`pq2hlg.cube`):
 

diff --git a/avifenc-hdr.md b/avifenc-hdr.md
@@ -33,10 +33,10 @@ Notes:
 
 ## PQ to HLG conversion
 
-Generate a look-up table (LUT) with [hlg-tools](https://github-wiki-see.page/m/wswartzendruber/hlg-tools) using a reference white-point:
+Generate a look-up table (LUT) with [hlg-tools](https://github.com/wswartzendruber/hlg-tools) using a reference white-point:
 
 ```
-hlg-tools/pq2hlg -r 203 pq2hlg.cube
+hlg-tools/pq2hlg -r 203 -s 128 pq2hlg.cube
 ```
 
 Note: there are three "popular" reference white points in use: 100 nits, 203 nits, and 300 nits. But 203 nits seems to be becoming the standard in photography.

diff --git a/avifenc-hdr.md b/avifenc-hdr.md
@@ -33,26 +33,42 @@ Notes:
 
 ## PQ to HLG conversion
 
+Generate a look-up table (LUT) with [hlg-tools](https://github-wiki-see.page/m/wswartzendruber/hlg-tools) using a reference white-point:
+
+```
+hlg-tools/pq2hlg -r 203 pq2hlg.cube
+```
+
+Note: there are three "popular" reference white points in use: 100 nits, 203 nits, and 300 nits. But 203 nits seems to be becoming the standard in photography.
+
+Map the pixel values with FFMPEG using the above generated LUT (`pq2hlg.cube`):
+
 ```
-# source https://github-wiki-see.page/m/wswartzendruber/hlg-tools
-hlg-tools/pq2hlg -r 210 -m 4000 pq2hlg.cube
-# color-map using the above LUT
 ffmpeg -i HDR_sample_pq.png -vf format=rgb48le,lut3d=pq2hlg.cube -color_primaries bt2020 -color_trc arib-std-b67 -colorspace bt2020nc HDR_sample_hlg.png
-# the above PNG will have bad metadata (ffmpeg issue?), so viewer apps will render it badly by default
-# convert to avif with the correct transfer function (HLG: 18)
+```
+
+Note: `HDR_sample_hlg.png` will have bad metadata even though we specified the correct transfer function `arib-std-b67` (ffmpeg issue?), so viewer apps will render it badly.
+
+Convert to avif with the correct transfer function (the `18` in `9/18/9` indicates HLG):
+
+```
 avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a tune=ssim -a color:enable-chroma-deltaq=1 -a color:enable-qm=1 -d 12 --cicp 9/18/9 HDR_sample_hlg.png HDR_sample_hlg.avif
-# copy EXIF tags from the original DNG file
-exiftool -TagsFromFile IMG_0025.DNG "-all:all>all:all" HDR_sample_hlg.avif
+```
+
+Copy EXIF tags from the original DNG file:
+
+```
+exiftool -TagsFromFile RAW_sample.DNG "-all:all>all:all" HDR_sample_hlg.avif
 ```
 
 ## PQ optimized
 
-Opening the AVIF file converted from the direct PNG (PQ or HLG) export from Affinity Photo 2 in iPhone is slower than doing it after these steps. The only explanation I could come up with is the removal of alpha channel perhaps... :thinking:
+Opening the AVIF file converted from the HDR PNG (PQ or HLG) export from Affinity Photo 2 in iPhone is slower than doing it after these steps. The only explanation I could come up with is the removal of alpha channel perhaps... :thinking:
 
 ```
-ffmpeg -i .\IMG_0025-0027_pq.png -vf format=rgb48le -color_primaries bt2020 -color_trc smpte2084 -colorspace bt2020nc IMG_0025-0027_pq2.png
-avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a tune=ssim -a color:enable-chroma-deltaq=1 -a color:enable-qm=1 -d 12 --cicp 9/16/9 IMG_0025-0027_pq2.png IMG_0025-0027_pq2.avif
-exiftool -TagsFromFile IMG_0025.DNG "-all:all>all:all" IMG_0025-0027_pq2.avif
+ffmpeg -i IMG_0025_pq.png -vf format=rgb48le -color_primaries bt2020 -color_trc smpte2084 -colorspace bt2020nc IMG_0025_pq2.png
+avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a tune=ssim -a color:enable-chroma-deltaq=1 -a color:enable-qm=1 -d 12 --cicp 9/16/9 IMG_0025_pq2.png IMG_0025_pq2.avif
+exiftool -TagsFromFile IMG_0025.DNG "-all:all>all:all" IMG_0025_pq2.avif
 ```
 
 Sources:
@@ -65,3 +81,4 @@ Sources:
 - https://github-wiki-see.page/m/wswartzendruber/hlg-tools/wiki/pq2hlg
 - https://trac.ffmpeg.org/wiki/colorspace
 - https://wiki.x266.mov/docs/colorimetry/transfer#14-bt2020-10-bit
+- https://gist.github.com/kiding/fa4876ab4ddc797e3f18c71b3c2eeb3a?permalink_comment_id=4754146#gistcomment-4754146
diff --git a/avifenc-hdr.md b/avifenc-hdr.md
@@ -30,10 +30,38 @@ Notes:
 - Setting `deltaq-mode` to `5` (HDR) doesn't seem to make a difference at all, `3` produces slightly smaller files for SDR images.
 - If `--cicp` is ignored and the source image doesn't specify any profile, `2/2/6` is used where `2` means unspecified. This is okay for sRGB.
 
+
+## PQ to HLG conversion
+
+```
+# source https://github-wiki-see.page/m/wswartzendruber/hlg-tools
+hlg-tools/pq2hlg -r 210 -m 4000 pq2hlg.cube
+# color-map using the above LUT
+ffmpeg -i HDR_sample_pq.png -vf format=rgb48le,lut3d=pq2hlg.cube -color_primaries bt2020 -color_trc arib-std-b67 -colorspace bt2020nc HDR_sample_hlg.png
+# the above PNG will have bad metadata (ffmpeg issue?), so viewer apps will render it badly by default
+# convert to avif with the correct transfer function (HLG: 18)
+avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a tune=ssim -a color:enable-chroma-deltaq=1 -a color:enable-qm=1 -d 12 --cicp 9/18/9 HDR_sample_hlg.png HDR_sample_hlg.avif
+# copy EXIF tags from the original DNG file
+exiftool -TagsFromFile IMG_0025.DNG "-all:all>all:all" HDR_sample_hlg.avif
+```
+
+## PQ optimized
+
+Opening the AVIF file converted from the direct PNG (PQ or HLG) export from Affinity Photo 2 in iPhone is slower than doing it after these steps. The only explanation I could come up with is the removal of alpha channel perhaps... :thinking:
+
+```
+ffmpeg -i .\IMG_0025-0027_pq.png -vf format=rgb48le -color_primaries bt2020 -color_trc smpte2084 -colorspace bt2020nc IMG_0025-0027_pq2.png
+avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a tune=ssim -a color:enable-chroma-deltaq=1 -a color:enable-qm=1 -d 12 --cicp 9/16/9 IMG_0025-0027_pq2.png IMG_0025-0027_pq2.avif
+exiftool -TagsFromFile IMG_0025.DNG "-all:all>all:all" IMG_0025-0027_pq2.avif
+```
+
 Sources:
 - https://github.com/AOMediaCodec/libavif/wiki/CICP
 - https://en.wikipedia.org/wiki/Coding-independent_code_points
 - https://old.reddit.com/r/AV1/comments/o7s8hk/high_quality_encoding_of_avif_images_using/
 - https://wiki.x266.mov/docs/encoders/aomenc#avif-encoding
 - (av1 video) https://www.reddit.com/r/AV1/comments/t59j32/encoder_tuning_part_4_a_2nd_generation_guide_to/
 - (av1 video) https://gist.github.com/nico-lab/a6508f283a77696e79a131e07abd86b9
+- https://github-wiki-see.page/m/wswartzendruber/hlg-tools/wiki/pq2hlg
+- https://trac.ffmpeg.org/wiki/colorspace
+- https://wiki.x266.mov/docs/colorimetry/transfer#14-bt2020-10-bit
diff --git a/avifenc-hdr.md b/avifenc-hdr.md
@@ -1,33 +1,33 @@
 To convert an HDR PNG that's exported with HLG transfer function in Rec. 2020 color space, do:
 
 ```
-avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a color:deltaq-mode=1 -a tune=ssim \
+avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a tune=ssim \
     -a color:enable-chroma-deltaq=1 -a color:enable-qm=1 -d 12 --cicp 9/18/9 IMG_0186.png IMG_0186.avif
 ```
 
 For HDR with PQ transfer function in Rec. 2020 color space, do:
 
 ```
-avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a color:deltaq-mode=1 -a tune=ssim \
+avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a tune=ssim \
     -a color:enable-chroma-deltaq=1 -a color:enable-qm=1 -d 12 --cicp 9/16/9 IMG_0186.png IMG_0186.avif
 ```
 
 For the default SDR image (sRGB with BT.601 coefficients), simply do:
 
 ```
-avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a color:deltaq-mode=1 -a tune=ssim \
+avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a color:deltaq-mode=3 -a tune=ssim \
     -a color:enable-chroma-deltaq=1 -a color:enable-qm=1 --cicp 1/13/6 IMG_0186.png IMG_0186.avif
 ```
 
 For the same with BT.709 coefficients, do:
 
 ```
-avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a color:deltaq-mode=1 -a tune=ssim \
+avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a color:deltaq-mode=3 -a tune=ssim \
     -a color:enable-chroma-deltaq=1 -a color:enable-qm=1 --cicp 1/13/1 IMG_0186.png IMG_0186.avif
 ```
 
 Notes:
-- `-a color:deltaq-mode=1` might be redundant (or ignored)
+- Setting `deltaq-mode` to `5` (HDR) doesn't seem to make a difference at all, `3` produces slightly smaller files for SDR images.
 - If `--cicp` is ignored and the source image doesn't specify any profile, `2/2/6` is used where `2` means unspecified. This is okay for sRGB.
 
 Sources:

diff --git a/avifenc-hdr.md b/avifenc-hdr.md
@@ -26,6 +26,10 @@ avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a color:deltaq
     -a color:enable-chroma-deltaq=1 -a color:enable-qm=1 --cicp 1/13/1 IMG_0186.png IMG_0186.avif
 ```
 
+Notes:
+- `-a color:deltaq-mode=1` might be redundant (or ignored)
+- If `--cicp` is ignored and the source image doesn't specify any profile, `2/2/6` is used where `2` means unspecified. This is okay for sRGB.
+
 Sources:
 - https://github.com/AOMediaCodec/libavif/wiki/CICP
 - https://en.wikipedia.org/wiki/Coding-independent_code_points

diff --git a/avifenc-hdr.md b/avifenc-hdr.md
@@ -1,5 +1,35 @@
 To convert an HDR PNG that's exported with HLG transfer function in Rec. 2020 color space, do:
 
 ```
-avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a color:deltaq-mode=1 -a tune=ssim -a color:enable-chroma-deltaq=1 -a color:enable-qm=1 -d 12 --cicp 9/18/9 IMG_0186.png IMG_0186.avif
-```
+avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a color:deltaq-mode=1 -a tune=ssim \
+    -a color:enable-chroma-deltaq=1 -a color:enable-qm=1 -d 12 --cicp 9/18/9 IMG_0186.png IMG_0186.avif
+```
+
+For HDR with PQ transfer function in Rec. 2020 color space, do:
+
+```
+avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a color:deltaq-mode=1 -a tune=ssim \
+    -a color:enable-chroma-deltaq=1 -a color:enable-qm=1 -d 12 --cicp 9/16/9 IMG_0186.png IMG_0186.avif
+```
+
+For the default SDR image (sRGB with BT.601 coefficients), simply do:
+
+```
+avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a color:deltaq-mode=1 -a tune=ssim \
+    -a color:enable-chroma-deltaq=1 -a color:enable-qm=1 --cicp 1/13/6 IMG_0186.png IMG_0186.avif
+```
+
+For the same with BT.709 coefficients, do:
+
+```
+avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a color:deltaq-mode=1 -a tune=ssim \
+    -a color:enable-chroma-deltaq=1 -a color:enable-qm=1 --cicp 1/13/1 IMG_0186.png IMG_0186.avif
+```
+
+Sources:
+- https://github.com/AOMediaCodec/libavif/wiki/CICP
+- https://en.wikipedia.org/wiki/Coding-independent_code_points
+- https://old.reddit.com/r/AV1/comments/o7s8hk/high_quality_encoding_of_avif_images_using/
+- https://wiki.x266.mov/docs/encoders/aomenc#avif-encoding
+- (av1 video) https://www.reddit.com/r/AV1/comments/t59j32/encoder_tuning_part_4_a_2nd_generation_guide_to/
+- (av1 video) https://gist.github.com/nico-lab/a6508f283a77696e79a131e07abd86b9
diff --git a/gistfile1.txt → avifenc-hdr.md b/gistfile1.txt → avifenc-hdr.md
diff --git a/gistfile1.txt b/gistfile1.txt
@@ -0,0 +1,5 @@
+To convert an HDR PNG that's exported with HLG transfer function in Rec. 2020 color space, do:
+
+```
+avifenc -s 4 -j 4 --min 1 --max 56 -a end-usage=q -a cq-level=18 -a color:deltaq-mode=1 -a tune=ssim -a color:enable-chroma-deltaq=1 -a color:enable-qm=1 -d 12 --cicp 9/18/9 IMG_0186.png IMG_0186.avif
+```