JXL/HEIF/AVIF/WebP/PNG Exif data support #213
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qbnu
changed the title
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thanks for all the new updates. I'm going to make sure to make time to merge them asap. |
sylikc
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bug
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| if (!exif_blocks.empty()) { | ||
| std::vector<uint8_t> exif = handle.get_metadata(exif_blocks[0]); | ||
| if (exif.size() > 8 && exif.size() < 65538) { |
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where's the magic 65538 number come from? I see it in other EXIF chunks of the code, where size+some number is 65538. It's an odd number, not a power of 2?
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These libraries all have their own ideas about where to start the Exif data from. JPEG Exif blocks are in the format FF E1 SS SS 45 78 69 66 00 00 [data]. The SS SS is a big-endian unsigned short representing the size of everything after FF E1.
libjxl gives 00 00 00 00 [data], libheif gives 00 00 00 00 45 78 69 66 00 00 [data], libavif, libwebp and libpng give [data], so they have different limits for size. If you want I can change it to 65536 + an offset and add notes explaining why.
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I see, now it makes sense. Regarding the documentation, I'll just refer to this comment. This is good investigative information.
Adds support for reading JPEG XL, HEIF, AVIF, WebP and PNG Exif data.
Doesn't work for animated JXLs. e1852b2 fixes a memory leak I introduced in #208 (my bad) and 2ce3887 partially fixes #207.