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A comment on A dumb reason computer vision apps aren’t working: Exif Orientation. Parent comment

Re:A dumb reason computer vision apps aren’t working: Exif O... by fireattack on Wednesday October 09, 2019 @06:01PM (#21208640)
JPEG lossless rotation can only be done if the dimensions (height and width in px) of the image are multiples of MCU (typically 8x8 for 4:4:4 or 16x16 for 4:2:0).
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Re:A dumb reason computer vision apps aren’t working: Exif O... by zaat on Wednesday October 09, 2019 @07:26PM (#21209304)
For the uninitiated, MCU is not Marvel Cinematic Universe as the search results might try to confuse you. It's Minimum Coded Units, and a nice explanation is over here:

>https://www.impulseadventure.com/photo/rotation-partial-mcu....

Edit: the link also closed for me a forgotten open loop about the meaning of an annoying error message Windows XP era. Thanks for making me look it up!

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Re:A dumb reason computer vision apps aren’t working: Exif O... by fireattack on Wednesday October 09, 2019 @08:31PM (#21209711)
ImpulseAdventure is THE place when I look for reference related to anything about JPEG.

He also has a very useful utility (I normally use it to check DCT table) called JPEGSnoop [1].

[1] https://www.impulseadventure.com/photo/jpeg-snoop.html

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Re:A dumb reason computer vision apps aren’t working: Exif O... by klyrs on Wednesday October 09, 2019 @06:16PM (#21208759)
Sure, that's a good enough excuse. I look forward to defeating government facial recognition algorithms by holding my head at an angle.
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