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> Officially supports Exif data Probably the best news here. While you already can write custom data into a header, having Exif is good. BTW: Does Exif have a

> Officially supports Exif data Probably the best news here. While you already can write custom data into a header, having Exif is good. BTW: Does Exif have a magnetometer (rotation) and acceleration (gravity) field? I often wonder about why Google isn't saving this information in the images which the camera app saves. It could help so much with post-processing, like with leveling the horizon or creating panoramas.

jandrese 1y ago
Yes, but websites frequently strip all or almost all Exif data from uploaded images because some fields are used by stalkers to track people down to their real address.
- johnisgood 1y ago
  And I strip Exif data, too, intentionally, for similar reasons.
  - bspammer 1y ago
    That makes sense to me for any image you want to share publicly, but for private images having the location and capture time embedded in the image is incredibly useful.
    - johnisgood 1y ago
      If by private you mean "never shared", I agree.
    - jandrese 1y ago
      If you are uploading it to a website you are sharing it. Even if the image is supposedly "private" you have to assume it will be leaked at some point. Remember, the cloud is just someone else's computer, and they can do what they want with their computer. They may also not be entirely competent at their job.
      - johnisgood 1y ago
        Yes, once something has been shared (or stolen), you lost control over it, be it information or an image. EXIF data is fine, if it never leaves your device or if your device is not compromised.
- sunaookami 1y ago
  That reminds me when I first uploaded a picture to some forum and it showed my full home address together with a map as a "feature"
  - account42 1y ago
    It is a feature because now you are aware of what you are sharing and can potentially delete it before too many others see it.
Aardwolf 1y ago
Exif can also cause confusion for how to render the image: should its rotation be applied or not? Old decoders and new decoders now could render an image with exif rotation differently since it's an optional chunk that can be ignored, and even for new decoders, the spec lists no decoder recommendations for how to use the exif rotation It does say "It is recommended that unless a decoder has independent knowledge of the validity of the Exif data, the data should be considered to be of historical value only.", so hopefully the rotation will not be used by renderers, but it's only a vague recommendation, there's no strict "don't rotate the image" which would be the only backwards compatible way With jpeg's exif, there have also been bugs with the rotation being applied twice, e.g. desktop environment and underlying library both doing it independently
- DidYaWipe 1y ago
  The stupid thing is that any device with an orientation sensor is still writing images the wrong way and then setting a flag, expecting every viewing application to rotate the image. The camera knows which way it's oriented, so it should just write the pixels out in the correct order. Write the upper-left pixel first. Then the next one. And so on. WTF.
  - mavhc 1y ago
    Because your non-smartphone camera doesn't have enough ram/speed to do that I assume (when in burst mode) If a smartphone camera is doing it, then bad camera app!
    - Joel_Mckay 1y ago
      Most modern camera modules have built in hardware codecs like mjpeg, region of interest selection, and frame mirror/flip options. This is particularly important on smartphones and battery operated devices. However, most smartphone devices simply save the photo the same way regardless of orientation, and simply add a display-rotated flag to the metadata. It can be super annoying sometimes, as one can't really disable the feature on many devices. =3
    - 1y ago
andsoitis 1y ago
There is no standard field to record readouts of a camera's accelerometers or inertial navigation system. Exif fields: https://exiv2.org/tags.html https://exiv2.org/tags.html
bawolff 1y ago
Personally i wish people just used XMP. Exif is such a bizarre fotmat. Its essentially embedding a tiff image inside a png.
Findecanor 1y ago
Does the meta-data have support for opting in/out of "AI training"? And is being able to read an image without an opt-in tag something that has to be explicitly enabled in the reference implementation's API?
joshvm 1y ago
There is an acceleration field (Exif.Photo.Acceleration) and (Exif.Photo.CameraElevationAngle) for elevation but oddly not 3 axes. Similarly there are fields for ambient environmental conditions, but only whatever specific things the spec-writers considered. You could store this in Exif.Photo.MakerNote: "A tag for manufacturers of Exif writers to record any desired information. The contents are up to the manufacturer." I think it can be pretty big, certainly more than enough for 9 DoF position data.
pezezin 1y ago
Ages ago I worked on photogrammetry software, and the lack of such information was indeed painful for us. One of the most important parts of the processing pipeline is calculation the position and orientation of each camera; having at least the orientation would have made our life much easier.

jandrese 1y ago

Yes, but websites frequently strip all or almost all Exif data from uploaded images because some fields are used by stalkers to track people down to their real address.

johnisgood 1y ago
And I strip Exif data, too, intentionally, for similar reasons.
- bspammer 1y ago
  That makes sense to me for any image you want to share publicly, but for private images having the location and capture time embedded in the image is incredibly useful.
  - johnisgood 1y ago
    If by private you mean "never shared", I agree.
  - jandrese 1y ago
    If you are uploading it to a website you are sharing it. Even if the image is supposedly "private" you have to assume it will be leaked at some point. Remember, the cloud is just someone else's computer, and they can do what they want with their computer. They may also not be entirely competent at their job.
    - johnisgood 1y ago
      Yes, once something has been shared (or stolen), you lost control over it, be it information or an image. EXIF data is fine, if it never leaves your device or if your device is not compromised.
sunaookami 1y ago
That reminds me when I first uploaded a picture to some forum and it showed my full home address together with a map as a "feature"
- account42 1y ago
  It is a feature because now you are aware of what you are sharing and can potentially delete it before too many others see it.

Aardwolf 1y ago

Exif can also cause confusion for how to render the image: should its rotation be applied or not? Old decoders and new decoders now could render an image with exif rotation differently since it's an optional chunk that can be ignored, and even for new decoders, the spec lists no decoder recommendations for how to use the exif rotation It does say "It is recommended that unless a decoder has independent knowledge of the validity of the Exif data, the data should be considered to be of historical value only.", so hopefully the rotation will not be used by renderers, but it's only a vague recommendation, there's no strict "don't rotate the image" which would be the only backwards compatible way With jpeg's exif, there have also been bugs with the rotation being applied twice, e.g. desktop environment and underlying library both doing it independently

DidYaWipe 1y ago
The stupid thing is that any device with an orientation sensor is still writing images the wrong way and then setting a flag, expecting every viewing application to rotate the image. The camera knows which way it's oriented, so it should just write the pixels out in the correct order. Write the upper-left pixel first. Then the next one. And so on. WTF.
- mavhc 1y ago
  Because your non-smartphone camera doesn't have enough ram/speed to do that I assume (when in burst mode) If a smartphone camera is doing it, then bad camera app!
  - Joel_Mckay 1y ago
    Most modern camera modules have built in hardware codecs like mjpeg, region of interest selection, and frame mirror/flip options. This is particularly important on smartphones and battery operated devices. However, most smartphone devices simply save the photo the same way regardless of orientation, and simply add a display-rotated flag to the metadata. It can be super annoying sometimes, as one can't really disable the feature on many devices. =3
  - 1y ago

andsoitis 1y ago

There is no standard field to record readouts of a camera's accelerometers or inertial navigation system. Exif fields: https://exiv2.org/tags.html https://exiv2.org/tags.html

bawolff 1y ago

Personally i wish people just used XMP. Exif is such a bizarre fotmat. Its essentially embedding a tiff image inside a png.

Findecanor 1y ago

Does the meta-data have support for opting in/out of "AI training"? And is being able to read an image without an opt-in tag something that has to be explicitly enabled in the reference implementation's API?

joshvm 1y ago

There is an acceleration field (Exif.Photo.Acceleration) and (Exif.Photo.CameraElevationAngle) for elevation but oddly not 3 axes. Similarly there are fields for ambient environmental conditions, but only whatever specific things the spec-writers considered. You could store this in Exif.Photo.MakerNote: "A tag for manufacturers of Exif writers to record any desired information. The contents are up to the manufacturer." I think it can be pretty big, certainly more than enough for 9 DoF position data.

pezezin 1y ago

Ages ago I worked on photogrammetry software, and the lack of such information was indeed painful for us. One of the most important parts of the processing pipeline is calculation the position and orientation of each camera; having at least the orientation would have made our life much easier.