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My biggest image format question, which I haven’t seen a clear answer to, is as an iPhone camera user should I be keeping the JPEG or the HEIC as my archival fo

My biggest image format question, which I haven’t seen a clear answer to, is as an iPhone camera user should I be keeping the JPEG or the HEIC as my archival format? I theorized the HEIC had more information, but I don’t really know. Unfortunately keeping both is a usability nightmare in all the tools I’ve seen. Anyone have an informed opinion or good link?

zaarn 5y ago
If you want to preserve fidelity indefinitely, PNG or RAW might be a better bet. Lossless formats usually are better for archival, you can always get a lossy compression out of it later and don't have to worry about generational losses.
- pjc50 5y ago
  .. but this is an iPhone, so the options for "original" are HEIC, JPEG, and "proraw" https://support.apple.com/en-gb/HT211965 https://support.apple.com/en-gb/HT211965
  - thehappypm 5y ago
    If you convert the full-resolution JPEG/HEIC to PNG you won't lose any information, right?
    - sp332 5y ago
      Sure, but what's the advantage to blowing up the file size to losslessly preserve all the lossy artifacts from JPEG or HEIC?
    - jonsneyers 5y ago
      Technically, you do lose _some_ information. PNG cannot represent DCT coefficients nor YCbCr data, and the conversion of those things to (8-bit) RGB is a (slightly) lossy operation.
  - MontagFTB 5y ago
    ProRAW is lossless, if you’re willing to pay the size price (~40MB/image.)
  - zaarn 5y ago
    I don't have an iPhone, hence a minor speculation on what it supports, if you forgive that. If you're looking into archival, you'll probably want the PRORAW then, sounds like that is the lossless format. Converting from JPEG/HEIV to lossless is a bit of a pointless thing to do, you already incur generational loss from that.
    - lazide 5y ago
      For archival, you need to worry about long term ability to read the format easily. JPEG wins that fight out of the three easily.
      - zaarn 5y ago
        RAW is a very old format that has been around for some time, Apple's ProRAW is backwards compatible and has some additional metadata attached (IIRC ProRaw attaches the image pipeline the iphone would have used, so that image software can recover this and produce the same image the iphone would have after the image pipeline). RAW is older (1988) than JPEG (1992), largely because RAW is largely based on TIFF (and any vendor specific variation is usually TIFF-like too) in it's mid-1980s state. The latest standard RAW standard (TIFF/EP) is from 2001. So in terms of long term ability to read... RAW wins, various versions aren't as old but JPEG got it's fair few of extensions too. For long term readability, I don't think JPEG would win on another standpoint; bitrot. It'll happen eventually, even if you use ZFS, you will eventually loose some bits. Maybe a sector of data. JPEG doesn't like loosing parts of the file. On the other hand, a TIFF file can be recovered from bitrot, if you don't mind loosing a part of the image. Because there is no compression, loosing a sector of data amounts to loosing the bits on that sector. The only sensitive part of the file would be the header, which isn't terribly complex and can be typed on notepad if needed be.
        lazide 5y ago
        You obviously have a very different experience with TIFF or RAW than I have had? Every vendor and application has weird extensions or behaviors with the format that means only custom built support for the software that makes it actually works well. Every piece of software on the planet seems to support jpeg out of the box.
jonsneyers 5y ago
HEIC is in general better than JPEG (as a codec; not in terms of interoperability), but the way Apple does HEIC, I strongly suspect that JPEG is actually a better choice. Your files will of course be larger, but the HEIC will be a bit overcompressed compared to the JPEG: it will have some blurring/smearing artifacts that the JPEG will not have. The reason is that they do fast hardware HEIC encoding at relatively aggressive quality settings in order to get the file size savings they want to boast about. They claim the quality to be the same, but that's not actually true. It is a lower quality. One advantage of HEIC though is that it can also contain the depth map (in 'Portrait mode'), which I assume gets lost when you use JPEG. This is the information that gives a rough separation of foreground and background, so you can later do effects like applying bokeh to the background only.
- kalleboo 5y ago
  The Apple portrait depth map is also stored in a JPEG. I believe they use MPO. The Google camera can do it too. Apparently it uses XMP metadata for this purpose.
- mceachen 5y ago
  The depth map is actually stored as an image: PhotoStructure accidentally used them as preview images several versions back (when depth maps were fairly novel) and I had some interesting discussions with users complaining about "ghosts" in their library: https://forum.photostructure.com/t/i-see-ghosts/41 https://forum.photostructure.com/t/i-see-ghosts/41
mceachen 5y ago
Apple used to have a spectacular record with stable formats: see HFS+. Unfortunately, over the last several years, that's gone out the window. Mojave can't read some Big Sur volumes, even though both are using "Apple File System". HEIC image formats coming out of iPhones have changed /several/ times in the past couple years: witness the scrambling by the libheif project as they find out they can't read images from the latest iDevice. Apple's in-device conversion to JPEG is lossy, but I don't expect you will notice. Most of the metadata it's retained (at least with the current iOS), and I couldn't see egregious artifacting. I'd personally keep the original and hope tooling keeps up with Apple shenanigans, but disk is cheap, and if you're worried at all, use `sips` (if you're on a Mac), the built-in "compatibility mode" conversion, or `heif-convert` to transcode to JPEG. (Source: building support for HEIC in PhotoStructure)

zaarn 5y ago

If you want to preserve fidelity indefinitely, PNG or RAW might be a better bet. Lossless formats usually are better for archival, you can always get a lossy compression out of it later and don't have to worry about generational losses.

pjc50 5y ago
.. but this is an iPhone, so the options for "original" are HEIC, JPEG, and "proraw" https://support.apple.com/en-gb/HT211965 https://support.apple.com/en-gb/HT211965
- thehappypm 5y ago
  If you convert the full-resolution JPEG/HEIC to PNG you won't lose any information, right?
  - sp332 5y ago
    Sure, but what's the advantage to blowing up the file size to losslessly preserve all the lossy artifacts from JPEG or HEIC?
  - jonsneyers 5y ago
    Technically, you do lose _some_ information. PNG cannot represent DCT coefficients nor YCbCr data, and the conversion of those things to (8-bit) RGB is a (slightly) lossy operation.
- MontagFTB 5y ago
  ProRAW is lossless, if you’re willing to pay the size price (~40MB/image.)
- zaarn 5y ago
  I don't have an iPhone, hence a minor speculation on what it supports, if you forgive that. If you're looking into archival, you'll probably want the PRORAW then, sounds like that is the lossless format. Converting from JPEG/HEIV to lossless is a bit of a pointless thing to do, you already incur generational loss from that.
  - lazide 5y ago
    For archival, you need to worry about long term ability to read the format easily. JPEG wins that fight out of the three easily.
    - zaarn 5y ago
      RAW is a very old format that has been around for some time, Apple's ProRAW is backwards compatible and has some additional metadata attached (IIRC ProRaw attaches the image pipeline the iphone would have used, so that image software can recover this and produce the same image the iphone would have after the image pipeline). RAW is older (1988) than JPEG (1992), largely because RAW is largely based on TIFF (and any vendor specific variation is usually TIFF-like too) in it's mid-1980s state. The latest standard RAW standard (TIFF/EP) is from 2001. So in terms of long term ability to read... RAW wins, various versions aren't as old but JPEG got it's fair few of extensions too. For long term readability, I don't think JPEG would win on another standpoint; bitrot. It'll happen eventually, even if you use ZFS, you will eventually loose some bits. Maybe a sector of data. JPEG doesn't like loosing parts of the file. On the other hand, a TIFF file can be recovered from bitrot, if you don't mind loosing a part of the image. Because there is no compression, loosing a sector of data amounts to loosing the bits on that sector. The only sensitive part of the file would be the header, which isn't terribly complex and can be typed on notepad if needed be.
      - lazide 5y ago
        You obviously have a very different experience with TIFF or RAW than I have had? Every vendor and application has weird extensions or behaviors with the format that means only custom built support for the software that makes it actually works well. Every piece of software on the planet seems to support jpeg out of the box.

jonsneyers 5y ago

HEIC is in general better than JPEG (as a codec; not in terms of interoperability), but the way Apple does HEIC, I strongly suspect that JPEG is actually a better choice. Your files will of course be larger, but the HEIC will be a bit overcompressed compared to the JPEG: it will have some blurring/smearing artifacts that the JPEG will not have. The reason is that they do fast hardware HEIC encoding at relatively aggressive quality settings in order to get the file size savings they want to boast about. They claim the quality to be the same, but that's not actually true. It is a lower quality. One advantage of HEIC though is that it can also contain the depth map (in 'Portrait mode'), which I assume gets lost when you use JPEG. This is the information that gives a rough separation of foreground and background, so you can later do effects like applying bokeh to the background only.

kalleboo 5y ago
The Apple portrait depth map is also stored in a JPEG. I believe they use MPO. The Google camera can do it too. Apparently it uses XMP metadata for this purpose.
mceachen 5y ago
The depth map is actually stored as an image: PhotoStructure accidentally used them as preview images several versions back (when depth maps were fairly novel) and I had some interesting discussions with users complaining about "ghosts" in their library: https://forum.photostructure.com/t/i-see-ghosts/41 https://forum.photostructure.com/t/i-see-ghosts/41

mceachen 5y ago

Apple used to have a spectacular record with stable formats: see HFS+. Unfortunately, over the last several years, that's gone out the window. Mojave can't read some Big Sur volumes, even though both are using "Apple File System". HEIC image formats coming out of iPhones have changed /several/ times in the past couple years: witness the scrambling by the libheif project as they find out they can't read images from the latest iDevice. Apple's in-device conversion to JPEG is lossy, but I don't expect you will notice. Most of the metadata it's retained (at least with the current iOS), and I couldn't see egregious artifacting. I'd personally keep the original and hope tooling keeps up with Apple shenanigans, but disk is cheap, and if you're worried at all, use `sips` (if you're on a Mac), the built-in "compatibility mode" conversion, or `heif-convert` to transcode to JPEG. (Source: building support for HEIC in PhotoStructure)