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On my iPhone, when I backup my photos with photosync, I notice that I get two files for every live photo. One HEIC and one MOV. Eg:

Recents/IMG_0941.HEIC
Recents/IMG_0941.MOV
Recents/IMG_0942.HEIC
Recents/IMG_0942.Mov

What's not clear to me is if this is redundant or just a quirk of photosync.

Is this something the IPhone itself is doing (storing two files on the iphone) or is it likely that photo sync is extracting the MOV file itself?

Are the two files redundant (can I delete the MOV and get back to it from just the HEIC file?)

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  • How many physical camera lenses does your iPhone have?
    – bmike ♦
    Commented Oct 8, 2021 at 10:39
  • @bmike why does that make a difference?
    – Philip Couling
    Commented Oct 8, 2021 at 22:38

1 Answer 1

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It is not redundant. Live Photos consist of an high-res image and a video (lower quality than the image).

  • The HEIC (High Efficiency Image Codec) format is only for images, and it's the one when you actually hit the exposure button.
  • The .MOV files are displayed when you long press the photo.

Therefore you can extract the single HEIC image from the MOV file (with lower quality though), while you can't turn the single image into a video. This also means, this is something the iPhone is doing and not photo sync. You would also get those files when using AirDrop for example.

Note: Since the video is lower quality than a single image, changing the key frame must change the quality. However, I could imagine (this is speculation though) that Apple might use some ML/smart algorithm to make the new key frame look better (similar to something like night mode, where a lot of processing happens).

Sources:

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  • 1
    So does that mean selecting a different key frame in the photos app produces a lower quality photo?
    – Philip Couling
    Commented Jan 10, 2021 at 15:13
  • I edited my answer to include that info: the highest quality image is the original key frame.
    – X_841
    Commented Jan 10, 2021 at 19:15
  • Thanks for your great explanation on how "Live Photos" works regarding interframe and intraframe compression and how it persists this info on the file level (HEIC + MOV sidecar file).
    – porg
    Commented Sep 4 at 9:39

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