HT202158: iCloud: Limits for Contacts, Calendars, Reminders, and Bookmarks

Learn about iCloud: Limits for Contacts, Calendars, Reminders, and Bookmarks
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Q: What transcode/compression method/parameters does Apple use for iCloud Contacts photos?

'HT202158: iCloud: Limits for Contacts, Calendars, Reminders, and Bookmarks' indicates what image input formats are supported for the 'Add Photo' / 'Choose Photo' field in an iCloud Contact record.  It also indicates the account-specific limit on cumulative consumed storage capacity for all image files stored in this field within the account's Contacts database.

 

Does anyone know the (initial) transcode/compression/cropping method/parameters Apple uses for iCloud Contacts photos?  How about the method/parameters for any additional transcode/compression/cropping performed when syncing a new iCloud-based contact record down to an iDevice such as the iPhone 6 Plus (running iOS 8.x)?

 

Clearly, photos for iCloud Web app and iOS "iContact" app records do not represent a particularly image-quality-critical application based on how most iCloud account-holders use these apps.  However, out of curiosity, I populated a sample iCloud contact record with a 600x600-pixel excerpt from a test-target photo recorded by a high-resolution digital camera.  I see that the corresponding image subsequently available to me in the 'Add Photo' / 'Choose Photo' field demonstrates that the method used to produce that image from the one I uploaded has introduced substantial moiré patterning into test target components with radially arrayed and tapered lines that was NOT present in the original uploaded image, and has also substantially reduced the apparent resolution of visual detail.  This is true for the image as sync'd to my iPhone and then displayed in enlarged form (effectively ~880x880 pixels based on my evaluation of an iPhone screen capture of this image) via a 3rd-party iOS app (Photogenda Mini).  It is also true for the image preview provided when entering Edit mode for the applicable Contact record within the iCloud Web app, then clicking on the applicable photo to produce the enlarged preview within the 'Choose Photo...' Window.

 

It is not entirely clear to me whether and to what extent Apple accounts for the full file size (in terms of Bytes) of the original image selected by the iCloud user for the 'Add Photo' / 'Choose Photo' field of a particular Contact record when it determines the cumulative consumed storage capacity for all image files stored in this field within the account's Contacts database.  However, my past experience -- including direct feedback on this point from Apple support representatives -- suggests that this storage accounting is based on the full (pixel) resolution of the original selected image, whether or not it is based on the file (Byte) size of that image or of some transcoded/compressed version.  Does anyone have accurate information on this point?

 

Thx

iPhone 6 Plus, iOS 8.1.3, iCloud Web App (MS Win 8.1 Desktop)

Posted on Feb 9, 2015 1:18 PM

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