Expected timestamp ranges between AVCapturePhoto photos when using .builtInDualWideCamera?

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Created Apr ’24

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I have built a camera application which uses a AVCaptureSession with the AVCaptureDevice set to .builtInDualWideCamera and isVirtualDeviceConstituentPhotoDeliveryEnabled=true to enable delivery of "simultaneous" photos (AVCapturePhoto) for a single capture request.

Our app ideally would have the timestamp difference between the photos in a single capture request as short as possible, but we don't have a good idea of what the theoretical or practical limits of this timestamp difference are.

In my testing on an iPhone 12 Pro, with a frame rate of 33Hz and the preset set to hd1920x1080, I get the timestamp difference between photos at approx 0.3ms, which seems smaller than I would expect, unless the frames are being synchronised incredibly well under the hood.

This leaves the following unanswered questions:

What sort of ranges of values should we expect to come out of these timestamp differences between photos?
What factors influence this?
Is there any way to control these values to ensure they are as small as possible? (Will likely be answered by (2))

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Answer 1

spelunker OP

Apr ’24

Hi @nanders, this is only tangentially related: would you be willing to detail your configuration used to get both images of the .builtInDualWideCamera? I've been playing around with doing the same exact thing but haven't been able to find any setup where isVirtualDeviceConstituentPhotoDeliverySupported is true, and I don't see much documentation out there on this topic. Are there specific settings you changed to make this possible?

Thanks!

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Answer 2

nanders OP

May ’24

Hi @spelunker, here's a broad strokes gist of how we are doing this. Hopefully it provides you with the guidance you need.

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