We make a camera app (AVCaptureSession at 4K, live preview, recording with AVAssetWriter). Since updating to iOS 27.2, a user with an iPhone 13 Pro reports that the phone gets hot while using our app. Our own iPhone 14 Pro also runs warmer on 27.2 than it did on 27.0. To check, we reran on the 14 Pro the same automated test we ran there on iOS 27.0 in September. Each run lasts 300 seconds with the phone on power and fully charged, Low Power Mode off, and starts at ProcessInfo.thermalState == .nominal. We log thermalState every 5 seconds. Capture is 3840x2160 at 60 fps in all three runs: Idle preview, no processing: iOS 27.0: stayed Nominal for all 300 s iOS 27.2 (24B115): Fair at 278 s Idle preview with a Metal overlay: iOS 27.0: stayed Nominal for all 300 s iOS 27.2: Fair at 123 s Recording, HEVC 10-bit: iOS 27.0: Fair at 38 s, Serious at 108 s iOS 27.2: Fair at 33 s, Serious at 83 s Frame delivery held up. The 5-minute recording lost no frames, even at Serious. Questions: Are there known changes in iOS 27.2 to power use or thermal management during camera capture (AVCaptureSession at 4K) on A15 / A16 devices? Have the thresholds behind ProcessInfo.thermalState or AVCaptureDevice.SystemPressureState changed in 27.2? What data would be most useful in a Feedback report for this: a sysdiagnose taken right after a run, or a specific Instruments template?

iOS 27.2: iPhone 13 Pro / 14 Pro heat up sooner during 4K camera capture than on iOS 27.0

We make a camera app (AVCaptureSession at 4K, live preview, recording with AVAssetWriter). Since updating to iOS 27.2, a user with an iPhone 13 Pro reports that the phone gets hot while using our app. Our own iPhone 14 Pro also runs warmer on 27.2 than it did on 27.0.

To check, we reran on the 14 Pro the same automated test we ran there on iOS 27.0 in September. Each run lasts 300 seconds with the phone on power and fully charged, Low Power Mode off, and starts at ProcessInfo.thermalState == .nominal. We log thermalState every 5 seconds.

Capture is 3840x2160 at 60 fps in all three runs:

Idle preview, no processing:
iOS 27.0: stayed Nominal for all 300 s
iOS 27.2 (24B115): Fair at 278 s
Idle preview with a Metal overlay:
iOS 27.0: stayed Nominal for all 300 s
iOS 27.2: Fair at 123 s
Recording, HEVC 10-bit:
iOS 27.0: Fair at 38 s, Serious at 108 s
iOS 27.2: Fair at 33 s, Serious at 83 s

Frame delivery held up. The 5-minute recording lost no frames, even at Serious.

Questions:

Are there known changes in iOS 27.2 to power use or thermal management during camera capture (AVCaptureSession at 4K) on A15 / A16 devices?
Have the thresholds behind ProcessInfo.thermalState or AVCaptureDevice.SystemPressureState changed in 27.2?
What data would be most useful in a Feedback report for this: a sysdiagnose taken right after a run, or a specific Instruments template?