Local Recording Failures

[scyc314]

On newer iPhones, local recordings frequently stop and restart multiple times. This behavior can occur in seconds or up to 30 minutes after recording first starts. Increasing bitrate, resolution and fps for the stream all seem to cause the behavior to occur more quickly. The behavior does not appear to present itself at very low settings (e.g., 1mbps bitrate, 420p resolution, 15fps).

On an iPhone 13 changing to the HLG BT2020 color profile for the camera appears to avoid the issue (recording of 6 hours was successful). More testing with other modern iPhones is needed. The BT2020 profile uses kVTProfileLevel_HEVC_Main10_AutoLevel which is the only 10-bit profile in Moblin.

Curious if there is an incompatibility or similar issue where older iPhones that only support 8-bit color can use the 8-bit profiles without issue, but newer iPhones that support 10-bit (and 8-bit) prefer a 10-bit profile and eventually cause an error if using an 8-bit profile.

Edit: Local recording fails only when streaming and recording at the same time. Recording by itself, regardless of the color profile selected, works fine.

[scyc314]

Several more tests done, with approximately 20 hours of video in total with no issues using the HLG BT2020 profile.

[eerimoq]

thanks for testing. interesting conclusion, but also a bit hard to explain