1.What should be treated as the live edge, and how should the current live latency be measured?
seekableTimeRanges.end is a good working approximation of the live edge — it represents the furthest point in the stream the player can seek to
Live latency at any moment is therefore (Note: Live latency is playhead distance from Live Edge)
## let latency = playerItem.seekableTimeRanges.last
.map { CMTimeRangeGetEnd($0.timeRangeValue) }
.map { $0 - playerItem.currentTime() }
2. Is rate > 1.0 the right mechanism? What happens when the playhead reaches the end?
Yes — playing above 1.0x to reduce live latency is a supported pattern.
The concern about AVPlayerItemDidPlayToEndTimeNotification firing does not apply here. For live streams (duration == kCMTimeIndefinite) this notification is only posted if forwardPlaybackEndTime is explicitly set on the item. Reaching seekableTimeRanges.end during live playback at rate > 1.0 does not trigger it.
from iOS/macOS 26.4 onwards, when the playhead reaches the live edge at rate > 1.0, the player automatically steps the rate back to 1.0, no guard needed.
3. Differences between regular HLS and LL-HLS
The fundamental model is the same for both — seekableTimeRanges, configuredTimeOffsetFromLive, recommendedTimeOffsetFromLive, and the rate > 1.0 pattern all apply.
The differences are in scale:
seekableTimeRanges.end granularity
Regular HLS : Advances by full segment.
LL-HLS : Advances by partial segment
For LL-HLS, seekableTimeRanges.end moves forward continuously at part traget intervals, so the rate > 1.0 catch-up converges smoothly. For regular HLS, the boundary advances in segment-sized steps, so the playhead catches up in larger increments.
Summary :- the intended contract
Live latency = seekableTimeRanges.end − currentTime(). This is slightly conservative relative to the true live edge but is the closest approximation.- Target latency :- set via configuredTimeOffsetFromLive. Follow recommendedTimeOffsetFromLive for network-adaptive targets.
- Catch-up :- playing at rate > 1.0 is supported. From (iOS/macOS 26.4+) the player automatically steps back to 1.0 when the playhead reaches the live edge,. No additional guard is needed.
- AVPlayerItemDidPlayToEndTimeNotification does not fire during normal live playback. Only fires if forwardPlaybackEndTime s explicitly set.
- LL-HLS vs regular HLS :- same API surface, different numeric scales. Always use recommendedTimeOffsetFromLive rather than a hardcoded offset.
