enricobuehler
069fcdfca6
Add an "Allow VRR" toggle (Settings → Display; default on, non-tvOS) that hands the presenter's display link a wide frame-rate RANGE — preferred = the stream rate — so a ProMotion / adaptive-sync display can vary its physical refresh to match the stream. `SessionPresenter.syncFrameRate` now runs on macOS too: on it requests min 24 / max display / preferred stream Hz; off restores the prior behavior (macOS free-runs at the native rate, iOS keeps its 30 Hz floor). A no-op on fixed-refresh displays. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
178 lines
9.4 KiB
Swift
178 lines
9.4 KiB
Swift
// Per-session presenter stack shared by the macOS and iOS/tvOS stream views: stage-2 (explicit
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// VTDecompressionSession decode → CAMetalLayer, driven by the hosting view's CADisplayLink) is the
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// default; stage-1 (StreamPump → AVSampleBufferDisplayLayer) is the Metal-unavailable / DEBUG
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// fallback. The views own the platform bits — capture, window/scale tracking, and constructing the
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// display link — and delegate the shared presenter lifecycle here.
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//
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// Main-thread only: start/layout/stop and the display-link tick all run on the main runloop.
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#if canImport(Metal) && canImport(QuartzCore)
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import AVFoundation
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import Foundation
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import QuartzCore
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/// Weak-target wrapper for CADisplayLink. The link retains its target, so targeting a view or
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/// presenter directly makes a `owner → link → owner` cycle that only `invalidate()` breaks — if a
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/// teardown is ever missed the owner leaks and keeps ticking. The proxy is what the link retains;
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/// the handler closure captures the owner `[weak]`, so the owner can deallocate and its `deinit`
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/// invalidate the link.
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public final class DisplayLinkProxy: NSObject {
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private let onTick: (CADisplayLink) -> Void
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public init(_ onTick: @escaping (CADisplayLink) -> Void) { self.onTick = onTick }
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@objc public func tick(_ link: CADisplayLink) { onTick(link) }
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}
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final class SessionPresenter {
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private var pump: StreamPump?
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private var stage2: Stage2Pipeline?
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private var stage2Link: CADisplayLink?
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private var metalLayer: CAMetalLayer?
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private var connection: PunktfunkConnection?
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/// Start the presenter for `connection`. `baseLayer` is the view's AVSampleBufferDisplayLayer:
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/// stage-1 enqueues into it; stage-2 leaves it idle and composites an opaque CAMetalLayer
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/// sublayer over it. `makeDisplayLink` supplies the platform link (macOS `NSView.displayLink`
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/// tracks the view's display; iOS/tvOS uses the plain `CADisplayLink` init) — only called when
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/// stage-2 engages. Call `layout(in:contentsScale:)` right after so the sublayer has a frame
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/// before the first tick.
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func start(
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connection: PunktfunkConnection,
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baseLayer: AVSampleBufferDisplayLayer,
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endToEndMeter: LatencyMeter?,
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decodeMeter: LatencyMeter? = nil,
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displayMeter: LatencyMeter? = nil,
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makeDisplayLink: (AnyObject, Selector) -> CADisplayLink,
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onFrame: (@Sendable (AccessUnit) -> Void)?,
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onSessionEnd: (@Sendable () -> Void)?
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) {
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stop()
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self.connection = connection
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// Presenter choice — stage-2 is the DEFAULT (explicit VTDecompressionSession decode + a
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// CAMetalLayer/display-link present): it can detect + recover a wedged decoder where
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// stage-1's AVSampleBufferDisplayLayer freezes hard on a lost HEVC reference. Stage-1 is
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// reachable only via the DEBUG presenter toggle; release always takes stage-2 (the stage-1
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// pump below stays the automatic fallback if Metal is missing).
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#if DEBUG
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let forceStage1 = UserDefaults.standard.string(forKey: DefaultsKey.presenter) == "stage1"
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#else
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let forceStage1 = false
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#endif
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if !forceStage1,
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let pipeline = Stage2Pipeline(
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endToEndMeter: endToEndMeter, decodeMeter: decodeMeter,
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displayMeter: displayMeter) {
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let metal = pipeline.layer
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// The opaque metal layer composites OVER the AVSampleBufferDisplayLayer base, which
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// sits idle (un-enqueued) in stage-2. contentsScale + frame are set in layout().
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baseLayer.addSublayer(metal)
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metalLayer = metal
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stage2 = pipeline
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// The link is the vsync CLOCK + putBack-retry nudge, not the presentation trigger
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// (frame arrival is — see Stage2Pipeline's header). timestamp→targetTimestamp is the
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// link's own report of the current refresh period (tracks VRR rate changes).
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let proxy = DisplayLinkProxy { [weak self] link in
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self?.stage2?.renderTick(
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targetMediaTime: link.targetTimestamp,
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period: link.targetTimestamp - link.timestamp)
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}
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let link = makeDisplayLink(proxy, #selector(DisplayLinkProxy.tick(_:)))
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link.add(to: .main, forMode: .common)
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stage2Link = link
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syncFrameRate(hz: connection.currentMode().refreshHz)
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pipeline.start(connection: connection, onFrame: onFrame, onSessionEnd: onSessionEnd)
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} else {
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let pump = StreamPump()
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pump.start(
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connection: connection, layer: baseLayer,
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onFrame: onFrame, onSessionEnd: onSessionEnd)
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self.pump = pump
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}
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}
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/// Hint the display link with the stream's cadence. On iOS/tvOS a range is always required:
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/// without one, ProMotion devices cap CADisplayLink at 60 Hz (iPhones additionally need
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/// `CADisableMinimumFrameDurationOnPhone` in Info.plist), so a 120 fps stream would present
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/// at half rate with the ring silently dropping every other frame. `maximum` allows up to 120
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/// so the system MAY tick faster than a sub-120 stream (each extra tick is a near-free empty
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/// `renderTick`, and presenting on a denser grid shortens the decode→glass wait).
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///
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/// The `allowVRR` setting (default on) widens that hint into a true variable-refresh request:
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/// `preferred` = the stream rate with a low floor, so a ProMotion / adaptive-sync display can
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/// drop its physical refresh to match the content. With VRR off we fall back to the proven
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/// behavior — iOS keeps a 30 Hz floor; macOS leaves the NSView link at its display's native
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/// rate (it already tracks the display and must NOT be capped to the stream rate).
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/// Re-applied from `layout` so a mid-session `Reconfigure` picks up a new refresh.
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private func syncFrameRate(hz: UInt32) {
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guard hz > 0, let link = stage2Link else { return }
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let hzF = Float(hz)
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let allowVRR = UserDefaults.standard.object(forKey: DefaultsKey.allowVRR) as? Bool ?? true
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#if os(macOS)
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// Off: `.default` = the link free-runs at the display's native rate (pre-VRR behavior).
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// On: request the content rate with a 24 Hz floor — capped at the display, never at the
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// stream rate, so an adaptive-sync panel can track the stream.
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let range: CAFrameRateRange = allowVRR
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? CAFrameRateRange(minimum: min(hzF, 24), maximum: max(hzF, 120), preferred: hzF)
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: .default
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#else
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// A range is mandatory here (see above); VRR only lowers the floor (24 vs 30) so the
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// panel can drop deeper to match content on a sub-rate or momentarily stalling stream.
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let floor = allowVRR ? min(hzF, 24) : min(hzF, 30)
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let range = CAFrameRateRange(minimum: floor, maximum: max(hzF, 120), preferred: hzF)
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#endif
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if link.preferredFrameRateRange != range { link.preferredFrameRateRange = range }
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}
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/// Position the stage-2 metal sublayer aspect-fit in the hosting view (the host streams at the
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/// client's native mode, so this is usually the full bounds; it letterboxes a resized window).
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/// The layer FRAME + contentsScale set here are what the presenter sizes its drawable from
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/// (frame × scale) — the shader then performs the decoded→on-screen scale (bicubic luma), so a
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/// native-mode session stays pixel-exact 1:1 and a mismatched window beats the compositor's
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/// bilinear. No-op for stage-1 or before start.
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func layout(in bounds: CGRect, contentsScale: CGFloat) {
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guard let metalLayer, let connection else { return }
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let mode = connection.currentMode()
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syncFrameRate(hz: mode.refreshHz) // track a mid-session Reconfigure's new refresh
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let fit: CGRect = (mode.width > 0 && mode.height > 0)
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? AVMakeRect(
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aspectRatio: CGSize(width: Int(mode.width), height: Int(mode.height)),
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insideRect: bounds)
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: bounds
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// No implicit resize animation; contentsScale tracks the view's backing/display scale.
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CATransaction.begin()
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CATransaction.setDisableActions(true)
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metalLayer.contentsScale = contentsScale
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metalLayer.frame = fit
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CATransaction.commit()
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// Hand the resulting pixel size to the render thread (it must not read layer geometry
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// cross-thread) — this is what the presenter sizes its drawable to.
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stage2?.setDrawableTarget(CGSize(
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width: (fit.width * contentsScale).rounded(),
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height: (fit.height * contentsScale).rounded()))
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}
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/// Stop the active pump/pipeline (≤ one poll timeout; stage-2 joins its pump) and detach the
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/// stage-2 layer + link. Does not close the connection — that stays with whoever owns it.
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/// Idempotent.
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func stop() {
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pump?.stop()
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pump = nil
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stage2Link?.invalidate()
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stage2Link = nil
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stage2?.stop() // stops the pump (synchronous join) + drops the decode session
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stage2 = nil
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metalLayer?.removeFromSuperlayer()
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metalLayer = nil
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connection = nil
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}
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deinit {
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// The owning view's stop() normally ran already; this covers a missed teardown so the
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// display link can't keep ticking a deallocated pipeline.
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stage2Link?.invalidate()
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stage2?.stop()
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pump?.stop()
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}
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}
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#endif
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