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Fix mid-stream audio loudness jumps

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Root cause: the quality upgrade path called replaceCurrentItem mid-stream,
which re-loaded the HLS master manifest and re-picked an audio rendition,
producing a perceived loudness jump 10-30s into playback. .moviePlayback
mode amplified this by re-initializing cinematic audio processing on each
variant change.

- Start streams directly at user's desiredResolution; remove
  scheduleQualityUpgrade, qualityUpgradeTask, and the 504p->best swap.
- Switch AVAudioSession mode from .moviePlayback to .default in both
  MultiStreamView and SingleStreamPlayerView.
- Pin the HLS audio rendition by selecting the default audible
  MediaSelectionGroup option on every new AVPlayerItem, preventing
  ABR from swapping channel layouts mid-stream.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
Trey t
2026-04-14 20:04:39 -05:00
parent ba24c767a0
commit 85a19fdd71
2 changed files with 54 additions and 102 deletions
Download Patch File Download Diff File Expand all files Collapse all files

111
mlbTVOS/Views/MultiStreamView.swift
View File

@@ -352,7 +352,6 @@ private struct MultiStreamTile: View {
@State private var player: AVPlayer?
@State private var hasError = false
@State private var startupPlaybackTask: Task<Void, Never>?
@State private var qualityUpgradeTask: Task<Void, Never>?
@State private var werkoutMonitorTask: Task<Void, Never>?
@State private var clipTimeLimitObserver: Any?
@State private var isAdvancingClip = false
@@ -446,8 +445,6 @@ private struct MultiStreamTile: View {
logMultiView("tile disappeared id=\(stream.id) label=\(stream.label)")
startupPlaybackTask?.cancel()
startupPlaybackTask = nil
qualityUpgradeTask?.cancel()
qualityUpgradeTask = nil
werkoutMonitorTask?.cancel()
werkoutMonitorTask = nil
if let player {
@@ -536,11 +533,8 @@ private struct MultiStreamTile: View {
.clipShape(Capsule())
}
private var multiViewStartupResolution: String { "504p" }
private var multiViewUpgradeTargetResolution: String? {
let desiredResolution = viewModel.defaultResolution
return desiredResolution == multiViewStartupResolution ? nil : desiredResolution
private var multiViewStartupResolution: String {
viewModel.defaultResolution
}
private func startStream() async {
@@ -556,7 +550,6 @@ private struct MultiStreamTile: View {
onPlaybackEnded: playbackEndedHandler(for: player)
)
scheduleStartupPlaybackRecovery(for: player)
scheduleQualityUpgrade(for: player)
installClipTimeLimit(on: player)
logMultiView("startStream reused inline player id=\(stream.id) muted=\(player.isMuted)")
return
@@ -564,10 +557,10 @@ private struct MultiStreamTile: View {
if !Self.audioSessionConfigured {
do {
try AVAudioSession.sharedInstance().setCategory(.playback, mode: .moviePlayback)
try AVAudioSession.sharedInstance().setCategory(.playback, mode: .default)
try AVAudioSession.sharedInstance().setActive(true)
Self.audioSessionConfigured = true
logMultiView("startStream audio session configured id=\(stream.id)")
logMultiView("startStream audio session configured id=\(stream.id) mode=default")
} catch {
logMultiView("startStream audio session failed id=\(stream.id) error=\(error.localizedDescription)")
}
@@ -583,7 +576,6 @@ private struct MultiStreamTile: View {
onPlaybackEnded: playbackEndedHandler(for: existingPlayer)
)
scheduleStartupPlaybackRecovery(for: existingPlayer)
scheduleQualityUpgrade(for: existingPlayer)
installClipTimeLimit(on: existingPlayer)
logMultiView("startStream reused shared player id=\(stream.id) muted=\(existingPlayer.isMuted)")
return
@@ -620,7 +612,6 @@ private struct MultiStreamTile: View {
onPlaybackEnded: playbackEndedHandler(for: avPlayer)
)
scheduleStartupPlaybackRecovery(for: avPlayer)
scheduleQualityUpgrade(for: avPlayer)
logMultiView("startStream attached player id=\(stream.id) muted=\(avPlayer.isMuted) startupResolution=\(multiViewStartupResolution) fastStart=true calling playImmediately(atRate: 1.0)")
avPlayer.playImmediately(atRate: 1.0)
installClipTimeLimit(on: avPlayer)
@@ -637,15 +628,32 @@ private struct MultiStreamTile: View {
}
private func makePlayerItem(url: URL, headers: [String: String]) -> AVPlayerItem {
let item: AVPlayerItem
if headers.isEmpty {
return AVPlayerItem(url: url)
}
item = AVPlayerItem(url: url)
} else {
let assetOptions: [String: Any] = [
"AVURLAssetHTTPHeaderFieldsKey": headers,
]
let asset = AVURLAsset(url: url, options: assetOptions)
return AVPlayerItem(asset: asset)
item = AVPlayerItem(asset: asset)
}
pinAudioSelection(on: item)
return item
}
/// Lock the HLS audio rendition to the default option so ABR can't swap
/// to a different channel layout / loudness mid-stream.
private func pinAudioSelection(on item: AVPlayerItem) {
let streamID = stream.id
let asset = item.asset
Task { @MainActor [weak item] in
guard let group = try? await asset.loadMediaSelectionGroup(for: .audible),
let option = group.defaultOption ?? group.options.first,
let item else { return }
item.select(option, in: group)
logMultiView("pinAudioSelection id=\(streamID) selected=\(option.displayName) options=\(group.options.count)")
}
}
private func scheduleStartupPlaybackRecovery(for player: AVPlayer) {
@@ -686,75 +694,6 @@ private struct MultiStreamTile: View {
}
}
private func scheduleQualityUpgrade(for player: AVPlayer) {
qualityUpgradeTask?.cancel()
guard stream.overrideURL == nil else {
logMultiView("qualityUpgrade skip id=\(stream.id) reason=override-url")
return
}
guard let targetResolution = multiViewUpgradeTargetResolution else {
logMultiView("qualityUpgrade skip id=\(stream.id) reason=target-already-\(multiViewStartupResolution)")
return
}
let streamID = stream.id
let label = stream.label
qualityUpgradeTask = Task { @MainActor in
let checkDelays: [Double] = [2.0, 4.0, 7.0, 15.0, 30.0]
for delay in checkDelays {
try? await Task.sleep(for: .seconds(delay))
guard !Task.isCancelled else { return }
guard let currentPlayer = self.player, currentPlayer === player else {
logMultiView("qualityUpgrade abort id=\(streamID) label=\(label) reason=player-changed")
return
}
let itemStatus = multiViewItemStatusDescription(player.currentItem?.status ?? .unknown)
let likelyToKeepUp = player.currentItem?.isPlaybackLikelyToKeepUp ?? false
let bufferEmpty = player.currentItem?.isPlaybackBufferEmpty ?? false
let indicatedBitrate = player.currentItem?.accessLog()?.events.last?.indicatedBitrate ?? 0
let stable = (itemStatus == "readyToPlay" || likelyToKeepUp) && !bufferEmpty
logMultiView(
"qualityUpgrade check id=\(streamID) delay=\(delay)s targetResolution=\(targetResolution) stable=\(stable) rate=\(player.rate) indicatedBitrate=\(Int(indicatedBitrate))"
)
guard stable else { continue }
guard let upgradedURL = await viewModel.resolveStreamURL(
for: stream,
resolutionOverride: targetResolution,
preserveServerResolutionWhenBest: false
) else {
logMultiView("qualityUpgrade failed id=\(streamID) targetResolution=\(targetResolution) reason=resolve-nil")
return
}
if let currentURL = currentStreamURL(for: player), currentURL == upgradedURL {
logMultiView("qualityUpgrade skip id=\(streamID) reason=same-url targetResolution=\(targetResolution)")
return
}
logMultiView("qualityUpgrade begin id=\(streamID) targetResolution=\(targetResolution) url=\(upgradedURL.absoluteString)")
let upgradedItem = AVPlayerItem(url: upgradedURL)
upgradedItem.preferredForwardBufferDuration = 4
player.replaceCurrentItem(with: upgradedItem)
player.automaticallyWaitsToMinimizeStalling = false
playbackDiagnostics.attach(to: player, streamID: streamID, label: label)
viewModel.attachPlayer(player, to: streamID)
scheduleStartupPlaybackRecovery(for: player)
logMultiView("qualityUpgrade replay id=\(streamID) targetResolution=\(targetResolution)")
player.playImmediately(atRate: 1.0)
return
}
logMultiView("qualityUpgrade timeout id=\(streamID) targetResolution=\(targetResolution)")
}
}
private func currentStreamURL(for player: AVPlayer) -> URL? {
(player.currentItem?.asset as? AVURLAsset)?.url
}

31
mlbTVOS/Views/SingleStreamPlayerView.swift
View File

@@ -57,24 +57,37 @@ private func singleStreamTimeControlDescription(_ status: AVPlayer.TimeControlSt
}
private func makeSingleStreamPlayerItem(from source: SingleStreamPlaybackSource) -> AVPlayerItem {
let item: AVPlayerItem
if source.httpHeaders.isEmpty {
let item = AVPlayerItem(url: source.url)
item.preferredForwardBufferDuration = 8
return item
}
item = AVPlayerItem(url: source.url)
} else {
let assetOptions: [String: Any] = [
"AVURLAssetHTTPHeaderFieldsKey": source.httpHeaders,
]
let asset = AVURLAsset(url: source.url, options: assetOptions)
let item = AVPlayerItem(asset: asset)
item.preferredForwardBufferDuration = 8
item = AVPlayerItem(asset: asset)
logSingleStream(
"Configured authenticated AVURLAsset headerKeys=\(singleStreamHeaderKeysDescription(source.httpHeaders))"
)
}
item.preferredForwardBufferDuration = 8
pinSingleStreamAudioSelection(on: item)
return item
}
/// Lock the HLS audio rendition to the default option so ABR can't swap
/// to a different channel layout / loudness mid-stream.
private func pinSingleStreamAudioSelection(on item: AVPlayerItem) {
let asset = item.asset
Task { @MainActor [weak item] in
guard let group = try? await asset.loadMediaSelectionGroup(for: .audible),
let option = group.defaultOption ?? group.options.first,
let item else { return }
item.select(option, in: group)
logSingleStream("pinAudioSelection selected=\(option.displayName) options=\(group.options.count)")
}
}
struct SingleStreamPlaybackScreen: View {
@Environment(\.dismiss) private var dismiss
let resolveSource: @Sendable () async -> SingleStreamPlaybackSource?
@@ -544,9 +557,9 @@ struct SingleStreamPlayerView: UIViewControllerRepresentable {
)
do {
try AVAudioSession.sharedInstance().setCategory(.playback, mode: .moviePlayback)
try AVAudioSession.sharedInstance().setCategory(.playback, mode: .default)
try AVAudioSession.sharedInstance().setActive(true)
logSingleStream("AVAudioSession configured for playback")
logSingleStream("AVAudioSession configured for playback mode=default")
} catch {
logSingleStream("AVAudioSession configuration failed error=\(error.localizedDescription)")
}