Skip to content

fix: don't hang the main thread on live streams during chapter inspection #106

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
pke wants to merge 3 commits into
base: main
Choose a base branch
from
Open

fix: don't hang the main thread on live streams during chapter inspection #106

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
7d1402d
fix: don't hang the main thread on live streams during chapter inspec…
pke Jul 17, 2026
89ff7d8
fix: inspect chapters/metadata only after playback starts
pke Jul 17, 2026
2b62b4e
fix: defer asset metadata inspection until the item reports a finite …
pke Jul 17, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
65 changes: 40 additions & 25 deletions Sources/SwiftAudioEx/AVPlayerWrapper/AVPlayerWrapper.swift
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,7 @@ class AVPlayerWrapper: AVPlayerWrapperProtocol {
private let playerItemObserver = AVPlayerItemObserver()
fileprivate var timeToSeekToAfterLoading: TimeInterval?
fileprivate var asset: AVAsset? = nil
fileprivate var didInspectAssetMetadata = false
fileprivate var item: AVPlayerItem? = nil
fileprivate var url: URL? = nil
fileprivate var urlOptions: [String: Any]? = nil
Expand Down Expand Up @@ -236,33 +237,9 @@ class AVPlayerWrapper: AVPlayerWrapperProtocol {
if let url = url {
let pendingAsset = AVURLAsset(url: url, options: urlOptions)
asset = pendingAsset
didInspectAssetMetadata = false
state = .loading

// Load metadata keys asynchronously and separate from playable, to allow that to execute as quickly as it can
let metdataKeys = ["commonMetadata", "availableChapterLocales", "availableMetadataFormats"]
pendingAsset.loadValuesAsynchronously(forKeys: metdataKeys, completionHandler: { [weak self] in
guard let self = self else { return }
if (pendingAsset != self.asset) { return; }

let commonData = pendingAsset.commonMetadata
if (!commonData.isEmpty) {
self.delegate?.AVWrapper(didReceiveCommonMetadata: commonData)
}

if pendingAsset.availableChapterLocales.count > 0 {
for locale in pendingAsset.availableChapterLocales {
let chapters = pendingAsset.chapterMetadataGroups(withTitleLocale: locale, containingItemsWithCommonKeys: nil)
self.delegate?.AVWrapper(didReceiveChapterMetadata: chapters)
}
} else {
for format in pendingAsset.availableMetadataFormats {
let timeRange = CMTimeRange(start: CMTime(seconds: 0, preferredTimescale: 1000), end: pendingAsset.duration)
let group = AVTimedMetadataGroup(items: pendingAsset.metadata(forFormat: format), timeRange: timeRange)
self.delegate?.AVWrapper(didReceiveTimedMetadata: [group])
}
}
})

// Load playable portion of the track and commence when ready
let playableKeys = ["playable"]
pendingAsset.loadValuesAsynchronously(forKeys: playableKeys, completionHandler: { [weak self] in
Expand Down Expand Up @@ -500,6 +477,43 @@ extension AVPlayerWrapper: AVPlayerItemNotificationObserverDelegate {

}

extension AVPlayerWrapper {
/// Chapter/common-metadata inspection, deferred until the playing item
/// reports its duration. Probing an in-use asset's duration/chapter
/// properties makes iOS 26 stall the asset's serialized inspector for
/// ~20s on live streams — which either blocks item preparation (delayed
/// audio start) or, done synchronously, hangs the calling thread. The
/// item's observed duration tells live from file without touching the
/// asset: only finite-duration (file) assets are inspected.
fileprivate func inspectAssetMetadataIfNeeded(itemDuration: Double) {
guard !didInspectAssetMetadata, let asset = asset else { return }
didInspectAssetMetadata = true
guard itemDuration.isFinite && itemDuration > 0 else { return }
let metadataKeys = ["commonMetadata", "availableChapterLocales", "availableMetadataFormats"]
asset.loadValuesAsynchronously(forKeys: metadataKeys, completionHandler: { [weak self] in
guard let self = self, asset == self.asset else { return }

let commonData = asset.commonMetadata
if (!commonData.isEmpty) {
self.delegate?.AVWrapper(didReceiveCommonMetadata: commonData)
}

if asset.availableChapterLocales.count > 0 {
for locale in asset.availableChapterLocales {
let chapters = asset.chapterMetadataGroups(withTitleLocale: locale, containingItemsWithCommonKeys: nil)
self.delegate?.AVWrapper(didReceiveChapterMetadata: chapters)
}
} else {
for format in asset.availableMetadataFormats {
let timeRange = CMTimeRange(start: CMTime(seconds: 0, preferredTimescale: 1000), end: CMTime(seconds: itemDuration, preferredTimescale: 1000))
let group = AVTimedMetadataGroup(items: asset.metadata(forFormat: format), timeRange: timeRange)
self.delegate?.AVWrapper(didReceiveTimedMetadata: [group])
}
}
})
}
}

extension AVPlayerWrapper: AVPlayerItemObserverDelegate {
// MARK: - AVPlayerItemObserverDelegate

Expand All @@ -511,6 +525,7 @@ extension AVPlayerWrapper: AVPlayerItemObserverDelegate {

func item(didUpdateDuration duration: Double) {
delegate?.AVWrapper(didUpdateDuration: duration)
inspectAssetMetadataIfNeeded(itemDuration: duration)
}

func item(didReceiveTimedMetadata metadata: [AVTimedMetadataGroup]) {
Expand Down