We're downloading HLS content for offline playback using AVAssetDownloadConfiguration. It's critical for our app that all subtitle tracks are downloaded together with the video, so users can watch any subtitle and audio option while offline. On iOS 16, not all tracks are downloaded, and when the user goes offline, playback fails with NSURLErrorNotConnectedToInternet (error -1009) because AVFoundation tries to fetch the missing subtitle segments over the network. On iOS 17 and later, everything works as expected — all subtitle and audio tracks are downloaded. However, on iOS 16 we observe two issues: First issue: Supplemental tracks are not downloaded on iOS 16 (device) Only the default audio track is downloaded. All non-default supplemental tracks — both subtitles and additional audio tracks — exhibit the same problem: Some supplemental tracks listed in the manifest don't even get a directory created in the .movpkg package Some supplemental tracks do get a directory created, but it contains only StreamInfoBoot.xml and StreamInfoRoot.xml — no actual segment data (.frag files) is downloaded. The StreamInfoBoot.xml for these directories shows NO, 0, and 0, with Supplemental Additionally, a Manifest.m3u8 stream directory is created with Complete=NO and no segment data. On iOS 17+ devices, all supplemental track directories are created and all contain segment data. Second issue: Downloads fail entirely on iOS 16 Simulator We receive the following error: Error Domain=NSURLErrorDomain Code=-16090 UserInfo={ NSLocalizedDescription=The operation could not be completed, _NSURLErrorFailingURLSessionTaskErrorKey=BackgroundAVAssetDownloadTask <DEC0D555-6C05-416C-91B8-F490F5A29046>.<3>, _NSURLErrorRelatedURLSessionTaskErrorKey=( "BackgroundAVAssetDownloadTask <DEC0D555-6C05-416C-91B8-F490F5A29046>.<3>" ), NSLocalizedFailureReason=An unknown error occurred (-16090) } On iOS 17+ Simulators, downloads work without issues. Our setup: let urlAsset = AVURLAsset(url: manifestURL) let preferredMediaSelection = try await urlAsset.load(.allMediaSelections) let config = AVAssetDownloadConfiguration(asset: urlAsset, title: title) config.primaryContentConfiguration.mediaSelections = preferredMediaSelection let task = assetDownloadURLSession.makeAssetDownloadTask(downloadConfiguration: config) task.resume() Example HLS manifest: #EXTM3U #EXT-X-VERSION:7 #EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="French",LANGUAGE="fr",DEFAULT=NO,AUTOSELECT=YES,FORCED=NO,URI="s_25/stream.m3u8" #EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="French (forced)",LANGUAGE="fr-x-cc",DEFAULT=NO,AUTOSELECT=YES,FORCED=YES,URI="s_31/stream.m3u8" #EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="English",LANGUAGE="en",DEFAULT=NO,AUTOSELECT=YES,FORCED=NO,URI="s_37/stream.m3u8" #EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="Kazakh",LANGUAGE="kk",DEFAULT=NO,AUTOSELECT=YES,FORCED=NO,URI="s_43/stream.m3u8" #EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="Uzbek",LANGUAGE="uz",DEFAULT=NO,AUTOSELECT=YES,FORCED=NO,URI="s_49/stream.m3u8" #EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aud_ec3",NAME="French 5.1",LANGUAGE="fr",DEFAULT=YES,AUTOSELECT=YES,CHANNELS="6",URI="a_18/stream.m3u8" #EXT-X-STREAM-INF:AUDIO="aud_ec3",SUBTITLES="subs",BANDWIDTH=1931408,VIDEO-RANGE=SDR,CODECS="hvc1.1.6.L90.90,ec-3",RESOLUTION=1024x428,FRAME-RATE=25,HDCP-LEVEL=NONE v_6/stream.m3u8 #EXT-X-SESSION-KEY:METHOD=SAMPLE-AES,URI="skd://XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX",KEYFORMAT="com.apple.streamingkeydelivery",KEYFORMATVERSIONS="1" Questions: What is the correct way to make sure all supplemental tracks (subtitles, non-default audio) are actually downloaded on an iOS 16 real device? We pass asset.load(.allMediaSelections) to primaryContentConfiguration.mediaSelections — is there a different configuration, or should we use auxiliaryContentConfigurations, or something else entirely? Is there any way to make asset downloads work on the iOS 16 Simulator at all? We always get NSURLErrorDomain error -16090, while iOS 17+ Simulators work fine. If the supplemental tracks download bug on iOS 16 cannot be fixed or worked around from the app side, do you have any recommended approach for handling incomplete .movpkg packages at offline playback time?

I’m trying to understand which storage capacity key is the correct one to use when deciding whether my app can start downloading offline video content. I read the documentation here: https://developer.apple.com/documentation/foundation/checking-volume-storage-capacity but I still don’t fully understand the intended usage difference between: volumeAvailableCapacityKey volumeAvailableCapacityForImportantUsageKey My app allows users to download videos for offline viewing. These downloads may remain on the device for a long time (days or even months), so they are not just temporary cache files. On one hand, this seems to match the description of “storing data based on a user request”, which suggests using volumeAvailableCapacityForImportantUsageKey. On the other hand, my understanding is that this value may assume the system is willing to aggressively purge caches and reclaim space for this “important usage”. I’m worried this could lead to unexpected or unpleasant side effects for the user if my app relies on that space. What confuses me even more is that the values are significantly different on my device: iPhone Settings reports about 142 GB free volumeAvailableCapacityKey returns only ~56 GB volumeAvailableCapacityForImportantUsageKey returns ~132 GB So my question is: For an app that downloads videos for offline playback — where the user explicitly requested the download, but the content may stay on device for a long time — which value is the recommended one to use when deciding whether there is enough free space to start the download? Should offline media downloads generally be treated as “important usage” in the sense intended by this API?

I’m working with FairPlay offline licenses using AVContentKeySession and ran into behavior that I cannot find documented. I am explicitly calling: contentKeySession.processContentKeyRequest( withIdentifier: identifier as NSString, initializationData: nil, options: nil ) Expected behavior I expect that each call to processContentKeyRequest will eventually result in the delegate callback: contentKeySession(_:didProvide:) Observed behavior If I call processContentKeyRequest with a new identifier, everything works as expected: didProvide is called I complete the request successfully However, if I call processContentKeyRequest again with the same identifier that was already processed earlier, then: No delegate callbacks are triggered at all The session does not appear to be blocked or stuck If I issue another request with a different identifier, it is processed normally So the behavior looks like the session is silently ignoring repeated requests for the same content key identifier. Important context This is not a concurrency issue — the session continues processing other requests This is reproducible consistently I am not using renewExpiringResponseData(for:) because I do not have a live AVContentKeyRequest at the time of retry Use case My use case is offline playback with periodically refreshed licenses. The app can stay alive for a long time (days/weeks), and I need to proactively refresh licenses before expiration. In this scenario: I only have the contentKeyIdentifier I do not have a current AVContentKeyRequest Calling processContentKeyRequest again for the same identifier does not trigger any delegate callbacks Questions Is this behavior expected — that AVContentKeySession ignores repeated processContentKeyRequest calls for the same identifier? What is the recommended way to re-fetch or refresh a license when: I only have the identifier I do not have a current AVContentKeyRequest I need to refresh proactively (not just in response to playback) What is the intended approach in this case? Maybe to create a new AVContentKeySession to force a new request cycle? Or something else? Is there any way to guarantee that a call to processContentKeyRequest will result in a delegate callback, or is it expected that it may be ignored in some cases? Any clarification on the intended lifecycle of AVContentKeySession and how repeated requests should be handled would be greatly appreciated.

Hi, I’m trying to better understand how AVAssetDownloadConfiguration selects video variants when downloading HLS content for offline playback. Suppose I have an HLS master playlist (.m3u8) that contains several video variants defined with #EXT-X-STREAM-INF. For example, the master playlist may contain multiple video streams like this: Same resolution, different BANDWIDTH Or different resolutions (for example 720p, 1080p, etc.) My question is: How many video variants are actually downloaded when using AVAssetDownloadConfiguration without specifying any variantQualifiers? In other words: If the master playlist contains multiple video variants, will the download task fetch only one variant, or multiple variants? Does the behavior differ depending on whether the variants differ only by BANDWIDTH or also by RESOLUTION? What I observed in testing In my tests, I always end up with only one video variant downloaded, specifically the one with the highest BANDWIDTH parameter. In the m3u8 files I tested, all video variants had identical parameters (resolution, codec, frame rate, etc.) and differed only by the BANDWIDTH attribute in the master playlist. However, when inspecting the downloaded .movpkg, I noticed something interesting in boot.xml. It lists two video streams: one with complete="true" (the one with highest bandwidth) another with complete="no" (the one with lowest bandwidth) I actually had 3 video streams listed in m3u8, but the one with middle bandwidth wasn't listed in boot.xml file at all. There are also additional streams for audio and subtitles in boot.xml file. This made me wonder whether the system initially attempts to download another video variant (possibly a lower bitrate one), but then switches to the highest-quality variant and only completes that one. Additional question about variantQualifiers If I provide a predicate such as: NSPredicate(format: "peakBitRate > 0") which should theoretically match all variants, will the download task attempt to download all matching video variants, or will it still select only one? Summary So the main questions are: Without variantQualifiers, does AVAssetDownloadConfiguration always download a single video variant, and if so, how is it chosen? Does the behavior differ if variants have different resolutions vs only different bitrates? When a predicate matches multiple variants, can multiple video variants actually be downloaded in a single .movpkg? Why might boot.xml list multiple video streams when only one appears to be fully downloaded? Any clarification on the intended behavior would be greatly appreciated. Thanks!