Evidence-graded engineering knowledge base
Apple playback investigations, written to be linked.
Diagnose AVFoundation, HLS and LL-HLS, FairPlay Streaming, CoreMedia, and related Apple platform behavior from durable engineering records.
Knowledge index
Investigations
14 investigations
iOS 16 may omit requested supplemental HLS tracks from offline .movpkg downloads
AvfoundationHlsBugApple forumIos
AVMutableComposition can lose audio on iOS 26 when source media is streamed over HTTP/2
AvfoundationPlaybackBugIosInvestigating
iOS 26 can decrypt scrubbed frames while continuous AVPlayer playback never starts
AvfoundationPlaybackBugApple forumInferred
Offline HLS `.variants` can fall back to the original master URL from a downloaded `.movpkg`
AvfoundationHlsPlaybackApple forumIos
Live playlist discontinuity state changes for the same media sequence across reloads
HlsPlaybackApple forumInvestigatingGuideline
AVPlayerItemSampleBufferOutput returns no decoded audio for HLS on iOS 27 beta
AvfoundationHlsPlaybackApple forumInferred
Attaching AVContentKey to app-created CMSampleBuffer fails with authorization error
AvfoundationPlaybackInferredIosInvestigating
AVQueuePlayer may attempt network access during offline HLS after multiple queued transitions
AvfoundationHlsPlaybackApple forumInferred
Short looping streams re-request segments because HLS playback is not disk-cached by default
AvfoundationHlsPlaybackApple forumIos
SDK 26 rejects SPC when certificate-bundle credentials are mismatched or unreadable
AvfoundationApple forumIosGuidelineApple confirmed
Manual subtitle selection reverts to Off during live LL-HLS playback
AvfoundationHlsPlaybackBugApple forum
AVPlayer remains on SDR when HDR variants exist only at higher bitrates
AvfoundationHlsPlaybackApple forumInferred
Alternate-audio selection becomes order-sensitive on iOS 26
AvfoundationHlsPlaybackBugApple forum
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Method
Problem → evidence → platform behavior → guideline → verification.
Each record separates documented platform contract from reproduced behavior and engineering inference. The site is a reading layer; GitHub remains the place to author, discuss, and revise the underlying issue.