AVAssetDownloadURLSession 简述 NSURLSession 的子类,用于支持创建和执行资产下载任务的URL会话,主要是用来下载HLS资源内容的 AVAssetDownloadURLSession reference https://developer.apple.com/documentation/avfoundation/avassetdownloadurlsession?language=objc#topics 可以用来下载HLS内容 https://developer.apple.com/documentation/avfoundation/media_assets_playback_and_editing/asset_manipulation/downloading_and_playing_offline_http_live_streaming_content?language=objc 官方demo https://developer.apple.com/library/content/samplecode/HLSCatalog/Introduction/Intro.html#//apple_ref/doc/uid/TP40017320