iOS 10下，AVplayer新增屬性 automaticallyWaitsToMinimizeStalling。

蘋果官方文檔地址https://developer.apple.com/reference/avfoundation/avplayer/1643482-automaticallywaitstominimizestal

HTTP Live Streaming (HLS): When playing HLS media, the player behaved as if automaticallyWaitsToMinimizeStalling istrue.

File-based Media: When playing file-based media, including PRogressively downloaded content, the player behaved as if automaticallyWaitsToMinimizeStalling isfalse.

文檔中的兩句話

HTTP Live Streaming (HLS): 當播放HLS媒體時,  automaticallyWaitsToMinimizeStalling 的值為true.

File-based Media: 當播放基于文件的媒體, 包括逐漸下載的內容,  automaticallyWaitsToMinimizeStalling 的值為false.

avplayer在新系統下有時會播放不了

self.player.automaticallyWaitsToMinimizeStalling = NO;

一句話解決。