I've implemented KVO for playbackLikelyToKeepUp and playbackBufferEmpty and also added an observer for the AVPlayerItemPlaybackStalledNotification notification.
I'm using the Buffer Empty, and Keep up events to show/hide my buffering activity indicator, and if I get the Playback Stalled notification I show an error message over the player until I get the Keep Up event to return true; I've noticed that sometimes after a stall, the buffer does not attempt to resume playback. Also, seeking the playhead will resolve this issue.
Is there any way for the player to automatically keep buffering, or let me know if the buffer has stopped entirely and will not continue attempting to play?
I've annotated the logs to show this functionality.
**APP HITS LOW BANDWIDTH STALL NOTIFICATION GOES OUT
2014-11-22 09:09:16.887 SampleApp[216:60b] Playback Stall Notification: Show Error Slate
2014-11-22 09:09:29.072 SampleApp[216:60b] Playback Buffer Event: Buffer Empty - False
2014-11-22 09:09:29.373 SampleApp[216:60b] Playback Buffer Event: Playback Likely to keep up - True (If showing, hide error)
2014-11-22 09:09:44.466 SampleApp[216:60b] Playback Buffer Event: Playback Likely to keep up - False
**VIDEO PLAYBACK RESUMES
2014-11-22 09:09:44.468 SampleApp[216:60b] Playback Buffer Event: Buffer Empty - True
2014-11-22 09:09:45.839 SampleApp[216:60b] Playback Buffer Event: Buffer Empty - False
2014-11-22 09:09:47.582 SampleApp[216:60b] Playback Buffer Event: Playback Likely to keep up - True (If showing, hide error)
**VIDEO HAS JUST BEEN SEEKED FORWARD
2014-11-22 09:10:03.556 SampleApp[216:60b] Playback Buffer Event: Playback Likely to keep up - False
2014-11-22 09:10:03.558 SampleApp[216:60b] Playback Buffer Event: Buffer Empty - True
**PLAY BACK STALLS BUFFER MAKES NO ATTEMPT TO RESUME -- LOGS GENERATED BY HITTING PLAY BUTTON
2014-11-22 09:10:03.560 SampleApp[216:60b] Playback Stall Notification: Show Error Slate
2014-11-22 09:10:25.491 SampleApp[216:60b] Playback Buffer Event: Playback Likely to keep up - False
2014-11-22 09:10:25.494 SampleApp[216:60b] Playback Buffer Event: Buffer Empty - True
2014-11-22 09:10:25.495 SampleApp[216:60b] Playback Stall Notification: Show Error Slate
2014-11-22 09:10:27.302 SampleApp[216:60b] Playback Buffer Event: Playback Likely to keep up - False
2014-11-22 09:10:27.304 SampleApp[216:60b] Playback Buffer Event: Buffer Empty - True
2014-11-22 09:10:27.305 SampleApp[216:60b] Playback Stall Notification: Show Error Slate
2014-11-22 09:10:52.266 SampleApp[216:60b] Playback Buffer Event: Playback Likely to keep up - False
2014-11-22 09:10:52.269 SampleApp[216:60b] Playback Buffer Event: Buffer Empty - True
2014-11-22 09:10:52.270 SampleApp[216:60b] Playback Stall Notification: Show Error Slate
2014-11-22 09:10:53.521 SampleApp[216:60b] Playback Buffer Event: Playback Likely to keep up - False
2014-11-22 09:10:53.523 SampleApp[216:60b] Playback Buffer Event: Buffer Empty - True
2014-11-22 09:10:53.525 SampleApp[216:60b] Playback Stall Notification: Show Error Slate
2014-11-22 09:10:57.542 SampleApp[216:60b] Playback Buffer Event: Playback Likely to keep up - False
2014-11-22 09:10:57.545 SampleApp[216:60b] Playback Buffer Event: Buffer Empty - True
**I'VE MOVED THE PLAYHEAD UP SLIGHTLY AND THE BUFFERING EVENTS AND PLAYBACK HAVE RETURNED
2014-11-22 09:10:58.817 SampleApp[216:60b] Playback Buffer Event: Buffer Empty - False
2014-11-22 09:10:59.502 SampleApp[216:60b] Playback Buffer Event: Playback Likely to keep up - True (If showing, hide error slate)