Please can someone tell me if there is a way to selectively pre-buffer the avplayeritems in the AVQueuePlayer array rather than leaving it down to the AVQueuePlayer automatic way of only loading the next item in as the first item finishes playing.
I'm loading a sequence of 4 short movie clips and I'd like to pre-cache them before telling the AVQueuePlayer to play the array. Is there actually a way of getting under the bonet of avqueueplayer and controlling the pre-buffering as desired?
Right now with its default lazy-loading behaviour, I'm getting some chugging in the playback, with the clips not even playing-out properly because the AVQueuePlayer is trying to loading-in the next clip while it's playing. I'm doing this on iPad deployed to the actual device and not with the simulator.
You can do this with the mpmovieplayer by calling [player prepareToPlay]; which basically manually initiates the loading of each video file you want and then you can check for the completeion of loading by watching for the mpmovieplayerLoadstateDidChange notification and testing the loadState value to see if it has fully loaded ,then telling the mpmovieplayer to play. How can you effectively do a similar thing with AVQueuePlayer?
Is this even possible or have I discovered one of the major drawbacks of the AVQueuePlayer?
Nice suggestion with the playerObserver Stephen, but what is needed is something like you need to be able to explicitly get individual items to load into memory and then tell the AVQueuePlayer 'do not play the first item in the array until ALL items in the array are loaded into memory' There currently seems to be no way to start even the second item in the array loading until the first one is coming to an end!
As a slightly separate issue, I've also noticed some weirdness in the AVQueuePlayer where, if you load two of the same source video file into the array (both referenced as two completely separate AVPlayerItems as you should do) when you play the video clips in the array all the way through, the first time the clip plays through ok, but when it comes to playing that same clip again (as a separate AVPlayerItem) it plays-through very quickly until a certain point in the video then finally starts playing at normal speed from there.
Has anyone else noticed this behaviour?
Apple Developer Support just confirmed to me that AVQueuePlayer does not buffer video items.
I have the same question. I wish AV Foundation has something like asset fully loaded notification.
Following code may partially solve the problem:
Float64 durationSeconds = CMTimeGetSeconds([<#An asset#> duration]);
CMTime secondThird = CMTimeMakeWithSeconds(durationSeconds*2.0/3.0, 1);
NSArray *times = [NSArray arrayWithObjects:[NSValue valueWithCMTime:secondThird], nil];
self.playerObserver = [<#A player#> addBoundaryTimeObserverForTimes:times queue:NULL usingBlock:^{
}];
Related
I found myself in a situation where I need to simulate audio playback to trick OS controls and MPNowPlayingInfoCenter into thinking that an audio is being played. This is because I am building a player that plays multiple audio tracks, with pauses in-between creating one, continuous "audio" track. I have already everything setup inside the app itself, and the lock screen controls are working correctly but the only problem I am facing is while the actual audio stops and a pause is being "played", the lock screen info center stops the timer, and it only continues with showing correct time and overall state once another audio track starts playing.
Here is the example of my audio track built from audio files and pause items:
let items: [AudioItem] = [
.audio("part-1.mp3"),
.pause(duration: 5), // value of type: TimeInterval
.audio("part-2.mp3"),
.pause(duration: 3),
... // the list goes on
]
then in my custom player, once AVAudioPlayer finishes its job with current item, I get the next one from the array and play either a .pause with a scheduled Timer or another .audio with AVAudioPlayer.
extension Player: AVAudioPlayerDelegate {
func audioPlayerDidFinishPlaying(_ player: AVAudioPlayer, successfully flag: Bool) {
playNextItem()
}
}
And here lies the problem, once the AVAudioPlayer stops, the Now Playing info center automatically stops too, even tho I keep feeding it fresh nowPlayingInfo. Then when it hits another .audio item, it resumes correctly and shows current time, etc.
And here lies the question
how do I trick the MPNowPlayingInfoCenter into thinking that audio is being played while I "play" my .pause item?
I realise that it may still not be clear, what I am trying to achieve but I am happy to share more insight if needed. Thanks!
Some solutions I am currently thinking about:
A. Keeping 1s long empty audio track that would play on loop for as long as the pause is needed to play.
B. Creating programatically empty audio track with appropriate lenght and playing it instead of using Timer for keeping track of pause duration/progress and relying completely on AVAudioPlayer for both .audio and .pause items. Not sure this is possible though.
C. Maybe there is a way to tell the MPNowPlayingInfoCenter that the audio keeps playing without the need of using AVAudioPlayer but some API I am not familiar with?
AVAudioPlayer is probably the wrong tool here. You want AVAudioPlayerNode, which is slightly lower-level. Create an AVAudioEngine, and attach an AVAudioPlayerNode. You can then call scheduleFile(_:at:completionHandler:) to play the audio at the times you want.
Much of the Apple documentation on AVAudioEngine appears broken right this moment, but the links hopefully will be available again shortly in the links for Audio Engine Building Blocks. (If it stays down and you have trouble finding docs, leave a comment and I'll hunt down the WWDC videos and other tutorials on using AVAudioEngine. It's not particularly difficult for simple problems.)
If you know in advance how you want to compose these items (and it looks like you may), see also AVMutableComposition, which lets you glue together assets very efficiently, including adding empty segments of silence. See Media Composition and Editing for the various tools in that space.
I am working on an app that supports video playback similar to what snapchat is doing (you can tap through a bunch of remote videos). After tapping through a handful of videos, buffering seems to become slower, and comes to a complete stop at some point of you keep going. Sounds a lot like a memory leak to me.
After diving into it in Instruments, I found that all AVPlayers, AVPlayerItems, and AVPlayerLayers get deallocated correctly. The only leaks I find are these:
However, by studying the Connections graph and the Memory Usage, I can clearly see that even after dismissing the video player and sitting in the camera view of the app, some buffering is still occurring. The network activity stays fairly high and the memory slowly grows.
To get a better understanding of how I do video playback, here's a short explanation. I have a VideoPlayer object that I only initiate one of, then I give it new assets to play. Before giving it a new asset, I call stopBuffering, just to make sure nothing gets left behind (we all see how successful that was).
- (void)stopBuffering
{
[self removeObservers];
[self.player pause];
[self.avPlayer replaceCurrentItemWithPlayerItem:nil];
self.avPlayer = nil;
self.player = nil;
self.playerItem = nil;
}
I have verified that this method gets called every time a new asset is loaded.
This is the All Heap & Anonymous VM graph, in which the first generation is before any video playback, and the third generation is after leaving the video player. In between, I quickly jumped through about 20 videos.
The reason for this was that I began loading values with loadValuesAsynchronouslyForKeys whenever I loaded an asset, but if I moved on the next asset before this method completed, I never canceled it. After storing the AVURLAsset as a property and then calling
[self.asset cancelLoading];
at appropriate times, the problem disappeared.
I have some issue with avqueueplayer like app freezing for 2-3 seconds when each item ends in the queue. I am using queueplayer to play the records one after the other without gap. In order to achieve no gaps b/w player items, I need to load the assets for a player item in advance. I load assets for current playing player item and next player item so that there will be no gap at the end of 1st record. As the 1st record ends, I add 2nd player item to queueplayer to play and also load assets for 3rd player item.
In this way my playerqueue always contains a single player item but asset loading will be done for current playing item and next playing item. This will keep moving as the new records are added.
I found that a freeze of half a second is observed in new iOS devices and around 3-4 seconds in old iPod devices like iPod 4?
Can I know how we can achieve gapless and yet non freeze UI experience?
Thanks
Try lifting your requirement to only have a single player item in the queue.
An AVQueuePlayer will operate more effectively at item transitions if there is an item in its queue beyond what's currently playing.
"Loading" media can mean a few different things, and it's not clear what you're doing. Maybe you're downloading media outside of AVFoundation, building an AVAsset or building an AVPlayerItem. The work you're doing or deferring will vary depending on the kind of media (e.g an mp4 vs an HLS stream). Even if you "preload" everything (which is much more complicated for HLS media), AVFoundation still has more work to do that it won't start until the AVPlayerItem is put in a player. It has to set up a render pipeline specific to the media it needs to play back, and then start the rendering process. AVQueuePlayer can achieve gapless playback by starting some of that process before playback for that item needs to start. The queue player is also efficient about its use of resources in that it won't start loading items far down the queue until it needs to.
I am using [MPMusicPlayerController iPodMusicPlayer] to handle playback. The app starts with a playlist and eventually while listening to a track, if the user takes a certain action I want to change the part of the playlist AFTER the nowPlayingItem.
Since I generate the original playlist and the new one, I am able to create a new queue that represents the previously played MPMediaItems and the new ones. Everything works fine until I try pausing, scrubbing or doing anything that affects playback. It will immediately skip to the track after the nowPlayingItem.
Example code:
- (void)exampleAction{
//Remove tracks after currentItem
[self.playbackQueue removeObjectsInRange:NSMakeRange(self.indexInQueue+1, self.playbackQueue.count-self.indexInQueue-1)];
NSMutableArray *newQueue = [NSMutableArray array];
//ADD ITEMS TO newQueue here
[self.playbackQueue addObjectsFromArray:newQueue];
MPMediaItemCollection *collection = [MPMediaItemCollection collectionWithItems:self.playbackQueue];
[self.playbackController setQueueWithItemCollection:collection];
}
Playback of the nowPlayingItem cannot be interrupted. Using this method, if I do not attempt to alter playback (play\pause\scrub) and the track finishes normally, everything works as it should and continues to work properly for the remainder of the playlist. It seems that modifying the playback queue during playback has some sort of side-effect that I don't understand. Can anyone give me some insight on how I can achieve what I am trying to do? This bug is killing me.
Have you tried calling play on your MPMusicPlayerController immediately after setting the playback queue? It should produce at most a momentary blip in playback.
I am using AVPlayer to play videos. The lenght of them is short, 2-5 second. They are played in a random order. The problem is, when changing video, and a new video starts to play, the device lags for a very short time, but i wan't the change to be fluid. Is there a way to preload videos with AVPlayer?
Try using AVQueuePlayer. I am assuming that what you described as a lag, in fact is the pre buffering delay. This should be minimized or actually entirely be gotten rid of when using AVQueuePlayer as that baby will buffer the next AVPlayerItem while playing the current one.
From the AVFoundation documentation:
On iOS 4.1 and later, you can use an AVQueuePlayer object to play a
number of items in sequence (AVQueuePlayer is a subclass of AVPlayer).
Also see Mihai's answer on Pre-buffering-for-avqueueplayer.