Given an HLS manifest with multiple variants/renditions:
#EXTM3U
#EXT-X-VERSION:3
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1612430,CODECS="avc1.4d0020,mp4a.40.5",RESOLUTION=640x360
a.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=3541136,CODECS="avc1.4d0020,mp4a.40.5",RESOLUTION=960x540
b.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=5086455,CODECS="avc1.640029,mp4a.40.5",RESOLUTION=1280x720
c.m3u8
Is it possible to get an array of the three variants (with the attributes such as bandwidth and resolution) from either the AVAsset or AVPlayerItem?
I am able to get the currently playing AVPlayerItemTrack by using KVO on the AVPlayerItem, but again, it's only the track that's actively being played not the full list of variants.
I'm interested in knowing if the asset is being played at it's highest possible quality, so that I can make a decision on whether the user has enough bandwidth to start a simultaneous secondary video stream.
To know which variant you are currently playing, you can keep a KVO on AVPlayerItemNewAccessLogEntryNotification and by looking at AVPlayerItemAcessLogEvent in the access log, you can tell current bitrate and any change in bitrate.
AVPlayerItemAccessLog *accessLog = [((AVPlayerItem *)notif.object) accessLog];
AVPlayerItemAccessLogEvent *lastEvent = accessLog.events.lastObject;
if( lastEvent.indicatedBitrate != self.previousBitrate )
{
self.bitrate = lastEvent.indicatedBitrate
}
As far as knowing the entire list of available bitrates, you can simply make a GET request for the master m3u8 playlist and parse it. You will only need to do it once so not much of an overhead.
New in iOS 15, there’s AVAssetVariant
Related
Through AVCaptureSession I record a video and then immediately play it back via an AVPlayer once recording has stopped.
My problem is that the audio from the video sometimes plays out of the ear speaker at a really low volume and other times plays out of the bottom speaker.
How can I default the audio to output to the bottom speaker?
I've looked at other related posts with instances of the below code, which I tried, but to no avail..Any guidance would be appreciated.
let session = AVAudioSession.sharedInstance()
do {
try session.setCategory(.playAndRecord)
try session.overrideOutputAudioPort(AVAudioSession.PortOverride.none)
try session.setActive(true)
} catch {
print ("error")
}
You're explicitly turning that off here:
try session.overrideOutputAudioPort(AVAudioSession.PortOverride.none)
If you want to prefer the speaker, you'd use:
try session.overrideOutputAudioPort(.speaker)
AVAudioSession is very complicated, and many parts of it are not intuitive. Do not copy code you find on the internet without reading the docs on each command. The docs are pretty good, but you have to read them.
That said, rather than doing this, I'd probably switch your category and options when you switch to playback. You can do that at any time:
try session.setCategory(.playback, options: [.defaultToSpeaker])
It is generally best to keep your category aligned what you're doing. If you set .playback here as the category, you may not even need .defaultToSpeaker, depending on what precisely you're trying to achieve.
Be certain to read all the relevant docs on .defaultToSpeaker, setCategory, overrideOutputAudioPort, etc. Don't just copy my suggestions. These settings have many subtle (and documented) interactions, you need to configure it based on your actual use case, not just copy something that "seems to work." You may be very surprised at what happens when the user switches to Bluetooth, or plugs headphones, or switches to CarPlay.
You can change the audio output device for a given AVPlayer instance by setting the instance property 'audioOutputDeviceUniqueID' to the UniqueID of the desired device.
I can confirm that this works as expected in MacOS 10.11.6, using Key-Value coding ( setValue:forKey:)
Apple's doc on this:
Instance Property
audioOutputDeviceUniqueID
Specifies the unique ID of the Core Audio output device used to play audio.
Declaration
#property(nonatomic, copy) NSString *audioOutputDeviceUniqueID;
Discussion
The default value of this property is nil, indicating that the default audio output device is used. Otherwise the value of this property is a string containing the unique ID of the Core Audio output device to be used for audio output.
Core Audio's kAudioDevicePropertyDeviceUID is a suitable source of audio output device unique IDs.
I'm working on a video app, we are changing form regular mp4 files to HLS, one of the many reasons we have to do the change is that we hace much more control over the bandwidth usage of videos (we load lots of other stuff in our player, so we need to optimize the experience the best way).
So, AVFoundation introduced in iOS10 the ability to control the bandwidth using:
AVPlayerItem *playerItem = [AVPlayerItem playerItemWithAsset:self.urlAsset];
playerItem.preferredForwardBufferDuration = 30.0;
playerItem.preferredPeakBitRate = 200000.0; // Remember this line
There's also a configuration introduced on iOS11 to set the maximum resolution of the item with preferredMaximumResolution, So we're using it, but we still need a solution for iOS10 devices.
Well, now we have control over the preferredPeakBitRate that's nice, but we have a problem, not all the HLS sources are generated by us, so, let's say we want to set a maximum resolution of 480p when you're not connected to a wifi network, today I don't have way to achieve that, not always I'm going to be able to know how much bandwidth needs the 480p source for the selected HLS playlist.
One thing I was thinking about is to read the information inside the m3u8 file, to at least know which are the different quality sources that my player can show and how much bandwidth needs everyone.
One way to do this, would download the m3u8 playlist as a plain text, use a regex to read the file and process this data, well, I'm trying to avoid that, I think that this should far less difficult.
I cannot read this information from the tracks, because a) I can't find the information, b) the tracks are replaced dynamically when changing the quality, yeah 1 track for every quality level.
So, I don't know how I can get this information, I've searched google, stackoverflow and I can't find this information, does any one can help me?
Here's an example for what I want to do, I have this example playlist:
#EXTM3U
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=314000,RESOLUTION=228x128,CODECS="mp4a.40.2"
test-hls-1-16a709300abeb08713a5cada91ab864e_hls_duplex_192k.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=478000,RESOLUTION=400x224,CODECS="avc1.42001e,mp4a.40.2"
test-hls-1-16a709300abeb08713a5cada91ab864e_hls_duplex_400k.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=691000,RESOLUTION=480x270,CODECS="avc1.42001e,mp4a.40.2"
test-hls-1-16a709300abeb08713a5cada91ab864e_hls_duplex_600k.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1120000,RESOLUTION=640x360,CODECS="avc1.4d001f,mp4a.40.2"
test-hls-1-16a709300abeb08713a5cada91ab864e_hls_duplex_1000k.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1661000,RESOLUTION=960x540,CODECS="avc1.4d001f,mp4a.40.2"
test-hls-1-16a709300abeb08713a5cada91ab864e_hls_duplex_1500k.m3u8
And I just want to have that information available on an array inside my code, something like this:
NSArray<ZZMetadata *> *metadataArray = self.urlAsset.bandwidthMetadata;
NSLog(#"Metadata info: %#", metadataArray);
And print something like this:
<__NSArrayM 0x123456789> (
<ZZMetadata 0x234567890> {
trackId: 1
neededBandwidth: 314000
resolution: 228x128
codecs: ...
...
}
<ZZMetadata 0x345678901> {
trackId: 2
neededBandwidth: 478000
resolution: 400x224
}
...
}
I have an URL. It looks like this:
https://content.stage.someCompany.net/deliveries/artistNameHere/songNameHere-128.mp3?Expires=someNumberHere&Signature=someReallyReallyReallyLongStringHere&Key-Pair-Id=someIdHere
Let me break it down in pieces:
https://content.stage.someCompany.net/deliveries/artistNameHere/songNameHere-128.mp3
?Expires=someNumberHere
&Signature=someReallyReallyReallyLongStringHere
&Key-Pair-Id=someIdHere
As you can see, it's just a glorified .mp3 restricted to 128 kbps, with some security stuff at the end.
If I load it in Safari on my Mac, it will play. If I pass it to an AVPlayer constructor in my iOS app, it will play as well.
If, however, I use it to create an AVURLAsset, it reports that .isPlayable is false. If I stubbornly persist in further creating an AVPlayerItem based on that asset, it will report AVPlayerItemStatusFailed.
Needless to say, in these conditions my AVURLAsset + AVPlayerItem + AVPLayer infrastructure, which culminates in player.play(), actually plays no music.
However, it does successfully play if I substitute other URLs, like Apple's own https://devimages.apple.com.edgekey.net/streaming/examples/bipbop_4x3/bipbop_4x3_variant.m3u8
or
(some random .mp3 from another stackoverflow topic) http://podcast.cbc.ca/mp3/podcasts/asithappens_20160907_50906.mp3
The differences that I see: Apple's url is in fact a "playlist" of some sort, while the second one in a plain, "civilised" .mp3. No more security mambo-jumbo at the end of the link.
Why won't my url play? Do I need to do something specific with the security stuff? Right now, I'm just naively "hey, AVURLAsset...here's my (entire) URL...do your stuff with it..."
Found it.
The links that I receive are valid only once. Apparently that's why "the security" is in place at the end of them.
Testing one in Safari and "seeing that it works" invalidates it. Subsequently, trying the same one in the app results is .isPlayable = false.
Simply requesting & using directly in the app results in .isPlayable = true.
So AVURLAsset + AVPlayerItem + AVPLayer are working just fine. I was just a bloody fool.
I'm looping my streamed videos (not live stream) via .m3u8 playlist and each time the video restarts, it plays the video with the same bitrate adapting that occurs the first time you watch the video (bad quality -> good quality). Is there a way to refresh the stream quality each time the video loops so that the beginning gets replaced with the higher-rate bitrate seamlessly? Instead of just re-playing what was initially loaded?
Apple's AVPlayer attempts to load the first stream listed in the HLS playlist. So if you want the highest quality stream to be loaded first by default, you need to specify it as the first stream in the playlist file.
With that in mind, one way of achieving what you need to achieve is to have a different m3u8 file for each of your streams.
For example, if you have a three variant stream playlist, you would have three .m3u8 playlists.
Then in your view controller where you are using your AVPlayer, you need to keep a reference to the last observed bitrate and most recent bit rate:
var lastObservedBitrate: double = 0
var mostRecentBitrate: double = 0
You would then need to register a notification observer on your player with notification name: AVPlayerItemNewAccessLogEntryNotification
NSNotificationCenter.defaultCenter().addObserver(self, selector:#selector(MyViewController.accessEventLog(_:)), name: AVPlayerItemNewAccessLogEntryNotification, object: nil)
Whenever the access log is updated, you can then inspect the bitrate and stream used using the following code:
func accessLogEvent(notification: NSNotification) {
guard let item = notification.object as? AVPlayerItem,
accessLog = item.accessLog() else {
return
}
accessLog.events.forEach { lastEvent in
let bitrate = lastEvent.indicatedBitrate
lastObservedBitrate = lastEvent.observedBitrate
if let mostRecentBitrate = self.mostRecentBitrate where bitrate != mostRecentBitrate {
self.mostRecentBitrate = bitrate
}
}
}
Whenever your player loops, you can load the appropriate m3u8 file based on your lastObservedBitrate. So if your lastObservedBitrate is 2500 kbps, you would load your m3u8 file that has the 2500kbps stream at the top of the file.
Shameless plug: We've designed something similar in our video api. All you need to do is request the m3u8 file with your connection type: wifi or cellular and lastObservedBitrate and our API will vend you the best possible stream for that bitrate, but still have the ability to downgrade/upgrade the stream if network conditions change.
If you are interested in checking it out visit: https://api.storie.com or https://github.com/Storie/StorieCloudSDK
An HLS (m3u8) file references mpeg-ts files. During its playback in iOS' AVPlayer, how can i determine the currently playing mpeg-ts URI?
If your looking for a reference to the URI of the currently downloading TS, it's not available. You can get the URI of the stream for the current bit-rate by looking at the current AVPlayerItem's -accessLog.
E.g.:
[[[player currentItem] accessLog] events]
It's an NSArray of AVPlayerItemAccessLogEvent's.
But it's not going to give you the URI of the TS per se. You may just have to calculate the current TS by where the playhead is currently at in relation to the duration as well as the segment size.