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
}
...
}
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 am using Google cloud speech through Python and finding many transcriptions are inaccurate and missing several words. This is a simple script I'm using to return a transcript of an audio file, in this case 'out307.wav':
client = speech.SpeechClient()
with io.open('out307.wav', 'rb') as audio_file:
content = audio_file.read()
audio = speech.types.RecognitionAudio(content=content)
config = speech.types.RecognitionConfig(
enable_word_time_offsets=True,
language_code='en-US',
audio_channel_count=1)
response = client.recognize(config, audio)
for result in response.results:
alternative = result.alternatives[0]
print(u'Transcript: {}'.format(alternative.transcript))
This returns the following transcript:
to do this the tensions and suspicions except
This is very far off what the actual audio says (I've uploaded it at https://vocaroo.com/i/s1zdZ0SOH1Ki). The audio is a .wav and very clear with no background noise. This is worse than average, as in some cases it will get the transcription fully correct on a 10 second audio file, or it may miss just a couple of words. Is there anything I can do to improve results?
This is weird, I tried your audio file with your code and I get the same result, but, if I change the language_code to "en-UK" I am able to get the full response.
I'm working for Google Cloud and I created for you a public issue here, you can track there the updates.
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
I have a question.
Recently I needed to add custom tags for recorded video. Local video on device not a streamed video. The task is to add some event specific tags in video, position of which could be set by pressing forward/backward like buttons like in any player.
It is not important whether the movie file will be mov file or mp4 format.
I searched on forum, found several samples how to add metadata using AVExportSession & it worked.
Although, when I tried to add metadata using AVAssetWriter. I wasn't able to append attributes to video.
What I do not understand is that after adding attribute, returned (time & duration) properties are always invalid.
For instance let's say I have a video with duration 2 seconds.
I have tried different key spaces. I am not able to write keys' from ID3 space.
IS ID3 used for stream video? (as far as I understood ID3 metadata of .mp3). Therefore, I was not able to write it into MPEG-4 file
I also used QuickTimeUserData & ISOUserData but again results are the same.
Here is an example
AVMutableMetadataItem *item2 = [AVMutableMetadataItem new];
item2.keySpace = AVMetadataKeySpaceiTunes;
item2.key = AVMetadataiTunesMetadataKeyUserComment;
item2.value = #"One two three";
item2.duration =CMTimeMakeWithSeconds(1, 1);
item2.time = CMTimeMakeWithSeconds(0, 1);
After reading I got the following:
AVMutableMetadataItem: 0xa4301f0, keySpace=itsk, key=\U00a9cmt, commonKey=(null), locale= (null), value=One two three, time={INVALID}, duration={INVALID}, extras={\n dataType = 1;\n}
I would like to use time & duration properties for metadata instead of writing custom data and processing it after that.
Ideally it would be great to append array of items with time = t1, duration = d1, .... (tn,dn).
Does anyone know how to accomplish that?
I've ended with a solution adding chapters to a video file instead of using metadata.
I looked at available libraries, took mpv4lib.
The library currently is not compiled for iOS, therefore, I ported the source project into static library for iOS platform.
That library allows to add custom "atoms" to mp4 file, and one of them is Quick Time text track, containing chapters.
I do similar with that post
The library is located here.
My understanding currently is that:
CameraUI
I can use the CameraUI to access the built in camera for MediaType.VIDEO and that delegates to the built-in video camera app and lets me record a video. My app does that now.
When I stop recording and click the "Use" button, I am returned to my app and theoretically I have a valid MediaPromise.
iOS does -not- provide a valid/usable url/filename to the recorded video (or to photos) and so I would have to use a Loader to bring-in/use/access the 'recorded' video... AND... iOS does not actually create a file anywhere on the device, most importantly, in the Camera Roll where one would expect by the normal behavior when uses the system native camera/video app.
The documentation says that the Loader can load various image types and SWFs but nothing about video data, so I conclude from that that I cannot actually use the CameraUI to generate a valid MediaPromise that I can then pass to a Loader class or similar to read in the information created by the system camera and then manipulate (upload, save to applicationStorageDirectory, and/or display in one of the two video player components available in the API).
CameraRoll
I can have video entities in the iOS Camera Roll but the AS3/Air3.5 CameraRoll class won't let me view/access/reference them in any way.
Normal File I/O
All my attempts to use the Air3.5 File classes to browse to the storage location of the iOS Camera Roll have been rebuffed.
------- Questions -------
Am I correct in believing that there is a way to take video but no way to use the video that's been captured. (No way to use the resulting MediaPromise successfully).
I believe you can take video and access it using Android, but there's nothing in the documentation that says that you cannot using iOS.
Am I correct in believing that iOS sandboxes apps so that they cannot browse to video/photo storage using standard File I/O, but only through the apparently non-workable means I've tried (CameraUI & CameraRoll)
Am I wrong to think that these should be rather obvious NEEDS that one can achieve using the XCode Objective C++ etc route but the AIR Mobile Framework does not allow either because of Apple blocking functionality or because Adobe has failed to meet reasonable expectations?
One item of ironic note to convey. If I use the iOS system camera app to record a video, a thumnail of that video then appears in the Gallery/Camera Roll, and of course, I can share it or view it, or whatever... If I use AIR's CameraRoll.browseForImage(), provided I haven't used the camera to take another image, when it shows me the folder where the pictures are stored, the folder icon uses the thumbnail of the last object added... in this case, the video I took, but if I then enter the folder, the video cannot be found. It's teasing us. It knows it's there, but it is apparently forbidden fruit.
I can't answer all your questions, so this entry may not be acceptable, but I found this page while searching a solution for some the problems you described and thought that someone else may find this answer (partially) useful.
To save the movie you just took you need to open and read the data from the promise.
The iOS won't save the file anywere, so the MediaPromise.file is always null.
This is my solution to the problem:
private var camera:CameraUI;
private var dataInput:IDataInput;
public function recordVideo():void
{
// Start the camera and ask for a video
camera = new CameraUI();
camera.addEventListener(MediaEvent.COMPLETE, onCameraComplete);
camera.launch(MediaType.VIDEO);
}
private function onCameraComplete(event:MediaEvent):void
{
// event.data is a MediaPromise and MediaPromise.open() returns a IDataInput
// Let's cast it to a dispatcher and check when it's complete
dataInput = event.data.open();
var dispatcher:IEventDispatcher = IEventDispatcher(dataInput);
dispatcher.addEventListener(Event.COMPLETE, onDataInputComplete);
}
private function onDataInputComplete(event:Event):void
{
// We can do whatever we want with the data, so we'll store it in a File
var file:File = new File();
var bytes:ByteArray = new ByteArray();
var stream:FileStream = new FileStream();
// Reading the data from the opened MediaPromise
dataInput.readBytes(bytes);
stream.open(file, FileMode.WRITE);
stream.writeBytes(bytes, 0, bytes.bytesAvailable);
stream.close();
}
Also, I'm still looking for a way to put the movie in the CameraRoll