I'm currently writing a small application which takes a folder containing many short video files (~1mn each) and plays them like they were ONE long video file.
I've been using AVQueuePlayer to play them all one after another but I was wondering if there were an alternative to this, because I'm running into some problems:
there is a small but noticeable gap when the player switches to the next file
I can't go back to the previous video file without having to remove all the items in the queue and put them back
I'd like to be able to go to any point in the video, just as if it were a single video file. Is AVPlayer the best approach for this?
I realize that it's been about 6 years since this was asked, but I found a solution to this shortly after seeing this question and maybe it will be helpful to someone else.
Instead of using a an AVQueuePlayer, I combined the clips in an AVMutableComposition (a subclass of AVAsset) which I could then play in a normal AVPlayer.
let assets: [AVAsset] = urlsOfVideos.map(AVAsset.init)
let composition = AVMutableComposition()
let compositionVideoTrack = composition.addMutableTrack(withMediaType: .video, preferredTrackID: kCMPersistentTrackID_Invalid)
let compositionAudioTrack = composition.addMutableTrack(withMediaType: .audio, preferredTrackID: kCMPersistentTrackID_Invalid)
var insertTime = CMTime.zero
for asset in assets {
let range = CMTimeRange(start: .zero, duration: asset.duration)
guard let videoTrack = asset.tracks(withMediaType: .video).first,
let audioTrack = asset.tracks(withMediaType: .audio).first else {
continue
}
compositionVideoTrack?.preferredTransform = orientation!
try? compositionVideoTrack?.insertTimeRange(range, of: videoTrack, at: insertTime)
try? compositionAudioTrack?.insertTimeRange(range, of: audioTrack, at: insertTime)
insertTime = CMTimeAdd(insertTime, asset.duration)
}
Then you create the player like this
let player = AVPlayer(playerItem: AVPlayerItem(asset: composition))
Related
I have 0.2sec long sound file "beep.caf" that I am trying to get to play rapidly. If I set the sounds to play 1 second apart, they play just fine, but if I set them to play any less like 0.8, only the first sound plays. I have the same problem using AudioServicesPlaySystemSound too.
To play the sound twice rapidly I have the following function:
func runAfterDelay(delay: NSTimeInterval, block: dispatch_block_t) {
let time = dispatch_time(DISPATCH_TIME_NOW, Int64(delay * Double(NSEC_PER_SEC)))
dispatch_after(time, dispatch_get_main_queue(), block)
}
I first setup my sound in the viewDidLoad with the following:
let path = NSBundle.mainBundle().pathForResource("beep", ofType: "caf")!
let url = NSURL(fileURLWithPath: path)
do{
self.startBeep = try AVAudioPlayer(contentsOfURL: url)
self.startBeep.prepareToPlay()
}catch{
print("Audio didn't load")
}
Then when a button is pressed the following code is run:
let start_time:Double = 1.0
let end_time:Double = start_time + 0.8
runAfterDelay(start_time ) {
self.startBeep.play()
}
runAfterDelay(end_time ) {
self.startBeep.play()
}
I have tried to stop the sound before the next play, but that doesn't help either. I have even duplicated the should file (beep & beepStop) to see if it had something to do with playing the same sound file and I get the same problems.
Any ideas??
The problem is with the time and not the players. The delay time was supposed to be in a 10th of a millisecond but was a 100th of a millisecond (.1 vs .01) which was so short of time between beeps that it often didn't fire accurately. A false positive was created when the time was set to 1.0 seconds.
I'm just getting started with TVOS and was wondering if anyone has addressed looping in TVOS / TVJS / TVML. I'm using this tutorial to create a simple interface for playing videos. My wrinkle is that I want these videos to play in a continuous seamless loop - basically a moving screensaver type effect - see example videos at art.chrisbaily.com.
Is there a simple way to do this, or do I need to build some kind of event listener to do the looping manually? I'd like the videos to be fairly hi res, and the videos would be somewhere between 1 and 3 minutes.
I was looking for an answer for this question as well. And found that the only way this would be possible is to create an event listener and adding a duplicate media item to the playlist. But honestly it is not that hard, given if you followed the tutorial that you listed in your post.
So the code would be something like
player.playlist = playlist;
player.playlist.push(mediaItem);
//Again push the same type of media item in playlist so now you have two of the same.
player.playlist.push(mediaItem);
player.present();
This will make sure that once your first video ends the second one starts playing which is essentially a loop. Then for the third one and on you implement an event listener using "mediaItemWillChange" property. This will make sure that once a video ends a new copy of the same video is added to the playlist.
player.addEventListener("mediaItemWillChange", function(e) {
player.playlist.push(mediaItem);
});
Just put the event listener before you start the player using
player.present();
Note this question and idea of this sort was already asked/provided on Apple's discussion board. I merely took the idea and had implemented it in my own project and now knowing that it works I am posting the solution. I found that if I pop the first video out of the playlist and add then push a new on the playlist as mentioned in the linked thread below, my videos were not looping. Below is the link to the original post.
How to repeat video with TVJS Player?
You could also set repeatMode on the playlist object
player.playlist.repeatMode = 1;
0 = no repeat
1 = repeat all items in playlist
2 = repeat current item
There's really no need to push a second media item onto the. Simply listen for the media to reach its end, then set the seek time back to zero. Here's the code.
Play the media.
private func playVideo(name: String) {
guard name != "" else {
return
}
let bundle = NSBundle(forClass:object_getClass(self))
let path = bundle.pathForResource(name, ofType:"mp4")
let url = NSURL.fileURLWithPath(path!)
self.avPlayer = AVPlayer(URL: url)
if (self.avPlayerLayer == nil) {
self.avPlayerLayer = AVPlayerLayer(player: self.avPlayer)
self.avPlayerLayer.frame = previewViews[1].frame
previewViews[1].layer.addSublayer(self.avPlayerLayer)
avPlayer.actionAtItemEnd = .None
//Listen for AVPlayerItemDidPlayToEndTimeNotification
NSNotificationCenter.defaultCenter().addObserver(self, selector: "playerItemDidReachEnd:", name: AVPlayerItemDidPlayToEndTimeNotification, object: self.avPlayer.currentItem)
}
avPlayer.play()
}
Play Again
func playerItemDidReachEnd(notification: NSNotification) {
let item = notification.object as? AVPlayerItem
item?.seekToTime(kCMTimeZero)
}
I am very new to both programming and swift (please be kind!). I have a working example of how to generate a random image (by assigning a number and using Int(arc4random_uniform(x)). However I do not know how I can say if this image is shown, then assign this sound to the button. Every time an image is displayed it will have a matching sound to go with it. With my limited experience I can only think of doing long winded if statements?
Answer
Pass the name of the image to a NSMutableString, without the extension (.png, or just remove the extension.). Then (hopefully the audio file has the same name as the images name) you can now call the audio file with from the mutableString.
Explanation
For Example. If you have an image named Dog.png. Name your audio file that goes with the dog image: dog.mp3. (.mp3 is an example). When the user selects the dog image, pass the name to a muatableString. Lets call the mutableString name selectedImage.
Right now, selectedImage should have a value of .png. (Or whatever extension you have.) Remove the last 3 letters of selectedImage like this:
func deleteCharactersInRange(_ aRange: NSRange)
Next you want to call the audio file using selectedImage, and add the extension name like this:
func appendString(_ aString: String)
So selectedImage's value should now be: dog.mp3. And you can now call the audio file with selectedImgae.
Hope this helps!!
Edit
Here is code to play audio files:
var player : AVAudioPlayer! = nil // will be Optional, must supply initializer
let path = NSBundle.mainBundle().pathForResource("audioFile", ofType:"m4a")
let fileURL = NSURL(fileURLWithPath: path)
player = AVAudioPlayer(contentsOfURL: fileURL, error: nil)
player.prepareToPlay()
player.delegate = self
player.play()
I want to play Beep sound in my Mac Os X and specify duration and frequency. On Windows it can be done by using Beep function (Console.Beep in .Net). Is there anything equivalent in Mac? I am aware of NSBeep but it does not take any parameters.
On the Mac, the system alert sound is a sampled (prerecorded) sound that the user chooses. It often sounds nothing like a beep—it may be a honk, thunk, blare, or other sound that can't be as a simple constant waveform of fixed shape, frequency, and amplitude. It can even be a recording of the user's voice, or a clip from a TV show or movie or game or song.
It also does not need to be only a sound. One of the accessibility options is to flash the screen when an alert sound plays; this happens automatically when you play the alert sound (or a custom alert sound), but not when you play a sound through regular sound-playing APIs such as NSSound.
As such, there's no simple way to play a custom beep of a specified and constant shape, frequency, and amplitude. Any such beep would differ from the user's selected alert sound and may not be perceptible to the user at all.
To play the alert sound on the Mac, use NSBeep or the slightly more complicated AudioServicesPlayAlertSound. The latter allows you to use custom sounds, but even these must be prerecorded, or at least generated by your app in advance using more Core Audio code than is worth writing.
I recommend using NSBeep. It's one line of code to respect the user's choices.
PortAudio has cross platform C code for doing this here: https://subversion.assembla.com/svn/portaudio/portaudio/trunk/examples/paex_sine.c
That particular sample generates tones on the left and right speaker, but doesn't show how the frequencies are calculated. For that, you can use the formula in this code: Is there an library in Java for emitting a certain frequency constantly?
I needed a similar functionality for an app. I ended up writing a small, reusable class to handle this for me.
Source on GitHub
A reusable class for generating simple sine waveform audio tones with specified frequency and amplitude. Can play continuously or for a specified duration.
The interface is fairly straightforward and is shown below:
#interface TGSineWaveToneGenerator : NSObject
{
AudioComponentInstance toneUnit;
#public
double frequency;
double amplitude;
double sampleRate;
double theta;
}
- (id)initWithFrequency:(double)hertz amplitude:(double)volume;
- (void)playForDuration:(float)time;
- (void)play;
- (void)stop;
#end
Here's a way of doing this with the newer AVAudioEngine/AVAudioNode APIs, and Swift:
import AVFoundation
import Accelerate
// Specify the audio format we're going to use
let sampleRateHz = 44100
let numChannels = 1
let pcmFormat = AVAudioFormat(standardFormatWithSampleRate: Double(sampleRateHz), channels: UInt32(numChannels))
let noteFrequencyHz = 440
let noteDuration: NSTimeInterval = 1
// Create a buffer for the audio data
let numSamples = UInt32(noteDuration * Double(sampleRateHz))
let buffer = AVAudioPCMBuffer(PCMFormat: pcmFormat, frameCapacity: numSamples)
buffer.frameLength = numSamples // the buffer will be completely full
// The "standard format" is deinterleaved float, so we can assume the stride is 1.
assert(buffer.stride == 1)
for channelBuffer in UnsafeBufferPointer(start: buffer.floatChannelData, count: numChannels) {
// Generate a sine wave with the specified frequency and duration
var length = Int32(numSamples)
var dc: Float = 0
var multiplier: Float = 2*Float(M_PI)*Float(noteFrequencyHz)/Float(sampleRateHz)
vDSP_vramp(&dc, &multiplier, channelBuffer, buffer.stride, UInt(numSamples))
vvsinf(channelBuffer, channelBuffer, &length)
}
// Hook up a player and play the buffer, then exit
let engine = AVAudioEngine()
let player = AVAudioPlayerNode()
engine.attachNode(player)
engine.connect(player, to: engine.mainMixerNode, format: pcmFormat)
try! engine.start()
player.scheduleBuffer(buffer, completionHandler: { exit(1) })
player.play()
NSRunLoop.mainRunLoop().run() // Keep running in a playground
I want to play Beep sound in my Mac Os X and specify duration and frequency. On Windows it can be done by using Beep function (Console.Beep in .Net). Is there anything equivalent in Mac? I am aware of NSBeep but it does not take any parameters.
On the Mac, the system alert sound is a sampled (prerecorded) sound that the user chooses. It often sounds nothing like a beep—it may be a honk, thunk, blare, or other sound that can't be as a simple constant waveform of fixed shape, frequency, and amplitude. It can even be a recording of the user's voice, or a clip from a TV show or movie or game or song.
It also does not need to be only a sound. One of the accessibility options is to flash the screen when an alert sound plays; this happens automatically when you play the alert sound (or a custom alert sound), but not when you play a sound through regular sound-playing APIs such as NSSound.
As such, there's no simple way to play a custom beep of a specified and constant shape, frequency, and amplitude. Any such beep would differ from the user's selected alert sound and may not be perceptible to the user at all.
To play the alert sound on the Mac, use NSBeep or the slightly more complicated AudioServicesPlayAlertSound. The latter allows you to use custom sounds, but even these must be prerecorded, or at least generated by your app in advance using more Core Audio code than is worth writing.
I recommend using NSBeep. It's one line of code to respect the user's choices.
PortAudio has cross platform C code for doing this here: https://subversion.assembla.com/svn/portaudio/portaudio/trunk/examples/paex_sine.c
That particular sample generates tones on the left and right speaker, but doesn't show how the frequencies are calculated. For that, you can use the formula in this code: Is there an library in Java for emitting a certain frequency constantly?
I needed a similar functionality for an app. I ended up writing a small, reusable class to handle this for me.
Source on GitHub
A reusable class for generating simple sine waveform audio tones with specified frequency and amplitude. Can play continuously or for a specified duration.
The interface is fairly straightforward and is shown below:
#interface TGSineWaveToneGenerator : NSObject
{
AudioComponentInstance toneUnit;
#public
double frequency;
double amplitude;
double sampleRate;
double theta;
}
- (id)initWithFrequency:(double)hertz amplitude:(double)volume;
- (void)playForDuration:(float)time;
- (void)play;
- (void)stop;
#end
Here's a way of doing this with the newer AVAudioEngine/AVAudioNode APIs, and Swift:
import AVFoundation
import Accelerate
// Specify the audio format we're going to use
let sampleRateHz = 44100
let numChannels = 1
let pcmFormat = AVAudioFormat(standardFormatWithSampleRate: Double(sampleRateHz), channels: UInt32(numChannels))
let noteFrequencyHz = 440
let noteDuration: NSTimeInterval = 1
// Create a buffer for the audio data
let numSamples = UInt32(noteDuration * Double(sampleRateHz))
let buffer = AVAudioPCMBuffer(PCMFormat: pcmFormat, frameCapacity: numSamples)
buffer.frameLength = numSamples // the buffer will be completely full
// The "standard format" is deinterleaved float, so we can assume the stride is 1.
assert(buffer.stride == 1)
for channelBuffer in UnsafeBufferPointer(start: buffer.floatChannelData, count: numChannels) {
// Generate a sine wave with the specified frequency and duration
var length = Int32(numSamples)
var dc: Float = 0
var multiplier: Float = 2*Float(M_PI)*Float(noteFrequencyHz)/Float(sampleRateHz)
vDSP_vramp(&dc, &multiplier, channelBuffer, buffer.stride, UInt(numSamples))
vvsinf(channelBuffer, channelBuffer, &length)
}
// Hook up a player and play the buffer, then exit
let engine = AVAudioEngine()
let player = AVAudioPlayerNode()
engine.attachNode(player)
engine.connect(player, to: engine.mainMixerNode, format: pcmFormat)
try! engine.start()
player.scheduleBuffer(buffer, completionHandler: { exit(1) })
player.play()
NSRunLoop.mainRunLoop().run() // Keep running in a playground