just_audio: Why does my audio player work the first time but not the second time? - flutter

Tagging this with the appropriate tag so that the repo author can see it.
When my app uses an audio file saved on the user's phone, it works just fine the first time. It shows the audio source as:
justAudioPlayer.audioSource: Instance of 'ProgressiveAudioSource'
playerState: playing=true,processingState=ProcessingState.ready
When I hit the back button (Navigator.pop()) and then go back into the screen and try to play the audio source again, the audio source is now null:
justAudioPlayer.audioSource: null
playerState: playing=true,processingState=ProcessingState.idle

This is likely a simple programming error with your app's state management which, for example, results in your creating a new player instance instead of reusing the same instance.
(Copied from my comment above since you confirmed it was the correct answer)

Related

Is it possible to record the audio that comes out of the iPhone?

I am working on an app that allows the user to create a sort of dub. There is an audio file playing, and the user can tap at certain moments to insert sound (kind of like a censor button.) I'm wondering how to go about capturing the final product.
Capturing audio directly from the iPhone seems the easiest route, as the user already hears the finished product as it is made. However, I can't find anything on how to do this. If not possible, are there any suggestions?
The best way would probably be to be using the AV Foundation framework for mixing and then buffering the audio as well as playing it. This would allow for a high abstraction level while guaranteeing both played back and saved audio to be equal.
Apart from that: from a How can I achieve this with minimum code-perspective, without more information about your setup, the question is way too broad and/or opinion-based.
You will have to work with buffers. Don't know right now how it is done in Swift but you can implement it in Obj-C and then bridge it out.
You can refer to this answers here in StackOverflow (They are a bit old)
https://stackoverflow.com/a/11218339/2683201
https://stackoverflow.com/a/10101877/2683201
and a project also exists (but is in Obj-C)
https://github.com/alexbw/novocaine
Mainly the idea for your case would be to have 2 separated buffers and your sound effect.
Then, you will be playing from buffer A (your music) and copying played data into buffer B (final Output) unless you are playing the effect. In wich case you will be copying the effect data into your buffer B.
Other option is to do it offline:
Play your music (or audio) and keep a timer running synced with the elapsed time of your "to be censored audio".
Save the timestamp of when you start and end tapping the censor button (for example).
Overlap buffer A with your effect in those recorded (start-end) timestamps.
Save the buffer as a file (or do whatever you need to do with it)
UPDATE:
You should take a look into the Apple implementation of something like this:
https://developer.apple.com/library/ios/samplecode/AVAEMixerSample/Introduction/Intro.html

jPlayer doesn't play audio file automatically in iPad

I am trying to play audio file using jPlayer in iPad. It works fine in Safari on my local PC but when I tried to open it in my iPad it doesn't play audio automatically.
Please help me.
Thanks
You may have to initialize jPlayer on user action in Mobile Safari.
The first time a media element is played must be initiated by a user gester. ie., The user must click the play button. This affects the operation of a jPlayer("play") in the ready event handler. The browser will ignore the command. jPlayer will simply wait until the user presses the play button.
Once the first gesture has been received, JavaScript code is then allowed to do whatever you want with the media element. Note that a jPlayer media player instance uses a audio and a video element. Each require their own gesture.
As a hack, you could possibly add a handler for a touch event on an outer container element (or body) and initialize any jPlayer instances that you want.
Ref: http://www.jplayer.org/latest/developer-guide/#jPlayer-known-issues-event-driven
Do you mean it doesn't play automatically? Because if it does, I don't see what your problem is.
Check if you have entered the correct path for option swfPath.

Play a video whose URL is not known in advance - without reload - without extra tab

I have lots of buttons on a web page. Depending on which one is clicked, I want to play a different video.
A large number of <video> elements doesn't seem to work particularly quickly or reliably.
So far, I have tried to:
Create and play() the video element dynamically, after an image is clicked:
var video = document.createElement('video');
video.src = 'video.mp4';
document.body.appendChild(video.play);
video.play();
This works on iOS 4, but not on iOS 3.
Create the video element before, and just change the src.
Doesn't work either.
It seems like the video object must have already done "it's thing", before it can be played.
Use window.open() to open the video URL.
This will cause an annoying new tab to open, which will remain open after playback has completed.
Set window.location
This will cause the current page to be reloaded after playback has completed, which I'm trying to avoid.
Any more ideas?

How to record a video automatically in Iphone app without user interaction

I am working an iphone app that needs to record a vedio automatically.
I used mobile coreservices framework and using that. I made it to came into video mode and clicking on record option its start capturing a vedio. But I want it automatically that is.. I should able to record a video without clicking on record option. That is when video mode comes up its automatically start record video.
Could any one help?
You can look at UIImagePickerControllers startVideoCapture method which is used to start taking video from the camera, this is to be used when you arent using the camera standard controlors and you provide and overlay view. Here is a reference UIImagePickerCOntroller ref. If this is not enough for you, you might want to look into AVFoundation framework which gives you a lot more control over video capturing process...hope that helps

UIAccelerometer is Shaking

I want a functionality in which i want to detect if my device is being shaked.The problem is i can detect the shake with didAccelerate method of UIAcceleratorDelegate , but i dont know how to detect if the device is still shaking. I want to play an audio file when the user shakes the device for first time,i have to check if the user is still shaking the device while playing the 1st audio file,if it is still being shaked, then i have to play another file.
See the sample project GLPaint from Apple which was found by visiting http://developer.apple.com/iphone and entering "shake" in the search box. Developer account not required.
You might consider writing a Method that runs in a separate thread that polls wether your device is being shaken every now and then and fire events that you handle somewhere else in your code (or instead of that, handle whatever you want to handle within the threads context itself, even tough i would not recommend doing that).
You just have to make sure, that your "shake-detektor"-thread exits at some point in time, you probably want to do that when the second audio file stopped playing. So your loop could test on that condition.
Hope I could help a bit.