I work on a VOIP app.
I use Core Audio Audio Units for playing and recording audio. I need to be able to manipulate sound volume and output devices. I am trying to use MPVolumeView to set sound volume and choose output devices.
My problem is: When I start using(start playout and capture for RemoteIO Audio Unit) Audio Units it seems MPVolumeView no longer control volume of my session but instead it controls system wide sound preferences. At the same time hardware buttons control volume of sounds played by Audio Units. Also when I start using Audio Units MPVolumeView start showing button to change output devices but before that it doesn't.
It seems that MPVolumeView controls sound volume for some system wide audio session but when I start using Audio Units another app wide (or even Audio Unit wide) audio session is created and used to play sound.
So the question is how to make MPVolumeView control sound volume for my Core Audio audio session?
I would appreciate any hints on why this happens. I've spent almost all day googling and I see that some people have related problems but none got any hints :(. I can also post more details if needed.
Confirmed as a bug by Apple engineer.
In more details - MPVolumeView should be tied to a specific audio route (in more broad sense, like audio route + audio category + mode etc.), and it is for a couple of most common routes (e.g. headphones + play category + default mode) but not to all custom routes you can create.
So basically when one creates some custom route MPVolumeView still tries to control it's last (workable) or default route.
Related
We have a VOIP application, that records and plays audio. As such, we are using PlayAndRecord (kAudioSessionCategory_PlayAndRecord) audio session category.
So far, we have used it successfully with iPhone 4/4s/5 with both iOS 6 and iOS 7 where call audio and tones played clearly and were audible.
However, with iPhone 5s, we observed that both the call audio and tones sound robotic/garbled in speaker mode. When using earpiece/bluetooth/headset, sound is clear and audible.
iOS Version used with iPhone 5s: 7.0.4
We are using audiounits for recording/playing of call audio.
When setting audio properties like session category, audio route, session mode etc., we tried both the older (deprecated) AudioSessionSetProperty() and AVAudioSession APIs.
For playing tones, we are using AVAudioPlayer. Playing of tones during the VOIP call and also when pressing keypad controller within the app produces robotic sound.
When instantiating the audio component using AudioComponentInstanceNew, we set componentSubType to kAudioUnitSubType_VoiceProcessingIO.
When replacing kAudioUnitSubType_VoiceProcessingIO with kAudioUnitSubType_RemoteIO, we noticed that the sound of call audio and tones was no longer robotic, it was quite clear, but the volume level was very low when using speaker mode.
In summary, keeping all the other audio APIs the same:
kAudioUnitSubType_VoiceProcessingIO: Volume is high (desirable) but sound of tones and call audio was robotic in speaker mode.
kAudioUnitSubType_RemoteIO: Sound of tones and call audio was clear but it is not audible.
STEPS TO REPRODUCE
- Set audio session category to playAndRecord.
- Set audio route to speaker
- Set all the other audio properties like starting audio unit, activating the audio session, instantiating the audio components.
- Set the input and render callbacks
- Try both options
1. Play tones using AVAudioPlayer
2. Play call audio
Any suggestions on how to get over this issue. Raised as an issue with Apple but no response yet from them.
i have shared the code here github link
The only difference between kAudioUnitSubType_VoiceProcessingIO and kAudioUnitSubType_RemoteIO is that voiceProcessing includes code to tune out acoustic echo i.e. tunes out the noise from the speaker so the microphone doesn't pick it up. Its been a long time since I've played with the audio framework but I remember that to sound off there could be any number of things,
Are you doing any work in the audio callbacks that could be taking a long time?
The callbacks run on realtime threads. if your processing takes too long you can miss data. Would be helpful to track the data over a fixed period of time to see are you capturing it all. Use something like wireShark to sniff the network. Record the number of packets and see did the phone capture the same.
Are you modifying any of the audio?
Do you have a circular buffer that might be causing an issue?
I've had several issues doing this and one was using a third party circular buffer that was described as low latency and efficient ... it wasn't. I answered my own question here and included my circular buffer implementation that greatly improved my audio as the issue was I was skipping data.
Give this a go and let me know:
iOS UI are causing a glitch in my audio stream
Please be aware that some of this code is unique to the audio format ALaw, 0xD5 is a byte of silence in ALaw, if you are using linear PCM or any other that will probably be a noise of some kind.
In my app I use the AudioToolbox framework so that I can use the iSpeech SDK. If music is playing (in the background, from the Apple music app), when the app starts, the music skips (stops playing completely) for just a moment (half a second), then resumes at a diminished volume. I'm not at all sure why this is happening, but Google had nothing to say about it. Has anyone experienced a problem like this? Thanks!
Core Audio needs to insert a mixer in the audio output path so that your app has a way to make sounds. (Think of the "skip" as pulling out and plugging in patch cords.) The mixer allocates some volume to your app; what's left for the music player is less than 100%, thus the disminished volume.
I am trying to be able to record audio through the iPhone's microphone while simultaneously playing music from the iPod.
The recording and playback work separately, but if I try to playback from the iPod and record at the same time the recording stops.
By the way, I am not actually recording the audio to save the sound file, but merely analyzing it. It's for my app that flashes to the beat of the music you play.
Does Apple just not allow record and playback at the same time?
You should be able to do this by setting the Audio Session to AVAudioSessionCategoryPlayAndRecord. Information on this is in the Apple docs, although admittedly the Core Audio documentation is (and has always been) lacking in clarity.
AVSession Class Reference
Also, it's worth noting that AVAudioRecorder and AVAudioPlayer automatically set the session for you. You can wrestle control and set the session manually using the key I highlighted above.
the problem may be you are recording audio to the same path where the playing file is saved.
try to play an audio from a url with AVAudioPlayer and you can record with AVAudioRecorder at the same time.
Cheers :) :)
I'm developing an interactive storybook type application for the iPhone and I've recently encountered a frustrating bug concerning audio mixing on the device.
Firstly, I setup an audio session. I set the category to AVAudioSessionCategoryAmbient and then init and play my AVAudioPlayer instance. Now, in the background whilst the audio is playing I'm pre-loading a video to play using an MPMoviePlayerController followed by a call to prepareToPlay. The reason I pre-load the video this way is because I need it to play instantly later on cue with fairly strict timing.
In this configuration, the audio/movie works fine and they mix and do not interrupt each other. However, this particular audio session category does not permit audio to continue playing while the device is locked, a feature I really need. As a result I'm forced to consider a different category: AVAudioSessionCategoryPlayback.
By default this category does not permit mixing with other audio, according to the Apple docs. To enable mixing with other audio I am overriding the relevant category:
OSStatus propertySetError = 0;
UInt32 setProperty = 1;
propertySetError = AudioSessionSetProperty(kAudioSessionProperty_OverrideCategoryMixWithOthers, sizeof(setProperty), &setProperty);
assert(propertySetError == 0);
Unfortunately, this solves my playing whilst locked issue but introduces another issue: the AVAudioPlayer audio is interrupted briefly as the video loads with a minor stutter. The stutter is small, perhaps less than a second but is enough to disrupt the user experience. I've read this related post which enabled me to pre-load the video with the AVAudioSessionCategoryAmbient, but unfortunately the same approach doesn't seem to work with the new category.
The audio session category is applied successfully, according to the return code. Does anyone know why enabling audio mixing with this category is not the same as the mixing facility provided by ambient category?
The best way I've found working a similar problem is to use the newer AVPlayer (+1 #adam) and set your app to enable background audio and receive remote control notifications. I was tipped off to this by #MarquelV following How can you play music from the iPod app while still receiving remote control events in your app?
If you can get backgrounding working properly, that should enable you to continue playing while the device is locked. Oh, and don't forget to add keys to info.plist, its easy to do and then have no idea why it isn't working.
I am writing an iPad app that uses the "Flite" text-to-speech engine to announce specific events. The Flite engine uses an AVAudioPlayer instance to play the speech audio once it renders. For fun, I decided to add some simple controls to my app to allow the user to control iPod playback (next, prev, play/pause and volume - the basics) while my app is running using MPMusicPlayerController (of course).
The problem I am having is that when I adjust the iPod volume using MPMusicPlayerController, all of my audio is affected, including other sound effects and the speech audio. I set the volume for these other audio players (AVAudioPlayer instances) to 1.0 before playing the sound but it seems that the volume is always capped at whatever the iPod player volume is set to...
Is this normal? And what can I do to get around it? I want my app's audio to play at system full volume regardless of the volume level of the iPod player. (Example: The user had set the system volume to 80% of the device's max. I want my app to play audio at 100% of that 80% while allowing the user to adjust the iPod audio playback to 0-100% of that 80%.) Note: I am not interested in "ducking" but setting the iPod volume lower at all times while my app is running (background music).
I also have the problem, that -sometimes- when you first launch the app and press play on the iPod player (which sends the [player play] call), the iPod does not respond. If I press the home button, go into the iPod app and start playback then, once returning to my app, it works fine. What the deal with that?
Thanks in advance for any help!!
It could be something to do with the audio session category you've specified. Check out the Audio Session Programming Guide to see if you've chosen the right category.
The volume buttons on the side control the system volume and by extension the volume of your app's sounds.
I guess it's considered to be the Master volume control.
you can set the volume for specific samples or sounds using the AVItem's setVolume
[item setVolume]
You can create an AVItem to reference an existing sound file in your application or on the iphone. The code is pretty simple and looks like this -->
AVItem *item [[AVItem alloc]
initWithPath:#"the file"];
[item setVolume];
btw, this will not affect the rest of the audio channel (instantiated by some kinda AVController object) and the volume that you've set in your code will not be displayed on you screen so im not sure if you can change it at run time.