CODEWITHSUNDEEP
objective-cmacoscocoa
Alex Marchant
Alex Marchant

Reputation: 2510

Setup separate app volume controls

How can i control my app's output volume.

I've got an app that uses https://github.com/mattgallagher/AudioStreamer to stream mp3 files from the internet. The AudioStreamer class does not have a way to change output volume and I don't want to change system volume.

Many apps do this:

Edit: If you're hear about AudioStreamer, I've since switched to Apple's AVPlayer, which i've found far simpler and superior. Easy volume adjustment too!

Upvotes: 0

Views: 673

Answers (2)

Alex Marchant
Alex Marchant

Reputation: 2510

AudioStreamer and I'm guessing most OSX media players use the AudioToolbox framework. AudioToolbox uses a programming interface called AudioQueue to playback media files. Here is the way to adjust the volume using AudioQueue.

AudioQueueSetParameter(audioQueue, kAudioQueueParam_Volume, 0.5);
  • audioQueue is an AudioQueRef
  • kAudioQueueParam_Volume tells AudioQueueSetParameter() to change the Volume Parameter
  • 0.5 is the volume from 0.0 - 1.0

More details on AudioQueue: https://developer.apple.com/library/mac/#documentation/MusicAudio/Reference/AudioQueueReference/Reference/reference.html

Upvotes: 2

Kjuly
Kjuly

Reputation: 35131

You can use AVAudioPlayer, it has an instance method setVolume: to set the output volume:

AVAudioPlayer * audioPlayer = ...
float volume = aVolumeValue / 100.f; // aVolumeValue can be 0~100
[audioPlayer setVolume:volume];
[audioPlayer play];

By the way, you can store the aVolumeValue into NSUserDefaults, and control it by UISlider object.

Upvotes: 0

Related Questions