I am developing an iPhone game with cocos2d,
I have used CDAudioManager for playing sound(this is why because i have to change the pitch of output sound). I want to measure the output sounds power. Not the gain.
I know about peakpowerForChannel: for avAudioplayer. But it can't be used here because I want to change the pitch of o/p sound. Is there any method like this for CDAudioEngine
Thank you
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I have a sound effect that I play on a certain event in the game. When the player chains a few of these events together the same sound may play from 1 to 4 times in a row.
Its hard to find sfx that increase in pitch but are the same sound effect, so I was wondering is there a trick/method in iOS that you can use that will play a sound file but change the pitch(correct term?) of the sound while playing?
Many Thanks,
-Code
The scenario is that I start the recording at in my iphone app maybe by using AVAudioRecoder and when i have some input sound above certain threshold then i will do some thing. Is it possible to process the input audio while recoding??
Is there any way to know the input loudness in iPhone. Like what is the level of the loudness in numbers or if there is any other measure for that.
Look at AVFoundation, AVAudioRecorder and enable the property meteringEnabled to get threshold change callbacks.
I need to create an audio loudness (decibel) detector. To clarify, I am not trying to find the volume at which the iPhone is playing, but instead the volume of its surrounding in decibels. How can I do this?
It can be done using AVAudioRecorder: http://b2cloud.com.au/tutorial/obtaining-decibels-from-the-ios-microphone
Use one of the Audio Queue or Audio Unit APIs to record low latency audio, run the samples through a DSP filter to weight the spectrum for the particular type or color of loudness you want to measure, then calibrate the mic on all the particular models of iOS devices you want to run your detector on against calibrated sound sources, perhaps in an anechoic chamber.
I have been facing this since so many days but I have not reach to any conclusion.
My problem is : I want to play an mp3 file but not simply by clicking on a play button.
It is this way I want to play it.
*There is a slider that I can drag using finger, I want that the mp3 should play with the frequency with which I am dragging the finger (or speed with which I am dragging my finger, so that it will give an effect of fast forwarding (funny type of voice)) or if I drag slider slowyly the output will be slow *
The problem is the output of the sound is not coming out smooth. its very distorted and disturbed voice.
I want the outuput to be smoother.
Please help. Any suggestions please. Presently I am using AVAudioPlayer and passing the time value based upon slider input to play the file. (It does not seems to be feasible though).
I feel that it is possible using openAL only and no other way. Because using openAL we can modify the frequency of the sound file (pitch)
CAN SOME ONE PLEASE REFER ME A LINK TO openAL implementation for iPhone . I have never played a sound file using openAL
Help!!
You won't be able to do it with AVAudioPlayer, as it does not support pitch operations.
You can load and decode the entire track into memory for playback with OpenAL (which supports pitch), or you can do realtime loading/decoding and pitch changing using Audio Units (MUCH lower level, and more complicated, though).
Is there an easy way to control the playback speed/tempo of a sound file loop played using Audio Queue Services? For example, if a game is playing background music, I want to make the BGM speed up as time runs out, but without changing the pitch of the music. Thx!
There's no trivial way to do this that I know of. On the Mac, you'd presumably use Audio Units to do this, but I think the support for those is limited on the iPhone SDK.
You can do some processing during your AudioQueue playback callback, between AudioFileReadPackets() and AudioQueueEnqueueBuffer() but I think speed-shifting without changing the tone will require rather a lot of CPU time.
It'd probably be easier to have more than one recording of the music, and switch files during a silent passage of the music.