core-audio

问题 I am trying to make an app that controls the volume of another process using the Windows 7 Audio API. What I'm looking for is the ISimpleAudioVolume for the session used by the other process. I have tried using the IAudioSessionEnumerator but it will only give me the IAudioSessionControl2 of the session. Using the IAudioSessionControl I have managed to receive notifications when I change the volume through sndvol but not change it myself. I have also tried using GetSimpleAudioVolume() from

问题 I have an app which can change the volume under OSX. What it lacks is the visual feedback provided when one presses the sound up/down keys. Does anyone know how to programmatically invoke that behavior? Thanks 回答1: Here's a little code from George Warner and Casey Fleser that does this trick. Think carefully that this is really the way you want to do things. // Save as sound_up.m // Compile: gcc -o sound_up sound_up.m -framework IOKit -framework Cocoa #import <Cocoa/Cocoa.h> #import <IOKit

问题 I initialize my AVAudioPlayer instance like: [self.audioPlayer initWithContentsOfURL:url error:&err]; url contains the path of an .m4a file The following error is displayed in the console when this line is called :" Error Domain=NSOSStatusErrorDomain Code=1685348671 "Operation could not be completed. (OSStatus error 1685348671.) " What is the reason for this error? 回答1: The error code is a four-char-code for "dta?" (you can use the Calculator app in programmer mode to convert the int values

问题 I initialize my AVAudioPlayer instance like: [self.audioPlayer initWithContentsOfURL:url error:&err]; url contains the path of an .m4a file The following error is displayed in the console when this line is called :" Error Domain=NSOSStatusErrorDomain Code=1685348671 "Operation could not be completed. (OSStatus error 1685348671.) " What is the reason for this error? 回答1: The error code is a four-char-code for "dta?" (you can use the Calculator app in programmer mode to convert the int values

问题 I'm making something like streaming the audio from iPod library, send the data via network or bluetooth, and playback using audio queue. Thanks for this question and code. Help me a lot. I have two question about it. what should I send from one device to another? CMSampleBufferRef? AudioBuffer? mData? AudioQueueBuffer? packet? I have no idea. When the app finished the playing, it crashed, and I got error (-12733). I just want to know how to handle the errors instead of letting it crash.

问题 I am currently creating an app that plays music. I would like to add a feature that shows the music lyrics while the music plays, with the current position of the text marked to match the current position in the song. The Bouncing Ball effect, just like you see on every Karaoke screen as the song plays. I have been looking into extending my caf files, adding "string chunks" and then reading them out again. Is this the correct way to do this? Does anybody know of a better/easier/normal way to

问题 I have been scratching my head since long now but not getting around to this. I haven't found a single example for Audio editing! I want to insert new Audio file in between somewhere in original Audio file, save it as new converted audio files. For this I have written following code. I got this idea from here. NSString *file1 = [[NSBundle mainBundle] pathForResource:@"file1" ofType:@"caf"]; // Using PCM format NSString *file2 = [[NSBundle mainBundle] pathForResource:@"file2" ofType:@"caf"];

问题 I want to send microphone audio data over Multipeer Connectivity (iOS 8) and play it through the speaker of the receiving peer. I've also setup the AVAudioEngine and I can hear the microphone data from the (upper) speaker output, but I don't know how to send AVAudioPCMBuffer over the network. Here's my code snippet: AVAudioInputNode *inputNode =[self.engine inputNode]; AVAudioMixerNode *mainMixer = [self.engine mainMixerNode]; [self.engine connect:inputNode to:mainMixer format:[inputNode

问题 I have used to following code the stream the i/o of audio from microphone. What I want to do is want to select the rear microphone for recording. I have read that setting kAudioSessionProperty_Mode to kAudioSessionMode_VideoRecording can do the work but I am not sure how to use this with my code. Can any one help me in successfully setting this parameter. I have these lines for setting the property status = AudioUnitSetProperty(audioUnit, kAudioSessionProperty_Mode, kAudioSessionMode

问题 So I looked into core data recently a bit and am still a newbie. I have trouble understanding what data I am taping into and how it is effecting the overall data flow. So for some background, I have an app that does video/audio streaming between phones using webRTC. However, I want to check out the data that is being inputed into the device through my mic and the data outputted through the speaker. I looked into AurioTouch demo and Core Audio and currently I have this: - (void)setupIOUnit { /