core-audio

I am trying to write an iOS application that will pass the sound received from microphone to speaker without any changes. I've read apple docs and guides. I choosed the first pattern from this guide . But nothing happening - silence. As you can see I've tried to use the AUAudioGraph (commented) - same result (do I need it in this simple example at all?). I saw few examples in the internet where callbacks are used, but I do not want use any. Is it possible? Any suggestions? Thanks for attention. The actual code #import "AudioController.h" #import <AudioToolbox/AudioToolbox.h> #import

Closed. This question is off-topic. It is not currently accepting answers. Learn more . Want to improve this question? Update the question so it's on-topic for Stack Overflow. I am using the afconvert command line utility to convert an audio file from .caf to .mp3 format. I have used afconvert : afconvert -f 'MPG3 ' -d '.mp3' -v input.caf output.mp3 But this gives me the following error: Input file: input.caf, 19008 frames Error: ExtAudioFileSetProperty ('cfmt') failed ('fmt?') I have also tried the following: afconvert -f 'MPG3 ' -d LEI32@44100 -v input.caf output.mp3 This also gives me the

I'm looking for a way to change the pitch of recorded audio as it is saved to disk, or played back (in real time). I understand Audio Units can be used for this. The iPhone offers limited support for Audio Units (for example it's not possible to create/use custom audio units, as far as I can tell), but several out-of-the-box audio units are available, one of which is AUPitch. How exactly would I use an audio unit (specifically AUPitch)? Do you hook it into an audio queue somehow? Is it possible to chain audio units together (for example, to simultaneously add an echo effect and a change in

I've made an app with tab bar,nav bar and table view . In the table view you can choose to listen to some audio. New view opens and there I have some controls like: play,pause,volume slider, progress slider, label with the current time. It works, but not perfect. I can play the audio, I can pause the audio, I can also use the slider to skip forward or back. But now: When I hit the Back button on the navbar, the song keeps playing. That's ok, but when I go back to the view again, the timer and the slider reset themselves. I can't pause the song, just need to wait util it stops playing. Also,

Been banging my head against this problem all morning. I have setup a connection to a datasource which returns audio data (It is a recording device, so there is no set length on the data. the data just streams in. Like, if you would open a stream to a radio) and I have managed to receive all the packets of data in my code. Now I just need to play it. I want to play the data that is coming in, so I do not want to queue a few minutes or anything, I want to use the data I am recieving at that exact moment and play it. Now I been searching all morning finding different examples but none were

I'm having difficulty extracting amplitude data from linear PCM on the iPhone stored in a audio.caf. My questions are: Linear PCM stores amplitude samples as 16-bit values. Is this correct? How is amplitude stored in packets returned by AudioFileReadPacketData()? When recording mono linear PCM, isn't each sample, (in one frame, in one packet) just an array for SInt16? What is the byte order (big endian vs. little endian)? What does each step in linear PCM amplitude mean physically? When linear PCM is recorded on the iPhone, is the center point 0 (SInt16) or 32768 (UInt16)? What do the max min