I want to record audio using the iphone (< 2 minutes) and save it to a file.
I looked at SpeakHere, but it confuses me. Which classes do I use? What delegate methods do I create?
Thanks!
iphone
I want to record audio using the iphone (< 2 minutes) and save it to a file.
I looked at SpeakHere, but it confuses me. Which classes do I use? What delegate methods do I create?
Thanks!
It's certainly possible to develop on a Windows machine, in fact, my first application was exclusively developed on the old Dell Precision I had at the time :)
There are three routes;
The first route requires modifying (or using a pre-modified) image of Leopard that can be installed on a regular PC. This is not as hard as you would think, although your success/effort ratio will depend upon how closely the hardware in your PC matches that in Mac hardware - e.g. if you're running a Core 2 Duo on an Intel Motherboard, with an NVidia graphics card you are laughing. If you're running an AMD machine or something without SSE3 it gets a little more involved.
If you purchase (or already own) a version of Leopard then this is a gray area since the Leopard EULA states you may only run it on an "Apple Labeled" machine. As many point out if you stick an Apple sticker on your PC you're probably covered.
The second option is more costly. The EULA for the workstation version of Leopard prevents it from being run under emulation and as a result, there's no support in VMWare for this. Leopard server, however, CAN be run under emulation and can be used for desktop purposes. Leopard server and VMWare are expensive, however.
If you're interested in option 1) I would suggest starting at Insanelymac and reading the OSx86 sections.
I do think you should consider whether the time you will invest is going to be worth the money you will save though. It was for me because I enjoy tinkering with this type of stuff and I started during the early iPhone betas, months before their App Store became available.
Alternatively, you could pick up a low-spec Mac Mini from eBay. You don't need much horsepower to run the SDK and you can always sell it on later if you decide to stop development or buy a better Mac.
Update: You cannot create a Mac OS X Client virtual machine for OS X 10.6 and earlier. Apple does not allow these Client OSes to be virtualized. With Mac OS X 10.7 (Lion) onwards, Apple has changed its licensing agreement in regards to virtualization. Source: VMWare KnowledgeBase
Actually, there are no examples at all. Here is my working code. Recording is triggered by the user pressing a button on the navBar. The recording uses cd quality (44100 samples), stereo (2 channels) linear pcm. Beware: if you want to use a different format, especially an encoded one, make sure you fully understand how to set the AVAudioRecorder settings (read carefully the audio types documentation), otherwise you will never be able to initialize it correctly. One more thing. In the code, I am not showing how to handle metering data, but you can figure it out easily. Finally, note that the AVAudioRecorder method deleteRecording as of this writing crashes your application. This is why I am removing the recorded file through the File Manager. When recording is done, I save the recorded audio as NSData in the currently edited object using KVC.
#define DOCUMENTS_FOLDER [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"]
- (void) startRecording{
UIBarButtonItem *stopButton = [[UIBarButtonItem alloc] initWithTitle:@"Stop" style:UIBarButtonItemStyleBordered target:self action:@selector(stopRecording)];
self.navigationItem.rightBarButtonItem = stopButton;
[stopButton release];
AVAudioSession *audioSession = [AVAudioSession sharedInstance];
NSError *err = nil;
[audioSession setCategory :AVAudioSessionCategoryPlayAndRecord error:&err];
if(err){
NSLog(@"audioSession: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
return;
}
[audioSession setActive:YES error:&err];
err = nil;
if(err){
NSLog(@"audioSession: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
return;
}
recordSetting = [[NSMutableDictionary alloc] init];
[recordSetting setValue :[NSNumber numberWithInt:kAudioFormatLinearPCM] forKey:AVFormatIDKey];
[recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey];
[recordSetting setValue:[NSNumber numberWithInt: 2] forKey:AVNumberOfChannelsKey];
[recordSetting setValue :[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];
[recordSetting setValue :[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsBigEndianKey];
[recordSetting setValue :[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsFloatKey];
// Create a new dated file
NSDate *now = [NSDate dateWithTimeIntervalSinceNow:0];
NSString *caldate = [now description];
recorderFilePath = [[NSString stringWithFormat:@"%@/%@.caf", DOCUMENTS_FOLDER, caldate] retain];
NSURL *url = [NSURL fileURLWithPath:recorderFilePath];
err = nil;
recorder = [[ AVAudioRecorder alloc] initWithURL:url settings:recordSetting error:&err];
if(!recorder){
NSLog(@"recorder: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
UIAlertView *alert =
[[UIAlertView alloc] initWithTitle: @"Warning"
message: [err localizedDescription]
delegate: nil
cancelButtonTitle:@"OK"
otherButtonTitles:nil];
[alert show];
[alert release];
return;
}
//prepare to record
[recorder setDelegate:self];
[recorder prepareToRecord];
recorder.meteringEnabled = YES;
BOOL audioHWAvailable = audioSession.inputIsAvailable;
if (! audioHWAvailable) {
UIAlertView *cantRecordAlert =
[[UIAlertView alloc] initWithTitle: @"Warning"
message: @"Audio input hardware not available"
delegate: nil
cancelButtonTitle:@"OK"
otherButtonTitles:nil];
[cantRecordAlert show];
[cantRecordAlert release];
return;
}
// start recording
[recorder recordForDuration:(NSTimeInterval) 10];
}
- (void) stopRecording{
[recorder stop];
NSURL *url = [NSURL fileURLWithPath: recorderFilePath];
NSError *err = nil;
NSData *audioData = [NSData dataWithContentsOfFile:[url path] options: 0 error:&err];
if(!audioData)
NSLog(@"audio data: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
[editedObject setValue:[NSData dataWithContentsOfURL:url] forKey:editedFieldKey];
//[recorder deleteRecording];
NSFileManager *fm = [NSFileManager defaultManager];
err = nil;
[fm removeItemAtPath:[url path] error:&err];
if(err)
NSLog(@"File Manager: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
UIBarButtonItem *startButton = [[UIBarButtonItem alloc] initWithTitle:@"Record" style:UIBarButtonItemStyleBordered target:self action:@selector(startRecording)];
self.navigationItem.rightBarButtonItem = startButton;
[startButton release];
}
- (void)audioRecorderDidFinishRecording:(AVAudioRecorder *) aRecorder successfully:(BOOL)flag
{
NSLog (@"audioRecorderDidFinishRecording:successfully:");
// your actions here
}
Best Answer
I agree, SpeakHere is not a very good starting point to learn iPhone audio.
iPhone audio uses two concepts. AudioQueues, and AudioSessions. If you want to record to a file, you will need to create one AudioSession, activate the session, and create an AudioInputQueue and an AudioOutputQueue.
The reference for AudioQueues (by far the part you will deal with most) is:
http://developer.apple.com/iphone/library/documentation/MusicAudio/Conceptual/AudioQueueProgrammingGuide/Introduction/Introduction.html
As for AudioSessions:
http://developer.apple.com/iphone/library/documentation/Audio/Conceptual/AudioSessionProgrammingGuide/Introduction/Introduction.html
Though you can ignore most of the AudioSession stuff since you won't be doing anything quite that complicated. So basically, here are the steps:
I didn't include all parameters here, but that's what the API is for.
Hope that helps.
[EDIT]
Sorry, forgot to include the output stuff, though they are fairly straight forward. Create another AudioQueue, initialize with an AudioQueueNewOutput, and the API should be able to guide you the rest of the way.
Cheers.