有没有办法使用Matt Gallagher的音频流来录制音频流？ [英] Is there a way to record an audio stream using Matt Gallagher's audio streamer?
问题描述
我使用 Matt Gallagher的音频流媒体来播放电台广播电台。但是如何录制音频？有没有办法将下载的数据包放入NSData并将其保存在iPhone上的文档文件夹中的音频文件中？
I use Matt Gallagher's audio streamer for streaming radio stations. But how to record the audio? Is there a way to get the downloaded packets into NSData and save it in an audio file in the documents folder on the iPhone?
谢谢
推荐答案
是的，我已经完成了。我的问题是能够在同一个流媒体上播放它（在别处问）。它将与iOS中的标准AVAudioPlayer一起播放。但是，这会通过在流式传输代码中写出来将数据保存到文件中。
Yes, there is and I have done it. My problem is being able to play it back IN the same streamer (asked elsewhere). It will play back with the standard AVAudioPlayer in iOS. However, this will save the data to a file by writing it out in the streamer code.
这个例子缺少一些错误检查，但会给你一个主要的想法。
This example is missing some error checks, but will give you the main idea.
首先，从主线程调用开始和停止录制。当有人按下记录时，这是在我的viewController中：
First, a call from the main thread to start and stop recording. This is in my viewController when someone presses record:
//---------------------------------------------------------
// Record button was pressed (toggle on/off)
// writes a file to the documents directory using date and time for the name
//---------------------------------------------------------
-(IBAction)recordButton:(id)sender {
// only start if the streamer is playing (self.streamer is my streamer instance)
if ([self.streamer isPlaying]) {
NSDate *currentDateTime = [NSDate date]; // get current date and time
NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setDateFormat:@"EEEE MMMM d YYYY 'at' HH:mm:ss"];
NSString *dateString = [dateFormatter stringFromDate:currentDateTime];
self.isRecording = !self.isRecording; // toggle recording state BOOL
if (self.isRecording)
{
// start recording here
// change the record button to show it is recording - this is an IBOutlet
[self.recordButtonImage setImage:[UIImage imageNamed:@"Record2.png"] forState:0];
// call AudioStreamer to start recording. It returns the file pointer back
//
self.recordFilePath = [self.streamer recordStream:TRUE fileName:dateString]; // start file stream and get file pointer
} else
{
//stop recording here
// change the button back
[self.recordButtonImage setImage:[UIImage imageNamed:@"Record.png"] forState:0];
// call streamer code, stop the recording. Also returns the file path again.
self.recordFilePath = [self.streamer recordStream:FALSE fileName:nil]; // stop stream and get file pointer
// add to "recorded files" for selecting a recorderd file later.
// first, add channel, date, time
dateString = [NSString stringWithFormat:@"%@ Recorded on %@",self.model.stationName, dateString]; // used to identify the item in a list laster
// the dictionary will be used to hold the data on this recording for display elsewhere
NSDictionary *row1 = [[[NSDictionary alloc] initWithObjectsAndKeys: self.recordFilePath, @"path", dateString, @"dateTime", nil] autorelease];
// save the stream info in an array of recorded Streams
if (self.model.recordedStreamsArray == nil) {
self.model.recordedStreamsArray = [[NSMutableArray alloc] init]// init the array
}
[self.model.recordedStreamsArray addObject:row1]; // dict for this recording
}
}
}
现在，在AudioStreamer.m我需要处理上面的记录设置调用
NOW, in AudioStreamer.m I need to handle the record setup call above
- (NSString*)recordStream:(BOOL)record fileName:(NSString *)fileName
{
// this will start/stop recording, and return the file pointer
if (record) {
if (state == AS_PLAYING)
{
// now open a file to save the data into
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
// will call this an mp3 file for now (this may need to change)
NSMutableString *temp = [NSMutableString stringWithString:[documentsDirectory stringByAppendingFormat:@"/%@.mp3",fileName]];
// remove the ':' in the time string, and create a file name w/ time & date
[temp replaceOccurrencesOfString:@":" withString:@"" options:NSLiteralSearch range:NSMakeRange(0, [temp length])];
self.filePath = temp; // file name is date time generated.
NSLog(@"Stream Save File Open = %@", self.filePath);
// open the recording file stream output
self.fileStream = [NSOutputStream outputStreamToFileAtPath:self.filePath append:NO];
[self.fileStream open];
NSLog(@"recording to %@", self.fileStream);
self.isRecording = TRUE;
return (self.filePath); // if started, send back the file path
}
return (nil); // if not started, return nil for error checking
} else {
// save the stream here to a file.
// we are done, close the stream.
if (self.fileStream != nil) {
[self.fileStream close];
self.fileStream = nil;
}
NSLog(@"stop recording");
self.isRecording = FALSE;
return (self.filePath); // when stopping, return nil
}
}
最后，我们需要修改流转化器的数据部分以实际保存字节。您需要修改方法中的流代码： - （void）handleReadFromStream：（CFReadStreamRef）aStreameventType：（CFStreamEventType）eventType
向下滚动该方法直到找到：
LASTLY, we need to modify the data portion of the streamer to actually save the bytes. You need to modify the stream code in the method: -(void)handleReadFromStream:(CFReadStreamRef)aStreameventType:(CFStreamEventType)eventType Scroll down in that method until you find:
@synchronized(self)
{
if ([self isFinishing] || !CFReadStreamHasBytesAvailable(stream))
{
return;
}
//
// Read the bytes from the stream
//
length = CFReadStreamRead(stream, bytes, kAQDefaultBufSize);
if (length == -1)
{
[self failWithErrorCode:AS_AUDIO_DATA_NOT_FOUND];
return;
}
在length =行之后右键，添加以下代码：
RIGHT after the length = line, add the following code:
//
// if recording, save the raw data to a file
//
if(self.isRecording && length != 0){
//
// write the data to a file
//
NSInteger bytesWritten;
NSInteger bytesWrittenSoFar;
bytesWrittenSoFar = 0;
do {
bytesWritten = [self.fileStream write:&bytes[bytesWrittenSoFar] maxLength:length - bytesWrittenSoFar];
NSLog(@"bytesWritten = %i",bytesWritten);
if (bytesWritten == -1) {
[self.fileStream close];
self.fileStream = nil;
NSLog(@"File write error");
break;
} else {
bytesWrittenSoFar += bytesWritten;
}
} while (bytesWrittenSoFar != length);
}
以下是.h声明：
添加到AudioStreamer.h的界面
Added to the interface for AudioStreamer.h
// for recording and saving a stream
NSString* filePath;
NSOutputStream* fileStream;
BOOL isRecording;
BOOL isPlayingFile;
在视图控制器中，您需要：
In your view controller you will need:
@property(nonatomic, assign) IBOutlet UIButton* recordButtonImage;
@property(nonatomic, assign) BOOL isRecording;
@property (nonatomic, copy) NSString* recordFilePath;
希望这有助于某人。如果有问题，请告诉我，并且总是很高兴听到有人可以改进这一点。
Hope this helps someone. Let me know if questions, and always happy to hear someone who can improve this.
此外，有人问过self.model.xxx模型是我创建的数据对象允许我轻松传递多个对象使用的数据，并且还可以由多个对象修改。我知道，全局数据是糟糕的形式，但有时候只是让它更容易访问。我在调用时将数据模型传递给每个新对象。我在模型中保存了一系列频道，歌曲名称，艺术家姓名和其他与流相关的数据。我还在此处通过启动来保存我想要保留的任何数据，例如设置，并在每次更改持久数据时将此数据模型写入文件。在此示例中，您可以在本地保留数据。如果您需要模型传递方面的帮助，请告诉我。
Also, someone asked about self.model.xxx Model is a Data Object I created to allow me to easily pass around data that is used by more than one object, and is also modified by more than one object. I know, global data is bad form, but there are times that just make it easier to access. I pass the data model to each new object when called. I save an array of channels, song name, artist name, and other stream related data inside the model. I also put any data I want to persist through launches here, like settings, and write this data model to a file each time a persistent data is changed. IN this example, you can keep the data locally. If you need help on the model passing, let me know.
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