今天我们来说一下如何实现录音与播放功能。AVAudioRecorder这个类可用来实现录音的采集，而我们用AVAudioPlayer则可实现录音的播放。首先记得导入#import <AVFoundation/AVFoundation.h>
我的做法是自己写了个类，重写了init方法，稍微封装了一下。你也可以在controller中直接用。 废话不多说，上代码：
- (id)init {
if (self = [super init]) {
NSMutableDictionary *recordSetting = [[NSMutableDictionary alloc]init];
//设置录音格式 AVFormatIDKey==kAudioFormatLinearPCM
[recordSetting setValue:[NSNumber numberWithInt:kAudioFormatAppleIMA4] forKey:AVFormatIDKey];
//设置录音采样率(Hz) 如：AVSampleRateKey==8000/44100/96000（影响音频的质量）
[recordSetting setValue:[NSNumber numberWithFloat:44100] forKey:AVSampleRateKey];
//录音通道数 1 或 2
[recordSetting setValue:[NSNumber numberWithInt:1] forKey:AVNumberOfChannelsKey];
//线性采样位数 8、16、24、32
[recordSetting setValue:[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];
//录音的质量
[recordSetting setValue:[NSNumber numberWithInt:AVAudioQualityHigh] forKey:AVEncoderAudioQualityKey];
//文件存放路径
_url = [NSURL URLWithString:[self getFilePath]];
_recorder = [[AVAudioRecorder alloc]initWithURL:_url settings:recordSetting error:nil];
AVAudioSession *audioSession = [AVAudioSession sharedInstance];
[audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];
[audioSession setActive:YES error:nil];
//_recorder.meteringEnabled = YES;
//设置录音时长，超过这个时间后，会暂停单位是秒
//[_recorder recordForDuration:30];
//准备录音
[_recorder prepareToRecord];
}
return self;
}
- (NSString *)getFilePath {
NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
NSString *urlPath = [path stringByAppendingPathComponent:@"123.caf"];
return urlPath;
}
//录音开始
- (void)beginSoundRecording {
[_recorder record];
}
//录音暂停
- (void)pauseSoundRecording {
[_recorder pause];
}
//录音结束
- (void)stopSoundRecording {
[_recorder stop];
}
播放的代码：
- (void)beginPlay {
if (_url) {
_player = [[AVAudioPlayer alloc]initWithContentsOfURL:[NSURL fileURLWithPath:[self getFilePath]] error:nil];
//设置播放循环次数
//[_player setNumberOfLoops:0];
//音量，0-1之间
//[_player setVolume:1];
[_player prepareToPlay];
//开始播放
[_player play];
}
}
- (void)resumePlay {
//暂停之后恢复播放
[_player play];
}
- (void)pausePlay {
//暂停播放
[_player pause];
}
录音出来的通常是caf pcm格式，文件较大，而且在其他设备上还可能无法播放，可以使用lame进行mp3转码：
- (NSString *)mp3FilePath {
NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
NSString *urlPath = [path stringByAppendingPathComponent:@"123.mp3"];
return urlPath;
}
//转为Mp3
- (NSString *)audioCAFtoMP3 {
NSString *cafFilePath = [self getFilePath];
NSString *mp3FilePath = [self mp3FilePath];
@try {
int read, write;
FILE *pcm = fopen([cafFilePath cStringUsingEncoding:1], "rb"); //source 被转换的音频文件位置
fseek(pcm, 4*1024, SEEK_CUR); //skip file header
FILE *mp3 = fopen([mp3FilePath cStringUsingEncoding:1], "wb"); //output 输出生成的Mp3文件位置
const int PCM_SIZE = 8192;
const int MP3_SIZE = 8192;
short int pcm_buffer[PCM_SIZE*2];
unsigned char mp3_buffer[MP3_SIZE];
lame_t lame = lame_init();
lame_set_in_samplerate(lame, 44100.0);
lame_set_VBR(lame, vbr_default);
lame_set_brate(lame,8);
lame_set_mode(lame,3);
lame_set_quality(lame,2);
lame_init_params(lame);
do {
read = fread(pcm_buffer, 2*sizeof(short int), PCM_SIZE, pcm);
if (read == 0)
write = lame_encode_flush(lame, mp3_buffer, MP3_SIZE);
else
write = lame_encode_buffer_interleaved(lame, pcm_buffer, read, mp3_buffer, MP3_SIZE);
fwrite(mp3_buffer, write, 1, mp3);
} while (read != 0);
lame_close(lame);
fclose(mp3);
fclose(pcm);
}
@catch (NSException *exception) {
NSLog(@"%@",[exception description]);
}
@finally {
return mp3FilePath;
}
}
功能代码差不多就这些，UI界面大家各抒己见。
下面是一份带UI界面功能实现的Demo，有兴趣的可以看一下：
