//------------------ 设置录音格式及参数 --------------------------
NSDictionary *settings = [[NSDictionary alloc] initWithObjectsAndKeys:
[NSNumber numberWithInt:AVAudioQualityMin], AVEncoderAudioQualityKey,
[NSNumber numberWithInt:kAudioFormatLinearPCM], AVFormatIDKey,
[NSNumber numberWithFloat:8000.0], AVSampleRateKey,
[NSNumber numberWithInt:16], AVLinearPCMBitDepthKey,
[NSNumber numberWithInt:1], AVNumberOfChannelsKey,
[NSNumber numberWithBool:NO], AVLinearPCMIsBigEndianKey,
[NSNumber numberWithBool:NO], AVLinearPCMIsFloatKey, nil];
// NSDictionary *settings = [[NSDictionary alloc] initWithObjectsAndKeys:
// [NSNumber numberWithInt:kAudioFormatLinearPCM],AVFormatIDKey,//格式
// [NSNumber numberWithFloat:8000.0],AVSampleRateKey, //采样率8000次
// [NSNumber numberWithInt:1], AVNumberOfChannelsKey, //通道的数目
// [NSNumber numberWithInt:16],AVLinearPCMBitDepthKey, //采样位数 默认 16
// [NSNumber numberWithBool:NO],AVLinearPCMIsBigEndianKey, //大端还是小端 是内存的组织方式
// [NSNumber numberWithBool:NO],AVLinearPCMIsFloatKey, //采样信号是整数还是浮点数
// //Encoder
// [NSNumber numberWithInt:12800],AVEncoderBitRateKey, //解码率
// [NSNumber numberWithInt:8],AVEncoderBitDepthHintKey, //位深度
// [NSNumber numberWithInt:8],AVEncoderBitRatePerChannelKey, //声道采样率
// [NSNumber numberWithInt:AVAudioQualityLow],AVEncoderAudioQualityKey, //音频编码质量
// nil];
[[AVAudioRecorder alloc] initWithURL:[NSURL fileURLWithPath:cafFilePath] settings:settings error:&error];
原文：http://leerain.blog.51cto.com/8277864/1360147