用aac初始化AVAudioRecorder

Question

我想用aac文件格式初始化AVAudioRecorder，但它不起作用......

以下代码有什么问题？

soundFilePath = [soundFilePath stringByAppendingPathExtension:@"aac"];
NSURL *url = [NSURL fileURLWithPath:soundFilePath isDirectory:FALSE];
NSMutableDictionary *recordSetting = [[NSMutableDictionary alloc] init];
[recordSetting setValue:[NSNumber numberWithInt: 'aac '] forKey:AVFormatIDKey];                                     //General Audio Format Settings 
[recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey];                                 //          "
[recordSetting setValue:[NSNumber numberWithInt: 2] forKey:AVNumberOfChannelsKey];                                  //          "
[recordSetting setValue:[NSNumber numberWithInt: 32] forKey:AVLinearPCMBitDepthKey];                                //Linear PCM Format Settings 
[recordSetting setValue:[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsBigEndianKey];                             //          "
[recordSetting setValue:[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsFloatKey];                                 //          "
[recordSetting setValue:[NSNumber numberWithInt:AVAudioQualityLow] forKey:AVEncoderAudioQualityKey];                //Encoder Settings 
[recordSetting setValue:[NSNumber numberWithInt:96] forKey:AVEncoderBitRateKey];                                    //          "
[recordSetting setValue:[NSNumber numberWithInt:16] forKey:AVEncoderBitDepthHintKey];                               //          "
[recordSetting setValue:[NSNumber numberWithInt:AVAudioQualityLow] forKey:AVSampleRateConverterAudioQualityKey];    //Sample Rate Conversion Settings

_recorder = [[AVAudioRecorder alloc] initWithURL:url settings:recordSetting error:nil];

这个分配只返回nil ...

任何帮助将不胜感激......！

Answer 1

删除有关PCM的每一行，并将formatIDKey更改为

[NSNumber numberWithInt: kAudioFormatMPEG4AAC], AVFormatIDKey,

顺便说一下，使用m4a作为扩展而不是aac更合适，因为aac扩展用于MPEG2 AAC格式。

Answer 2

iOS 5允许您录制到AAC。使用“kAudioFormatMPEG4AAC”为AVFormatIDKey尝试此操作。

Answer 3

虽然您可以动态转换，但没有可以录制到AAC的设置：

https://github.com/michaeltyson/TPAACAudioConverter

Answer 4

[recordSetting setValue :[NSNumber numberWithInt:kAudioFormatMPEG4AAC_HE_V2] forKey:AVFormatIDKey]; 这种格式是枚举。尝试查看枚举。 'aac'没有formatIDKey。它有aacp等。

Answer 5

只需使用以下设置在aac文件中录制人声。

    recordSetting = [[NSMutableDictionary alloc] init];
    [recordSetting setValue:[NSNumber numberWithInt:kAudioFormatAppleLossless] 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];