ios - iOS - 如何使录制的音频文件变小（就像微信一样）？

Question

我使用以下设置使录制的音频文件更小

NSMutableDictionary *settings = [[NSMutableDictionary alloc] initWithCapacity:0];                                                                              
[settings setValue :[NSNumber numberWithInt:kAudioFormatMPEG4AAC] forKey:AVFormatIDKey];
[settings setValue:[NSNumber numberWithFloat:8000.0] forKey:AVSampleRateKey]; 
[settings setValue:[NSNumber numberWithInt: 1] forKey:AVNumberOfChannelsKey];
[settings setValue :[NSNumber numberWithInt:8] forKey:AVLinearPCMBitDepthKey];
[settings setValue :[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsBigEndianKey];
[settings setValue :[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsFloatKey];
//Encoder
[settings setValue :[NSNumber numberWithInt:12000] forKey:AVEncoderBitRateKey];
[settings setValue :[NSNumber numberWithInt:8] forKey:AVEncoderBitDepthHintKey];    [settings setValue :[NSNumber numberWithInt:8] forKey:AVEncoderBitRatePerChannelKey];
[settings setValue :AVAudioQualityMin forKey:AVEncoderAudioQualityKey];

但是，对于 60 秒的声音，我需要 100K 左右，而微信只需要 30K 左右。有谁知道他们是如何做到这一点的？或者有人知道如何进一步压缩尺寸吗？谢谢你。

Answer 1

[settings setValue :[NSNumber numberWithInt:kAudioFormatMPEG4AAC] forKey:AVFormatIDKey];

kAudioFormatMPEG4AAC的尺寸最小。

然后你可以将文件分成多个小块。有关参考，请参阅以下链接：

http://sspbond007.blogspot.in/2012/01/objective-c-filesplitter-and-joiner.html