// 為pcm文件寫(xiě)入wav頭
+ (NSData*) writeWavHead:(NSData *)audioData {
 long sampleRate = [[self GetAudioRecorderSettingDict][AVSampleRateKey] longValue];
 long numOfChannelsKey = [[self GetAudioRecorderSettingDict][AVNumberOfChannelsKey] longValue];
 Byte waveHead[44];
 waveHead[0] = 'R';
 waveHead[1] = 'I';
 waveHead[2] = 'F';
 waveHead[3] = 'F';
 
 long totalDatalength = [audioData length] + 44;
 waveHead[4] = (Byte)(totalDatalength & 0xff);
 waveHead[5] = (Byte)((totalDatalength >> 8) & 0xff);
 waveHead[6] = (Byte)((totalDatalength >> 16) & 0xff);
 waveHead[7] = (Byte)((totalDatalength >> 24) & 0xff);
 
 waveHead[8] = 'W';
 waveHead[9] = 'A';
 waveHead[10] = 'V';
 waveHead[11] = 'E';
 
 waveHead[12] = 'f';
 waveHead[13] = 'm';
 waveHead[14] = 't';
 waveHead[15] = ' ';
 
 waveHead[16] = 16; //size of 'fmt '
 waveHead[17] = 0;
 waveHead[18] = 0;
 waveHead[19] = 0;
 
 waveHead[20] = 1; //format
 waveHead[21] = 0;
 
 waveHead[22] = numOfChannelsKey; //chanel
 waveHead[23] = 0;
 
 waveHead[24] = (Byte)(sampleRate & 0xff);
 waveHead[25] = (Byte)((sampleRate >> 8) & 0xff);
 waveHead[26] = (Byte)((sampleRate >> 16) & 0xff);
 waveHead[27] = (Byte)((sampleRate >> 24) & 0xff);
 
 long byteRate = sampleRate * 2 * (16 >> 3);;
 waveHead[28] = (Byte)(byteRate & 0xff);
 waveHead[29] = (Byte)((byteRate >> 8) & 0xff);
 waveHead[30] = (Byte)((byteRate >> 16) & 0xff);
 waveHead[31] = (Byte)((byteRate >> 24) & 0xff);
 
 waveHead[32] = 2*(16 >> 3);
 waveHead[33] = 0;
 
 waveHead[34] = 16;
 waveHead[35] = 0;
 
 waveHead[36] = 'd';
 waveHead[37] = 'a';
 waveHead[38] = 't';
 waveHead[39] = 'a';
 
 long totalAudiolength = [audioData length];
 
 waveHead[40] = (Byte)(totalAudiolength & 0xff);
 waveHead[41] = (Byte)((totalAudiolength >> 8) & 0xff);
 waveHead[42] = (Byte)((totalAudiolength >> 16) & 0xff);
 waveHead[43] = (Byte)((totalAudiolength >> 24) & 0xff);
 
 NSMutableData *pcmData = [[NSMutableData alloc]initWithBytes:&waveHead length:sizeof(waveHead)];
 [pcmData appendData:audioData];
 
 
 return pcmData;
 // [pcmData writeToFile:kVoiceWav atomically:true];
 
}

//錄音格式的設(shè)置
+ (NSDictionary*)GetAudioRecorderSettingDict{
 NSDictionary *recordSetting = [[NSDictionary alloc] initWithObjectsAndKeys:
         [NSNumber numberWithFloat: 8000],AVSampleRateKey, //采樣率
         [NSNumber numberWithInt: kAudioFormatLinearPCM],AVFormatIDKey,
         [NSNumber numberWithInt:16],AVLinearPCMBitDepthKey,//采樣位數(shù) 默認(rèn) 16
         [NSNumber numberWithInt: 2], AVNumberOfChannelsKey,//通道的數(shù)目
         nil];
 return recordSetting;
}

/**
 * 轉(zhuǎn)換wav到amr
 *
 * @param wavPath wav文件路徑
 * @param isDelete 轉(zhuǎn)換成功后是否刪除源文件
 *
 * @return NO 失敗 YES成功
 */
+ (BOOL) wav2Amr:(NSString *)wavPath isDeleteSourchFile:(BOOL)isDelete;
 
/**
 * 轉(zhuǎn)換amr到wav
 *
 * @param amrPath amr文件路徑
 * @param isDelete 轉(zhuǎn)換成功后是否刪除源文件
 *
 * @return NO 失敗 YES成功
 */
+ (BOOL) amr2Wav:(NSString *)amrPath isDeleteSourchFile:(BOOL)isDelete;
 
/**
 * 轉(zhuǎn)換pcm到mp3
 *
 * @param pcmPath pcm文件路徑
 * @param isDelete 轉(zhuǎn)換成功后是否刪除源文件
 *
 * @return NO 失敗 YES成功
 */
+ (BOOL) pcm2Mp3: (NSString *)pcmPath isDeleteSourchFile:(BOOL)isDelete;
/**
 * 轉(zhuǎn)換pcm到wav
 *
 * @param pcmPath pcm文件路徑
 * @param isDelete 轉(zhuǎn)換成功后是否刪除源文件
 *
 * @return NO 失敗 YES成功
 */
+ (BOOL) pcm2Wav: (NSString *)pcmPath isDeleteSourchFile:(BOOL)isDelete;
 
/**
 * 轉(zhuǎn)換pcm到amr
 *
 * @param pcmPath pcm文件路徑
 * @param isDelete 轉(zhuǎn)換成功后是否刪除源文件
 *
 * @return NO 失敗 YES成功
 */
+ (BOOL) pcm2Amr:(NSString *)pcmPath isDeleteSourchFile:(BOOL)isDelete;
 
/**
 * 為pcm文件寫(xiě)入wav頭 
 */
+ (NSData*) writeWavHead:(NSData *)audioData;
void conventToMp3(NSString *pcmFile,NSString *mp3File);
 
/**
 錄音格式設(shè)置,轉(zhuǎn)換的時(shí)候需要獲取.(如:采樣率、采樣位數(shù)、通道的數(shù)目)
 建議使用此設(shè)置，如有修改，則轉(zhuǎn)換amr時(shí)也要對(duì)應(yīng)修改參數(shù)，比較麻煩
 
 @returns 錄音設(shè)置
 */
+ (NSDictionary*)GetAudioRecorderSettingDict;