wav格式音频转换成aac格式音频(二)

来源：互联网发布：淘宝售后服务编辑：程序博客网时间：2024/05/21 06:39

根据前一篇的分析，则需要实现在AACCodecHelper.h中声明的几个函数，如下：

#include"AACCodecHelper.h"
#include"faac.h"
ULONG nSampleRate = 11025; // 采样率
UINT      nChannels = 1; // 声道数
UINT      nPCMBitSize = 16; // 单样本位数
ULONG nInputSamples = 0;
ULONG nMaxOutputBytes = 0;
faacEncHandle hEncoder;
faacEncConfigurationPtr pConfiguration;
BYTE* pbPCMBuffer;
BYTE* pbAACBuffer;
INT32 nPCMBufferSize;
INT32 nRet = 0;
//////////////////
INT32 t = 0;
//////////////////
void openFaacEngine(){//打开Faac引擎
   hEncoder = faacEncOpen(nSampleRate, nChannels, &nInputSamples, &nMaxOutputBytes);
   pConfiguration = faacEncGetCurrentConfiguration(hEncoder);
   pConfiguration->inputFormat = FAAC_INPUT_16BIT;
   nRet = faacEncSetConfiguration(hEncoder, pConfiguration);
   nPCMBufferSize = nInputSamples * nPCMBitSize / 8;
   pbPCMBuffer = new BYTE[nPCMBufferSize];
   pbAACBuffer = new BYTE [nMaxOutputBytes];
}
void closeFaacEngine(){//关闭Faac引擎
   nRet = faacEncClose(hEncoder);
   delete[] pbPCMBuffer;
   delete[] pbAACBuffer;
}
int wavToAAC(const char* wavData,int wavDataLen,char* aacData){
   /**
   * 将长为wavDataLen个字节的wav音频数据转化为aac，写入aacData
   * 成功返回aac数据的字节数，失败返回-1
   */
   if (hEncoder == NULL) {
       return -1;
   }
    INT32 nInputSamples = 0;
    INT32 readPCMByteSum = 0;
    INT32 writeAACByteSum = 0;
    INT32 nAACEncRet = 0;
    INT32 j = 0;
    INT32 k = 0;
    while (readPCMByteSum < wavDataLen) {
       for (j = 0; j < nPCMBufferSize; j++) {
           *(pbPCMBuffer + j) = *(wavData + j + readPCMByteSum);
       }
       readPCMByteSum += nPCMBufferSize;

nInputSamples = nPCMBufferSize / (nPCMBitSize / 8);//计算输入样本的个数

/**

*调用faacEncEncode()函数，这里略过

        for (k = 0; k < nAACEncRet; k++) {
           *(aacData + k + writeAACByteSum) = *(pbAACBuffer + k);
       }
       writeAACByteSum += nAACEncRet;
                fprintf(stderr,"%d: faacEncEncode returns %d\n", t++, nAACEncRet);
   }
    return writeAACByteSum;
}
未完待续~

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