faad解码aac

- 日理万妓 2022-03-28 08:10 247阅读 0赞

// faad2.cpp : 定义控制台应用程序的入口点。
    #include "stdafx.h"
    #include <cassert>
    #include <iostream>
    #pragma comment(lib, "libfaad2.lib")
    #include <stdio.h>  
    #include <memory.h>
    #include <string>
    //#ifdef UNICODE
    //typedef  std::wstring _tstring;
    //#else
    //typedef  std::string _tstring;
    //#endif
    #include <faad.h>  
    #include "WavMaker1.h"
    const unsigned int g_frmMaxLen = 1024 * 5;   
    const unsigned int g_BufMaxLen = 1024 * 2048;//1024 * 1024
     
    /** 
     * fetch one ADTS frame 
     * buffer 传递的是指针而不是指针的引用真是非常巧妙的一种方式.
     */  
    int get_one_ADTS_frame(unsigned char* buffer, size_t buf_size, unsigned char* data ,size_t* data_size)  
    {  
     size_t size = 0;  
    
     if(!buffer || !data || !data_size )  
     {
      assert(0);
      return -1;  
     }  
     while(1)  
     {  
      if(buf_size  < 7 )  
      {
       assert(0);
       return -1;  
      }  
    
      if((buffer[0] == 0xff) && ((buffer[1] & 0xf0) == 0xf0) )  
      {  
       // profile; 2 uimsbf
       // sampling_frequency_index; 4 uimsbf
       // private_bit; 1 bslbf
       // channel_configuration; 3 uimsbf
       // original/copy; 1 bslbf
       // home; 1 bslbf
       // copyright_identification_bit; 1 bslbf
       // copyright_identification_start; 1 bslbf
       // frame_length; 13 bslbf
       size |= ((buffer[3] & 0x03) <<11);     //high 2 bit  
       size |= buffer[4]<<3;                //middle 8 bit  
       size |= ((buffer[5] & 0xe0)>>5);        //low 3bit  
       break;  
      }  
      --buf_size;  
      ++buffer;  
     }  
    
     if(buf_size < size)  
     {  
      return -1;  
     }  
    
     memcpy(data, buffer, size);  
     *data_size = size;  
    
     return 0;  
    }  
    int _tmain(int argc, _TCHAR* argv[])
    {  
     static unsigned char aacFrm[g_frmMaxLen];  //aac   最大帧长
     static unsigned char buffer[g_BufMaxLen];  //截取  aac文件的最大长度
    
     string src_file = "mp410.AAC";//输入文件	
     string dst_file = "mp410.wav";//输出文件
     FILE* ifile = NULL;  
    
     unsigned long samplerate = 0;  
     unsigned char channels  = 0;
     NeAACDecHandle decoder  = 0;  
     size_t data_size   = 0;  
     size_t size     = 0;  
    
     NeAACDecFrameInfo frame_info;
     memset(&frame_info, 0, sizeof(frame_info));
     unsigned char* input_data = buffer;  
     unsigned char* pcm_data  = NULL;  
     
     ifile   = fopen(src_file.c_str(), "rb"); //打开输入文件
     const char* p = dst_file.c_str();
     WavMaker   WavFile(p);
     if(!ifile)  
     {  
      assert(0);
      printf("source or destination file");  
      return -1;  
     }  
    
    
     //* 读取AAC文件.
     data_size = fread(buffer, 1, g_BufMaxLen, ifile);  //读取AAC文件长度  
     //* 打开解码器  
     decoder = NeAACDecOpen();
     //* 初始化解码器
     if(get_one_ADTS_frame(buffer, data_size, aacFrm, &size) < 0)  
     {
      assert(0);
      return -1;  
     } 
     NeAACDecInit(decoder, aacFrm, size, &samplerate, &channels);  
     printf("samplerate %d, channels %d\n", samplerate, channels);
     //* 初始化Wav结构
     //WAVEFORMATEX fmt;
     //fmt.wFormatTag = WAVE_FORMAT_PCM;
     //fmt.nChannels = channels;
     //fmt.nSamplesPerSec = samplerate;
     //fmt.wBitsPerSample = 16;
     //fmt.nBlockAlign = fmt.nChannels * fmt.wBitsPerSample /8;
     //fmt.nAvgBytesPerSec = fmt.nBlockAlign * samplerate;
     //fmt.cbSize = 0;
     //ofile.Init(fmt);
     //* 循环解码,写文件
    
     while(get_one_ADTS_frame(input_data, data_size, aacFrm, &size) == 0)  
     {  
    	  pcm_data = (unsigned char*)NeAACDecDecode(decoder, &frame_info, aacFrm, size);   //解码信息在frame_info
    
    	  if(frame_info.error > 0)  
    	  {  
    	   std::cout<<NeAACDecGetErrorMessage(frame_info.error)<<std::endl;
    	  }  
    	  else if(pcm_data && frame_info.samples > 0)  
    	  {  
    	   printf("frame info: bytesconsumed %d, channels %d, header_type %d\
    		   object_type %d, samples %d, samplerate %d\n",   
    		frame_info.bytesconsumed,   
    		frame_info.channels, frame_info.header_type,   
    		frame_info.object_type, frame_info.samples,   
    		frame_info.samplerate);  
    		WavFile.writebody(pcm_data, frame_info.samples * frame_info.channels  );//may be 有问题
    	  }          
    	  data_size -= size;  
    	  input_data += size;  
     }      
    	 NeAACDecClose(decoder);  
    	 fclose(ifile);
    	 WavFile.writeheader(frame_info.channels,frame_info.samplerate);
    	 WavFile.closeFile();
     return 0;
    }