faad解码aac

// 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;

}