www.pudn.com > MyPlayerbylqh.rar > AudioDecoderMP3.cpp

/************************************************************************************** 
 *                                                                                    * 
 *                                                                                    * 
 **************************************************************************************/ 
 
#include "AudioDecoderMP3.h" 
 
/* 
 * ACM封装器 
 * 
 */ 
 
MediaAudioDecoderMP3::MediaAudioDecoderMP3() 
{ 
	this->oFormat     = NULL; 
	this->out_buffer  = NULL; 
	this->in_buffer   = NULL; 
} 
 
 
MediaAudioDecoderMP3::~MediaAudioDecoderMP3() 
{ 
 
} 
 
/* 
 * MP3解码封装器 
 * 
 */ 
 
int MediaAudioDecoderMP3::DecompressMp3(char *outmemory, int outmemsize, int *done) 
{ 
 
	if(this->last_result == MP3_OK) { 
		this->last_result = decodeMP3(&this->mp, NULL, 0, outmemory, outmemsize, done); 
     
    if(this->last_result == MP3_NEED_MORE) { 
      
      if( this->decaps->ReadAudioData(0, this->in_buffer, 16384) == 16384) { 
		 
		  this->last_result = decodeMP3(&this->mp, (char *) this->in_buffer, 16384, outmemory, outmemsize, done); 
		  return 1; 
      } 
      else { 
	 
		  return 0; 
      } 
    } 
    else { 
      return 1; 
    } 
 
  } 
  else { 
     
    if( this->decaps->ReadAudioData(0, this->in_buffer, 16384) == 16384) { 
      this->last_result = decodeMP3(&this->mp, (char *) this->in_buffer, 16384, outmemory, outmemsize, done); 
      return 1; 
    } 
    else { 
       
      return 0; 
    } 
  } 
} 
 
/* 
 * 媒体项方法 
 */ 
 
media_type_t  MediaAudioDecoderMP3::GetType() 
{ 
	return MEDIA_TYPE_AUDIO_DECODER; 
} 
 
char         *MediaAudioDecoderMP3::GetName() 
{ 
	/* 
	 * 更新! 
	 */ 
 
	return "MPEG-1 Layer III Audio Decoder"; 
} 
	 
MP_RESULT     MediaAudioDecoderMP3::Connect(MediaItem *item) 
{ 
	WAVEFORMATEX *inFormat; 
 
	if(item && item->GetType() == MEDIA_TYPE_DECAPS) { 
 
		this->decaps = (MediaItemDecaps *) item; 
 
		inFormat = this->decaps->GetAudioFormat(0); 
 
		if(inFormat->wFormatTag == 0x55 || inFormat->wFormatTag == 0x50) { 
 
			/* 
			 * 音频流是MPEG-1 
			 */ 
 
 
			/*  
			 * 初始化解码器 
			 */ 
 
			InitMP3(&this->mp); 
	   
		    this->last_result = MP3_NEED_MORE; 
	        ring_init(); 
 
			this->in_buffer  = (char *) new char[16384]; 
			this->out_buffer = (char *) new char[65536]; 
 
			if(this->DecompressMp3(this->out_buffer, 16384, &this->real_size) == MP3_ERR) { 
 
				ExitMP3(&this->mp); 
			    return MP_RESULT_ERROR; 
			} 
	 
			/* 
			 * 缓冲 
			 */ 
 
			while(!ring_full(this->real_size)) 
				{ 
					if(this->DecompressMp3(this->out_buffer, 16384, &this->real_size) == 1) 
				        ring_write(this->out_buffer, this->real_size); 
				} 
 
			/* 
			 * 为补偿器建立输出格式（and sets up the output 
			 * format for the renderer） 
			 */ 
 
			this->oFormat = (WAVEFORMATEX *) new WAVEFORMATEX; 
			 
			memcpy(this->oFormat, inFormat, sizeof(WAVEFORMATEX)); 
			this->oFormat->wFormatTag = WAVE_FORMAT_PCM; 
 
			if (oFormat->wBitsPerSample != 8 && oFormat->wBitsPerSample != 16) 
				oFormat->wBitsPerSample = 16; 
 
			if (oFormat->nChannels!=1 && oFormat->nChannels!=2) 
				oFormat->nChannels = 2; 
 
			oFormat->nBlockAlign		= (oFormat->wBitsPerSample/8) * oFormat->nChannels; 
			oFormat->nAvgBytesPerSec	=  oFormat->nBlockAlign * oFormat->nSamplesPerSec; 
			oFormat->cbSize		        =  0; 
			 
			return MP_RESULT_OK; 
		} 
	} 
 
	return MP_RESULT_ERROR; 
} 
 
MP_RESULT     MediaAudioDecoderMP3::ReleaseConnections() 
{ 
	/* 
	 * 清除 
	 */ 
 
	this->decaps = NULL; 
 
	free(this->in_buffer); 
	this->in_buffer = NULL; 
	 
	free(this->out_buffer); 
	this->out_buffer = NULL; 
 
	free(this->oFormat); 
	this->oFormat = NULL; 
 
	ExitMP3(&this->mp); 
 
	return MP_RESULT_OK; 
} 
 
DWORD         MediaAudioDecoderMP3::GetCaps() 
{ 
	return 0; 
} 
 
MP_RESULT     MediaAudioDecoderMP3::Configure(HINSTANCE hInstance, HWND hwnd) 
{ 
	return MP_RESULT_ERROR; 
} 
 
/* 
 * 音频解码器 
 */ 
 
WAVEFORMATEX *MediaAudioDecoderMP3::GetAudioFormat() 
{ 
	return this->oFormat; 
} 
 
MP_RESULT     MediaAudioDecoderMP3::EmptyAudioBuffer() 
{ 
	ring_init(); 
 
	this->last_result = MP3_NEED_MORE; 
	ExitMP3(&this->mp); 
	InitMP3(&this->mp); 
 
	return MP_RESULT_OK; 
} 
 
unsigned int MediaAudioDecoderMP3::Decompress(void *buffer, unsigned int size) 
{ 
	DWORD i; 
 
	if(this->oFormat && buffer) { 
		 
		if(size == 0) 
			return 0; 
 
		if(size < 32768) { 
 
			/* 
			 * 只读一次 
			 */ 
 
			while(!ring_full(this->real_size)) { 
     
				if(this->DecompressMp3(this->out_buffer, 16384, &this->real_size) == 1) { 
					ring_write(this->out_buffer, this->real_size); 
				} 
				else { 
 
					return 0; 
				} 
			} 
   
			ring_read((char *) buffer, size); 
 
			return size; 
		} 
		else { 
 
			int blocks = size / 32768; 
 
			for(i = 0; i < blocks; i++) { 
			 
				while(!ring_full(this->real_size)) { 
     
					if(this->DecompressMp3(this->out_buffer, 16384, &this->real_size) == 1) { 
						ring_write(this->out_buffer, this->real_size); 
					} 
					else { 
 
						return 0; 
					} 
				} 
   
				ring_read(((char *) buffer) + i*32768, 32768); 
			} 
 
			/* 
			 * 最后一比特 
			 */ 
			 
			int left = size - (blocks * 32768); 
 
			if(left > 0) 
				Decompress((void *) (((char *) buffer) + size - left), left); 
 
			return size; 
		} 
	} 
 
	return 0; 
}