avistream.cpp

一个播放器 使用了evc 大家可以参考下 哦

	InputMediaClose=(pInputMediaClose)GetProcAddress(hDLL,_T("InputMediaClose"));
	if (!InputMediaOpen(lpFilename, 0, type,2000000,CacheSize))
	{
		FreeLibrary(hDLL);
		hDLL=NULL;
		return 0;
	}
	vidinfo.hIOMutex = CreateMutex (NULL, FALSE, NULL);

	viddata.video_pos  = 0;
	vidinfo.audio_posc = 0;
	vidinfo.audio_posb = 0;

	vidinfo.idx         = NULL;
	vidinfo.video_index = NULL;
	vidinfo.audio_index = NULL;

	if(AVIDecaps_IsAVI()) {

		
		if(AVIDecaps_FillHeader(1)) {
		
			ret= 1;
		}
		else {

			InputMediaSeek(0, INPUT_SEEK_SET);

			AVIDecaps_IsAVI();
			
			if(AVIDecaps_FillHeader(0)) {
		
				ret=1;
			}
		}
	}
	*vid=&::viddata;
	return ret;
}

void GetNextChunkInfo()
{
	unsigned long  n; 
	long           hdrl_len = 0;
	int            lasttag = 0;
	int            vids_strh_seen = 0;
	int            vids_strf_seen = 0;
	int            auds_strh_seen = 0;
	int            auds_strf_seen = 0;
	int            num_stream = 0;
	char           data[256];
	InputMediaSeek(PAD_EVEN(vidinfo.currentchunk.pos+vidinfo.currentchunk.len),INPUT_SEEK_SET);
	while(1)
	{
		
		if( InputMediaRead(data, 8) != 8 ) 
		{
			vidinfo.currentchunk.pos+=vidinfo.currentchunk.len;
			vidinfo.currentchunk.len=0;
			break;
		}
		
		n = str2ulong(data + 4);
		
		/* 
		* the movi list may contain sub-lists, 
		* ignore them 
		*
		*/
		
		if(strncmp(data,"LIST", 4) == 0)
		{
			InputMediaSeek(4, INPUT_SEEK_CUR);
			continue;
		}
		
		/* 
		* check if we got a tag ##db, 
		* ##dc or ##wb 
		* 
		*/
		
		if( ( (data[2]=='d' || data[2]=='D') &&
			(data[3]=='b' || data[3]=='B' || data[3]=='c' || data[3]=='C') ) || 
			( (data[2]=='w' || data[2]=='W') &&
			(data[3]=='b' || data[3]=='B') ) )
		{
			if(strncmp(data, viddata.audio_tag, 4) == 0)
			{
				vidinfo.currentchunk.pos = InputMediaSeek(0, INPUT_SEEK_CUR);
				vidinfo.currentchunk.len = n;
				return;				
			}
		}
		
		InputMediaSeek(PAD_EVEN(n),
			INPUT_SEEK_CUR);
	}
	
	
}

void GetNextFrameInfo()
{
	unsigned long  n; 
	long           hdrl_len = 0;
	int            lasttag = 0;
	int            vids_strh_seen = 0;
	int            vids_strf_seen = 0;
	int            auds_strh_seen = 0;
	int            auds_strf_seen = 0;
	int            num_stream = 0;
	char           data[256];
	InputMediaSeek(PAD_EVEN(vidinfo.currentframe.pos+vidinfo.currentframe.len),INPUT_SEEK_SET);
	while(1)
	{
		
		if( InputMediaRead(data, 8) != 8 ) 
			break;
		
		n = str2ulong(data + 4);
		
		/* 
		* the movi list may contain sub-lists, 
		* ignore them 
		*
		*/
		
		if(strncmp(data,"LIST", 4) == 0)
		{
			InputMediaSeek(4, INPUT_SEEK_CUR);
			continue;
		}
		
		/* 
		* check if we got a tag ##db, 
		* ##dc or ##wb 
		* 
		*/
		
		if( ( (data[2]=='d' || data[2]=='D') &&
			(data[3]=='b' || data[3]=='B' || data[3]=='c' || data[3]=='C') ) || 
			( (data[2]=='w' || data[2]=='W') &&
			(data[3]=='b' || data[3]=='B') ) )
		{
			if(strncmp(data, viddata.video_tag, 3) == 0)
			{
				vidinfo.currentframe.flags = 0;//(BYTE) (str2ulong(data+4) & AVIIF_KEYFRAME)>1;//str2ulong(vidinfo.idx[i]+ 4);
				vidinfo.currentframe.pos   = InputMediaSeek(0, INPUT_SEEK_CUR);
				vidinfo.currentframe.len   = n;
				return;				
			}
		}
		
		InputMediaSeek(PAD_EVEN(n),
			INPUT_SEEK_CUR);
	}
	
	
}
/*
 * Returns the wavefromatex
 * associated with the first audio 
 * stream.
 */
	
/*
 * Reads the next video Frame into
 * buffer, return the actual size of
 * the frame.
 *
 */

AVISTREAM_API int AVIDecaps_NextVideoFrame(char *buffer, int drop)
{
   //unsigned int n;

   //if(vidinfo.video_pos >= vidinfo.video_frames) {
   //  
//	   return -2;
   //}
   /*
    * Request the mutex 
    * for reading the file;
    */

   WaitForSingleObject(vidinfo.hIOMutex, INFINITE);
   GetNextFrameInfo();
   //n = vidinfo.video_index[vidinfo.video_pos].len;

   InputMediaSeek(vidinfo.currentframe.pos, INPUT_SEEK_SET);

   InputMediaRead(buffer, vidinfo.currentframe.len);

   viddata.video_pos++;

   /*
    * Release the Mutex.
    */

   ReleaseMutex(vidinfo.hIOMutex);
   return vidinfo.currentframe.len;
}

/*
 * Reads any amount of audio
 * data. FIXME : should return
 * the actual number read.
 */

AVISTREAM_API int AVIDecaps_ReadAudio(char *audbuf, int bytes)
{
	int nr, left = 0, todo;


   nr = 0; 

   /*
    * Request the read Mutex 
    */

   WaitForSingleObject(vidinfo.hIOMutex, INFINITE);
   /*
    * We loop until we parsed enough
	* chunks for the amount we want
    *
    */

   while(bytes > 0)
   {
      left = vidinfo.currentchunk.len - vidinfo.audio_posb;

      if(!left)
      {
         //if(vidinfo.audio_posc>=vidinfo.audio_chunks-1) 
		 //{
		//	ReleaseMutex(vidinfo.hIOMutex);
		//	return nr;
		// }
         vidinfo.audio_posc++;
         vidinfo.audio_posb = 0;
		 GetNextChunkInfo();
		 if (!vidinfo.currentchunk.len)
		 {
			ReleaseMutex(vidinfo.hIOMutex);
			return nr;
		 }
         continue;
      }
      if(bytes<left)
         todo = bytes;
      else
         todo = left;
      
	  InputMediaSeek(vidinfo.currentchunk.pos + vidinfo.audio_posb, INPUT_SEEK_SET);

      InputMediaRead(audbuf + nr, todo);

      bytes -= todo;
      nr    += todo;
      vidinfo.audio_posb += todo;
   }

   /*
    * And release the Mutex.
    */

   ReleaseMutex(vidinfo.hIOMutex);
	abytes_read+=nr;
   return nr;
}

/*
 * Return the actual framerate
 * FIXME : should be a double...
 *
 */

AVISTREAM_API double AVIDecaps_FrameRate()
{
	/*
	 * Fix for some trailers
	 */

	if(viddata.fps == 0)
		viddata.fps = 25;

	if(viddata.fps == 23)
		viddata.fps = 25;

	return (double) viddata.fps;
}


/*
 * Seek to a particular 
 * video frame.
 */


AVISTREAM_API int AVIDecaps_Seek(int percent, int isFrame)
{
	
	long frame;
	double ratio;
	long audio_bytes;
	int look=0;
//	double ratio;
	char temp[512];
	int nShouldbe;
	int apos;
	WaitForSingleObject(vidinfo.hIOMutex, INFINITE);

	/*
     * compute the desired 
     * frame number
     *
     */
	if (!isFrame)
		frame = (long) (percent * viddata.video_frames / 100);
	else
		frame=percent;

    /*
     * and go to the next 
     * keyframe.
     *
     */
	while(vidinfo.video_index[look+1].flags<frame)
	{
		look++;
	}
	frame=vidinfo.video_index[look].flags;
	vidinfo.currentframe.len=0;
	vidinfo.currentframe.pos=vidinfo.video_index[look].pos-8;

    ratio = (double) ((double) frame / (double) viddata.video_frames);
    apos = (long) (ratio * (double)viddata.audio_bytes);

	look=0;
	while(vidinfo.audio_index[look+1].tot<apos)
	{
		look++;
	}
	if (look) abytes_read=vidinfo.audio_index[look].tot;
	else abytes_read=0;
	vidinfo.currentchunk.len=0;
	vidinfo.currentchunk.pos=vidinfo.audio_index[look].pos-8;
	vidinfo.audio_posb=0;

	viddata.video_pos = frame;

    /*
     * calculate what ratio 
     * it corresponds to
     *
     */
    if(vidinfo.audio_strn > 0) {
      
      
	  nShouldbe=0;
	  while(nShouldbe<viddata.video_pos)
	  {
		  AVIDecaps_ReadAudio(temp,512);
		  nShouldbe=(abytes_read*(__int64)viddata.video_frames)/viddata.audio_bytes+1;
	  }



	  ReleaseMutex(vidinfo.hIOMutex);

      return viddata.audio_bytes-abytes_read;
	}

	return 1;
}

AVISTREAM_API int AVIDecaps_ReSeekAudio()
{
	double ratio;
	char temp[512];
	int nShouldbe;
	  WaitForSingleObject(vidinfo.hIOMutex, INFINITE);
	  nShouldbe=0;
	  while(nShouldbe<viddata.video_pos)
	  {
		  AVIDecaps_ReadAudio(temp,512);
		  nShouldbe=(abytes_read*(__int64)viddata.video_frames)/viddata.audio_bytes+1;
	  }
      ReleaseMutex(vidinfo.hIOMutex);


    return viddata.audio_bytes-abytes_read;
}

AVISTREAM_API double AVIDecaps_GetProgress()
{
	return (double) ((double)(viddata.video_pos))*100.0/((double)viddata.video_frames);
}


AVISTREAM_API int AVIDecaps_Close()
{
	if (hDLL)
	{
		InputMediaClose();
		if (vidinfo.video_index) free(vidinfo.video_index);
		if (vidinfo.audio_index) free(vidinfo.audio_index);
		if (vidinfo.idx) free(vidinfo.idx);
		viddata.video_pos=0;
		vidinfo.audio_posb=0;
		vidinfo.audio_posc=0;
		FreeLibrary(hDLL);
		hDLL=NULL;
	}

	return 1;
}

int AVIDecaps_Stop()
{
	if (WaitForSingleObject(vidinfo.hIOMutex, 500)==WAIT_TIMEOUT)
		AVIDecaps_Close();
	else
		ReleaseMutex(vidinfo.hIOMutex);
	return 1;
	
}

AVISTREAM_API void InitializeReader(reader* rd)
{
	rd->READER_Open=AVIDecaps_Open;
	rd->READER_ReadAudio=AVIDecaps_ReadAudio;
	rd->READER_NextVideoFrame=AVIDecaps_NextVideoFrame;
	rd->READER_Seek=AVIDecaps_Seek;
	rd->READER_ReSeekAudio=AVIDecaps_ReSeekAudio;
	rd->READER_GetProgress=AVIDecaps_GetProgress;
	rd->READER_Close=AVIDecaps_Close;
	rd->READER_Stop=AVIDecaps_Stop;

}
BOOL APIENTRY DllMain( HANDLE hModule, 
                       DWORD  ul_reason_for_call, 
                       LPVOID lpReserved
					 )
{
    switch (ul_reason_for_call)
	{
		case DLL_PROCESS_ATTACH:
		case DLL_THREAD_ATTACH:
		case DLL_THREAD_DETACH:
		case DLL_PROCESS_DETACH:
			break;
    }
    return TRUE;
}


// This is the constructor of a class that has been exported.
// see AVIStream.h for the class definition
CAVIStream::CAVIStream()
{ 
	return; 
}