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  man pages->IRIX man pages -> old-compression/clOpenDemux (3d)              


cl Demultiplexing(3dm)					cl Demultiplexing(3dm)

NAME    [Toc]    [Back]

     clOpenDemux, clDemux, clCloseDemux	- Demultiplex into video and audio

SYNOPSIS    [Toc]    [Back]

     #include <dmedia/cl.h>

     int clOpenDemux(int scheme, CLhandle *handlePtr)
     int clDemux(CLhandle handle, int count)
     int clCloseDemux(CLhandle handle)

ARGUMENTS    [Toc]    [Back]

     scheme	    The	demultiplexing scheme to use.

     handlePtr	    A pointer to the returned handle of	the demultiplexer.
		    Used by subsequent calls to	identify the demultiplexer.

     handle	    A handle to	the demultiplexer.

     count	    The	number of iterations to	execute.  The amount of
		    processing done during each	iteration is scheme and	data
		    dependent.	count may also be specified as

DESCRIPTION    [Toc]    [Back]

     clOpenDemux opens a demultiplexer for a given scheme.  It is called
     before clDemux or any call	that requires a	demultiplexer handle.
     clCloseDemux closes the demultiplexer after which handle is no longer

     clDemux takes no buffer arguments so it always invokes the	Implicit
     Buffering model (see CLintro(3dm)).  An input buffer of type CL_BUF_MUX,
     and output	buffers	of types CL_BUF_VIDEO and CL_BUF_AUDIO,	must have been
     created previously	with clCreateBuf.  The input buffer is filled with
     calls to clQueryFree, clUpdateHead, and clDoneUpdatingHead.  The output
     buffers are emptied with calls to clQueryValid and	clUpdateTail.

     Buffers should be appropriately sized for proper execution	of clDemux.
     The input buffer should have a minimum capacity of	CL_MUX_BUFFER_SIZE.
     The output	buffers	should have minimum capacities of CL_VIDEO_BUFFER_SIZE
     and CL_AUDIO_BUFFER_SIZE. These parameters	may be determined by calling
     clGetParams, after	first calling clReadHeader to configure	the

     If	count is non-negative, clDemux attempts	to perform count iterations of
     the demultiplexing	operation.  The	actual amount of data processed	in
     each iteration is scheme and data dependent.  The call to clDemux may
     consume up	to CL_MUX_BUFFER_SIZE *	count bytes of multiplexed data.  This
     may produce up to CL_VIDEO_BUFFER_SIZE * count bytes of video data, and
     up	to CL_AUDIO_BUFFER_SIZE	* count	bytes of audio data.  The call does
     not return	until processing is completed.

									Page 1

cl Demultiplexing(3dm)					cl Demultiplexing(3dm)

     then clDemux continues until the input buffer is marked done, or a	call
     to	clCloseDemux is	made.  CL_CONTINUOUS_NONBLOCK differs from
     CL_CONTINUOUS_BLOCK in that the call to clDemux returns immediately while
     the demultiplexing	occurs in a separate thread.

     Several demultiplexers can	be open	simultaneously.	 handle	identifies
     which one is being	referenced.

RETURN VALUES    [Toc]    [Back]

     Each routine returns a negative error code	if the call fails.  Upon
     success, clOpenDemux and clCloseDemux return SUCCESS, and clDemux returns
     either the	count actually processed or, in	the case of
     CL_CONTINUOUS_NONBLOCK, returns SUCCESS immediately.

EXAMPLE    [Toc]    [Back]

	  #include <dmedia/cl.h>

	  int paramValueBuffer[][2] = {

	  /* Open the demultiplexer */
	  clOpenDemux(CL_MPEG1_SYSTEMS_SOFTWARE, &handle);

	  /* Configure the demultiplexer by reading the	header */
	  headerSize = clQueryMaxHeaderSize(CL_MPEG1_SYSTEMS_SOFTWARE);
	  /* Get the header data from somewhere	*/
	  clReadHeader(handle, headerSize, header);

	  /* Allocate buffers of the required size */
	  clGetParams(handle, (int *)paramValueBuffer, 6);
	  clCreateBuf(handle, CL_BUF_MUX, paramValueBuffer[0][1], 1, NULL);
	  clCreateBuf(handle, CL_BUF_VIDEO, paramValueBuffer[1][1], 1, NULL);
	  clCreateBuf(handle, CL_BUF_AUDIO, paramValueBuffer[2][1], 1, NULL);

	  /* Demultiplex a few iterations */
	  for(i	= 0; i < N; i++)
	      /* Keep the input	buffer full */
	      clDemux(handle, 1);
	      /* Write the video and audio data	to somewhere */

	  /* Close the demultiplexer */

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cl Demultiplexing(3dm)					cl Demultiplexing(3dm)


SEE ALSO    [Toc]    [Back]

     CLintro(3dm), clReadHeader(3dm), clGetParams(3dm),	clCreateBuf(3dm),
     clQueryFree(3dm), clUpdateHead(3dm), clQueryValid(3dm),
     clUpdateTail(3dm),	clDoneUpdatingHead(3dm)

									PPPPaaaaggggeeee 3333
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