*nix Documentation Project
·  Home
 +   man pages
·  Linux HOWTOs
·  FreeBSD Tips
·  *niX Forums

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


cl Compression(3dm)					   cl Compression(3dm)

NAME    [Toc]    [Back]

     clOpenCompressor, clCompress, clCloseCompressor - Compress	a video	or
     audio stream

SYNOPSIS    [Toc]    [Back]

     #include <dmedia/cl.h>

     int clOpenCompressor(int scheme, CLhandle *handlePtr)
     int clCompress(CLhandle handle, int numberOfFrames,
	 void *frameBuffer, int	*compressedBufferSize, void *compressedBuffer)
     int clCloseCompressor(CLhandle handle)

ARGUMENTS    [Toc]    [Back]

     scheme	    The	compression scheme to use.

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

     handle	    A handle to	the compressor.

     numberOfFrames The	number of frames to compress, which should be a
		    multiple of	CL_FRAMES_PER_CHUNK (usually 1 for video).
		    numberOfFrames may also be specified as

     frameBuffer    A pointer to the frame buffer to be	compressed. A value of
		    CL_EXTERNAL_DEVICE may be used with	some compressors to
		    indicate a direct connection to an external	video or audio
		    source.  A value of	NULL selects the use of	a previously
		    created buffer to supply the frame data (Implicit

		    A pointer to the returned size of the compressed data in

		    A pointer to where the compressed data is to be placed. A
		    value of NULL selects the use of a previously created
		    buffer to place the	compressed data	(Implicit Buffering).

DESCRIPTION    [Toc]    [Back]

     clOpenCompressor opens a compressor for a given scheme.  It is called
     before clCompress or any call that	requires a compressor handle.
     clCloseCompressor closes the compressor after which handle	is no longer

     clCompress	invokes	different buffering models depending on	the values of
     the buffer	arguments (see CLintro(3dm)).

     1.	Direct Buffering

									Page 1

cl Compression(3dm)					   cl Compression(3dm)

	  If frameBuffer and compressedBuffer are non-NULL,
	  clCompress compresses	numberOfFrames from
	  frameBuffer and stores the result in compressedBuffer
	  and the resulting size in compressedBufferSize.
	  frameBuffer may also be set to CL_EXTERNAL_DEVICE to indicate
	  a hardware input source (currently supported by CL_JPEG_COSMO).

     2.	Implicit Buffering

	  If frameBuffer and compressedBuffer are NULL,
	  clCompress operates on buffers that have been	created
	  previously with clCreateBuf.	The input buffer should	be
	  filled with calls to clQueryFree, clUpdateHead, and
	  clDoneUpdatingHead.  The output buffer should	be emptied
	  with calls to	clQueryValid and clUpdateTail.

     Direct and	Implicit Buffering models may be mixed in one call by setting
     one of the	buffer arguments to be non-NULL, and the other to be NULL.

     With either model,	buffers	should be appropriately	sized for proper
     execution of clCompress.  The input frame buffer should have a minimum
     capacity of CL_FRAMES_PER_CHUNK frames.  The output compressed buffer
     should have a minimum capacity of CL_COMPRESSED_BUFFER_SIZE bytes.	 These
     parameters	may be determined by calling clGetParams, after	first calling
     clSetParams to provide the	compressor with	initialization information
     such as input dimensions and format.

     If	numberOfFrames is non-negative,	clCompress attempts to consume
     numberOfFrames frames of input data and may produce up to
     output data.  The call does not return until processing is	completed.

     If	numberOfFrames is specified as CL_CONTINUOUS_BLOCK or
     CL_CONTINUOUS_NONBLOCK then clCompress continues until either the input
     buffer is marked done, or a call to clCloseCompressor is made.
     CL_CONTINUOUS_NONBLOCK differs from CL_CONTINUOUS_BLOCK in	that the call
     to	clCompress returns immediately while the compression occurs in a
     separate thread.  These special values should only	be used	with Implicit

     Multiple compressors can be open simultaneously.  handle identifies which
     one is being referenced.

RETURN VALUES    [Toc]    [Back]

     Upon success, clOpenCompressor and	clCloseCompressor return SUCCESS, and
     clCompress	returns	either the numberOfFrames actually consumed or,	in the
     case of CL_CONTINUOUS_NONBLOCK, returns SUCCESS immediately.

     Upon failure, each	routine	returns	a negative error code.	With some
     schemes, clOpenCompressor returns CL_SCHEME_BUSY if there is a system
     resource (e.g. a piece of hardware) which is in use by another process.

									Page 2

cl Compression(3dm)					   cl Compression(3dm)

     A return code of CL_SCHEME_NOT_AVAILABLE indicates	that the hardware or
     software required by the scheme is	not installed on the system.

EXAMPLE    [Toc]    [Back]

	  #include <dmedia/cl.h>

	  int paramValueBuffer[][2] = {
	      CL_IMAGE_WIDTH,  0,
	      CL_IMAGE_HEIGHT, 0,
	  /* Open the compressor */
	  clOpenCompressor(CL_MVC1_SOFTWARE, &handle);

	  /* Configure the compressor by setting some params */
	  paramValueBuffer[0][1] = 320;
	  paramValueBuffer[1][1] = 240;
	  clSetParams(handle, (int *)paramValueBuffer, 4);

	  /* Allocate output buffer of the required size */
	  clGetParams(handle, (int *)paramValueBuffer, 6);
	  compressedBuffer = malloc(paramValueBuffer[2][1]);

	  /* Compress a	series of frames */
	  for(i	= 0; i < N; i++)
	      /* Get a frame from somewhere */
	      clCompress(handle, 1, frameBuffer, &compressedBufferSize,
	      /* Write the compressed data to somewhere	else */

	  /* Close the compressor */

SEE ALSO    [Toc]    [Back]

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

									PPPPaaaaggggeeee 3333
[ Back ]
 Similar pages
Name OS Title
clOpenDecompressor IRIX Decompress a video or audio stream
aifccompress IRIX compress the audio data in an AIFF-C file
dmDVIAudioEncode IRIX compress audio data using the IMA (Interactive Multimedia Association) Recommended ADPCM compression, based on
dmPMSetAudioCallback IRIX sets the audio and video callbacks
clOpenMux IRIX Multiplex video and audio streams
clOpenDemux IRIX Demultiplex into video and audio streams
avplayback IRIX playback uncompressed video and audio in synchronization
CLintro IRIX A library for working with compressed video and audio data
avcapture IRIX capture and synchronization tool for uncompressed video and audio
glxcreateglxvideosourcesgix IRIX create a GLX handle for a video input stream
Copyright © 2004-2005 DeniX Solutions SRL
newsletter delivery service