Compaq Multimedia Services
for OpenVMS Alpha
Programmer's Guide
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ICDecompressPrepareHeader

 Name ICDecompressPrepareHeader --- Prepare decompression headers Syntax 


#include <mme/mme_api.h> 
 
MMRESULT ICDecompressPrepareHeader(HIC hic, 
                                   LPBITMAPINFOHEADER lpbiFormat, 
                                   LPVOID lpData, 
                                   LPBITMAPINFOHEADER lpbi, 
                                   LPVOID lpBits);
Arguments HIC hic
Specifies a handle to a decompressor.

LPBITMAPINFOHEADER lpbiFormat
Specifies a pointer to a BITMAPINFOHEADER data structure containing the format of the compressed data. The BITMAPINFOHEADER data structure must be allocated with the mmeAllocMem function before being passed to the ICDecompressPrepareHeader function. See Chapter 2 for more information about allocating memory for data structures.

LPVOID lpData
Specifies a pointer to the input data. The data buffer must be allocated with the mmeAllocBuffer function before being passed to the ICDecompressPrepareHeader function. See Chapter 2 for more information about allocating memory for data buffers.

LPBITMAPINFOHEADER lpbi
Specifies a pointer to a BITMAPINFOHEADER data structure containing the output format.

The BITMAPINFOHEADER data structure must be allocated with the mmeAllocMem function before being passed to the ICDecompressPrepareHeader function. See Chapter 2 for more information about allocating memory for data structures.

LPVOID lpBits
Specifies a pointer to a data buffer for the decompressed data. The data buffer must be allocated with the mmeAllocBuffer function before being passed to the ICDecompressPrepareHeader function. See Chapter 2 for more information about allocating memory for data buffers.

Description

The ICDecompressPrepareHeader function prepares buffers for video decompression streaming. If a hardware device requires locked-down memory regions to read and write data, then the standard interface would require a separate lock down and unlock each time a ICDecompress operation was called. This may be highly inefficient for some devices.

This routine allows a large region to be registered and any low level operations may be accomplished once for the entire region, possibly making ICDecompress calls much more efficient.

When the client and server are local to the same machine, memory may be shared between the client, server, and hardware device. ICDecompressPrepareHeader facilitates this sharing. When the client and server are on different machines (not yet supported), then the server has to allocate space for the buffers. ICDecompressPrepareHeader allows the server to allocate all the required space up front reducing the need to allocate space on every ICDecompress call.

This routine must be called after ICDecompressBegin and before ICDecompressEnd . Ideally, this routine is called once to register input and output buffers between the ICDecompressBegin call and the first ICDecompress call.

A buffer can only be prepared once. If the application attempts to register an already registered buffer or a buffer that overlaps with an already registered buffer, the ICDecompressPrepareHeader call will fail. If an application has several compressors and/or decompressors open, the same buffers may not be sharable between compressors and/or decompressors.

Buffers cannot be used for two different purposes. For example, one memory region can be used to hold multiple input buffers and another memory region can be used to hold multiple output buffers, but the same region cannot be used to hold both input and output buffers since they are used for different purposes.

Extensions The ICDecompressPrepareHeader function is a Compaq extension to the Microsoft multimedia API specification.

Compaq has extended the Microsoft video and ICM (Installable Compression Manager) interfaces to provide for memory optimization. See Section 1.5.8 for more information.

Return Values

1
Returns ICERR_OK if the function is successful; otherwise, it returns one of the following error codes:

Error Code Description
ICERR_BADHANDLE The hic argument is invalid, the decompressor is not open, or the decompressor is not open for decompression.
ICERR_BADFORMAT The lpbiFormat and lpbi arguments are not acceptable formats.
ICERR_BADIMAGESIZE The specified image size is invalid.
ICERR_BADPARAM The lpbiFormat or lpbi, or lpData or lpBits arguments are NULL; or the hardware cannot be properly set up for the operation. The parameters are not the same as those specified in the ICDecompressBegin call (with the exception of the biSizeImage fields).
ICERR_MEMORY The buffers specified are not valid. Most likely they were not allocated with mmeAllocBuffer or mmeAllocBufferAndGetShminfo .
ICERR_CANTUPDATE The decompressor is not already in operation, that is, ICDecompressBegin has not yet been called or ICDecompressEnd has been called.
ICERR_INTERNAL An internal driver error occurred. No more detailed information is available.
See Also ICDecompressBegin , ICDecompressEnd , ICDecompressUnprepareHeader

ICDecompressQuery

 Name ICDecompressQuery --- Determine if a decompressor can decompress data with a specific format Syntax 


#include <mme/mme_api.h> 
 
MMRESULT ICDecompressQuery(HIC hic, 
                           LPBITMAPINFOHEADER lpbiInput, 
                           LPBITMAPINFOHEADER lpbiOutput);
Arguments HIC hic
Specifies a handle to a decompressor.

LPBITMAPINFOHEADER lpbiInput
Specifies a pointer to a BITMAPINFOHEADER data structure indicating the format of the input data.

The BITMAPINFOHEADER data structure must be allocated with the mmeAllocMem function before being passed to the ICDecompressQuery function. See Chapter 2 for more information about the memory allocation functions.

LPBITMAPINFOHEADER lpbiOutput
Specifies a pointer to a BITMAPINFOHEADER data structure indicating the format of the output data. If NULL, any output format is acceptable.

The BITMAPINFOHEADER data structure must be allocated with the mmeAllocMem function before being passed to the ICDecompressQuery function. See Chapter 2 for more information about the memory allocation functions.

Description

The ICDecompressQuery function determines if a decompressor can decompress data with a specific format.
Extensions None.

Return Values

1
Returns ICERR_OK if the decompression is supported; otherwise, it returns one of the following error codes:
Error Code Description
ICERR_BADHANDLE The hic argument is invalid, the decompressor is not open, or the decompressor is not open for decompression.
ICERR_BADFORMAT The lpbiInput and lpbiOutput arguments are not acceptable formats.
See Also ICDecompressGetFormat

ICDecompressUnprepareHeader

 Name ICDecompressUnprepareHeader --- Unprepare decompression headers Syntax 


#include <mme/mme_api.h> 
 
MMRESULT ICDecompressUnprepareHeader(HIC hic, 
                                     LPBITMAPINFOHEADER lpbiFormat, 
                                     LPVOID lpData, 
                                     LPBITMAPINFOHEADER lpbi, 
                                     LPVOID lpBits);
Arguments HIC hic
Specifies a handle to a decompressor.

LPBITMAPINFOHEADER lpbiFormat
Specifies a pointer to a BITMAPINFOHEADER data structure holding the format of the compressed data. The BITMAPINFOHEADER data structure must be allocated with the mmeAllocMem function before being passed to the ICDecompressUnprepareHeader function. See Chapter 2 for more information about allocating memory for data structures.

LPVOID lpData
Specifies a pointer to the input data buffer. The data buffer must be allocated with the mmeAllocBuffer function before being passed to the ICDecompressUnprepareHeader function. See Chapter 2 for more information about allocating memory for data buffers.

LPBITMAPINFOHEADER lpbi
Specifies a pointer to a BITMAPINFOHEADER data structure containing the output format.

The BITMAPINFOHEADER data structure must be allocated with the mmeAllocMem function before being passed to the ICDecompressUnprepareHeader function. See Chapter 2 for more information about allocating memory for data structures.

LPVOID lpBits
Specifies a pointer to the output data buffer. The data buffer must be allocated with the mmeAllocBuffer function before being passed to the ICDecompressUnprepareHeader function. See Chapter 2 for more information about allocating memory for data buffers.

Description

The ICDecompressUnprepareHeader function unprepares buffers prepared with ICDecompressPrepareHeader .

This function must be called before ICDecompressEnd and after all decompression operations have been completed and all buffers have been returned to the application.

Extensions The ICDecompressUnprepareHeader function is a Compaq extension to the Microsoft multimedia API specification.

Return Values

1
Returns ICERR_OK if the function is successful; otherwise, it returns one of the following error codes:
Error Code Description
ICERR_BADHANDLE The hic argument is invalid, the decompressor is not open, or the decompressor is not open for decompression.
ICERR_BADPARAM The lpbiFormat or lpbi, or lpData or lpBits arguments are NULL; or the hardware cannot be properly set up for the operation. The parameters are not the same as those specified in the ICDecompressBegin call (with the exception of the biSizeImage fields). The buffers have not been previously prepared.
ICERR_CANTUPDATE The decompressor is not in operation, that is, ICDecompressBegin has not yet been called or ICDecompressEnd has been called. The buffer should be unprepared before calling ICDecompressEnd . Some compressors may choose to unprepare all prepared headers when ICDecompressEnd is called.
ICERR_INTERNAL An internal driver error occurred. No more detailed information is available.
See Also ICDecompressBegin , ICDecompressEnd , ICDecompressPrepareHeader

ICGetBrightness

 Name ICGetBrightness --- Obtain current brightness value Syntax 


#include <mme/mme_api.h> 
 
MMRESULT ICGetBrightness(HIC hic)
Arguments HIC hic
Specifies a handle to a compressor or decompressor.

Description

The ICGetBrightness function obtains the current brightness value.
Extensions The ICGetBrightness function is a Compaq extension to the Microsoft multimedia API specification.

Return Values

1
Returns the current brightness value if the function is successful; otherwise, it returns the following error code:
Error Code Description
ICERR_BADHANDLE The hic argument is invalid or the compressor or decompressor is not open.
See Also ICSetBrightness

ICGetContrast

 Name ICGetContrast --- Obtain current contrast value Syntax 


#include <mme/mme_api.h> 
 
MMRESULT ICGetContrast(HIC hic)
Arguments HIC hic
Specifies a handle to a compressor or decompressor.

Description

The ICGetContrast function obtains the current contrast value.
Extensions The ICGetContrast function is a Compaq extension to the Microsoft multimedia API specification.

Return Values

1
Returns the current contrast value if the function is successful; otherwise, it returns the following error code:
Error Code Description
ICERR_BADHANDLE The hic argument is invalid or the compressor or decompressor is not open.
See Also ICSetContrast

ICGetDefaultKeyFrameRate

 Name ICGetDefaultKeyFrameRate --- Obtain default key frame rate value Syntax 


#include <mme/mme_api.h> 
 
MMRESULT ICGetDefaultKeyFrameRate(HIC hic)
Arguments HIC hic
Specifies a handle to a compressor.

Description

The ICGetDefaultKeyFrameRate function obtains the default key frame rate value.
Extensions None.

Return Values

1
Returns the default key frame rate value if the function is successful; otherwise, it returns the following error code:
Error Code Description
ICERR_BADHANDLE The hic argument is invalid or the compressor is not open.
See Also None.

ICGetDefaultQuality

 Name ICGetDefaultQuality --- Obtain default quality setting used for compression Syntax 


#include <mme/mme_api.h> 
 
MMRESULT ICGetDefaultQuality(HIC hic)
Arguments HIC hic
Specifies a handle to a compressor.

Description

The ICGetDefaultQuality function obtains the default quality setting used for compression.
Extensions None.

Return Values

1
Returns the default quality setting used for compression if the function is successful; otherwise, it returns the following error code:
Error Code Description
ICERR_BADHANDLE The hic argument is invalid or the compressor is not open.
See Also None.

ICGetInfo

 Name ICGetInfo --- Obtain information about a compressor or decompressor Syntax 


#include <mme/mme_api.h> 
 
MMRESULT ICGetInfo(HIC hic, 
                   ICINFO *lpicinfo, 
                   DWORD cb);
Arguments HIC hic
Specifies a handle to a compressor or decompressor.

ICINFO *lpicinfo
Specifies a pointer to an ICINFO data structure used to return information about the compressor or decompressor. The ICINFO data structure must be allocated with the mmeAllocMem function before being passed to the ICGetInfo function.

DWORD cb
Specifies the size in bytes of the data structure pointed to by the lpicinfo argument.

Description

The ICGetInfo function obtains information about a compressor or decompressor.
Extensions None.

Return Values

1
Returns ICERR_OK if the function is succcessful; otherwise, it returns one of the following error codes:
Error Code Description
ICERR_BADHANDLE The hic argument is invalid or the compressor or decompressor is not open.
ICERR_BADPARAM The lpicinfo argument is NULL.
See Also ICCompress

ICGetMirror

 Name ICGetMirror --- Obtain current mirroring value Syntax 


#include <mme/mme_api.h> 
 
MMRESULT ICGetMirror(HIC hic)
Arguments HIC hic
Specifies a handle to a compressor or decompressor.

Description

The ICGetMirror function obtains the current mirroring value.
Extensions The ICGetMirror function is a Compaq extension to the Microsoft multimedia API specification.

Return Values

1
Returns the current mirroring value if the function is successful; otherwise, it returns the following error code:
Error Code Description
ICERR_BADHANDLE The hic argument is invalid or the compressor or decompressor is not open.
See Also ICSetMirror

ICGetSaturation

 Name ICGetSaturation --- Obtain current saturation value Syntax 


#include <mme/mme_api.h> 
 
MMRESULT ICGetSaturation(HIC hic)
Arguments HIC hic
Specifies a handle to a compressor or decompressor.

Description

The ICGetSaturation function obtains the current contrast value.
Extensions The ICGetSaturation function is a Compaq extension to the Microsoft multimedia API specification.

Return Values

1
Returns the current saturation value if the function is successful; otherwise, it returns the following error code:
Error Code Description
ICERR_BADHANDLE The hic argument is invalid or the compressor or decompressor is not open.
See Also ICSetSaturation

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