acmStreamPrepareHeader function (msacm.h)

  • Article

The ACMSTREAMHEADER structure for an ACM stream conversion. This function must be called for every stream header before it can be used in a conversion stream. An application needs to prepare a stream header only once for the life of a given stream. The stream header can be reused as long as the sizes of the source and destination buffers do not exceed the sizes used when the stream header was originally prepared.

Syntax

MMRESULT ACMAPI acmStreamPrepareHeader(
  HACMSTREAM        has,
  LPACMSTREAMHEADER pash,
  DWORD             fdwPrepare
);

Parameters

has

Handle to the conversion steam.

pash

Pointer to an ACMSTREAMHEADER structure that identifies the source and destination buffers to be prepared.

fdwPrepare

Reserved; must be zero.

Return value

Returns zero if successful or an error otherwise. Possible error values include the following.

Return code Description
MMSYSERR_INVALFLAG
 At least one flag is invalid.
MMSYSERR_INVALHANDLE
 The specified handle is invalid.
MMSYSERR_INVALPARAM
 At least one parameter is invalid.
MMSYSERR_NOMEM
 The system is unable to allocate resources.

Remarks

Preparing a stream header that has already been prepared has no effect, and the function returns zero. Nevertheless, you should ensure your application does not prepare a stream header multiple times.

Requirements

Requirement Value
Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Target Platform Windows
Header msacm.h
Library Msacm32.lib
DLL Msacm32.dll

See also

Audio Compression Functions

Audio Compression Manager