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ce47f986d8
NT4/private/windows/media/msacm/g711/codec.c
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2020-09-30 17:12:29 +02:00

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//==========================================================================;
//
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY
// KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR
// PURPOSE.
//
// Copyright (c) 1993 - 1995 Microsoft Corporation. All Rights Reserved.
//
//--------------------------------------------------------------------------;
//
// codec.c
//
// Description:
// This file contains the DriverProc and other routines which respond
// to ACM messages.
//
// Throughout this module, 'g711' refers to both the A-law and u-law
// coding standards. When the context requires that these coding
// standards be differentiated we use 'alaw' and 'mulaw' or a similar
// variation.
//
//
//==========================================================================;
#include <windows.h>
#include <windowsx.h>
#include <mmsystem.h>
#include <mmddk.h>
#include <mmreg.h>
#include <msacm.h>
#include <msacmdrv.h>
#include <memory.h>
#include "codec.h"
#include "g711.h"
#include "debug.h"
const UINT gauFormatTagIndexToTag[] =
{
WAVE_FORMAT_PCM,
WAVE_FORMAT_ALAW,
WAVE_FORMAT_MULAW
};
#define ACM_DRIVER_MAX_FORMAT_TAGS SIZEOF_ARRAY(gauFormatTagIndexToTag)
#define ACM_DRIVER_MAX_FILTER_TAGS 0
//
// array of sample rates supported
//
//
const UINT gauFormatIndexToSampleRate[] =
{
8000,
11025,
22050,
44100
};
#define ACM_DRIVER_MAX_SAMPLE_RATES SIZEOF_ARRAY(gauFormatIndexToSampleRate)
#define ACM_DRIVER_MAX_CHANNELS G711_MAX_CHANNELS
//
// bits per sample supported
//
//
#define ACM_DRIVER_MAX_BITSPERSAMPLE_PCM 1 // only 16 bit
#define ACM_DRIVER_MAX_BITSPERSAMPLE_G711 1 // only 8 bit
//
// number of formats we enumerate per channel is number of sample rates
// times number of channels times number of types (bits per sample).
//
#define ACM_DRIVER_MAX_FORMATS_PCM (ACM_DRIVER_MAX_SAMPLE_RATES * \
ACM_DRIVER_MAX_CHANNELS * \
ACM_DRIVER_MAX_BITSPERSAMPLE_PCM)
#define ACM_DRIVER_MAX_FORMATS_G711 (ACM_DRIVER_MAX_SAMPLE_RATES * \
ACM_DRIVER_MAX_CHANNELS * \
ACM_DRIVER_MAX_BITSPERSAMPLE_G711)
//==========================================================================;
//
//
//
//
//==========================================================================;
//--------------------------------------------------------------------------;
//
// int LoadStringCodec
//
// Description:
// This function should be used by all codecs to load resource strings
// which will be passed back to the ACM. It works correctly for all
// platforms, as follows:
//
// Win16: Compiled to LoadString to load ANSI strings.
//
// Win32: The 32-bit ACM always expects Unicode strings. Therefore,
// when UNICODE is defined, this function is compiled to
// LoadStringW to load a Unicode string. When UNICODE is
// not defined, this function loads an ANSI string, converts
// it to Unicode, and returns the Unicode string to the
// codec.
//
// Note that you may use LoadString for other strings (strings which
// will not be passed back to the ACM), because these strings will
// always be consistent with the definition of UNICODE.
//
// Arguments:
// Same as LoadString, except that it expects an LPSTR for Win16 and a
// LPWSTR for Win32.
//
// Return (int):
// Same as LoadString.
//
//--------------------------------------------------------------------------;
#ifndef _WIN32
#define LoadStringCodec LoadString
#else
#ifdef UNICODE
#define LoadStringCodec LoadStringW
#else
int FNGLOBAL LoadStringCodec
(
HINSTANCE hinst,
UINT uID,
LPWSTR lpwstr,
int cch)
{
LPSTR lpstr;
int iReturn;
lpstr = (LPSTR)GlobalAlloc(GPTR, cch);
if (NULL == lpstr)
{
return 0;
}
iReturn = LoadStringA(hinst, uID, lpstr, cch);
if (0 == iReturn)
{
if (0 != cch)
{
lpwstr[0] = '\0';
}
}
else
{
MultiByteToWideChar( GetACP(), 0, lpstr, cch, lpwstr, cch );
}
GlobalFree((HGLOBAL)lpstr);
return iReturn;
}
#endif // UNICODE
#endif // _WIN32
//==========================================================================;
//
//
//
//
//==========================================================================;
//--------------------------------------------------------------------------;
//
// BOOL pcmIsValidFormat
//
// Description:
// This function verifies that a wave format header is a valid PCM
// header that _this_ ACM driver can deal with.
//
// Arguments:
// LPWAVEFORMATEX pwfx: Pointer to format header to verify.
//
// Return (BOOL):
// The return value is non-zero if the format header looks valid. A
// zero return means the header is not valid.
//
//--------------------------------------------------------------------------;
BOOL FNLOCAL pcmIsValidFormat
(
LPWAVEFORMATEX pwfx
)
{
if (NULL == pwfx)
return (FALSE);
if (WAVE_FORMAT_PCM != pwfx->wFormatTag)
return (FALSE);
//
// verify nChannels member is within the allowed range
//
if ((pwfx->nChannels < 1) || (pwfx->nChannels > ACM_DRIVER_MAX_CHANNELS))
return (FALSE);
//
// only allow the bits per sample that we can encode and decode with
//
if (16 != pwfx->wBitsPerSample)
return (FALSE);
//
// now verify that the block alignment is correct..
//
if (PCM_BLOCKALIGNMENT((LPPCMWAVEFORMAT)pwfx) != pwfx->nBlockAlign)
return (FALSE);
//
// finally, verify that avg bytes per second is correct
//
if (PCM_AVGBYTESPERSEC((LPPCMWAVEFORMAT)pwfx) != pwfx->nAvgBytesPerSec)
return (FALSE);
return (TRUE);
} // pcmIsValidFormat()
//--------------------------------------------------------------------------;
//
// BOOL g711IsValidFormat
//
// Description:
// This function verifies that a wave format header is a valid
// G711 format header that _this_ ACM driver can deal with.
//
// Arguments:
// LPWAVEFORMATEX pwfx: Pointer to format header to verify.
//
// Return (BOOL):
// The return value is non-zero if the format header looks valid. A
// zero return means the header is not valid.
//
//--------------------------------------------------------------------------;
BOOL FNLOCAL g711IsValidFormat
(
LPWAVEFORMATEX pwfx
)
{
if (NULL == pwfx)
return (FALSE);
if ((WAVE_FORMAT_MULAW != pwfx->wFormatTag) &&
(WAVE_FORMAT_ALAW != pwfx->wFormatTag))
return (FALSE);
//
// check channels
//
if ((pwfx->nChannels < 1) || (pwfx->nChannels > ACM_DRIVER_MAX_CHANNELS))
return (FALSE);
//
// now verify that the block alignment is correct..
//
#if 0
if (G711_BLOCKALIGNMENT(pwfx) != (UINT)pwfx->nBlockAlign)
return (FALSE);
#else
//
// unfortunately there has been at least one company who didn't
// understand what the block alignment was really for and authored
// a bunch of files incorrectly. to allow those files to work, we
// will just make sure that whole samples remain...
//
// this codec will only author G711 formats with correct block
// alignments however.
//
if (0 != (pwfx->nBlockAlign % G711_BLOCKALIGNMENT(pwfx)))
return (FALSE);
#endif
//
// verify that avg bytes per second is correct
//
if (G711_AVGBYTESPERSEC(pwfx) != pwfx->nAvgBytesPerSec)
return (FALSE);
//
// check wBitsPerSample
//
if (G711_BITS_PER_SAMPLE != pwfx->wBitsPerSample)
return (FALSE);
//
// cbSize must be validated also..
//
if (G711_WFX_EXTRA_BYTES != pwfx->cbSize)
return (FALSE);
return (TRUE);
} // g711IsValidFormat()
//==========================================================================;
//
//
//
//
//==========================================================================;
//--------------------------------------------------------------------------;
//
// LRESULT acmdDriverOpen
//
// Description:
// This function is used to handle the DRV_OPEN message for the ACM
// driver. The driver is 'opened' for many reasons with the most common
// being in preperation for conversion work. It is very important that
// the driver be able to correctly handle multiple open driver
// instances.
//
// Read the comments for this function carefully!
//
// Note that multiple _streams_ can (and will) be opened on a single
// open _driver instance_. Do not store/create instance data that must
// be unique for each stream in this function. See the acmdStreamOpen
// function for information on conversion streams.
//
// Arguments:
// HDRVR hdrvr: Driver handle that will be returned to caller of the
// OpenDriver function. Normally, this will be the ACM--but this is
// not guaranteed. For example, if an ACM driver is implemented within
// a waveform driver, then the driver will be opened by both MMSYSTEM
// and the ACM.
//
// LPACMDRVOPENDESC paod: Open description defining how the ACM driver
// is being opened. This argument may be NULL--see the comments below
// for more information.
//
// Return (LRESULT):
// The return value is non-zero if the open is successful. A zero
// return signifies that the driver cannot be opened.
//
//--------------------------------------------------------------------------;
LRESULT FNLOCAL acmdDriverOpen
(
HDRVR hdrvr,
LPACMDRVOPENDESC paod
)
{
PDRIVERINSTANCE pdi;
//
// the [optional] open description that is passed to this driver can
// be from multiple 'managers.' for example, AVI looks for installable
// drivers that are tagged with 'vidc' and 'vcap'. we need to verify
// that we are being opened as an Audio Compression Manager driver.
//
// if paod is NULL, then the driver is being opened for some purpose
// other than converting (that is, there will be no stream open
// requests for this instance of being opened). the most common case
// of this is the Control Panel's Drivers option checking for config
// support (DRV_[QUERY]CONFIGURE).
//
// we want to succeed this open, but be able to know that this
// open instance is bogus for creating streams. for this purpose we
// leave most of the members of our instance structure that we
// allocate below as zero...
//
if (NULL != paod)
{
//
// refuse to open if we are not being opened as an ACM driver.
// note that we do NOT modify the value of paod->dwError in this
// case.
//
if (ACMDRIVERDETAILS_FCCTYPE_AUDIOCODEC != paod->fccType)
{
return (0L);
}
}
//
// we are being opened as an installable driver--we can allocate some
// instance data to be returned in dwId argument of the DriverProc;
// or simply return non-zero to succeed the open.
//
// this driver allocates a small instance structure. note that we
// rely on allocating the memory as zero-initialized!
//
pdi = (PDRIVERINSTANCE)LocalAlloc(LPTR, sizeof(*pdi));
if (NULL == pdi)
{
//
// if this open attempt was as an ACM driver, then return the
// reason we are failing in the open description structure..
//
if (NULL != paod)
{
paod->dwError = MMSYSERR_NOMEM;
}
//
// fail to open
//
return (0L);
}
//
// fill in our instance structure... note that this instance data
// can be anything that the ACM driver wishes to maintain the
// open driver instance. this data should not contain any information
// that must be maintained per open stream since multiple streams
// can be opened on a single driver instance.
//
// also note that we do _not_ check the version of the ACM opening
// us (paod->dwVersion) to see if it is at least new enough to work
// with this driver (for example, if this driver required Version 3.0
// of the ACM and a Version 2.0 installation tried to open us). the
// reason we do not fail is to allow the ACM to get the driver details
// which contains the version of the ACM that is _required_ by this
// driver. the ACM will examine that value (in padd->vdwACM) and
// do the right thing for this driver... like not load it and inform
// the user of the problem.
//
pdi->hdrvr = hdrvr;
pdi->hinst = GetDriverModuleHandle(hdrvr); // Module handle.
if (NULL != paod)
{
pdi->fnDriverProc = NULL;
pdi->fccType = paod->fccType;
pdi->vdwACM = paod->dwVersion;
pdi->fdwOpen = paod->dwFlags;
pdi->fdwConfig = 0L;
paod->dwError = MMSYSERR_NOERROR;
}
//
// non-zero return is success for DRV_OPEN
//
return ((LRESULT)(UINT)pdi);
} // acmdDriverOpen()
//--------------------------------------------------------------------------;
//
// LRESULT acmdDriverClose
//
// Description:
// This function handles the DRV_CLOSE message for the ACM driver. The
// driver receives a DRV_CLOSE message for each succeeded DRV_OPEN
// message (see acmdDriverOpen). The driver will only receive a close
// message for _successful_ opens.
//
// Arguments:
// PDRIVERINSTANCE pdi: Pointer to private ACM driver instance structure.
// This structure is [optionally] allocated during the DRV_OPEN message
// which is handled by the acmdDriverOpen function.
//
// Return (LRESULT):
// The return value is non-zero if the open instance can be closed.
// A zero return signifies that the ACM driver instance could not be
// closed.
//
// NOTE! It is _strongly_ recommended that the driver never fail to
// close. Note that the ACM will never allow a driver instance to
// be closed if there are open streams. An ACM driver does not need
// to check for this case.
//
//--------------------------------------------------------------------------;
LRESULT FNLOCAL acmdDriverClose
(
PDRIVERINSTANCE pdi
)
{
//
// check to see if we allocated instance data. if we did not, then
// immediately succeed.
//
if (NULL != pdi)
{
//
// close down the driver instance. this driver simply needs
// to free the instance data structure... note that if this
// 'free' fails, then this ACM driver probably trashed its
// heap; assume we didn't do that.
//
LocalFree((HLOCAL)pdi);
}
//
// non-zero return is success for DRV_CLOSE
//
return (1L);
} // acmdDriverClose()
//--------------------------------------------------------------------------;
//
// LRESULT acmdDriverConfigure
//
// Description:
// This function is called to handle the DRV_[QUERY]CONFIGURE messages.
// These messages are for 'configuration' support of the driver.
// Normally this will be for 'hardware'--that is, a dialog should be
// displayed to configure ports, IRQ's, memory mappings, etc if it
// needs to. However, a software only ACM driver may also require
// configuration for 'what is real time' or other quality vs time
// issues.
//
// The most common way that these messages are generated under Win 3.1
// and NT Product 1 is from the Control Panel's Drivers option. Other
// sources may generate these messages in future versions of Windows.
//
// Arguments:
// PDRIVERINSTANCE pdi: Pointer to private ACM driver instance structure.
// This structure is [optionally] allocated during the DRV_OPEN message
// which is handled by the acmdDriverOpen function.
//
// HWND hwnd: Handle to parent window to use when displaying the
// configuration dialog box. An ACM driver is _required_ to display a
// modal dialog box using this hwnd argument as the parent. This
// argument may be (HWND)-1 which tells the driver that it is only
// being queried for configuration support.
//
// LPDRVCONFIGINFO pdci: Pointer to optional DRVCONFIGINFO structure.
// If this argument is NULL, then the ACM driver should invent its own
// storage location.
//
// Return (LRESULT):
// If the driver is being 'queried' for configuration support (that is,
// hwnd == (HWND)-1), then non-zero should be returned specifying
// the driver does support a configuration dialog--or zero should be
// returned specifying that no configuration dialog is supported.
//
// If the driver is being called to display the configuration dialog
// (that is, hwnd != (HWND)-1), then one of the following values
// should be returned:
//
// DRVCNF_CANCEL (0x0000): specifies that the dialog was displayed
// and canceled by the user. this value should also be returned if
// no configuration information was modified.
//
// DRVCNF_OK (0x0001): specifies that the dialog was displayed and
// the user pressed OK. This value should be returned even if the
// user didn't change anything - otherwise, the driver may not
// install properly.
//
// DRVCNF_RESTART (0x0002): specifies that the dialog was displayed
// and some configuration information was changed that requires
// Windows to be restarted before the changes take affect. the driver
// should remain configured with current values until the driver
// has been 'rebooted'.
//
//--------------------------------------------------------------------------;
LRESULT FNLOCAL acmdDriverConfigure
(
PDRIVERINSTANCE pdi,
HWND hwnd,
LPDRVCONFIGINFO pdci
)
{
//
// first check to see if we are only being queried for configuration
// support. if hwnd == (HWND)-1 then we are being queried and should
// return zero for 'not supported' and non-zero for 'supported'.
//
if ((HWND)-1 == hwnd)
{
//
// this ACM driver does NOT support a configuration dialog box, so
// return zero...
//
return (0L);
}
//
// we are being asked to bring up our configuration dialog. if this
// driver supports a configuration dialog box, then after the dialog
// is dismissed we must return one of the following values:
//
// DRVCNF_CANCEL (0x0000): specifies that the dialog was displayed
// and canceled by the user. this value should also be returned if
// no configuration information was modified.
//
// DRVCNF_OK (0x0001): specifies that the dialog was displayed and
// the user pressed OK. This value should be returned even if the
// user didn't change anything - otherwise, the driver may not
// install properly.
//
// DRVCNF_RESTART (0x0002): specifies that the dialog was displayed
// and some configuration information was changed that requires
// Windows to be restarted before the changes take affect. the driver
// should remain configured with current values until the driver
// has been 'rebooted'.
//
//
// return DRVCNF_CANCEL--this ACM driver does not support configuration
//
return (DRVCNF_CANCEL);
} // acmdDriverConfigure()
//--------------------------------------------------------------------------;
//
// LRESULT acmdDriverDetails
//
// Description:
// This function handles the ACMDM_DRIVER_DETAILS message. The ACM
// driver is responsible for filling in the ACMDRIVERDETAILS structure
// with various information.
//
// NOTE! It is *VERY* important that you fill in your ACMDRIVERDETAILS
// structure correctly. The ACM and applications must be able to
// rely on this information.
//
// WARNING! The _reserved_ bits of any fields of the ACMDRIVERDETAILS
// structure are _exactly that_: RESERVED. Do NOT use any extra
// flag bits, etc. for custom information. The proper way to add
// custom capabilities to your ACM driver is this:
//
// o define a new message in the ACMDM_USER range.
//
// o an application that wishes to use one of these extra features
// should then:
//
// o open the driver with acmDriverOpen.
//
// o check for the proper wMid and wPid using acmDriverDetails.
//
// o send the 'user defined' message with acmDriverMessage
// to retrieve additional information, etc.
//
// o close the driver with acmDriverClose.
//
// Arguments:
// PDRIVERINSTANCE pdi: Pointer to private ACM driver instance structure.
// This structure is [optionally] allocated during the DRV_OPEN message
// which is handled by the acmdDriverOpen function.
//
// LPACMDRIVERDETAILS padd: Pointer to ACMDRIVERDETAILS structure to
// fill in for the caller. This structure may be larger or smaller than
// the current definition of ACMDRIVERDETAILS--cbStruct specifies the
// valid size.
//
// Return (LRESULT):
// The return value is zero (MMSYSERR_NOERROR) for success. Non-zero
// signifies that the driver details could not be retrieved.
//
// NOTE THAT THIS FUNCTION SHOULD NEVER FAIL! There are two possible
// error conditions:
//
// o if padd is NULL or an invalid pointer.
//
// o if cbStruct is less than four; in this case, there is not enough
// room to return the number of bytes filled in.
//
// Because these two error conditions are easily defined, the ACM
// will catch these errors. The driver does NOT need to check for these
// conditions.
//
//--------------------------------------------------------------------------;
LRESULT FNLOCAL acmdDriverDetails
(
PDRIVERINSTANCE pdi,
LPACMDRIVERDETAILS padd
)
{
ACMDRIVERDETAILS add;
DWORD cbStruct;
//
// it is easiest to fill in a temporary structure with valid info
// and then copy the requested number of bytes to the destination
// buffer.
//
cbStruct = min(padd->cbStruct, sizeof(ACMDRIVERDETAILS));
add.cbStruct = cbStruct;
//
// for the current implementation of an ACM driver, the fccType and
// fccComp members *MUST* always be ACMDRIVERDETAILS_FCCTYPE_AUDIOCODEC
// ('audc') and ACMDRIVERDETAILS_FCCCOMP_UNDEFINED (0) respectively.
//
add.fccType = ACMDRIVERDETAILS_FCCTYPE_AUDIOCODEC;
add.fccComp = ACMDRIVERDETAILS_FCCCOMP_UNDEFINED;
//
// the manufacturer id (wMid) and product id (wPid) must be filled
// in with your company's _registered_ identifier's. for more
// information on these identifier's and how to get them registered
// contact Microsoft and get the Multimedia Developer Registration Kit:
//
// Microsoft Corporation
// Multimedia Technology Group
// One Microsoft Way
// Redmond, WA 98052-6399
//
// Developer Services Phone: (800) 227-4679 x11771
//
// note that during the development phase or your ACM driver, you may
// use the reserved value of '0' for both wMid and wPid. however it
// is not acceptable to ship a driver with these values.
//
add.wMid = MM_MICROSOFT;
add.wPid = MM_MSFT_ACM_G711;
//
// the vdwACM and vdwDriver members contain version information for
// the driver.
//
// vdwACM: must contain the version of the *ACM* that the driver was
// _designed_ for. this is the _minimum_ version number of the ACM
// that the driver will work with. this value must be >= V2.00.000.
//
// vdwDriver: the version of this ACM driver.
//
// ACM driver versions are 32 bit numbers broken into three parts as
// follows (note these parts are displayed as decimal values):
//
// bits 24 - 31: 8 bit _major_ version number
// bits 16 - 23: 8 bit _minor_ version number
// bits 0 - 15: 16 bit build number
//
add.vdwACM = VERSION_MSACM;
add.vdwDriver = VERSION_ACM_DRIVER;
//
// the following flags are used to specify the type of conversion(s)
// that the ACM driver supports. note that a driver may support one or
// more of these flags in any combination.
//
// ACMDRIVERDETAILS_SUPPORTF_CODEC: this flag is set if the driver
// supports conversions from one format tag to another format tag. for
// example, if a converter compresses or decompresses WAVE_FORMAT_PCM
// and WAVE_FORMAT_IMA_ADPCM, then this bit should be set. this is
// true even if the data is not actually changed in size--for example
// a conversion from u-Law to A-Law will still set this bit because
// the format tags differ.
//
// ACMDRIVERDETAILS_SUPPORTF_CONVERTER: this flags is set if the
// driver supports conversions on the same format tag. as an example,
// the PCM converter that is built into the ACM sets this bit (and only
// this bit) because it converts only between PCM formats (bits, sample
// rate).
//
// ACMDRIVERDETAILS_SUPPORTF_FILTER: this flag is set if the driver
// supports transformations on a single format tag but does change
// the base characteristics of the format (bit depth, sample rate, etc
// will remain the same). for example, a driver that changed the
// 'volume' of PCM data or applied a low pass filter would set this bit.
//
add.fdwSupport = ACMDRIVERDETAILS_SUPPORTF_CODEC;
//
// the number of individual format tags this ACM driver supports. for
// example, if a driver uses the WAVE_FORMAT_IMA_ADPCM and
// WAVE_FORMAT_PCM format tags, then this value would be two. if the
// driver only supports filtering on WAVE_FORMAT_PCM, then this value
// would be one. if this driver supported WAVE_FORMAT_ALAW,
// WAVE_FORMAT_MULAW and WAVE_FORMAT_PCM, then this value would be
// three. etc, etc.
//
add.cFormatTags = ACM_DRIVER_MAX_FORMAT_TAGS;
//
// the number of individual filter tags this ACM driver supports. if
// a driver supports no filters (ACMDRIVERDETAILS_SUPPORTF_FILTER is
// NOT set in the fdwSupport member), then this value must be zero.
//
add.cFilterTags = ACM_DRIVER_MAX_FILTER_TAGS;
//
// the remaining members in the ACMDRIVERDETAILS structure are sometimes
// not needed. because of this we make a quick check to see if we
// should go through the effort of filling in these members.
//
if (FIELD_OFFSET(ACMDRIVERDETAILS, hicon) < cbStruct)
{
//
// fill in the hicon member will a handle to a custom icon for
// the ACM driver. this allows the driver to be represented by
// an application graphically (usually this will be a company
// logo or something). if a driver does not wish to have a custom
// icon displayed, then simply set this member to NULL and a
// generic icon will be displayed instead.
//
// See the MSFILTER sample for a codec which contains a custom icon.
//
add.hicon = NULL;
//
// the short name and long name are used to represent the driver
// in a unique description. the short name is intended for small
// display areas (for example, in a menu or combo box). the long
// name is intended for more descriptive displays (for example,
// in an 'about box').
//
// NOTE! an ACM driver should never place formatting characters
// of any sort in these strings (for example CR/LF's, etc). it
// is up to the application to format the text.
//
LoadStringCodec(pdi->hinst, IDS_ACM_DRIVER_SHORTNAME, add.szShortName, SIZEOFACMSTR(add.szShortName));
LoadStringCodec(pdi->hinst, IDS_ACM_DRIVER_LONGNAME, add.szLongName, SIZEOFACMSTR(add.szLongName));
//
// the last three members are intended for 'about box' information.
// these members are optional and may be zero length strings if
// the driver wishes.
//
// NOTE! an ACM driver should never place formatting characters
// of any sort in these strings (for example CR/LF's, etc). it
// is up to the application to format the text.
//
if (FIELD_OFFSET(ACMDRIVERDETAILS, szCopyright) < cbStruct)
{
LoadStringCodec(pdi->hinst, IDS_ACM_DRIVER_COPYRIGHT, add.szCopyright, SIZEOFACMSTR(add.szCopyright));
LoadStringCodec(pdi->hinst, IDS_ACM_DRIVER_LICENSING, add.szLicensing, SIZEOFACMSTR(add.szLicensing));
LoadStringCodec(pdi->hinst, IDS_ACM_DRIVER_FEATURES, add.szFeatures, SIZEOFACMSTR(add.szFeatures));
}
}
//
// now copy the correct number of bytes to the caller's buffer
//
_fmemcpy(padd, &add, (UINT)add.cbStruct);
//
// success!
//
return (MMSYSERR_NOERROR);
} // acmdDriverDetails()
//--------------------------------------------------------------------------;
//
// LRESULT acmdDriverAbout
//
// Description:
// This function is called to handle the ACMDM_DRIVER_ABOUT message.
// An ACM driver has the option of displaying its own 'about box' or
// letting the ACM (or calling application) display one for it. This
// message is normally sent by the Control Panel's Sound Mapper
// option.
//
// It is recommended that an ACM driver allow a default about box
// be displayed for it--there should be no reason to bloat the size
// of a driver to simply display copyright, etc information when that
// information is contained in the ACMDRIVERDETAILS structure.
//
// Arguments:
// PDRIVERINSTANCE pdi: Pointer to private ACM driver instance structure.
// This structure is [optionally] allocated during the DRV_OPEN message
// which is handled by the acmdDriverOpen function.
//
// HWND hwnd: Handle to parent window to use when displaying the
// configuration dialog box. An ACM driver is _required_ to display a
// modal dialog box using this hwnd argument as the parent. This
// argument may be (HWND)-1 which tells the driver that it is only
// being queried for about box support.
//
// Return (LRESULT):
// The return value is MMSYSERR_NOTSUPPORTED if the ACM driver does
// not support a custom dialog box. In this case, the ACM or calling
// application will display a generic about box using the information
// contained in the ACMDRIVERDETAILS structure returned by the
// ACMDM_DRIVER_DETAILS message.
//
// If the driver chooses to display its own dialog box, then after
// the dialog is dismissed by the user, MMSYSERR_NOERROR should be
// returned.
//
// If the hwnd argument is equal to (HWND)-1, then no dialog should
// be displayed (the driver is only being queried for support). The
// driver must still return MMSYSERR_NOERROR (supported) or
// MMSYSERR_NOTSUPPORTED (no custom about box supported).
//
//--------------------------------------------------------------------------;
LRESULT FNLOCAL acmdDriverAbout
(
PDRIVERINSTANCE pdi,
HWND hwnd
)
{
//
// first check to see if we are only being queried for custom about
// box support. if hwnd == (HWND)-1 then we are being queried and
// should return MMSYSERR_NOTSUPPORTED for 'not supported' and
// MMSYSERR_NOERROR for 'supported'.
//
if ((HWND)-1 == hwnd)
{
//
// this ACM driver does NOT support a custom about box, so
// return MMSYSERR_NOTSUPPORTED...
//
return (MMSYSERR_NOTSUPPORTED);
}
//
// this driver does not support a custom dialog, so tell the ACM or
// calling application to display one for us. note that this is the
// _recommended_ method for consistency and simplicity of ACM drivers.
// why write code when you don't have to?
//
return (MMSYSERR_NOTSUPPORTED);
} // acmdDriverAbout()
//==========================================================================;
//
//
//
//
//==========================================================================;
//--------------------------------------------------------------------------;
//
// LRESULT acmdFormatSuggest
//
// Description:
// This function handles the ACMDM_FORMAT_SUGGEST message. The purpose
// of this function is to provide a way for the ACM, a wave mapper or
// an application to quickly get a destination format that this driver
// can convert the source format to. The 'suggested' format should
// be as close to a common format as possible. This message is normally
// sent in response to an acmFormatSuggest function call.
//
// Another way to think about this message is: what format would this
// driver like to convert the source format to?
//
// The caller may place restrictions on the destination format that
// should be suggested. The padfs->fdwSuggest member contains the
// restriction bits passed by the caller--see the description for
// the return value for more information.
//
// Arguments:
// PDRIVERINSTANCE pdi: Pointer to private ACM driver instance structure.
// This structure is [optionally] allocated during the DRV_OPEN message
// which is handled by the acmdDriverOpen function.
//
// LPACMDRVFORMATSUGGEST padfs: Pointer to an ACMDRVFORMATSUGGEST
// structure that describes the source and destination (possibly with
// restrictions) for a conversion.
//
// Return (LRESULT):
// The return value is zero (MMSYSERR_NOERROR) if this function
// succeeds with no errors. The return value is a non-zero error code
// if the function fails.
//
// The driver should return MMSYSERR_NOTSUPPORTED if one or more of
// the destination restriction bits is not supported. It is strongly
// recommended that the driver support at least the following suggestion
// restriction bits:
//
// ACM_FORMATSUGGESTF_WFORMATTAG: The destination format tag must be
// the same as the wFormatTag member in the destination format header.
//
// ACM_FORMATSUGGESTF_NCHANNELS: The destination channel count must be
// the same as the nChannels member in the destination format header.
//
// ACM_FORMATSUGGESTF_NSAMPLESPERSEC: The destination samples per
// second must be the same as the nSamplesPerSec member in the
// destination format header.
//
// ACM_FORMATSUGGESTF_WBITSPERSAMPLE: The destination bits per sample
// must be the same as the wBitsPerSample member in the destination
// format header.
//
// If no destintation format can be suggested, then the driver should
// return ACMERR_NOTPOSSIBLE.
//
//--------------------------------------------------------------------------;
LRESULT FNLOCAL acmdFormatSuggest
(
PDRIVERINSTANCE pdi,
LPACMDRVFORMATSUGGEST padfs
)
{
#define ACMD_FORMAT_SUGGEST_SUPPORT (ACM_FORMATSUGGESTF_WFORMATTAG | \
ACM_FORMATSUGGESTF_NCHANNELS | \
ACM_FORMATSUGGESTF_NSAMPLESPERSEC |\
ACM_FORMATSUGGESTF_WBITSPERSAMPLE)
LPWAVEFORMATEX pwfxSrc;
LPWAVEFORMATEX pwfxDst;
DWORD fdwSuggest;
//
// grab the suggestion restriction bits and verify that we support
// the ones that are specified... an ACM driver must return the
// MMSYSERR_NOTSUPPORTED if the suggestion restriction bits specified
// are not supported.
//
fdwSuggest = (ACM_FORMATSUGGESTF_TYPEMASK & padfs->fdwSuggest);
if (~ACMD_FORMAT_SUGGEST_SUPPORT & fdwSuggest)
return (MMSYSERR_NOTSUPPORTED);
//
// get the source and destination formats in more convenient variables
//
pwfxSrc = padfs->pwfxSrc;
pwfxDst = padfs->pwfxDst;
//
//
//
//
switch (pwfxSrc->wFormatTag)
{
case WAVE_FORMAT_PCM:
//
// strictly verify that the source format is acceptable for
// this driver
//
if (!pcmIsValidFormat(pwfxSrc))
break;
//
// if the destination format tag is restricted, verify that
// it is within our capabilities...
//
// this driver is able to encode to A-Law and u-Law
//
if (ACM_FORMATSUGGESTF_WFORMATTAG & fdwSuggest)
{
if ((WAVE_FORMAT_ALAW != pwfxDst->wFormatTag) &&
(WAVE_FORMAT_MULAW != pwfxDst->wFormatTag))
return (ACMERR_NOTPOSSIBLE);
}
else
{
pwfxDst->wFormatTag = WAVE_FORMAT_ALAW;
}
//
// if the destination channel count is restricted, verify that
// it is within our capabilities...
//
// this driver is not able to change the number of channels
//
if (ACM_FORMATSUGGESTF_NCHANNELS & fdwSuggest)
{
if (pwfxSrc->nChannels != pwfxDst->nChannels)
return (ACMERR_NOTPOSSIBLE);
}
else
{
pwfxDst->nChannels = pwfxSrc->nChannels;
}
//
// if the destination samples per second is restricted, verify
// that it is within our capabilities...
//
// this driver is not able to change the sample rate
//
if (ACM_FORMATSUGGESTF_NSAMPLESPERSEC & fdwSuggest)
{
if (pwfxSrc->nSamplesPerSec != pwfxDst->nSamplesPerSec)
return (ACMERR_NOTPOSSIBLE);
}
else
{
pwfxDst->nSamplesPerSec = pwfxSrc->nSamplesPerSec;
}
//
// if the destination bits per sample is restricted, verify
// that it is within our capabilities...
//
// this driver is only able to encode to 8 bit
//
if (ACM_FORMATSUGGESTF_WBITSPERSAMPLE & fdwSuggest)
{
if (G711_BITS_PER_SAMPLE != pwfxDst->wBitsPerSample)
return (ACMERR_NOTPOSSIBLE);
}
else
{
pwfxDst->wBitsPerSample = G711_BITS_PER_SAMPLE;
}
//
// at this point, we have filled in all fields except the
// following for our 'suggested' destination format:
//
// nAvgBytesPerSec
// nBlockAlign
// cbSize
//
pwfxDst->nBlockAlign = G711_BLOCKALIGNMENT(pwfxDst);
pwfxDst->nAvgBytesPerSec = G711_AVGBYTESPERSEC(pwfxDst);
pwfxDst->cbSize = G711_WFX_EXTRA_BYTES;
return (MMSYSERR_NOERROR);
case WAVE_FORMAT_ALAW:
case WAVE_FORMAT_MULAW:
//
// strictly verify that the source format is acceptable for
// this driver
//
if (!g711IsValidFormat(pwfxSrc))
return (ACMERR_NOTPOSSIBLE);
//
// if the destination format tag is restricted, verify that
// it is within our capabilities...
//
// this driver is able to decode to PCM from u-Law and A-Law
// as well as convert between u-Law and A-Law
//
if (ACM_FORMATSUGGESTF_WFORMATTAG & fdwSuggest)
{
switch (pwfxDst->wFormatTag)
{
case WAVE_FORMAT_PCM:
break;
case WAVE_FORMAT_ALAW:
if (WAVE_FORMAT_MULAW != pwfxSrc->wFormatTag)
return (ACMERR_NOTPOSSIBLE);
break;
case WAVE_FORMAT_MULAW:
if (WAVE_FORMAT_ALAW != pwfxSrc->wFormatTag)
return (ACMERR_NOTPOSSIBLE);
break;
default:
return (ACMERR_NOTPOSSIBLE);
}
if (WAVE_FORMAT_PCM == pwfxDst->wFormatTag)
{
//
// if the destination bits per sample is restricted,
// verify that it is within our capabilities...
//
// this driver is only able to decode to 16 bit
//
if (ACM_FORMATSUGGESTF_WBITSPERSAMPLE & fdwSuggest)
{
if (16 != pwfxDst->wBitsPerSample)
return (ACMERR_NOTPOSSIBLE);
}
else
{
pwfxDst->wBitsPerSample = 16;
}
}
else
{
//
// if the destination bits per sample is restricted,
// verify that it is within our capabilities...
//
// this driver is only able to convert between u-Law and
// A-Law at the same bit depth (8 bit)
//
if (ACM_FORMATSUGGESTF_WBITSPERSAMPLE & fdwSuggest)
{
if (G711_BITS_PER_SAMPLE != pwfxDst->wBitsPerSample)
return (ACMERR_NOTPOSSIBLE);
}
else
{
pwfxDst->wBitsPerSample = G711_BITS_PER_SAMPLE;
}
}
}
else
{
if (ACM_FORMATSUGGESTF_WBITSPERSAMPLE & fdwSuggest)
{
if (16 == pwfxDst->wBitsPerSample)
{
pwfxDst->wFormatTag = WAVE_FORMAT_PCM;
}
else if (8 == pwfxDst->wBitsPerSample)
{
if (WAVE_FORMAT_ALAW == pwfxSrc->wFormatTag)
{
pwfxDst->wFormatTag = WAVE_FORMAT_MULAW;
}
else if (WAVE_FORMAT_MULAW == pwfxSrc->wFormatTag)
{
pwfxDst->wFormatTag = WAVE_FORMAT_ALAW;
}
else
{
return (ACMERR_NOTPOSSIBLE);
}
}
else
{
return (ACMERR_NOTPOSSIBLE);
}
}
else
{
pwfxDst->wFormatTag = WAVE_FORMAT_PCM;
pwfxDst->wBitsPerSample = 16;
}
}
//
// if the destination channel count is restricted, verify that
// it is within our capabilities...
//
// this driver is not able to change the number of channels
//
if (ACM_FORMATSUGGESTF_NCHANNELS & fdwSuggest)
{
if (pwfxSrc->nChannels != pwfxDst->nChannels)
return (ACMERR_NOTPOSSIBLE);
}
else
{
pwfxDst->nChannels = pwfxSrc->nChannels;
}
//
// if the destination samples per second is restricted, verify
// that it is within our capabilities...
//
// this driver is not able to change the sample rate
//
if (ACM_FORMATSUGGESTF_NSAMPLESPERSEC & fdwSuggest)
{
if (pwfxSrc->nSamplesPerSec != pwfxDst->nSamplesPerSec)
return (ACMERR_NOTPOSSIBLE);
}
else
{
pwfxDst->nSamplesPerSec = pwfxSrc->nSamplesPerSec;
}
//
//
//
//
if (WAVE_FORMAT_PCM == pwfxDst->wFormatTag)
{
//
// at this point, we have filled in all fields except the
// following for our 'suggested' destination format:
//
// nAvgBytesPerSec
// nBlockAlign
// cbSize !!! not used for PCM !!!
//
pwfxDst->nBlockAlign = PCM_BLOCKALIGNMENT((LPPCMWAVEFORMAT)pwfxDst);
pwfxDst->nAvgBytesPerSec = PCM_AVGBYTESPERSEC((LPPCMWAVEFORMAT)pwfxDst);
// pwfxDst->cbSize = not used;
}
//
// the suggested destination format tag is not PCM
//
else
{
//
// at this point, we have filled in all fields except the
// following for our 'suggested' destination format:
//
// nAvgBytesPerSec
// nBlockAlign
// cbSize
//
pwfxDst->nBlockAlign = G711_BLOCKALIGNMENT(pwfxDst);
pwfxDst->nAvgBytesPerSec = G711_AVGBYTESPERSEC(pwfxDst);
pwfxDst->cbSize = G711_WFX_EXTRA_BYTES;
}
return (MMSYSERR_NOERROR);
}
//
// can't suggest anything because either the source format is foreign
// or the destination format has restrictions that this ACM driver
// cannot deal with.
//
return (ACMERR_NOTPOSSIBLE);
} // acmdFormatSuggest()
//==========================================================================;
//
//
//
//
//==========================================================================;
//--------------------------------------------------------------------------;
//
// LRESULT acmdFormatTagDetails
//
// Description:
// This function handles the ACMDM_FORMATTAG_DETAILS message. This
// message is normally sent in response to an acmFormatTagDetails or
// acmFormatTagEnum function call. The purpose of this function is
// to get details about a specific format tag supported by this ACM
// driver.
//
// Arguments:
// PDRIVERINSTANCE pdi: Pointer to private ACM driver instance structure.
// This structure is [optionally] allocated during the DRV_OPEN message
// which is handled by the acmdDriverOpen function.
//
// LPACMFORMATTAGDETAILS padft: Pointer to an ACMFORMATTAGDETAILS
// structure that describes what format tag to retrieve details for.
//
// DWORD fdwDetails: Flags defining what format tag to retrieve the
// details for.
//
// Return (LRESULT):
// The return value is zero (MMSYSERR_NOERROR) if this function
// succeeds with no errors. The return value is a non-zero error code
// if the function fails.
//
// The driver should return MMSYSERR_NOTSUPPORTED if the query type
// specified in fdwDetails is not supported. An ACM driver must
// support at least the following query types:
//
// ACM_FORMATTAGDETAILSF_INDEX: Indicates that a format tag index
// was given in the dwFormatTagIndex member of the ACMFORMATTAGDETAILS
// structure. The format tag and details must be returned in the
// structure specified by padft. The index ranges from zero to one less
// than the cFormatTags member returned in the ACMDRIVERDETAILS
// structure for this driver.
//
// ACM_FORMATTAGDETAILSF_FORMATTAG: Indicates that a format tag
// was given in the dwFormatTag member of the ACMFORMATTAGDETAILS
// structure. The format tag details must be returned in the structure
// specified by padft.
//
// ACM_FORMATTAGDETAILSF_LARGESTSIZE: Indicates that the details
// on the format tag with the largest format size in bytes must be
// returned. The dwFormatTag member will either be WAVE_FORMAT_UNKNOWN
// or the format tag to find the largest size for.
//
// If the details for the specified format tag cannot be retrieved
// from this driver, then ACMERR_NOTPOSSIBLE should be returned.
//
//--------------------------------------------------------------------------;
LRESULT FNLOCAL acmdFormatTagDetails
(
PDRIVERINSTANCE pdi,
LPACMFORMATTAGDETAILS padft,
DWORD fdwDetails
)
{
UINT uFormatTag;
//
//
//
//
//
switch (ACM_FORMATTAGDETAILSF_QUERYMASK & fdwDetails)
{
case ACM_FORMATTAGDETAILSF_INDEX:
//
// if the index is too large, then they are asking for a
// non-existant format. return error.
//
if (ACM_DRIVER_MAX_FORMAT_TAGS <= padft->dwFormatTagIndex)
return (ACMERR_NOTPOSSIBLE);
uFormatTag = gauFormatTagIndexToTag[(UINT)padft->dwFormatTagIndex];
break;
case ACM_FORMATTAGDETAILSF_LARGESTSIZE:
switch (padft->dwFormatTag)
{
case WAVE_FORMAT_UNKNOWN:
case WAVE_FORMAT_ALAW:
uFormatTag = WAVE_FORMAT_ALAW;
break;
case WAVE_FORMAT_MULAW:
uFormatTag = WAVE_FORMAT_MULAW;
break;
case WAVE_FORMAT_PCM:
uFormatTag = WAVE_FORMAT_PCM;
break;
default:
return (ACMERR_NOTPOSSIBLE);
}
break;
case ACM_FORMATTAGDETAILSF_FORMATTAG:
switch (padft->dwFormatTag)
{
case WAVE_FORMAT_ALAW:
uFormatTag = WAVE_FORMAT_ALAW;
break;
case WAVE_FORMAT_MULAW:
uFormatTag = WAVE_FORMAT_MULAW;
break;
case WAVE_FORMAT_PCM:
uFormatTag = WAVE_FORMAT_PCM;
break;
default:
return (ACMERR_NOTPOSSIBLE);
}
break;
//
// if this ACM driver does not understand a query type, then
// return 'not supported'
//
default:
return (MMSYSERR_NOTSUPPORTED);
}
//
//
//
//
switch (uFormatTag)
{
case WAVE_FORMAT_PCM:
padft->dwFormatTagIndex = 0;
padft->dwFormatTag = WAVE_FORMAT_PCM;
padft->cbFormatSize = sizeof(PCMWAVEFORMAT);
padft->fdwSupport = ACMDRIVERDETAILS_SUPPORTF_CODEC;
padft->cStandardFormats = ACM_DRIVER_MAX_FORMATS_PCM;
//
// the ACM is responsible for the PCM format tag name
//
padft->szFormatTag[0] = '\0';
break;
case WAVE_FORMAT_ALAW:
padft->dwFormatTagIndex = 1;
padft->dwFormatTag = WAVE_FORMAT_ALAW;
padft->cbFormatSize = sizeof(WAVEFORMATEX) +
G711_WFX_EXTRA_BYTES;
padft->fdwSupport = ACMDRIVERDETAILS_SUPPORTF_CODEC;
padft->cStandardFormats = ACM_DRIVER_MAX_FORMATS_G711;
LoadStringCodec(pdi->hinst,
IDS_ACM_DRIVER_TAG_NAME_ALAW,
padft->szFormatTag,
SIZEOFACMSTR(padft->szFormatTag));
break;
case WAVE_FORMAT_MULAW:
padft->dwFormatTagIndex = 2;
padft->dwFormatTag = WAVE_FORMAT_MULAW;
padft->cbFormatSize = sizeof(WAVEFORMATEX) +
G711_WFX_EXTRA_BYTES;
padft->fdwSupport = ACMDRIVERDETAILS_SUPPORTF_CODEC;
padft->cStandardFormats = ACM_DRIVER_MAX_FORMATS_G711;
LoadStringCodec(pdi->hinst,
IDS_ACM_DRIVER_TAG_NAME_MULAW,
padft->szFormatTag,
SIZEOFACMSTR(padft->szFormatTag));
break;
default:
return (ACMERR_NOTPOSSIBLE);
}
//
// return only the requested info
//
// the ACM will guarantee that the ACMFORMATTAGDETAILS structure
// passed is at least large enough to hold the base information of
// the details structure
//
padft->cbStruct = min(padft->cbStruct, sizeof(*padft));
//
//
//
return (MMSYSERR_NOERROR);
} // acmdFormatTagDetails()
//--------------------------------------------------------------------------;
//
// LRESULT acmdFormatDetails
//
// Description:
// This function handles the ACMDM_FORMAT_DETAILS message. This
// message is normally sent in response to an acmFormatDetails or
// acmFormatEnum function call. The purpose of this function is
// to get details about a specific format for a specified format tag
// supported by this ACM driver.
//
// Note that an ACM driver can return a zero length string for the
// format name if it wishes to have the ACM create a format string
// for it. This is strongly recommended to simplify internationalizing
// the driver--the ACM will automatically take care of that. The
// following formula is used to format a string by the ACM:
//
// <nSamplesPerSec> kHz, <bit depth> bit, [Mono | Stereo | nChannels]
//
// <bit depth> = <nAvgBytesPerSec> * 8 / nSamplesPerSec / nChannels;
//
// Arguments:
// PDRIVERINSTANCE pdi: Pointer to private ACM driver instance structure.
// This structure is [optionally] allocated during the DRV_OPEN message
// which is handled by the acmdDriverOpen function.
//
// LPACMFORMATDETAILS padf: Pointer to an ACMFORMATDETAILS structure
// that describes what format (for a specified format tag) to retrieve
// details for.
//
// DWORD fdwDetails: Flags defining what format for a specified format
// tag to retrieve the details for.
//
// Return (LRESULT):
// The return value is zero (MMSYSERR_NOERROR) if this function
// succeeds with no errors. The return value is a non-zero error code
// if the function fails.
//
// The driver should return MMSYSERR_NOTSUPPORTED if the query type
// specified in fdwDetails is not supported. An ACM driver must
// support at least the following query types:
//
// ACM_FORMATDETAILSF_INDEX: Indicates that a format index for the
// format tag was given in the dwFormatIndex member of the
// ACMFORMATDETAILS structure. The format details must be returned in
// the structure specified by padf. The index ranges from zero to one
// less than the cStandardFormats member returned in the
// ACMFORMATTAGDETAILS structure for a format tag.
//
// ACM_FORMATDETAILSF_FORMAT: Indicates that a WAVEFORMATEX structure
// pointed to by pwfx of the ACMFORMATDETAILS structure was given and
// the remaining details should be returned. The dwFormatTag member
// of the ACMFORMATDETAILS will be initialized to the same format
// tag as the pwfx member specifies. This query type may be used to
// get a string description of an arbitrary format structure.
//
// If the details for the specified format cannot be retrieved
// from this driver, then ACMERR_NOTPOSSIBLE should be returned.
//
//--------------------------------------------------------------------------;
LRESULT FNLOCAL acmdFormatDetails
(
PDRIVERINSTANCE pdi,
LPACMFORMATDETAILS padf,
DWORD fdwDetails
)
{
LPWAVEFORMATEX pwfx;
UINT uFormatIndex;
UINT u;
//
//
//
//
//
switch (ACM_FORMATDETAILSF_QUERYMASK & fdwDetails)
{
//
// enumerate by index
//
// verify that the format tag is something we know about and
// return the details on the 'standard format' supported by
// this driver at the specified index...
//
case ACM_FORMATDETAILSF_INDEX:
//
// put some stuff in more accessible variables--note that we
// bring variable sizes down to a reasonable size for 16 bit
// code...
//
pwfx = padf->pwfx;
uFormatIndex = (UINT)padf->dwFormatIndex;
switch (padf->dwFormatTag)
{
case WAVE_FORMAT_PCM:
if (ACM_DRIVER_MAX_FORMATS_PCM <= padf->dwFormatIndex)
return (ACMERR_NOTPOSSIBLE);
//
// now fill in the format structure
//
pwfx->wFormatTag = WAVE_FORMAT_PCM;
u = uFormatIndex / (ACM_DRIVER_MAX_BITSPERSAMPLE_PCM * ACM_DRIVER_MAX_CHANNELS);
pwfx->nSamplesPerSec = gauFormatIndexToSampleRate[u];
u = uFormatIndex % ACM_DRIVER_MAX_CHANNELS;
pwfx->nChannels = u + 1;
pwfx->wBitsPerSample = 16;
pwfx->nBlockAlign = PCM_BLOCKALIGNMENT((LPPCMWAVEFORMAT)pwfx);
pwfx->nAvgBytesPerSec = PCM_AVGBYTESPERSEC((LPPCMWAVEFORMAT)pwfx);
//
// note that the cbSize field is NOT valid for PCM
// formats
//
// pwfx->cbSize = 0;
break;
case WAVE_FORMAT_MULAW:
case WAVE_FORMAT_ALAW:
if (ACM_DRIVER_MAX_FORMATS_G711 <= padf->dwFormatIndex)
return (ACMERR_NOTPOSSIBLE);
pwfx->wFormatTag = LOWORD(padf->dwFormatTag);
u = uFormatIndex / (ACM_DRIVER_MAX_BITSPERSAMPLE_G711 * ACM_DRIVER_MAX_CHANNELS);
pwfx->nSamplesPerSec = gauFormatIndexToSampleRate[u];
u = uFormatIndex % ACM_DRIVER_MAX_CHANNELS;
pwfx->nChannels = u + 1;
pwfx->wBitsPerSample = G711_BITS_PER_SAMPLE;
pwfx->nBlockAlign = G711_BLOCKALIGNMENT(pwfx);
pwfx->nAvgBytesPerSec = G711_AVGBYTESPERSEC(pwfx);
pwfx->cbSize = G711_WFX_EXTRA_BYTES;
break;
default:
return (ACMERR_NOTPOSSIBLE);
}
//
// return details on specified format
//
// the caller normally uses this to verify that the format is
// supported and to retrieve a string description...
//
case ACM_FORMATDETAILSF_FORMAT:
pwfx = padf->pwfx;
switch (pwfx->wFormatTag)
{
case WAVE_FORMAT_PCM:
if (!pcmIsValidFormat(pwfx))
return (ACMERR_NOTPOSSIBLE);
break;
case WAVE_FORMAT_ALAW:
case WAVE_FORMAT_MULAW:
if (!g711IsValidFormat(pwfx))
return (ACMERR_NOTPOSSIBLE);
break;
default:
return (ACMERR_NOTPOSSIBLE);
}
break;
default:
//
// don't know how to do the query type passed--return 'not
// supported'.
//
return (MMSYSERR_NOTSUPPORTED);
}
//
// return the size of the valid information we are returning
//
// the ACM will guarantee that the ACMFORMATDETAILS structure
// passed is at least large enough to hold the base structure
//
// note that we let the ACM create the format string for us since
// we require no special formatting (and don't want to deal with
// internationalization issues, etc). simply set the string to
// a zero length.
//
padf->cbStruct = min(padf->cbStruct, sizeof(*padf));
padf->fdwSupport = ACMDRIVERDETAILS_SUPPORTF_CODEC;
padf->szFormat[0] = '\0';
//
//
//
return (MMSYSERR_NOERROR);
} // acmdFormatDetails()
//==========================================================================;
//
//
//
//
//==========================================================================;
//--------------------------------------------------------------------------;
//
// LRESULT acmdStreamOpen
//
// Description:
// This function handles the ACMDM_STREAM_OPEN message. This message
// is sent to initiate a new conversion stream. This is usually caused
// by an application calling acmStreamOpen. If this function is
// successful, then one or more ACMDM_STREAM_CONVERT messages will be
// sent to convert individual buffers (user calls acmStreamConvert).
//
// Note that an ACM driver will not receive open requests for ASYNC
// or FILTER operations unless the ACMDRIVERDETAILS_SUPPORTF_ASYNC
// or ACMDRIVERDETAILS_SUPPORTF_FILTER flags are set in the
// ACMDRIVERDETAILS structure. There is no need for the driver to
// check for these requests unless it sets those support bits.
//
// If the ACM_STREAMOPENF_QUERY flag is set in the padsi->fdwOpen
// member, then no resources should be allocated. Just verify that
// the conversion request is possible by this driver and return the
// appropriate error (either ACMERR_NOTPOSSIBLE or MMSYSERR_NOERROR).
// The driver will NOT receive an ACMDM_STREAM_CLOSE for queries.
//
// If the ACM_STREAMOPENF_NONREALTIME bit is NOT set, then conversion
// must be done in 'real-time'. This is a tough one to describe
// exactly. If the driver may have trouble doing the conversion without
// breaking up the audio, then a configuration dialog might be used
// to allow the user to specify whether the real-time conversion
// request should be succeeded. DO NOT SUCCEED THE CALL UNLESS YOU
// ACTUALLY CAN DO REAL-TIME CONVERSIONS! There may be another driver
// installed that can--so if you succeed the call you are hindering
// the performance of the user's system! Don't be foolish.
//
// Arguments:
// PDRIVERINSTANCE pdi: Pointer to private ACM driver instance structure.
// This structure is [optionally] allocated during the DRV_OPEN message
// which is handled by the acmdDriverOpen function.
//
// LPACMDRVSTREAMINSTANCE padsi: Pointer to instance data for the
// conversion stream. This structure was allocated by the ACM and
// filled with the most common instance data needed for conversions.
// This structure will be passed back to all future stream messages
// if the open succeeds. The information in this structure will never
// change during the lifetime of the stream--so it is not necessary
// to re-verify the information referenced by this structure.
//
// Return (LRESULT):
// The return value is zero (MMSYSERR_NOERROR) if this function
// succeeds with no errors. The return value is a non-zero error code
// if the function fails.
//
// A driver should return ACMERR_NOTPOSSIBLE if the conversion cannot
// be performed due to incompatible source and destination formats.
//
// A driver should return MMSYSERR_NOTSUPPORTED if the conversion
// cannot be performed in real-time and the request does not specify
// the ACM_STREAMOPENF_NONREALTIME flag.
//
//--------------------------------------------------------------------------;
LRESULT FNLOCAL acmdStreamOpen
(
PDRIVERINSTANCE pdi,
LPACMDRVSTREAMINSTANCE padsi
)
{
LPWAVEFORMATEX pwfxSrc;
LPWAVEFORMATEX pwfxDst;
BOOL fRealTime;
STREAMCONVERTPROC fnConvert;
PSTREAMINSTANCE psi;
//
//
//
pwfxSrc = padsi->pwfxSrc;
pwfxDst = padsi->pwfxDst;
fRealTime = (0 == (padsi->fdwOpen & ACM_STREAMOPENF_NONREALTIME));
//
// the most important condition to check before doing anything else
// is that this ACM driver can actually perform the conversion we are
// being opened for. this check should fail as quickly as possible
// if the conversion is not possible by this driver.
//
// it is VERY important to fail quickly so the ACM can attempt to
// find a driver that is suitable for the conversion. also note that
// the ACM may call this driver several times with slightly different
// format specifications before giving up.
//
// this driver first verifies that the source and destination formats
// are acceptable...
//
switch (pwfxSrc->wFormatTag)
{
case WAVE_FORMAT_PCM:
if (!pcmIsValidFormat(pwfxSrc))
return (ACMERR_NOTPOSSIBLE);
if (!g711IsValidFormat(pwfxDst))
return (ACMERR_NOTPOSSIBLE);
//
//
//
if (WAVE_FORMAT_ALAW == pwfxDst->wFormatTag)
fnConvert = PcmToAlaw;
else
fnConvert = PcmToUlaw;
break;
case WAVE_FORMAT_ALAW:
case WAVE_FORMAT_MULAW:
if (!g711IsValidFormat(pwfxSrc))
return (ACMERR_NOTPOSSIBLE);
if (WAVE_FORMAT_PCM == pwfxDst->wFormatTag)
{
if (!pcmIsValidFormat(pwfxDst))
return (ACMERR_NOTPOSSIBLE);
//
//
//
if (WAVE_FORMAT_ALAW == pwfxSrc->wFormatTag)
fnConvert = AlawToPcm;
else
fnConvert = UlawToPcm;
}
else
{
if (!g711IsValidFormat(pwfxDst))
return (ACMERR_NOTPOSSIBLE);
//
// we are not a converter for equivelant format tags
//
if (pwfxSrc->wFormatTag == pwfxDst->wFormatTag)
return (ACMERR_NOTPOSSIBLE);
//
//
//
if (WAVE_FORMAT_ALAW == pwfxSrc->wFormatTag)
fnConvert = AlawToUlaw;
else
fnConvert = UlawToAlaw;
}
break;
default:
return (ACMERR_NOTPOSSIBLE);
}
//
// for this driver, we must also verify that the nChannels and
// nSamplesPerSec members are the same between the source and
// destination formats.
//
if (pwfxSrc->nChannels != pwfxDst->nChannels)
return (MMSYSERR_NOTSUPPORTED);
if (pwfxSrc->nSamplesPerSec != pwfxDst->nSamplesPerSec)
return (MMSYSERR_NOTSUPPORTED);
//
// we have determined that the conversion requested is possible by
// this driver. now check if we are just being queried for support.
// if this is just a query, then do NOT allocate any instance data
// or create tables, etc. just succeed the call.
//
if (0 != (ACM_STREAMOPENF_QUERY & padsi->fdwOpen))
{
return (MMSYSERR_NOERROR);
}
//
// we have decided that this driver can handle the conversion stream.
// so we want to do _AS MUCH WORK AS POSSIBLE_ right now to prepare
// for converting data. any resource allocation, table building, etc
// that can be dealt with at this time should be done.
//
// THIS IS VERY IMPORTANT! all ACMDM_STREAM_CONVERT messages need to
// be handled as quickly as possible.
//
// this driver allocates a small instance structure for each stream
//
//
psi = (PSTREAMINSTANCE)LocalAlloc(LPTR, sizeof(*psi));
if (NULL == psi)
{
return (MMSYSERR_NOMEM);
}
//
// fill out our instance structure
//
// this driver stores a pointer to the conversion function that will
// be used for each conversion on this stream. we also store a
// copy of the _current_ configuration of the driver instance we
// are opened on. this must not change during the life of the stream
// instance.
//
// this is also very important! if the user is able to configure how
// the driver performs conversions, the changes should only affect
// future open streams. all current open streams should behave as
// they were configured during the open.
//
psi->fnConvert = fnConvert;
psi->fdwConfig = pdi->fdwConfig;
//
// fill in our instance data--this will be passed back to all stream
// messages in the ACMDRVSTREAMINSTANCE structure. it is entirely
// up to the driver what gets stored (and maintained) in the
// fdwDriver and dwDriver members.
//
padsi->fdwDriver = 0L;
padsi->dwDriver = (DWORD)(UINT)psi;
return (MMSYSERR_NOERROR);
} // acmdStreamOpen()
//--------------------------------------------------------------------------;
//
// LRESULT acmdStreamClose
//
// Description:
// This function is called to handle the ACMDM_STREAM_CLOSE message.
// This message is sent when a conversion stream is no longer being
// used (the stream is being closed; usually by an application
// calling acmStreamClose). The ACM driver should clean up any resources
// that were allocated for the stream.
//
// Arguments:
// LPACMDRVSTREAMINSTANCE padsi: Pointer to instance data for the
// conversion stream. This structure was allocated by the ACM and
// filled with the most common instance data needed for conversions.
// The information in this structure is exactly the same as it was
// during the ACMDM_STREAM_OPEN message--so it is not necessary
// to re-verify the information referenced by this structure.
//
// Return (LRESULT):
// The return value is zero (MMSYSERR_NOERROR) if this function
// succeeds with no errors. The return value is a non-zero error code
// if the function fails.
//
// NOTE! It is _strongly_ recommended that a driver not fail to close
// a conversion stream.
//
// An asyncronous conversion stream may fail with ACMERR_BUSY if there
// are pending buffers. An application may call acmStreamReset to
// force all pending buffers to be posted.
//
//--------------------------------------------------------------------------;
LRESULT FNLOCAL acmdStreamClose
(
LPACMDRVSTREAMINSTANCE padsi
)
{
PSTREAMINSTANCE psi;
//
// the driver should clean up all privately allocated resources that
// were created for maintaining the stream instance. if no resources
// were allocated, then simply succeed.
//
// in the case of this driver, we need to free the stream instance
// structure that we allocated during acmdStreamOpen.
//
psi = (PSTREAMINSTANCE)(UINT)padsi->dwDriver;
if (NULL != psi)
{
//
// free the stream instance structure
//
LocalFree((HLOCAL)psi);
}
return (MMSYSERR_NOERROR);
} // acmdStreamClose()
//--------------------------------------------------------------------------;
//
// LRESULT acmdStreamSize
//
// Description:
// This function handles the ACMDM_STREAM_SIZE message. The purpose
// of this function is to provide the _largest size in bytes_ that
// the source or destination buffer needs to be given the input and
// output formats and the size in bytes of the source or destination
// data buffer.
//
// In other words: how big does my destination buffer need to be to
// hold the converted data? (ACM_STREAMSIZEF_SOURCE)
//
// Or: how big can my source buffer be given the destination buffer?
// (ACM_STREAMSIZEF_DESTINATION)
//
// Arguments:
// LPACMDRVSTREAMINSTANCE padsi: Pointer to instance data for the
// conversion stream. This structure was allocated by the ACM and
// filled with the most common instance data needed for conversions.
// The information in this structure is exactly the same as it was
// during the ACMDM_STREAM_OPEN message--so it is not necessary
// to re-verify the information referenced by this structure.
//
// LPACMDRVSTREAMSIZE padss: Specifies a pointer to the ACMDRVSTREAMSIZE
// structure that defines the conversion stream size query attributes.
//
// Return (LRESULT):
// The return value is zero (MMSYSERR_NOERROR) if this function
// succeeds with no errors. The return value is a non-zero error code
// if the function fails.
//
// An ACM driver should return MMSYSERR_NOTSUPPORTED if a query type
// is requested that the driver does not understand. Note that a driver
// must support both the ACM_STREAMSIZEF_DESTINATION and
// ACM_STREAMSIZEF_SOURCE queries.
//
// If the conversion would be 'out of range' given the input arguments,
// then ACMERR_NOTPOSSIBLE should be returned.
//
//--------------------------------------------------------------------------;
LRESULT FNLOCAL acmdStreamSize
(
LPACMDRVSTREAMINSTANCE padsi,
LPACMDRVSTREAMSIZE padss
)
{
PSTREAMINSTANCE psi;
LPWAVEFORMATEX pwfxSrc;
LPWAVEFORMATEX pwfxDst;
DWORD cb;
pwfxSrc = padsi->pwfxSrc;
pwfxDst = padsi->pwfxDst;
psi = (PSTREAMINSTANCE)(UINT)padsi->dwDriver;
//
//
//
//
//
switch (ACM_STREAMSIZEF_QUERYMASK & padss->fdwSize)
{
//
// how many destination bytes are needed to hold the source data
// of padss->cbSrcLength bytes
//
// always round UP (since G711 can be computed exactly, don't
// round. it is simply a 2:1 compression ratio--and we drop partial
// samples)
//
case ACM_STREAMSIZEF_SOURCE:
cb = padss->cbSrcLength;
switch (pwfxSrc->wFormatTag)
{
case WAVE_FORMAT_PCM:
cb = PCM_BYTESTOSAMPLES((LPPCMWAVEFORMAT)pwfxSrc, cb);
cb = PCM_SAMPLESTOBYTES((LPPCMWAVEFORMAT)pwfxSrc, cb);
if (0 == cb)
{
return (ACMERR_NOTPOSSIBLE);
}
cb = (cb / 2);
break;
case WAVE_FORMAT_ALAW:
case WAVE_FORMAT_MULAW:
cb = G711_BYTESTOSAMPLES(pwfxSrc, cb);
cb = G711_SAMPLESTOBYTES(pwfxSrc, cb);
if (0 == cb)
{
return (ACMERR_NOTPOSSIBLE);
}
if (WAVE_FORMAT_PCM == pwfxDst->wFormatTag)
{
// Make sure we won't overflow padss->cbDstLength
if ((0xFFFFFFFFL / 2) < cb)
{
return (ACMERR_NOTPOSSIBLE);
}
cb = (cb * 2);
}
break;
}
padss->cbDstLength = cb;
return (MMSYSERR_NOERROR);
//
// how many source bytes can be encoded into a
// destination buffer of padss->cbDstLength bytes
//
// always round DOWN (drop partial samples)
//
case ACM_STREAMSIZEF_DESTINATION:
cb = padss->cbDstLength;
switch (pwfxDst->wFormatTag)
{
case WAVE_FORMAT_PCM:
cb = PCM_BYTESTOSAMPLES((LPPCMWAVEFORMAT)pwfxDst, cb);
cb = PCM_SAMPLESTOBYTES((LPPCMWAVEFORMAT)pwfxDst, cb);
cb = (cb / 2);
if (0 == cb)
{
return (ACMERR_NOTPOSSIBLE);
}
break;
case WAVE_FORMAT_ALAW:
case WAVE_FORMAT_MULAW:
cb = G711_BYTESTOSAMPLES(pwfxDst, cb);
cb = G711_SAMPLESTOBYTES(pwfxDst, cb);
if (0 == cb)
{
return (ACMERR_NOTPOSSIBLE);
}
if (WAVE_FORMAT_PCM == pwfxSrc->wFormatTag)
{
// Make sure we won't overflow padss->cbDstLength
if ((0xFFFFFFFFL / 2) < cb)
{
return (ACMERR_NOTPOSSIBLE);
}
cb = (cb * 2);
}
break;
}
padss->cbSrcLength = cb;
return (MMSYSERR_NOERROR);
}
//
// if the query type is not understood by this driver, then we need
// to return MMSYSERR_NOTSUPPORTED.
//
return (MMSYSERR_NOTSUPPORTED);
} // acmdStreamSize()
//==========================================================================;
//
//
//
//
//==========================================================================;
//--------------------------------------------------------------------------;
//
// LRESULT DriverProc
//
// Description:
//
//
// Arguments:
// DWORD dwId: For most messages, dwId is the DWORD value that
// the driver returns in response to a DRV_OPEN message. Each time
// the driver is opened, through the OpenDriver API, the driver
// receives a DRV_OPEN message and can return an arbitrary, non-zero
// value. The installable driver interface saves this value and returns
// a unique driver handle to the application. Whenever the application
// sends a message to the driver using the driver handle, the interface
// routes the message to this entry point and passes the corresponding
// dwId. This mechanism allows the driver to use the same or different
// identifiers for multiple opens but ensures that driver handles are
// unique at the application interface layer.
//
// The following messages are not related to a particular open instance
// of the driver. For these messages, the dwId will always be zero.
//
// DRV_LOAD, DRV_FREE, DRV_ENABLE, DRV_DISABLE, DRV_OPEN
//
// HDRVR hdrvr: This is the handle returned to the application
// by the driver interface.
//
// UINT uMsg: The requested action to be performed. Message
// values below DRV_RESERVED are used for globally defined messages.
// Message values from DRV_RESERVED to DRV_USER are used for defined
// driver protocols. Messages above DRV_USER are used for driver
// specific messages.
//
// LPARAM lParam1: Data for this message. Defined separately for
// each message.
//
// LPARAM lParam2: Data for this message. Defined separately for
// each message.
//
// Return (LRESULT):
// Defined separately for each message.
//
//--------------------------------------------------------------------------;
EXTERN_C LRESULT FNEXPORT DriverProc
(
DWORD dwId,
HDRVR hdrvr,
UINT uMsg,
LPARAM lParam1,
LPARAM lParam2
)
{
LRESULT lr;
PDRIVERINSTANCE pdi;
//
// make pdi either NULL or a valid instance pointer. note that dwId
// is 0 for several of the DRV_* messages (ie DRV_LOAD, DRV_OPEN...)
// see acmdDriverOpen for information on what dwId is for other
// messages (instance data).
//
pdi = (PDRIVERINSTANCE)(UINT)dwId;
switch (uMsg)
{
//
// lParam1: Unused.
//
// lParam2: Unused.
//
case DRV_LOAD:
#ifdef _WIN32
DbgInitialize(TRUE);
#endif
return(1L);
//
// lParam1: Unused.
//
// lParam2: Unused.
//
case DRV_FREE:
return (1L);
//
// lParam1: Not used. Ignore this argument.
//
// lParam2: Pointer to ACMDRVOPENDESC (or NULL).
//
case DRV_OPEN:
lr = acmdDriverOpen(hdrvr, (LPACMDRVOPENDESC)lParam2);
return (lr);
//
// lParam1: Unused.
//
// lParam2: Unused.
//
case DRV_CLOSE:
lr = acmdDriverClose(pdi);
return (lr);
//
// lParam1: Unused.
//
// lParam2: Unused.
//
case DRV_INSTALL:
return ((LRESULT)DRVCNF_RESTART);
//
// lParam1: Unused.
//
// lParam2: Unused.
//
case DRV_REMOVE:
return ((LRESULT)DRVCNF_RESTART);
//
// lParam1: Not used.
//
// lParam2: Not used.
//
case DRV_QUERYCONFIGURE:
//
// set up lParam1 and lParam2 to values that can be used by
// acmdDriverConfigure to know that it is being 'queried'
// for configuration support.
//
lParam1 = -1L;
lParam2 = 0L;
//--fall through--//
//
// lParam1: Handle to parent window for the configuration dialog
// box.
//
// lParam2: Optional pointer to DRVCONFIGINFO structure.
//
case DRV_CONFIGURE:
lr = acmdDriverConfigure(pdi, (HWND)lParam1, (LPDRVCONFIGINFO)lParam2);
return (lr);
//
// lParam1: Pointer to ACMDRIVERDETAILS structure.
//
// lParam2: Size in bytes of ACMDRIVERDETAILS stucture passed.
//
case ACMDM_DRIVER_DETAILS:
lr = acmdDriverDetails(pdi, (LPACMDRIVERDETAILS)lParam1);
return (lr);
//
// lParam1: Handle to parent window to use if displaying your own
// about box.
//
// lParam2: Not used.
//
case ACMDM_DRIVER_ABOUT:
lr = acmdDriverAbout(pdi, (HWND)lParam1);
return (lr);
//--------------------------------------------------------------------------;
//--------------------------------------------------------------------------;
//
// lParam1: Pointer to ACMDRVFORMATSUGGEST structure.
//
// lParam2: Not used.
//
case ACMDM_FORMAT_SUGGEST:
lr = acmdFormatSuggest(pdi, (LPACMDRVFORMATSUGGEST)lParam1);
return (lr);
//
// lParam1: Pointer to FORMATTAGDETAILS structure.
//
// lParam2: fdwDetails
//
case ACMDM_FORMATTAG_DETAILS:
lr = acmdFormatTagDetails(pdi, (LPACMFORMATTAGDETAILS)lParam1, lParam2);
return (lr);
//
// lParam1: Pointer to FORMATDETAILS structure.
//
// lParam2: fdwDetails
//
case ACMDM_FORMAT_DETAILS:
lr = acmdFormatDetails(pdi, (LPACMFORMATDETAILS)lParam1, lParam2);
return (lr);
//--------------------------------------------------------------------------;
//--------------------------------------------------------------------------;
//
// lParam1: Pointer to ACMDRVSTREAMINSTANCE structure.
//
// lParam2: Not used.
//
case ACMDM_STREAM_OPEN:
lr = acmdStreamOpen(pdi, (LPACMDRVSTREAMINSTANCE)lParam1);
return (lr);
//
// lParam1: Pointer to ACMDRVSTREAMINSTANCE structure.
//
// lParam2: Not Used.
//
case ACMDM_STREAM_CLOSE:
lr = acmdStreamClose((LPACMDRVSTREAMINSTANCE)lParam1);
return (lr);
//
// lParam1: Pointer to ACMDRVSTREAMINSTANCE structure.
//
// lParam2: Pointer to ACMDRVSTREAMSIZE structure.
//
case ACMDM_STREAM_SIZE:
lr = acmdStreamSize((LPACMDRVSTREAMINSTANCE)lParam1, (LPACMDRVSTREAMSIZE)lParam2);
return (lr);
//
// lParam1: Pointer to ACMDRVSTREAMINSTANCE structure.
//
// lParam2: Pointer to ACMDRVSTREAMHEADER structure.
//
case ACMDM_STREAM_CONVERT:
{
PSTREAMINSTANCE psi;
LPACMDRVSTREAMINSTANCE padsi;
LPACMDRVSTREAMHEADER padsh;
//
// our stream instance data is a pointer to the conversion
// procedure needed to convert the pwfxSrc data to pwfxDst.
// the correct procedure to use was decided in acmdStreamOpen
//
padsi = (LPACMDRVSTREAMINSTANCE)lParam1;
padsh = (LPACMDRVSTREAMHEADER)lParam2;
psi = (PSTREAMINSTANCE)(UINT)padsi->dwDriver;
lr = psi->fnConvert(padsi, padsh);
return (lr);
}
}
//
// if we are executing the following code, then this ACM driver does not
// handle the message that was sent. there are two ranges of messages
// we need to deal with:
//
// o ACM specific driver messages: if an ACM driver does not answer a
// message sent in the ACM driver message range, then it must
// return MMSYSERR_NOTSUPPORTED. this applies to the 'user'
// range as well (for consistency).
//
// o other installable driver messages: if an ACM driver does not
// answer a message that is NOT in the ACM driver message range,
// then it must call DefDriverProc and return that result.
// the exception to this is ACM driver procedures installed as
// ACM_DRIVERADDF_FUNCTION through acmDriverAdd. in this case,
// the driver procedure should conform to the ACMDRIVERPROC
// prototype and also return zero instead of calling DefDriverProc.
//
if (uMsg >= ACMDM_USER)
return (MMSYSERR_NOTSUPPORTED);
else
return (DefDriverProc(dwId, hdrvr, uMsg, lParam1, lParam2));
} // DriverProc()
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