WadMme Class Reference

WaAudioDev implemention of MME audio API. More...

#include <WadMme.h>

Inheritance diagram for WadMme:

List of all members.

Public Member Functions
	WadMme ()
	Creator.
	~WadMme ()
	Destructor.
WadAPI	GetAPI ()
	return API enum
int	Init ()
	initialize the OS API and discover all devices
int	GetNumDevices (int *pNumDev)
	Get the count of devices discovered.
int	GetDevInfo (int devId, WadDevInfo *pInfo)
	Get device information.
int	GetDefaultInDevId (int *pId)
	Get the default input device.
int	GetDefaultOutDevId (int *pId)
	Get the default output device.
int	Open (WadParam *param, WadCallbackFn *inFn, WadCallbackFn *outFn, void *arg)
	Open devices for streaming.
int	Start ()
	Start streaming.
int	Stop ()
	Stop streaming.
void	Close ()
	Close devices and release memory.
void	Wait ()
	Wait for stream to complete.
int	SetVol (int devId, bool isOutput, float vol)
	Set volume.
int	GetVol (int devId, bool isOutput, float *pVol)
	Get volume.
int	GetBufTime (bool isOutput, int *pBufTimeMsec)
	Get buffer time.
bool	IsRunning ()
	Test if stream I/O thread is running.
bool	IsInOpen ()
	return T/F if device is open for input streaming
bool	IsOutOpen ()
	return T/F if device is open for output streaming
void	WaveOutProc (HWAVEOUT hwo, UINT uMsg, DWORD dwInstance, DWORD dwParam1, DWORD dwParam2)
	output callback from MME
void	WaveInProc (HWAVEIN hwi, UINT uMsg, DWORD dwInstance, DWORD dwParam1, DWORD dwParam2)
	input callback from MME
DWORD	Thread (void *arg)
	thread entry
Protected Member Functions
void	Release ()
	release memory
void	CloseInternal ()
	close
bool	Prime ()
	prime output with zeros
int	GetMmeDevId (int devId)
	get the MME device ID for given WaAudioDev ID
bool	WriteWHdr ()
	Write current WAVEHDR.
void	FreeOutWhdrItem (ITEM *item)
	Free WAVEHDR list item.
void	FreeOutBuffers ()
	Free all output buffers.
void	CloseOut ()
	Close output wave driver.
int	OpenWaveOut (int outDev, int sampRate, int numChan)
	Open wave output driver.
int	OpenOut (int outDev, int sampRate, int numChan, WadSampFmt smpFmt, int numBuf, int bufLen)
	Open output device.
bool	StartOut ()
	Start output streaming.
bool	StopOut ()
	Stop output streaming.
void	FreeInWhdrItem (ITEM *item)
	Free input WAVEHDR list item.
void	FreeInBuffers ()
	Free input buffers.
void	CloseIn ()
	Close input wave driver.
int	OpenWaveIn (int inDev, int sampRate, int numChan)
	Open input wave driver.
int	OpenIn (int inDev, int sampRate, int numChan, WadSampFmt smpFmt, int numBuf, int bufLen)
	Open input device.
bool	StartIn ()
	Start input streaming.
bool	StopIn ()
	Stop input streaming.
Static Protected Member Functions
static bool	AllocBufList (int numBuf, int bufLen, int sampBytes, LIST *list)
	Allocate a list of WAVEHDRs, using the WHDR_ITEM list item.
Protected Attributes
void *	m_OutBuf
	allocated output buffer in user sample format for callbacks
void *	m_InBuf
	allocated input buffer in user sample format for callbacks
HANDLE	m_QuitEvent
	signal when you want WadMmeThread to quit
HANDLE	m_ThreadHandle
	I/O thread handle.
WadMmeDevInfo *	m_Devs
	device table
int	m_NumDevs
	number of devices
bool	m_InIsOpen
	is input already open?
int	m_InBufLen
	input buffer length, samples
int	m_NumInBuf
	number of input buffers
LIST	m_InList
	list of input buffers with recorded data
LIST	m_InItemList
	list of all input WHDR_ITEMs not in m_InList
HWAVEIN	m_In
	handle to wave in driver
WAVEHDR *	m_InWHdr
	current WAVEHDR being read
bool	m_OutIsOpen
	is output already open?
int	m_OutBufLen
	output buffer length, samples
int	m_NumOutBuf
	number of output buffers
LIST	m_OutList
	list of output buffers waiting to be filled
LIST	m_OutItemList
	list of all output WHDR_ITEMs not in m_OutList
HWAVEOUT	m_Out
	handle to wave out driver
WAVEHDR *	m_OutWHdr
	current WAVEHDR being filled
void *	m_Arg
	argument to callback functions
WadCallbackFn *	m_InFn
	input (record) callback
WadCallbackFn *	m_OutFn
	output (play) callback
CRITICAL_SECTION	m_OutBufLock
	This lock is set whenever the output buffer queues are accessed by the main thread or the callback thread.
HANDLE	m_OutputReadyEvent
	If not signaled, output is blocked because there are no free buffers, or because things haven't initialized yet.
CRITICAL_SECTION	m_InBufLock
	This lock is set whenever the input buffer queues are accessed by the main thread or the callback thread.
HANDLE	m_InputReadyEvent
	If not signaled, input is blocked because there are no filled buffers, or because things haven't initialized yet.

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Detailed Description

WaAudioDev implemention of MME audio API.

This is based on original MME "wavio" code written in 1998. It's pretty verbose, and uses a lot of lists to keep track of used and free buffers.

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Member Function Documentation

void WadMme::Close

(

)

[virtual]

Close devices and release memory.

Close the devices and release all memory associated with streaming. Different devices can be re-opened with different parameters without having to recreate the WaAudioDev object.

Implements WaAudioDevPort.

WadAPI WadMme::GetAPI

(

)

[virtual]

return API enum

Return enum specifying the low level API in use.

Implements WaAudioDev.

int WadMme::GetBufTime	(	bool	isOutput,
		int *	pBufTimeMsec
	)		[virtual]

Get buffer time.

Parameters:

[in]	isOutput	true if get output buffer time, else get input buffer time
[out]	pBufTimeMsec	pointer to buffer time in milliseconds

Return total buffer times in msec for the currently open devices. This is useful in case we want to increase the buffering because we're getting dropouts.

Reimplemented from WaAudioDev.

int WadMme::GetDefaultInDevId

(

int *

pId

)

[virtual]

Get the default input device.

Parameters:

[out]

pId

pointer to default input device ID

Implements WaAudioDev.

int WadMme::GetDefaultOutDevId

(

int *

pId

)

[virtual]

Get the default output device.

Parameters:

[out]

pId

pointer to default output device ID

Implements WaAudioDev.

int WadMme::GetDevInfo	(	int	devId,
		WadDevInfo *	pInfo
	)		[virtual]

Get device information.

Parameters:

[in]	devId	the device ID, 0 to numDev-1
[out]	pInfo	pointer to device info

Implements WaAudioDev.

int WadMme::GetNumDevices

(

int *

pNumDev

)

[virtual]

Get the count of devices discovered.

Parameters:

[out]

pNumDev

pointer to number of devices

Implements WaAudioDev.

int WadMme::GetVol	(	int	devId,
		bool	isOutput,
		float *	pVol
	)		[virtual]

Get volume.

Parameters:

[in]	devId	device ID
[in]	isOutput	true if get output volume, else get input volume
[out]	vol	pointer to volume, 0.0 (min) to 1.0 (max)

Get volume of device. Any discovered device can be specified and the device does not need to be open for streaming.

Reimplemented from WaAudioDev.

int WadMme::Init

(

)

[virtual]

initialize the OS API and discover all devices

Initialize, which means do device discovery. The idea is that the devices are enumerated at Init time, and from then on only this device set can be used. Any dynamic changes to the device set can be caught via messages and then this WaAudioDev object must be recreated to discover the new devices updating the device table.

Implements WaAudioDev.

bool WadMme::IsRunning

(

)

[virtual]

Test if stream I/O thread is running.

Implement this to return false if the I/O thread has exited perhaps because a callback has returned false. This is a non-blocking alternative to Wait(). But why can't we just use IsOpen()? Ah, because the thread terminating doesn't automatically close the device, that's why.

Implements WaAudioDev.

int WadMme::Open	(	WadParam *	param,
		WadCallbackFn *	inFn,
		WadCallbackFn *	outFn,
		void *	arg
	)		[virtual]

Open devices for streaming.

Open devices for streaming with provided parameters. Asynchronous callbacks fetch and deliver sample buffers: inFn delivers input sample buffers and outFn fetches output sample buffers. Streaming directions are determined by valid device IDs in parameter structure, at least one direction must be enabled. Pass NULL for callback if that direction is not enabled.

Parameters:

[in]	param	Stream parameters
[in]	inFn	Input callback function, or NULL
[in]	outFn	Output callback function, or NULL
[in]	arg	Argument to callbacks

Implements WaAudioDevPort.

int WadMme::SetVol	(	int	devId,
		bool	isOutput,
		float	vol
	)		[virtual]

Set volume.

Parameters:

[in]	devId	device ID
[in]	isOutput	true if set output volume, else set input volume
[in]	vol	volume, 0.0 (min) to 1.0 (max)

Set volume of device. Any discovered device can be specified and the device does not need to be open for streaming.

Reimplemented from WaAudioDev.

int WadMme::Start

(

)

[virtual]

Start streaming.

Start streaming audio. This must be called after Open to actually start stream.

Implements WaAudioDevPort.

int WadMme::Stop

(

)

[virtual]

Stop streaming.

Stop streaming audio. Stream can be restarted by calling Start().

Implements WaAudioDevPort.

void WadMme::Wait

(

)

[virtual]

Wait for stream to complete.

Wait for streaming I/O thread to terminate. This call blocks and should only be called if the callbacks will return false status to stop streaming and terminate I/O thread.

Implements WaAudioDevPort.

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Member Data Documentation

CRITICAL_SECTION WadMme::m_InBufLock [protected]

This lock is set whenever the input buffer queues are accessed by the main thread or the callback thread.

HANDLE WadMme::m_InputReadyEvent [protected]

If not signaled, input is blocked because there are no filled buffers, or because things haven't initialized yet.

This is initially reset, reset when no filled buffers remain, and set when a filled buffer becomes available.

CRITICAL_SECTION WadMme::m_OutBufLock [protected]

This lock is set whenever the output buffer queues are accessed by the main thread or the callback thread.

HANDLE WadMme::m_OutputReadyEvent [protected]

If not signaled, output is blocked because there are no free buffers, or because things haven't initialized yet.

This is initially set, reset when free buffers run out, and set when a buffer becomes available.

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The documentation for this class was generated from the following files:

• WadMme.h
• WadMme.cpp