MpodAlsa Class Reference

Container for device specific input ALSA driver. More...

#include <MpodAlsa.h>

Inheritance diagram for MpodAlsa:

Collaboration diagram for MpodAlsa:

Public Member Functions
Creators
	MpodAlsa (const UtlString &name)
	Default constructor. More...
virtual	~MpodAlsa ()
	Destructor. More...
Manipulators
OsStatus	enableDevice (unsigned samplesPerFrame, unsigned samplesPerSec, MpFrameTime currentFrameTime, OsCallback &frameTicker)
	Initialize device driver and state. More...
OsStatus	disableDevice ()
	Uninitialize device driver. More...
OsStatus	pushFrame (unsigned int numSamples, const MpAudioSample *samples, MpFrameTime frameTime)
	Send data to output device. More...
OsStatus	setNotificationMode (UtlBoolean bThreadNotification)
Inquiry
Returns the number of output devices found
virtual OsStatus	canEnable ()
	Check if this device can connect. More...
UtlBoolean	isDeviceValid ()
	Inquire if the ALSA device is valid. More...
Public Member Functions inherited from MpOutputDeviceDriver
	MpOutputDeviceDriver (const UtlString &name)
	Default constructor. More...
virtual	~MpOutputDeviceDriver ()
	Destructor. More...
MpFrameTime	getFramePeriod () const
	Calculate the number of milliseconds that a frame occupies in time. More...
unsigned	getSamplesPerFrame () const
	Get number of samples in a frame. More...
unsigned	getSamplesPerSec () const
	Get number of samples per second. More...
const UtlString &	getDeviceName () const
	Get device name. More...
virtual UtlBoolean	isEnabled () const
	Inquire if this driver is enabled. More...

Static Public Member Functions
Accessors
static const char *	getDefaultDeviceName ()
	Get the name of the default output ALSA PCM audio device. More...
static int	getDeviceNames (UtlContainer &devicesNames)
	Get the list of names of the available output ALSA PCM audio device(s) More...
Static Public Member Functions inherited from MpOutputDeviceDriver
static MpFrameTime	getFramePeriod (unsigned samplesPerFrame, unsigned samplesPerSec)
	Calculate the number of milliseconds that a frame occupies in time. More...

Protected Member Functions
OsStatus	signalForNextFrame ()
	Signaling for next frame if notificator used do nothing otherwise. More...
void	skipFrame ()
	Adding frame time to mCurrentFrameTime. More...

Protected Attributes
MpAudioSample *	mAudioFrame
	Wave buffer. More...
MpFrameTime	mCurrentFrameTime
	The current frame time for this device. More...
UtlBoolean	mNotificationThreadEn
MpAlsaContainer *	mpCont
	Pointer to Wrapper container. More...
Protected Attributes inherited from MpOutputDeviceDriver
OsAtomicLightBool	mIsEnabled
	Whether this device driver is enabled or not. More...
OsAtomicLightUInt	mSamplesPerFrame
	number of samples. More...
OsAtomicLightUInt	mSamplesPerSec
	of samples per second. More...
OsCallback *	mpTickerNotification
	is ready to accept more data. See enableDevice() for details. More...

Private Member Functions
	MpodAlsa (const MpodAlsa &rMpOutputDeviceDriver)
	Copy constructor (not implemented for this class) More...
MpodAlsa &	operator= (const MpodAlsa &rhs)
	Assignment operator (not implemented for this class) More...

Private Attributes
MpAlsa *	pDevWrapper
int	mNullTickers

Static Private Attributes
static char	spDefaultDeviceName [MAX_DEVICE_NAME_SIZE]

Friends
class	MpAlsa

Detailed Description

Container for device specific input ALSA driver.

Constructor & Destructor Documentation

MpodAlsa

(

const UtlString &

name

)

Default constructor.

Parameters

name	- (in) unique device driver name (e.g. "/dev/dsp", "YAMAHA AC-XG WDM Audio", etc.).
nInputBuffers	- (in) Maximum number of frames in internal buffer.

~MpodAlsa ( )

virtual

Destructor.

MpodAlsa ( const MpodAlsa &  rMpOutputDeviceDriver )

private

Copy constructor (not implemented for this class)

Member Function Documentation

OsStatus enableDevice ( unsigned  samplesPerFrame, unsigned  samplesPerSec, MpFrameTime  currentFrameTime, OsCallback &  frameTicker  )

virtual

Initialize device driver and state.

This method enables the device driver.

this SHOULD NOT be used to mute/unmute a device. Disabling and enabling a device results in state and buffer queues being cleared.

Parameters

[in]	samplesPerFrame	- the number of samples in a frame of media
[in]	samplesPerSec	- sample rate for media frame in samples per second
[in]	currentFrameTime	- time in milliseconds for beginning of frame relative to the MpOutputDeviceManager reference time
[in]	frameTicker	- notification to signal when device become ready. Device driver MUST signal this notification as soon as it become ready to receive next portion of data to play back. Note, it is a callback which in turn calls pushFrame() method of this device driver. Also notification may be used to signal begin of frame interval for one or several flowgraphs, so it should be as uniform as possible, i.e. it should not burst or hold over, driver should signal this notification after equal intervals of time.

Returns

OS_INVALID_STATE if device already enabled.

This method is supposed to be used from MpAudioOutputConnection only. If you want enable device, use MpOutputDeviceManager or MpAudioOutputConnection methods.

Implements MpOutputDeviceDriver.

OsStatus disableDevice ( )

virtual

Uninitialize device driver.

This method disables the device driver and should release any platform device resources so that the device might be used else where.

this SHOULD NOT be used to mute/unmute a device. Disabling and enabling a device results in state and buffer queues being cleared.

This method is supposed to be used from MpAudioOutputConnection only. If you want disable device, use MpOutputDeviceManager or MpAudioOutputConnection methods.

Implements MpOutputDeviceDriver.

OsStatus pushFrame ( unsigned int  numSamples, const MpAudioSample *  samples, MpFrameTime  frameTime  )

virtual

Send data to output device.

This method is called from a callback which is called when we fire ticker notification. See enableDevice() for details.

Parameters

[in]	numSamples	- Number of samples in samples array.
[in]	samples	- Array of samples to push to device.
[in]	frameTime	- Time of pushed frame. Device may consider does it want it or not internally. If frame come too late driver should return OS_SUCCESS and throw out it silently. Common problem is when MediaTask queue is jammed - no frames are processed for some time and then they are processed bursty. Using given frameTime driver may keep its internal queue short. It is guaranteed that frame time would increase monotonically.

Returns

OS_LIMIT_REACHED if mixer buffer is full, i.e. frame come too early.

OS_FAILED for other errors.

OS_SUCCESS if frame sent correctly.

See also

enableDevice() for documentation when this is being called.

Implements MpOutputDeviceDriver.

OsStatus setNotificationMode

(

UtlBoolean

bThreadNotification

)

const char * getDefaultDeviceName ( )

static

Get the name of the default output ALSA PCM audio device.

int getDeviceNames ( UtlContainer &  devicesNames )

static

Get the list of names of the available output ALSA PCM audio device(s)

OsStatus canEnable ( )

virtual

Check if this device can connect.

Reimplemented from MpOutputDeviceDriver.

UtlBoolean isDeviceValid ( )

inline

Inquire if the ALSA device is valid.

OsStatus signalForNextFrame ( )

protected

Signaling for next frame if notificator used do nothing otherwise.

void skipFrame ( )

protected

Adding frame time to mCurrentFrameTime.

MpodAlsa& operator= ( const MpodAlsa &  rhs )

private

Assignment operator (not implemented for this class)

Friends And Related Function Documentation

friend class MpAlsa

friend

Member Data Documentation

MpAudioSample* mAudioFrame

protected

Wave buffer.

MpFrameTime mCurrentFrameTime

protected

The current frame time for this device.

UtlBoolean mNotificationThreadEn

protected

MpAlsaContainer* mpCont

protected

Pointer to Wrapper container.

MpAlsa* pDevWrapper

private

char spDefaultDeviceName

staticprivate

int mNullTickers

private