Alsa Interface. More...

#include <alsadevice.h>

Public Member Functions
	cAlsaDevice (cSoftHdConfig *)

bool	Init (void)
	Initialize the ALSA audio output module.

void	Exit (void)
	Cleanup the ALSA audio output module.

int	Setup (int, int, bool, int)
	Setup ALSA audio for requested format.

int	Write (const void *, int)
	Write data to the output device.

void	FlushBuffers (bool)
	Flush ALSA buffers internally.

bool	HandleError (int)
	Handle an alsa error.

void	SetVolume (int)
	Set alsa mixer volume (0-1000)

int	WaitUntilReady (void)
	Wait until data can be written or read to/from the device (Timeout is 150ms currently)

bool	CheckWrittenFrames (int, int)
	Check, if all frames have been written.

int	GetHwDelayFrames (void)
	Return the current hardware audio delay in frames.

int	GetAvailableBufferFrames (bool)
	Get the number of frames that could be written to the device.

std::vector< std::string >	GetChannelLayoutAsArray (void)
	Put ALSA channel layout in a dynamic array of strings.

int	GetBufferSizeFrames (void)

int	GetDownmix (void)

int	GetHwNumChannels (void)

int	GetHwSampleRate (void)

bool	IsRunning (void)

bool	IsPassthroughActive (void)

void	SetPassthroughMask (int mask)

int	GetPassthroughMask (void) const

void	SetAutoAES (bool appendAes)

void	SetDownmix (int downMix)

size_t	FramesToBytes (int frames)

int	BytesToFrames (size_t bytes)

int64_t	PtsToMs (int64_t pts, double timebase)

int64_t	MsToPts (int64_t ptsMs, double timebase)

int	MsToFrames (int milliseconds)

int	FramesToMs (int frames)

int64_t	FramesToPts (int frames, double timebase)

double	FramesToMsDouble (int frames)

Private Member Functions
bool	ShouldAppendAES (void)

char *	OpenDevice (const char *)
	Open an ALSA device.

char *	FindDevice (const char , const char )
	Find alsa device giving some search hints.

bool	InitDevice (void)
	Search for an alsa pcm device and open it.

void	InitMixer (void)
	Initialize the ALSA mixer.

Private Attributes
const char *	m_pPCMDevice
	Alsa PCM device name.

snd_pcm_t *	m_pPCMHandle = nullptr
	alsa pcm handle

const char *	m_pMixerDevice = nullptr
	mixer device name (not used)

const char *	m_pMixerChannel
	mixer channel name

snd_mixer_t *	m_pMixer = nullptr
	alsa mixer handle

snd_mixer_elem_t *	m_pMixerElem = nullptr
	alsa mixer element

snd_pcm_uframes_t	m_bufferSizeFrames = 0
	alsa buffer size in frames

int	m_ratio
	internal -> mixer ratio * 1000

bool	m_appendAES
	flag to automatic append AES

int	m_passthroughMask
	passthrough mask

std::atomic< bool >	m_passthroughActive = false
	set, if passthrough is active

unsigned int	m_hwSampleRate = 0
	hardware sample rate in Hz

unsigned int	m_hwNumChannels = 0
	number of hardware channels

int	m_downmix
	set stereo downmix

bool	m_useMmap
	use mmap

Detailed Description

Alsa Interface.

Definition at line 36 of file alsadevice.h.

Constructor & Destructor Documentation

◆ cAlsaDevice()

cAlsaDevice::cAlsaDevice ( cSoftHdConfig * m_pConfig )

Definition at line 39 of file alsadevice.cpp.

Member Function Documentation

◆ BytesToFrames()

int cAlsaDevice::BytesToFrames ( size_t bytes )

inline

Definition at line 68 of file alsadevice.h.

References m_pPCMHandle.

Referenced by cSoftHdAudio::Enqueue(), cSoftHdAudio::GetOutputPtsMsInternal(), cSoftHdAudio::GetUsedRingbufferMs(), cSoftHdAudio::SendAudio(), and cSoftHdAudio::SendPause().

◆ CheckWrittenFrames()

bool cAlsaDevice::CheckWrittenFrames	(	int	framesWritten,
		int	framesToWrite
	)

Check, if all frames have been written.

Return values

true,if	all frames have been written or we should try again later
false,if	not all frames have been written or an error occured

Definition at line 454 of file alsadevice.cpp.

References LOGERROR, LOGWARNING, and m_pPCMHandle.

Referenced by cSoftHdAudio::SendAudio(), and cSoftHdAudio::SendPause().

◆ Exit()

void cAlsaDevice::Exit ( void )

Cleanup the ALSA audio output module.

Definition at line 73 of file alsadevice.cpp.

References m_pMixer, m_pMixerElem, and m_pPCMHandle.

Referenced by cSoftHdAudio::Exit().

◆ FindDevice()

char * cAlsaDevice::FindDevice	(	const char *	devname,
		const char *	hint
	)

private

Find alsa device giving some search hints.

Parameters

devname	interface identification (e.g. "pcm")
hint	string to compare with device name hints

Returns: an opened alsa device name if successful, NULL otherwise NOTE: Returned string is allocated and must be freed by caller

Definition at line 141 of file alsadevice.cpp.

References LOGWARNING, and OpenDevice().

Referenced by InitDevice().

◆ FlushBuffers()

void cAlsaDevice::FlushBuffers ( bool drop )

Flush ALSA buffers internally.

Parameters

drop	force a snd_pcm_drop of the audio frames already in the kernel

Definition at line 479 of file alsadevice.cpp.

References L_SOUND, LOGDEBUG2, LOGERROR, m_passthroughActive, and m_pPCMHandle.

Referenced by cSoftHdAudio::DropAlsaBuffers(), and cSoftHdAudio::FlushAlsaBuffers().

◆ FramesToBytes()

size_t cAlsaDevice::FramesToBytes ( int frames )

inline

Definition at line 67 of file alsadevice.h.

References m_pPCMHandle.

Referenced by cSoftHdAudio::CyclicCall(), cSoftHdAudio::DropSamplesOlderThanPtsMs(), cSoftHdAudio::Enqueue(), and cSoftHdAudio::SendAudio().

◆ FramesToMs()

int cAlsaDevice::FramesToMs ( int frames )

inline

Definition at line 72 of file alsadevice.h.

References m_hwSampleRate.

Referenced by cSoftHdAudio::GetHardwareOutputDelayMs(), cSoftHdAudio::GetHardwareOutputPtsMs(), cSoftHdAudio::GetOutputPtsMsInternal(), cSoftHdAudio::GetUsedRingbufferMs(), and cSoftHdAudio::SetHwDelayBaseline().

◆ FramesToMsDouble()

double cAlsaDevice::FramesToMsDouble ( int frames )

inline

Definition at line 74 of file alsadevice.h.

References m_hwSampleRate.

Referenced by cSoftHdAudio::ClockDriftCompensation().

◆ FramesToPts()

int64_t cAlsaDevice::FramesToPts	(	int	frames,
		double	timebase
	)

inline

Definition at line 73 of file alsadevice.h.

References m_hwSampleRate, and MsToPts().

Referenced by cSoftHdAudio::Enqueue().

◆ GetAvailableBufferFrames()

int cAlsaDevice::GetAvailableBufferFrames ( bool sync )

Get the number of frames that could be written to the device.

Parameters

sync	synchronize with hardware first

Returns: number of frames, that could be written or negative error code in case of an error

Definition at line 554 of file alsadevice.cpp.

References L_SOUND, LOGDEBUG2, LOGWARNING, and m_pPCMHandle.

Referenced by cSoftHdAudio::ClockDriftCompensation(), and cSoftHdAudio::CyclicCall().

◆ GetBufferSizeFrames()

int cAlsaDevice::GetBufferSizeFrames ( void )

inline

Definition at line 55 of file alsadevice.h.

References m_bufferSizeFrames.

Referenced by cSoftHdAudio::ClockDriftCompensation().

◆ GetDownmix()

int cAlsaDevice::GetDownmix ( void )

inline

Definition at line 56 of file alsadevice.h.

References m_downmix.

Referenced by cSoftHdAudio::InitFilter(), and cSoftHdAudio::Setup().

◆ GetHwDelayFrames()

int cAlsaDevice::GetHwDelayFrames ( void )

Return the current hardware audio delay in frames.

Definition at line 516 of file alsadevice.cpp.

References m_pPCMHandle.

Referenced by cSoftHdAudio::GetHardwareOutputDelayMs(), cSoftHdAudio::GetHardwareOutputPtsMs(), and cSoftHdAudio::SetHwDelayBaseline().

◆ GetHwNumChannels()

int cAlsaDevice::GetHwNumChannels ( void )

inline

Definition at line 57 of file alsadevice.h.

References m_hwNumChannels.

Referenced by cSoftHdAudio::InitFilter(), cSoftHdAudio::Setup(), and cSoftHdAudio::SetVolume().

◆ GetHwSampleRate()

int cAlsaDevice::GetHwSampleRate ( void )

inline

Definition at line 58 of file alsadevice.h.

References m_hwSampleRate.

Referenced by cSoftHdAudio::InitFilter(), and cSoftHdAudio::Setup().

◆ GetPassthroughMask()

int cAlsaDevice::GetPassthroughMask ( void ) const

inline

Definition at line 62 of file alsadevice.h.

References m_passthroughMask.

Referenced by cSoftHdAudio::GetPassthroughMask().

◆ HandleError()

bool cAlsaDevice::HandleError ( int error )

Handle an alsa error.

Returns: true, if an audio underrun happened, false otherwise

Definition at line 531 of file alsadevice.cpp.

References LOGERROR, m_passthroughActive, and m_pPCMHandle.

Referenced by cSoftHdAudio::CyclicCall().

◆ Init()

bool cAlsaDevice::Init ( void )

Initialize the ALSA audio output module.

Returns: true, if device init was successful

Definition at line 53 of file alsadevice.cpp.

References AlsaNoopCallback(), InitDevice(), and InitMixer().

Referenced by cSoftHdAudio::LazyInit().

◆ InitDevice()

bool cAlsaDevice::InitDevice ( void )

private

Search for an alsa pcm device and open it.

Returns: true, if a device could be opened

Definition at line 179 of file alsadevice.cpp.

References FindDevice(), L_SOUND, LOGDEBUG2, LOGERROR, LOGINFO, LOGWARNING, m_pPCMDevice, m_pPCMHandle, and OpenDevice().

Referenced by Init().

◆ InitMixer()

void cAlsaDevice::InitMixer ( void )

private

Initialize the ALSA mixer.

Definition at line 248 of file alsadevice.cpp.

References L_SOUND, LOGDEBUG2, LOGERROR, m_pMixer, m_pMixerChannel, m_pMixerDevice, m_pMixerElem, and m_ratio.

Referenced by Init().

◆ IsPassthroughActive()

bool cAlsaDevice::IsPassthroughActive ( void )

inline

Definition at line 60 of file alsadevice.h.

References m_passthroughActive.

Referenced by cSoftHdAudio::ClockDriftCompensation(), cSoftHdAudio::CyclicCall(), cSoftHdAudio::Enqueue(), cSoftHdAudio::SendAudio(), cSoftHdAudio::SetHwDelayBaseline(), cSoftHdAudio::Setup(), and cSoftHdAudio::SetVolume().

◆ IsRunning()

bool cAlsaDevice::IsRunning ( void )

inline

Definition at line 59 of file alsadevice.h.

References m_hwSampleRate, and m_pPCMHandle.

Referenced by cSoftHdAudio::GetHardwareOutputDelayMs(), and cSoftHdAudio::GetHardwareOutputPtsMs().

◆ MsToFrames()

int cAlsaDevice::MsToFrames ( int milliseconds )

inline

Definition at line 71 of file alsadevice.h.

References m_hwSampleRate.

Referenced by cSoftHdAudio::DropSamplesOlderThanPtsMs().

◆ MsToPts()

int64_t cAlsaDevice::MsToPts	(	int64_t	ptsMs,
		double	timebase
	)

inline

Definition at line 70 of file alsadevice.h.

Referenced by FramesToPts(), and cSoftHdAudio::GetHardwareOutputPtsTimebaseUnits().

◆ OpenDevice()

char * cAlsaDevice::OpenDevice ( const char * device )

private

Open an ALSA device.

Parameters

device alsa device to be opened

Returns: the alsa device if successful, NULL otherwise

Definition at line 93 of file alsadevice.cpp.

References L_SOUND, LOGDEBUG2, LOGWARNING, m_pPCMHandle, and ShouldAppendAES().

Referenced by FindDevice(), and InitDevice().

◆ PtsToMs()

int64_t cAlsaDevice::PtsToMs	(	int64_t	pts,
		double	timebase
	)

inline

Definition at line 69 of file alsadevice.h.

Referenced by cSoftHdAudio::Enqueue(), cSoftHdAudio::GetInputPtsMs(), and cSoftHdAudio::GetOutputPtsMsInternal().

◆ SetAutoAES()

void cAlsaDevice::SetAutoAES ( bool appendAes )

inline

Definition at line 63 of file alsadevice.h.

References m_appendAES.

Referenced by cSoftHdAudio::SetAutoAES().

◆ SetDownmix()

void cAlsaDevice::SetDownmix ( int downMix )

inline

Definition at line 64 of file alsadevice.h.

References m_downmix.

Referenced by cSoftHdAudio::SetDownmix().

◆ SetPassthroughMask()

void cAlsaDevice::SetPassthroughMask ( int mask )

inline

Definition at line 61 of file alsadevice.h.

References m_passthroughMask.

Referenced by cSoftHdAudio::SetPassthroughMask().

◆ Setup()

int cAlsaDevice::Setup	(	int	channels,
		int	sample_rate,
		bool	passthrough,
		int	downmix
	)

Setup ALSA audio for requested format.

Parameters

channels	Channels requested
sample_rate	SampleRate requested
passthrough	use pass-through (AC-3, ...) device

Return values

0	everything ok
-1	something gone wrong

Definition at line 307 of file alsadevice.cpp.

References GetChannelLayoutAsArray(), L_SOUND, LOGDEBUG2, LOGERROR, LOGINFO, LOGWARNING, m_bufferSizeFrames, m_downmix, m_hwNumChannels, m_hwSampleRate, m_passthroughActive, m_pPCMHandle, and m_useMmap.

Referenced by cSoftHdAudio::Setup().

◆ SetVolume()

void cAlsaDevice::SetVolume ( int volume )

Set alsa mixer volume (0-1000)

Parameters

volume volume (0 .. 1000)

Definition at line 577 of file alsadevice.cpp.

References m_pMixer, m_pMixerElem, and m_ratio.

Referenced by cSoftHdAudio::SetVolume().

◆ ShouldAppendAES()

bool cAlsaDevice::ShouldAppendAES ( void )

inlineprivate

Definition at line 96 of file alsadevice.h.

References m_appendAES, and m_passthroughMask.

Referenced by OpenDevice().

◆ WaitUntilReady()

int cAlsaDevice::WaitUntilReady ( void )

Wait until data can be written or read to/from the device (Timeout is 150ms currently)

Returns: 0, if timeout occured 1, if device is ready negative error code, in case of an error

Definition at line 417 of file alsadevice.cpp.

References L_SOUND, LOGDEBUG2, LOGERROR, and m_pPCMHandle.

Referenced by cSoftHdAudio::CyclicCall().

◆ Write()

int cAlsaDevice::Write	(	const void *	data,
		int	framesToWrite
	)

Write data to the output device.

Returns: number of written frames, or negative error code in case of an error

Definition at line 440 of file alsadevice.cpp.

References m_pPCMHandle, and m_useMmap.

Referenced by cSoftHdAudio::SendAudio(), and cSoftHdAudio::SendPause().

Member Data Documentation

◆ m_appendAES

bool cAlsaDevice::m_appendAES

private

flag to automatic append AES

Definition at line 88 of file alsadevice.h.

Referenced by SetAutoAES(), and ShouldAppendAES().

◆ m_bufferSizeFrames

snd_pcm_uframes_t cAlsaDevice::m_bufferSizeFrames = 0

private

alsa buffer size in frames

Definition at line 86 of file alsadevice.h.

Referenced by GetBufferSizeFrames(), and Setup().

◆ m_downmix

int cAlsaDevice::m_downmix

private

set stereo downmix

Definition at line 93 of file alsadevice.h.

Referenced by GetDownmix(), SetDownmix(), and Setup().

◆ m_hwNumChannels

unsigned int cAlsaDevice::m_hwNumChannels = 0

private

number of hardware channels

Definition at line 92 of file alsadevice.h.

Referenced by GetHwNumChannels(), and Setup().

◆ m_hwSampleRate

unsigned int cAlsaDevice::m_hwSampleRate = 0

private

hardware sample rate in Hz

Definition at line 91 of file alsadevice.h.

Referenced by FramesToMs(), FramesToMsDouble(), FramesToPts(), GetHwSampleRate(), IsRunning(), MsToFrames(), and Setup().

◆ m_passthroughActive

std::atomic<bool> cAlsaDevice::m_passthroughActive = false

private

set, if passthrough is active

Definition at line 90 of file alsadevice.h.

Referenced by FlushBuffers(), HandleError(), IsPassthroughActive(), and Setup().

◆ m_passthroughMask

int cAlsaDevice::m_passthroughMask

private

passthrough mask

Definition at line 89 of file alsadevice.h.

Referenced by GetPassthroughMask(), SetPassthroughMask(), and ShouldAppendAES().

◆ m_pMixer

snd_mixer_t* cAlsaDevice::m_pMixer = nullptr

private

alsa mixer handle

Definition at line 83 of file alsadevice.h.

Referenced by Exit(), InitMixer(), and SetVolume().

◆ m_pMixerChannel

const char* cAlsaDevice::m_pMixerChannel

private

mixer channel name

Definition at line 82 of file alsadevice.h.

Referenced by InitMixer().

◆ m_pMixerDevice

const char* cAlsaDevice::m_pMixerDevice = nullptr

private

mixer device name (not used)

Definition at line 81 of file alsadevice.h.

Referenced by InitMixer().

◆ m_pMixerElem

snd_mixer_elem_t* cAlsaDevice::m_pMixerElem = nullptr

private

alsa mixer element

Definition at line 84 of file alsadevice.h.

Referenced by Exit(), InitMixer(), and SetVolume().

◆ m_pPCMDevice

const char* cAlsaDevice::m_pPCMDevice

private

Alsa PCM device name.

Definition at line 77 of file alsadevice.h.

Referenced by InitDevice().

◆ m_pPCMHandle

snd_pcm_t* cAlsaDevice::m_pPCMHandle = nullptr

private

alsa pcm handle

Definition at line 78 of file alsadevice.h.

Referenced by BytesToFrames(), CheckWrittenFrames(), Exit(), FlushBuffers(), FramesToBytes(), GetAvailableBufferFrames(), GetChannelLayoutAsArray(), GetHwDelayFrames(), HandleError(), InitDevice(), IsRunning(), OpenDevice(), Setup(), WaitUntilReady(), and Write().

◆ m_ratio

int cAlsaDevice::m_ratio

private

internal -> mixer ratio * 1000

Definition at line 87 of file alsadevice.h.

Referenced by InitMixer(), and SetVolume().

◆ m_useMmap

bool cAlsaDevice::m_useMmap

private

use mmap

Definition at line 94 of file alsadevice.h.

Referenced by Setup(), and Write().

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

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ cAlsaDevice()

Member Function Documentation

◆ BytesToFrames()

◆ CheckWrittenFrames()

◆ Exit()

◆ FindDevice()

◆ FlushBuffers()

◆ FramesToBytes()

◆ FramesToMs()

◆ FramesToMsDouble()

◆ FramesToPts()

◆ GetAvailableBufferFrames()

◆ GetBufferSizeFrames()

◆ GetDownmix()

◆ GetHwDelayFrames()

◆ GetHwNumChannels()

◆ GetHwSampleRate()

◆ GetPassthroughMask()

◆ HandleError()

◆ Init()

◆ InitDevice()

◆ InitMixer()

◆ IsPassthroughActive()

◆ IsRunning()

◆ MsToFrames()

◆ MsToPts()

◆ OpenDevice()

◆ PtsToMs()

◆ SetAutoAES()

◆ SetDownmix()

◆ SetPassthroughMask()

◆ Setup()

◆ SetVolume()

◆ ShouldAppendAES()

◆ WaitUntilReady()

◆ Write()

Member Data Documentation

◆ m_appendAES

◆ m_bufferSizeFrames

◆ m_downmix

◆ m_hwNumChannels

◆ m_hwSampleRate

◆ m_passthroughActive

◆ m_passthroughMask

◆ m_pMixer

◆ m_pMixerChannel

◆ m_pMixerDevice

◆ m_pMixerElem

◆ m_pPCMDevice

◆ m_pPCMHandle

◆ m_ratio

◆ m_useMmap