ost::AudioCodec Class Reference

The codec class is a virtual used for transcoding audio samples between linear frames (or other known format) and an encoded "sample" buffer. More...

#include <audio2.h>

Inheritance diagram for ost::AudioCodec:

List of all members.

Public Member Functions

AudioCodec (const char *name, Encoding encoding)

Base for codecs, create a named coded of a specific encoding.

virtual ~AudioCodec ()

virtual Level getImpulse (void *buffer, unsigned number=0)

Get the impulse energy level of a frame of X samples in the specified codec format.

virtual Level getPeak (void *buffer, unsigned number=0)

Get the peak energy level within the frame of X samples.

virtual bool isSilent (Level threashold, void *buffer, unsigned number=0)

Signal if the current audio frame is silent.

virtual unsigned encode (Linear buffer, void *dest, unsigned number=0)=0

Encode a linear sample frame into the codec sample buffer.

virtual unsigned encodeBuffered (Linear Buffer, Encoded dest, unsigned number)

Encode linear samples buffered into the coded.

virtual unsigned decode (Linear buffer, void *source, unsigned number=0)=0

Decode the sample frame into linear samples.

virtual unsigned decodeBuffered (Linear buffer, Encoded source, unsigned len)

Buffer and decode data into linear samples.

virtual unsigned getEstimated (void)

Get estimated data required for buffered operations.

virtual unsigned getRequired (void)

get required samples for encoding.

virtual unsigned getPacket (Encoded destination, Encoded data, unsigned size)

Get a packet of data rather than decode.

Info getInfo (void)

Get an info description for this codec.

Static Public Member Functions

static void endCodec (AudioCodec *codec)

End use of a requested codec.

static AudioCodec * getCodec (Encoding encoding, const char *format=NULL, bool loaded=false)

Get the codec base class for accessing a specific derived codec identified by encoding type and optional spd info.

static AudioCodec * getCodec (Info &info, bool loaded=false)

Get the codec base class for accessing a specific derived codec identified by audio source descriptor.

static bool load (const char *name)

Load a named codec set into process memory.

static bool load (Encoding encoding)

Find and load a codec file by it's encoding type.

Protected Member Functions

AudioCodec ()

virtual AudioCodec * getByFormat (const char *format)

often used to create a "new" codec of a subtype based on encoding format, default returns the current codec entity.

virtual AudioCodec * getByInfo (Info &info)

get a codec by audio source info descriptor.

Protected Attributes

AudioCodec * next

Encoding encoding

const char * name

Info info

Static Protected Attributes

static AudioCodec * first

Detailed Description

The codec class is a virtual used for transcoding audio samples between linear frames (or other known format) and an encoded "sample" buffer.

This class is only abstract and describes the core interface for loadable codec modules. This class is normally merged with AudioSample. A derived AudioCodecXXX will typically include a AudioRegisterXXX static class to automatically initialize and register the codec with the codec registry.

Author:: David Sugar <dyfet@ostel.com> process codec interface.

Constructor & Destructor Documentation

ost::AudioCodec::AudioCodec ( ) [protected]

ost::AudioCodec::AudioCodec	(	const char *	name,
		Encoding	encoding
	)

Base for codecs, create a named coded of a specific encoding.

Parameters:

	name	of codec.
	encoding	type of codec.

virtual ost::AudioCodec::~AudioCodec ( ) [inline, virtual]

Member Function Documentation

virtual AudioCodec* ost::AudioCodec::getByFormat ( const char * format ) [inline, protected, virtual]

often used to create a "new" codec of a subtype based on encoding format, default returns the current codec entity.

Returns:: pointer to an active codec or NULL if not found.

Parameters:

format

name from spd.

virtual AudioCodec* ost::AudioCodec::getByInfo ( Info & info ) [inline, protected, virtual]

get a codec by audio source info descriptor.

Returns:: pointer to an active codec or NULL if not found.

Parameters:

info

audio source descriptor.

static void ost::AudioCodec::endCodec ( AudioCodec * codec ) [static]

End use of a requested codec.

If constructed then will be deleted.

Parameters:

codec

pointer to getCodec returned coded pointer.

static AudioCodec* ost::AudioCodec::getCodec	(	Encoding	encoding,
		const char *	format = `NULL`,
		bool	loaded = `false`
	)			`[static]`

Get the codec base class for accessing a specific derived codec identified by encoding type and optional spd info.

Returns:: pointer to codec for processing.

Parameters:

	encoding	format requested.
	format	spd options to pass to codec being created.
	loaded	true to load if not already in memory.

static AudioCodec* ost::AudioCodec::getCodec	(	Info &	info,
		bool	loaded = `false`
	)			`[static]`

Get the codec base class for accessing a specific derived codec identified by audio source descriptor.

Returns:: pointer to codec for processing.

Parameters:

	info	source descriptor for codec being requested.
	loaded	true to load codec if not already in memory.

static bool ost::AudioCodec::load ( const char * name ) [static]

Load a named codec set into process memory.

Returns:: true if successful.

Parameters:

name

of codec set to load.

static bool ost::AudioCodec::load ( Encoding encoding ) [static]

Find and load a codec file by it's encoding type.

Converts the type into a codec name and invokes the other loader...

Returns:: true if successful.

Parameters:

encoding

type for file.

virtual Level ost::AudioCodec::getImpulse	(	void *	buffer,
		unsigned	number = `0`
	)			`[virtual]`

Get the impulse energy level of a frame of X samples in the specified codec format.

Returns:: average impulse energy of frame (sumnation).

Parameters:

	buffer	of encoded samples.
	number	of encoded samples.

virtual Level ost::AudioCodec::getPeak	(	void *	buffer,
		unsigned	number = `0`
	)			`[virtual]`

Get the peak energy level within the frame of X samples.

Returns:: peak energy impulse in frame (largest).

Parameters:

	buffer	of encoded samples.
	number	of encoded samples.

virtual bool ost::AudioCodec::isSilent	(	Level	threashold,
		void *	buffer,
		unsigned	number = `0`
	)			`[virtual]`

Signal if the current audio frame is silent.

This can be deterimed either by an impulse computation, or, in some cases, some codecs may signal and flag silent packets.

Returns:: true if silent

Parameters:

	threashold	to use if not signaled.
	buffer	of encoded samples.
	number	of encoded samples.

virtual unsigned ost::AudioCodec::encode	(	Linear	buffer,
		void *	dest,
		unsigned	number = `0`
	)			`[pure virtual]`

Encode a linear sample frame into the codec sample buffer.

Returns:: number of bytes written.

Parameters:

	buffer	linear sample buffer to use.
	dest	buffer to store encoded results.
	number	of samples.

virtual unsigned ost::AudioCodec::encodeBuffered	(	Linear	Buffer,
		Encoded	dest,
		unsigned	number
	)			`[virtual]`

Encode linear samples buffered into the coded.

Returns:: number of bytes written or 0 if incomplete.

Parameters:

	buffer	linear samples to post.
	destination	of encoded audio.
	number	of samples being buffered.

virtual unsigned ost::AudioCodec::decode	(	Linear	buffer,
		void *	source,
		unsigned	number = `0`
	)			`[pure virtual]`

Decode the sample frame into linear samples.

Returns:: number of bytes scanned or returned

Parameters:

	buffer	sample buffer to save linear samples into.
	source	for encoded data.
	number	of samples to extract.

virtual unsigned ost::AudioCodec::decodeBuffered	(	Linear	buffer,
		Encoded	source,
		unsigned	len
	)			`[virtual]`

Buffer and decode data into linear samples.

This is needed for audio formats that have irregular packet sizes.

Returns:: number of samples actually decoded.

Parameters:

	destination	for decoded data.
	source	for encoded data.
	number	of bytes being sent.

virtual unsigned ost::AudioCodec::getEstimated ( void ) [virtual]

Get estimated data required for buffered operations.

Returns:: estimated number of bytes required for decode.

virtual unsigned ost::AudioCodec::getRequired ( void ) [virtual]

get required samples for encoding.

Returns:: required number of samples for encoder buffer.

virtual unsigned ost::AudioCodec::getPacket	(	Encoded	destination,
		Encoded	data,
		unsigned	size
	)			`[virtual]`

Get a packet of data rather than decode.

This is tied with getEstimated.

Returns:: size of data packet or 0 if not complete.

Parameters:

	destination	to save.
	data	to push into buffer.
	number	of bytes to push.

Info ost::AudioCodec::getInfo ( void ) [inline]

Get an info description for this codec.

Returns:: info.

Member Data Documentation

AudioCodec* ost::AudioCodec::first [static, protected]

AudioCodec* ost::AudioCodec::next [protected]

Encoding ost::AudioCodec::encoding [protected]

const char* ost::AudioCodec::name [protected]

Info ost::AudioCodec::info [protected]

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

audio2.h


Public Member Functions
	AudioCodec (const char *name, Encoding encoding)
	Base for codecs, create a named coded of a specific encoding.
virtual	~AudioCodec ()
virtual Level	getImpulse (void *buffer, unsigned number=0)
	Get the impulse energy level of a frame of X samples in the specified codec format.
virtual Level	getPeak (void *buffer, unsigned number=0)
	Get the peak energy level within the frame of X samples.
virtual bool	isSilent (Level threashold, void *buffer, unsigned number=0)
	Signal if the current audio frame is silent.
virtual unsigned	encode (Linear buffer, void *dest, unsigned number=0)=0
	Encode a linear sample frame into the codec sample buffer.
virtual unsigned	encodeBuffered (Linear Buffer, Encoded dest, unsigned number)
	Encode linear samples buffered into the coded.
virtual unsigned	decode (Linear buffer, void *source, unsigned number=0)=0
	Decode the sample frame into linear samples.
virtual unsigned	decodeBuffered (Linear buffer, Encoded source, unsigned len)
	Buffer and decode data into linear samples.
virtual unsigned	getEstimated (void)
	Get estimated data required for buffered operations.
virtual unsigned	getRequired (void)
	get required samples for encoding.
virtual unsigned	getPacket (Encoded destination, Encoded data, unsigned size)
	Get a packet of data rather than decode.
Info	getInfo (void)
	Get an info description for this codec.
Static Public Member Functions
static void	endCodec (AudioCodec *codec)
	End use of a requested codec.
static AudioCodec *	getCodec (Encoding encoding, const char *format=NULL, bool loaded=false)
	Get the codec base class for accessing a specific derived codec identified by encoding type and optional spd info.
static AudioCodec *	getCodec (Info &info, bool loaded=false)
	Get the codec base class for accessing a specific derived codec identified by audio source descriptor.
static bool	load (const char *name)
	Load a named codec set into process memory.
static bool	load (Encoding encoding)
	Find and load a codec file by it's encoding type.
Protected Member Functions
	AudioCodec ()
virtual AudioCodec *	getByFormat (const char *format)
	often used to create a "new" codec of a subtype based on encoding format, default returns the current codec entity.
virtual AudioCodec *	getByInfo (Info &info)
	get a codec by audio source info descriptor.
Protected Attributes
AudioCodec *	next
Encoding	encoding
const char *	name
Info	info
Static Protected Attributes
static AudioCodec *	first