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ost::Audio

ost::Audio

Section: C Library Functions (3) Updated: 1 May 2009
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NAME

ost::Audio - Generic audio class to hold master data types and various useful class encapsulated friend functions as per GNU Common C++ 2 coding standard.

 

SYNOPSIS


#include <audio2.h>

Inherited by ost::AudioBase, ost::AudioCodec, ost::AudioResample, ost::AudioTone, and ost::DTMFDetect.

 

Classes


struct dtmf_detect_state_t

struct goertzel_state_t

class Info
Audio source description.
struct mpeg_audio

struct mpeg_tagv1

struct tone_detection_descriptor_t
 

Public Types


enum Rate { rateUnknown, rate6khz = 6000, rate8khz = 8000, rate16khz = 16000, rate32khz = 32000, rate44khz = 44100 }
Audio encoding rate, samples per second.
enum Mode { modeRead, modeReadAny, modeReadOne, modeWrite, modeCache, modeInfo, modeFeed, modeAppend, modeCreate }
File processing mode, whether to skip missing files, etc.
enum Encoding { unknownEncoding = 0, g721ADPCM, g722Audio, g722_7bit, g722_6bit, g723_2bit, g723_3bit, g723_5bit, gsmVoice, msgsmVoice, mulawAudio, alawAudio, mp1Audio, mp2Audio, mp3Audio, okiADPCM, voxADPCM, sx73Voice, sx96Voice, cdaStereo, cdaMono, pcm8Stereo, pcm8Mono, pcm16Stereo, pcm16Mono, pcm32Stereo, pcm32Mono, speexVoice, speexAudio, g729Audio, ilbcAudio, speexUltra, speexNarrow = speexVoice, speexWide = speexAudio, g723_4bit = g721ADPCM }
Audio encoding formats.
enum Format { raw, snd, riff, mpeg, wave }
Audio container file format.
enum DeviceMode { PLAY, RECORD, PLAYREC }
Audio device access mode.
enum Error { errSuccess = 0, errReadLast, errNotOpened, errEndOfFile, errStartOfFile, errRateInvalid, errEncodingInvalid, errReadInterrupt, errWriteInterrupt, errReadFailure, errWriteFailure, errReadIncomplete, errWriteIncomplete, errRequestInvalid, errTOCFailed, errStatFailed, errInvalidTrack, errPlaybackFailed, errNotPlaying, errNoCodec }
Audio error conditions.
typedef int16_t snd16_t

typedef int32_t snd32_t

typedef int16_t Level

typedef int16_t Sample

typedef int16_t * Linear

typedef unsigned long timeout_t

typedef unsigned char * Encoded

typedef enum Rate Rate

typedef enum Mode Mode

typedef enum Encoding Encoding

typedef enum Format Format

typedef enum DeviceMode DeviceMode

typedef enum Error Error
 

Static Public Member Functions


static Level tolevel (float dbm)
Convert dbm power level to integer value (0-32768).
static float todbm (Level power)
Convert integer power levels to dbm.
static bool hasDevice (unsigned device=0)
Test for the presense of a specified (indexed) audio device.
static AudioDevice * getDevice (unsigned device=0, DeviceMode mode=PLAY)
Get a audio device object that can be used to play or record audio.
static const char * getCodecPath (void)
Get pathname to where loadable codec modules are stored.
static const char * getMIME (Info &info)
Get the mime descriptive type for a given Audio encoding description, usually retrieved from a newly opened audio file.
static const char * getName (Encoding encoding)
Get the short ascii description used for the given audio encoding type.
static const char * getExtension (Encoding encoding)
Get the preferred file extension name to use for a given audio encoding type.
static Encoding getEncoding (const char *name)
Get the audio encoding format that is specified by a short ascii name.
static Encoding getStereo (Encoding encoding)
Get the stereo encoding format associated with the given format.
static Encoding getMono (Encoding encoding)
Get the mono encoding format associated with the given format.
static bool isLinear (Encoding encoding)
Test if the audio encoding format is a linear one.
static bool isBuffered (Encoding encoding)
Test if the audio encoding format must be packetized (that is, has irregular sized frames) and must be processed only through buffered codecs.
static bool isMono (Encoding encoding)
Test if the audio encoding format is a mono format.
static bool isStereo (Encoding encoding)
Test if the audio encoding format is a stereo format.
static Rate getRate (Encoding encoding)
Return default sample rate associated with the specified audio encoding format.
static Rate getRate (Encoding e, Rate request)
Return optional rate setting effect.
static timeout_t getFraming (Encoding encoding, timeout_t timeout=0)
Return frame timing for an audio encoding format.
static timeout_t getFraming (Info &info, timeout_t timeout=0)
Return frame time for an audio source description.
static bool isEndian (Encoding encoding)
Test if the endian byte order of the encoding format is different from the machine's native byte order.
static bool isEndian (Info &info)
Test if the endian byte order of the audio source description is different from the machine's native byte order.
static bool swapEndian (Encoding encoding, void *buffer, unsigned number)
Optionally swap endian of audio data if the encoding format endian byte order is different from the machine's native endian.
static void swapEncoded (Info &info, Encoded data, size_t bytes)
Optionally swap endian of encoded audio data based on the audio encoding type, and relationship to native byte order.
static bool swapEndian (Info &info, void *buffer, unsigned number)
Optionally swap endian of audio data if the audio source description byte order is different from the machine's native endian byte order.
static Level getImpulse (Encoding encoding, void *buffer, unsigned number)
Get the energey impulse level of a frame of audio data.
static Level getImpulse (Info &info, void *buffer, unsigned number=0)
Get the energey impulse level of a frame of audio data.
static Level getPeak (Encoding encoding, void *buffer, unsigned number)
Get the peak (highest energy) level found in a frame of audio data.
static Level getPeak (Info &info, void *buffer, unsigned number=0)
Get the peak (highest energy) level found in a frame of audio data.
static void toTimestamp (timeout_t duration, char *address, size_t size)
Provide ascii timestamp representation of a timeout value.
static timeout_t toTimeout (const char *timestamp)
Convert ascii timestamp representation to a timeout number.
static int getFrame (Encoding encoding, int samples=0)
Returns the number of bytes in a sample frame for the given encoding type, rounded up to the nearest integer.
static int getCount (Encoding encoding)
Returns the number of samples in all channels for a frame in the given encoding.
static unsigned long toSamples (Encoding encoding, size_t bytes)
Compute byte counts of audio data into number of samples based on the audio encoding format used.
static unsigned long toSamples (Info &info, size_t bytes)
Compute byte counts of audio data into number of samples based on the audio source description used.
static size_t toBytes (Info &info, unsigned long number)
Compute the number of bytes a given number of samples in a given audio encoding will occupy.
static size_t toBytes (Encoding encoding, unsigned long number)
Compute the number of bytes a given number of samples in a given audio encoding will occupy.
static void fill (unsigned char *address, int number, Encoding encoding)
Fill an audio buffer with 'empty' (silent) audio data, based on the audio encoding format.
static bool loadPlugin (const char *path)
Load a dso plugin (codec plugin), used internally.
static size_t maxFramesize (Info &info)
Maximum framesize for a given coding that may be needed to store a result.  

Static Public Attributes


static const unsigned ndata
 

Detailed Description

Generic audio class to hold master data types and various useful class encapsulated friend functions as per GNU Common C++ 2 coding standard.

Author:

David Sugar <dyfet@ostel.com> Master audio class.

 

Member Typedef Documentation

 

typedef enum DeviceMode ost::Audio::DeviceMode

 

typedef unsigned char* ost::Audio::Encoded

 

typedef enum Encoding ost::Audio::Encoding

 

typedef enum Error ost::Audio::Error

 

typedef enum Format ost::Audio::Format

 

typedef int16_t ost::Audio::Level

 

typedef int16_t* ost::Audio::Linear

 

typedef enum Mode ost::Audio::Mode

 

typedef enum Rate ost::Audio::Rate

 

typedef int16_t ost::Audio::Sample

 

typedef int16_t ost::Audio::snd16_t

 

typedef int32_t ost::Audio::snd32_t

 

typedef unsigned long ost::Audio::timeout_t

 

Member Enumeration Documentation

 

enum ost::Audio::DeviceMode

Audio device access mode.

Enumerator:

PLAY
RECORD
PLAYREC

 

enum ost::Audio::Encoding

Audio encoding formats.

Enumerator:

unknownEncoding
g721ADPCM
g722Audio
g722_7bit
g722_6bit
g723_2bit
g723_3bit
g723_5bit
gsmVoice
msgsmVoice
mulawAudio
alawAudio
mp1Audio
mp2Audio
mp3Audio
okiADPCM
voxADPCM
sx73Voice
sx96Voice
cdaStereo
cdaMono
pcm8Stereo
pcm8Mono
pcm16Stereo
pcm16Mono
pcm32Stereo
pcm32Mono
speexVoice
speexAudio
g729Audio
ilbcAudio
speexUltra
speexNarrow
speexWide
g723_4bit

 

enum ost::Audio::Error

Audio error conditions.

Enumerator:

errSuccess
errReadLast
errNotOpened
errEndOfFile
errStartOfFile
errRateInvalid
errEncodingInvalid
errReadInterrupt
errWriteInterrupt
errReadFailure
errWriteFailure
errReadIncomplete
errWriteIncomplete
errRequestInvalid
errTOCFailed
errStatFailed
errInvalidTrack
errPlaybackFailed
errNotPlaying
errNoCodec

 

enum ost::Audio::Format

Audio container file format.

Enumerator:

raw
snd
riff
mpeg
wave

 

enum ost::Audio::Mode

File processing mode, whether to skip missing files, etc.

Enumerator:

modeRead
modeReadAny
modeReadOne
modeWrite
modeCache
modeInfo
modeFeed
modeAppend
modeCreate

 

enum ost::Audio::Rate

Audio encoding rate, samples per second.

Enumerator:

rateUnknown
rate6khz
rate8khz
rate16khz
rate32khz
rate44khz

 

Member Function Documentation

 

static void ost::Audio::fill (unsigned char * address, int number, Encoding encoding) [static]

Fill an audio buffer with 'empty' (silent) audio data, based on the audio encoding format.

Parameters:

address of data to fill.
number of samples to fill.
encoding format of data.

 

static const char* ost::Audio::getCodecPath (void) [static]

Get pathname to where loadable codec modules are stored.

Returns:

file path to loadable codecs.

 

static int ost::Audio::getCount (Encoding encoding) [static]

Returns the number of samples in all channels for a frame in the given encoding.

For example, pcm32Stereo has a frame size of 8 bytes: Note that different codecs have different definitions of a frame - for example, compressed encodings have a rather large frame size relative to the sample size due to the way bytes are fed to the decompression engine.

Parameters:

encoding The encoding to calculate the frame sample count for.

Returns:

samples The number of samples in a frame of the given encoding.

 

static AudioDevice* ost::Audio::getDevice (unsigned device = 0, DeviceMode mode = PLAY) [static]

Get a audio device object that can be used to play or record audio.

This is normally a local soundcard, though an abstract base class is returned, so the underlying device may be different.

Parameters:

device index or 0 for default audio device.
mode of device; play, record, or full duplex.

Returns:

pointer to abstract audio device object interface class.

 

static Encoding ost::Audio::getEncoding (const char * name) [static]

Get the audio encoding format that is specified by a short ascii name.

This will either accept names like those returned from getName(), or .xxx file extensions, and return the audio encoding type associated with the name or extension.

Parameters:

name of encoding or file extension.

Returns:

audio encoding format.

See also:

getName

 

static const char* ost::Audio::getExtension (Encoding encoding) [static]

Get the preferred file extension name to use for a given audio encoding type.

Parameters:

encoding format.

Returns:

ascii file extension to use.

 

static int ost::Audio::getFrame (Encoding encoding, int samples = 0) [static]

Returns the number of bytes in a sample frame for the given encoding type, rounded up to the nearest integer.

A frame is defined as the minimum number of bytes necessary to create a point or points in the output waveform for all output channels. For example, 16-bit mono PCM has a frame size of two (because those two bytes constitute a point in the output waveform). GSM has it's own definition of a frame which involves decompressing a sequence of bytes to determine the final points on the output waveform. The minimum number of bytes you can feed to the decompression engine is 32.5 (260 bits), so this function will return 33 (because we round up) given an encoding type of GSM. Other compressed encodings will return similar results. Be prepared to deal with nonintuitive return values for rare encodings.

Parameters:

encoding The encoding type to get the frame size for.
samples Reserved. Use zero.

Returns:

The number of bytes in a frame for the given encoding.

 

static timeout_t ost::Audio::getFraming (Info & info, timeout_t timeout = 0) [static]

Return frame time for an audio source description.

Returns:

frame time to use in milliseconds.

Parameters:

info descriptor of frame encoding to get timing segment for.
timeout of frame time segment to request.

 

static timeout_t ost::Audio::getFraming (Encoding encoding, timeout_t timeout = 0) [static]

Return frame timing for an audio encoding format.

Returns:

frame time to use in milliseconds.

Parameters:

encoding of frame to get timing segment for.
timeout of frame time segment to request.

 

static Level ost::Audio::getImpulse (Info & info, void * buffer, unsigned number = 0) [static]

Get the energey impulse level of a frame of audio data.

Returns:

impulse energy level of audio data.

Parameters:

info encoding source description object.
buffer of audio data to examine.
number of audio samples to examine.

 

static Level ost::Audio::getImpulse (Encoding encoding, void * buffer, unsigned number) [static]

Get the energey impulse level of a frame of audio data.

Returns:

impulse energy level of audio data.

Parameters:

encoding format of data to examine.
buffer of audio data to examine.
number of audio samples to examine.

 

static const char* ost::Audio::getMIME (Info & info) [static]

Get the mime descriptive type for a given Audio encoding description, usually retrieved from a newly opened audio file.

Parameters:

info source description object

Returns:

text of mime type to use for this audio source.

 

static Encoding ost::Audio::getMono (Encoding encoding) [static]

Get the mono encoding format associated with the given format.

Parameters:

encoding format.

Returns:

associated mono audio encoding format.

 

static const char* ost::Audio::getName (Encoding encoding) [static]

Get the short ascii description used for the given audio encoding type.

Parameters:

encoding format.

Returns:

ascii name of encoding format.

 

static Level ost::Audio::getPeak (Info & info, void * buffer, unsigned number = 0) [static]

Get the peak (highest energy) level found in a frame of audio data.

Returns:

peak energy level found in data.

Parameters:

info description object of audio data.
buffer of audio data.
number of samples to examine.

 

static Level ost::Audio::getPeak (Encoding encoding, void * buffer, unsigned number) [static]

Get the peak (highest energy) level found in a frame of audio data.

Returns:

peak energy level found in data.

Parameters:

encoding format of data.
buffer of audio data.
number of samples to examine.

 

static Rate ost::Audio::getRate (Encoding e, Rate request) [static]

Return optional rate setting effect.

Many codecs are fixed rate.

Returns:

result rate for audio date.

Parameters:

encoding format.
requested rate.

 

static Rate ost::Audio::getRate (Encoding encoding) [static]

Return default sample rate associated with the specified audio encoding format.

Returns:

sample rate for audio data.

Parameters:

encoding format.

 

static Encoding ost::Audio::getStereo (Encoding encoding) [static]

Get the stereo encoding format associated with the given format.

Parameters:

encoding format being tested for stereo.

Returns:

associated stereo audio encoding format.

 

static bool ost::Audio::hasDevice (unsigned device = 0) [static]

Test for the presense of a specified (indexed) audio device.

This is normally used to test for local soundcard access.

Parameters:

device index or 0 for default audio device.

Returns:

true if device exists.

 

static bool ost::Audio::isBuffered (Encoding encoding) [static]

Test if the audio encoding format must be packetized (that is, has irregular sized frames) and must be processed only through buffered codecs.

Returns:

true if packetized audio.

Parameters:

encoding format.

 

static bool ost::Audio::isEndian (Info & info) [static]

Test if the endian byte order of the audio source description is different from the machine's native byte order.

Returns:

true if endian format is different.

Parameters:

info source description object.

 

static bool ost::Audio::isEndian (Encoding encoding) [static]

Test if the endian byte order of the encoding format is different from the machine's native byte order.

Returns:

true if endian format is different.

Parameters:

encoding format.

 

static bool ost::Audio::isLinear (Encoding encoding) [static]

Test if the audio encoding format is a linear one.

Returns:

true if encoding format is linear audio data.

Parameters:

encoding format.

 

static bool ost::Audio::isMono (Encoding encoding) [static]

Test if the audio encoding format is a mono format.

Returns:

true if encoding format is mono audio data.

Parameters:

encoding format.

 

static bool ost::Audio::isStereo (Encoding encoding) [static]

Test if the audio encoding format is a stereo format.

Returns:

true if encoding format is stereo audio data.

Parameters:

encoding format.

 

static bool ost::Audio::loadPlugin (const char * path) [static]

Load a dso plugin (codec plugin), used internally.

Returns:

true if loaded.

Parameters:

path to codec.

 

static size_t ost::Audio::maxFramesize (Info & info) [static]

Maximum framesize for a given coding that may be needed to store a result.

Parameters:

info source description object.

Returns:

maximum possible frame size to allocate for encoded data.

 

static void ost::Audio::swapEncoded (Info & info, Encoded data, size_t bytes) [static]

Optionally swap endian of encoded audio data based on the audio encoding type, and relationship to native byte order.

Parameters:

info source description of object.
buffer of audio data.
number of bytes of audio data.

 

static bool ost::Audio::swapEndian (Info & info, void * buffer, unsigned number) [static]

Optionally swap endian of audio data if the audio source description byte order is different from the machine's native endian byte order.

Returns:

true if endian format was different.

Parameters:

info source description object of data.
buffer of audio data.
number of audio samples.

 

static bool ost::Audio::swapEndian (Encoding encoding, void * buffer, unsigned number) [static]

Optionally swap endian of audio data if the encoding format endian byte order is different from the machine's native endian.

Returns:

true if endian format was different.

Parameters:

encoding format of data.
buffer of audio data.
number of audio samples.

 

static size_t ost::Audio::toBytes (Encoding encoding, unsigned long number) [static]

Compute the number of bytes a given number of samples in a given audio encoding will occupy.

Returns:

number of bytes samples will occupy.

Parameters:

encoding format.
number of samples.

 

static size_t ost::Audio::toBytes (Info & info, unsigned long number) [static]

Compute the number of bytes a given number of samples in a given audio encoding will occupy.

Returns:

number of bytes samples will occupy.

Parameters:

info encoding source description.
number of samples.

 

static float ost::Audio::todbm (Level power) [static]

Convert integer power levels to dbm.

Parameters:

power level.

Returns:

dbm power level.

 

static Level ost::Audio::tolevel (float dbm) [static]

Convert dbm power level to integer value (0-32768).

Parameters:

dbm power level

Returns:

integer value.

 

static unsigned long ost::Audio::toSamples (Info & info, size_t bytes) [static]

Compute byte counts of audio data into number of samples based on the audio source description used.

Returns:

number of audio samples in specified data.

Parameters:

info encoding source description.
bytes of data.

 

static unsigned long ost::Audio::toSamples (Encoding encoding, size_t bytes) [static]

Compute byte counts of audio data into number of samples based on the audio encoding format used.

Returns:

number of audio samples in specified data.

Parameters:

encoding format.
bytes of data.

 

static timeout_t ost::Audio::toTimeout (const char * timestamp) [static]

Convert ascii timestamp representation to a timeout number.

Parameters:

timestamp ascii data.

Returns:

timeout_t duration from data.

 

static void ost::Audio::toTimestamp (timeout_t duration, char * address, size_t size) [static]

Provide ascii timestamp representation of a timeout value.

Parameters:

duration timeout value
address for ascii data.
size of ascii data.

 

Member Data Documentation

 

const unsigned ost::Audio::ndata [static]

 

Author

Generated automatically by Doxygen for ccAudio from the source code.


 

Index

NAME
SYNOPSIS
Classes
Public Types
Static Public Member Functions
Static Public Attributes
Detailed Description
Member Typedef Documentation
typedef enum DeviceMode ost::Audio::DeviceMode
typedef unsigned char* ost::Audio::Encoded
typedef enum Encoding ost::Audio::Encoding
typedef enum Error ost::Audio::Error
typedef enum Format ost::Audio::Format
typedef int16_t ost::Audio::Level
typedef int16_t* ost::Audio::Linear
typedef enum Mode ost::Audio::Mode
typedef enum Rate ost::Audio::Rate
typedef int16_t ost::Audio::Sample
typedef int16_t ost::Audio::snd16_t
typedef int32_t ost::Audio::snd32_t
typedef unsigned long ost::Audio::timeout_t
Member Enumeration Documentation
enum ost::Audio::DeviceMode
enum ost::Audio::Encoding
enum ost::Audio::Error
enum ost::Audio::Format
enum ost::Audio::Mode
enum ost::Audio::Rate
Member Function Documentation
static void ost::Audio::fill (unsigned char * address, int number, Encoding encoding) [static]
static const char* ost::Audio::getCodecPath (void) [static]
static int ost::Audio::getCount (Encoding encoding) [static]
static AudioDevice* ost::Audio::getDevice (unsigned device = 0, DeviceMode mode = PLAY) [static]
static Encoding ost::Audio::getEncoding (const char * name) [static]
static const char* ost::Audio::getExtension (Encoding encoding) [static]
static int ost::Audio::getFrame (Encoding encoding, int samples = 0) [static]
static timeout_t ost::Audio::getFraming (Info & info, timeout_t timeout = 0) [static]
static timeout_t ost::Audio::getFraming (Encoding encoding, timeout_t timeout = 0) [static]
static Level ost::Audio::getImpulse (Info & info, void * buffer, unsigned number = 0) [static]
static Level ost::Audio::getImpulse (Encoding encoding, void * buffer, unsigned number) [static]
static const char* ost::Audio::getMIME (Info & info) [static]
static Encoding ost::Audio::getMono (Encoding encoding) [static]
static const char* ost::Audio::getName (Encoding encoding) [static]
static Level ost::Audio::getPeak (Info & info, void * buffer, unsigned number = 0) [static]
static Level ost::Audio::getPeak (Encoding encoding, void * buffer, unsigned number) [static]
static Rate ost::Audio::getRate (Encoding e, Rate request) [static]
static Rate ost::Audio::getRate (Encoding encoding) [static]
static Encoding ost::Audio::getStereo (Encoding encoding) [static]
static bool ost::Audio::hasDevice (unsigned device = 0) [static]
static bool ost::Audio::isBuffered (Encoding encoding) [static]
static bool ost::Audio::isEndian (Info & info) [static]
static bool ost::Audio::isEndian (Encoding encoding) [static]
static bool ost::Audio::isLinear (Encoding encoding) [static]
static bool ost::Audio::isMono (Encoding encoding) [static]
static bool ost::Audio::isStereo (Encoding encoding) [static]
static bool ost::Audio::loadPlugin (const char * path) [static]
static size_t ost::Audio::maxFramesize (Info & info) [static]
static void ost::Audio::swapEncoded (Info & info, Encoded data, size_t bytes) [static]
static bool ost::Audio::swapEndian (Info & info, void * buffer, unsigned number) [static]
static bool ost::Audio::swapEndian (Encoding encoding, void * buffer, unsigned number) [static]
static size_t ost::Audio::toBytes (Encoding encoding, unsigned long number) [static]
static size_t ost::Audio::toBytes (Info & info, unsigned long number) [static]
static float ost::Audio::todbm (Level power) [static]
static Level ost::Audio::tolevel (float dbm) [static]
static unsigned long ost::Audio::toSamples (Info & info, size_t bytes) [static]
static unsigned long ost::Audio::toSamples (Encoding encoding, size_t bytes) [static]
static timeout_t ost::Audio::toTimeout (const char * timestamp) [static]
static void ost::Audio::toTimestamp (timeout_t duration, char * address, size_t size) [static]
Member Data Documentation
const unsigned ost::Audio::ndata [static]
Author

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Time: 21:51:49 GMT, April 16, 2011