TagLib::MPEG::Header Class Reference

An implementation of MP3 frame headers. More...

#include <mpegheader.h>

Public Types
enum	Version { Version1 = 0 , Version2 = 1 , Version2_5 = 2 , Version4 = 3 }
enum	ChannelMode { Stereo = 0 , JointStereo = 1 , DualChannel = 2 , SingleChannel = 3 }
enum	ChannelConfiguration {   Custom = 0 , FrontCenter = 1 , FrontLeftRight = 2 , FrontCenterLeftRight = 3 ,   FrontCenterLeftRightBackCenter = 4 , FrontCenterLeftRightBackLeftRight = 5 , FrontCenterLeftRightBackLeftRightLFE = 6 , FrontCenterLeftRightSideLeftRightBackLeftRightLFE = 7 }

Public Member Functions
	Header (File *file, offset_t offset, bool checkLength=true)
	Header (const Header &h)
	~Header ()
bool	isValid () const
Version	version () const
int	layer () const
bool	protectionEnabled () const
int	bitrate () const
int	sampleRate () const
bool	isPadded () const
ChannelMode	channelMode () const
ChannelConfiguration	channelConfiguration () const
bool	isADTS () const
bool	isCopyrighted () const
bool	isOriginal () const
int	frameLength () const
int	samplesPerFrame () const
Header &	operator= (const Header &h)

Detailed Description

An implementation of MP3 frame headers.

This is an implementation of MPEG Layer III headers. The API follows more or less the binary format of these headers.

See these documents as a reference

• MPEG Audio Layer I/II/III frame header
• ADTS

Member Enumeration Documentation

ChannelConfiguration

enum TagLib::MPEG::Header::ChannelConfiguration

MPEG-4 channel configuration.

Enumerator
Custom	Defined in audio object type (AOT) specific configuration.
FrontCenter	1 channel: front-center
FrontLeftRight	2 channels: front-left, front-right
FrontCenterLeftRight	3 channels: front-center, front-left, front-right
FrontCenterLeftRightBackCenter	4 channels: front-center, front-left, front-right, back-center
FrontCenterLeftRightBackLeftRight	5 channels: front-center, front-left, front-right, back-left, back-right
FrontCenterLeftRightBackLeftRightLFE	6 channels: front-center, front-left, front-right, back-left, back-right, LFE-channel
FrontCenterLeftRightSideLeftRightBackLeftRightLFE	8 channels: front-center, front-left, front-right, side-left, side-right, back-left, back-right, LFE-channel

ChannelMode

enum TagLib::MPEG::Header::ChannelMode

There are a few combinations or one or two channel audio that are possible:

Enumerator
Stereo	Stereo.
JointStereo	Stereo.
DualChannel	Dual Mono.
SingleChannel	Mono.

Version

enum TagLib::MPEG::Header::Version

The MPEG Version.

Enumerator
Version1	MPEG Version 1.
Version2	MPEG Version 2.
Version2_5	MPEG Version 2.5.
Version4	MPEG Version 4.

Constructor & Destructor Documentation

Header() [1/2]

TagLib::MPEG::Header::Header	(	File *	file,
		offset_t	offset,
		bool	checkLength = true
	)

Parses an MPEG header based on file and offset.

Note

If checkLength is true, this requires the next MPEG frame to check if the frame length is parsed and calculated correctly. So it's suitable for seeking for the first valid frame.

Header() [2/2]

TagLib::MPEG::Header::Header

(

const Header &

h

)

Does a shallow copy of h.

~Header()

TagLib::MPEG::Header::~Header

(

)

Destroys this Header instance.

Member Function Documentation

bitrate()

int TagLib::MPEG::Header::bitrate

(

)

const

Returns the bitrate encoded in the header.

channelConfiguration()

ChannelConfiguration TagLib::MPEG::Header::channelConfiguration

(

)

const

Returns the MPEG-4 channel configuration.

channelMode()

ChannelMode TagLib::MPEG::Header::channelMode

(

)

const

Returns the channel mode for this frame.

frameLength()

int TagLib::MPEG::Header::frameLength

(

)

const

Returns the frame length in bytes.

isADTS()

bool TagLib::MPEG::Header::isADTS

(

)

const

Returns true if this is the header of an Audio Data Transport Stream (ADTS), usually AAC.

isCopyrighted()

bool TagLib::MPEG::Header::isCopyrighted

(

)

const

Returns true if the copyrighted bit is set.

isOriginal()

bool TagLib::MPEG::Header::isOriginal

(

)

const

Returns true if the "original" bit is set.

isPadded()

bool TagLib::MPEG::Header::isPadded

(

)

const

Returns true if the frame is padded.

isValid()

bool TagLib::MPEG::Header::isValid

(

)

const

Returns true if the frame is at least an appropriate size and has legal values.

layer()

int TagLib::MPEG::Header::layer

(

)

const

Returns the layer version. This will be between the values 1-3.

operator=()

Header & TagLib::MPEG::Header::operator=

(

const Header &

h

)

Makes a shallow copy of the header.

protectionEnabled()

bool TagLib::MPEG::Header::protectionEnabled

(

)

const

Returns true if the MPEG protection bit is enabled.

sampleRate()

int TagLib::MPEG::Header::sampleRate

(

)

const

Returns the sample rate in Hz.

samplesPerFrame()

int TagLib::MPEG::Header::samplesPerFrame

(

)

const

Returns the number of frames per sample.

version()

Version TagLib::MPEG::Header::version

(

)

const

Returns the MPEG Version of the header.

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

• mpegheader.h