FFMPEGReader Class Reference

This class reads a sound file via ffmpeg. More...

#include <FFMPEGReader.h>

Inheritance diagram for FFMPEGReader:

Public Member Functions
	FFMPEGReader (const std::string &filename, int stream=0)
	Creates a new reader.
	FFMPEGReader (std::shared_ptr< Buffer > buffer, int stream=0)
	Creates a new reader.
virtual	~FFMPEGReader ()
	Destroys the reader and closes the file.
virtual std::vector< StreamInfo >	queryStreams ()
	Queries the streams of a sound file.
virtual bool	isSeekable () const
	Tells whether the source provides seeking functionality or not.
virtual void	seek (int position)
	Seeks to a specific position in the source.
virtual int	getLength () const
	Returns an approximated length of the source in samples.
virtual int	getPosition () const
	Returns the position of the source as a sample count value.
virtual Specs	getSpecs () const
	Returns the specification of the reader.
virtual void	read (int &length, bool &eos, sample_t *buffer)
	Request to read the next length samples out of the source.
Public Member Functions inherited from IReader
virtual	~IReader ()
	Destroys the reader.

Static Public Member Functions
static int	read_packet (void *opaque, uint8_t *buf, int buf_size)
	Reads data to a memory buffer.
static int64_t	seek_packet (void *opaque, int64_t offset, int whence)
	Seeks within data.

Detailed Description

This class reads a sound file via ffmpeg.

Warning

Seeking may not be accurate! Moreover the position is updated after a buffer reading call. So calling getPosition right after seek normally results in a wrong value.

Constructor & Destructor Documentation

FFMPEGReader() [1/2]

FFMPEGReader::FFMPEGReader	(	const std::string &	filename,
		int	stream = 0 )

Creates a new reader.

Parameters

filename	The path to the file to be read.
stream	The index of the audio stream within the file if it contains multiple audio streams.

Exceptions

Exception

Thrown if the file specified does not exist or cannot be read with ffmpeg.

FFMPEGReader() [2/2]

FFMPEGReader::FFMPEGReader	(	std::shared_ptr< Buffer >	buffer,
		int	stream = 0 )

Creates a new reader.

Parameters

buffer	The buffer to read from.
stream	The index of the audio stream within the file if it contains multiple audio streams.

Exceptions

Exception

Thrown if the buffer specified cannot be read with ffmpeg.

Member Function Documentation

getLength()

virtual int FFMPEGReader::getLength ( ) const

virtual

Returns an approximated length of the source in samples.

Returns

The length as sample count. May be negative if unknown.

Implements IReader.

getPosition()

virtual int FFMPEGReader::getPosition ( ) const

virtual

Returns the position of the source as a sample count value.

Returns

The current position in the source. A negative value indicates that the position is unknown.

Warning

The value returned doesn't always have to be correct for readers, especially after seeking.

Implements IReader.

getSpecs()

virtual Specs FFMPEGReader::getSpecs ( ) const

virtual

Returns the specification of the reader.

Returns

The Specs structure.

Implements IReader.

isSeekable()

virtual bool FFMPEGReader::isSeekable ( ) const

virtual

Tells whether the source provides seeking functionality or not.

Warning

This doesn't mean that the seeking always has to succeed.

Returns

Always returns true for readers of buffering types.

Implements IReader.

queryStreams()

virtual std::vector< StreamInfo > FFMPEGReader::queryStreams ( )

virtual

Queries the streams of a sound file.

Returns

A vector with as many streams as there are in the file.

Exceptions

Exception

Thrown if the file specified cannot be read.

read()

virtual void FFMPEGReader::read ( int & length, bool & eos, sample_t * buffer )

virtual

Request to read the next length samples out of the source.

The buffer supplied has the needed size.

Parameters

[in,out]	length	The count of samples that should be read. Shall contain the real count of samples after reading, in case there were only fewer samples available. A smaller value also indicates the end of the reader.
[out]	eos	End of stream, whether the end is reached or not.
[in]	buffer	The pointer to the buffer to read into.

Implements IReader.

read_packet()

int FFMPEGReader::read_packet ( void * opaque, uint8_t * buf, int buf_size )

static

Reads data to a memory buffer.

This function is used for avio only.

Parameters

opaque	The FFMPEGReader.
buf	The buffer to read to.
buf_size	The size of the buffer.

Returns

How many bytes have been read.

seek()

virtual void FFMPEGReader::seek ( int position )

virtual

Seeks to a specific position in the source.

Parameters

position

The position to seek for measured in samples. To get from a given time to the samples you simply have to multiply the time value in seconds with the sample rate of the reader.

Warning

This may work or not, depending on the actual reader.

Implements IReader.

seek_packet()

int64_t FFMPEGReader::seek_packet ( void * opaque, int64_t offset, int whence )

static

Seeks within data.

This function is used for avio only.

Parameters

opaque	The FFMPEGReader.
offset	The byte offset to seek to.
whence	The seeking action.

Returns

The current position or the size of the data if requested.

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

• ffmpeg/FFMPEGReader.h