OStreamAudioEncoder Class Reference

#include <OStreamAudioEncoder.hh>

List of all members.

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Detailed Description

Utility class with reusable code. Depends on libavcodec/libavformat. Encodes PCM data packets to MP3 or, extendable, to other formats.

Definition at line 37 of file OStreamAudioEncoder.hh.

Public Member Functions
	OStreamAudioEncoder (unsigned int io_buf_size, ostream_encoding_type encoding_type, int num_channels=2)
	Constructor.
virtual	~OStreamAudioEncoder ()
const unsigned char *	encode_audio_frame (unsigned char *in_pcm_buffer, int in_pcm_buffer_size, int *out_size)
	Ecode an audio frame.
Private Member Functions
bool	encoder_initialize ()
	Initializing function for the encoder.
AVStream *	create_audio_stream (AVFormatContext *io_fmt_context, int codec_id)
	Use ffmpeg libraries to create an AVStream.
bool	open_codec (AVStream *stream)
	Open a codec, givin a stream.
bool	init_pcm_buffer (int size)
	Init an internal pcm data buffer.
void	free_pcm_buffer ()
	Free the pcm buffer.
int	read_pcm_buffer (unsigned char *buf, int buf_size)
	Get data from the ring buffer-.
void	write_pcm_buffer (const unsigned char *buf, int buf_size)
	Write data to the buffer ring.
Private Attributes
bool	_initialized
	Specify whether the class is initialized or not.
AVFormatContext *	_out_fmt_context
AVStream *	_audio_stream
AVOutputFormat *	_out_fmt
unsigned char *	_pcm_internal_buffer
	A buffer reserved for PCM data.
unsigned char *	_pcm_read_ptr
	Ring buffer controls.
unsigned char *	_pcm_write_ptr
unsigned char *	_pcm_end_ptr
unsigned char *	_internal_buffer
	Buffer internal used to encode.
int	_internal_buffer_size
	Size of internal buffer used to encode.
int	_encoding_type
	Enum parameter that specify the encoding type.
int	_frame_size
	Frame size of the dest packet format.
int	_encoded_frame_size
	Size of the encoded frame.
unsigned char *	_ready_to_encode_frame
	The encoded bytes will be contained here.
int	_num_channels
	Number of channels use in the encoding.

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Constructor & Destructor Documentation

OStreamAudioEncoder::OStreamAudioEncoder	(	unsigned int	io_buf_size,
		ostream_encoding_type	encoding_type,
		int	num_channels = 2
	)

Parameters:

	io_buf_size,:	internal buffer size used to store encoded frames. This must be <= fMaxSize, or liveMedia libraries will crash.
	encoding_type	A wrapper enum to use OStream encoding parameters.
	num_channels	Number of channel to encode: 1- mono, 2- stereo. Defaults to 2.

Note:

in case you want to add some new encoding type be sure to check all the "switch ( _encoding_type )" lines you'll find in the implementation file and to add them the correct parameters.

Definition at line 25 of file OStreamAudioEncoder.cpp.

References _initialized, _internal_buffer, _internal_buffer_size, _ready_to_encode_frame, DEBUG_PRINT, encoder_initialize(), and NULL.

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OStreamAudioEncoder::~OStreamAudioEncoder

(

)

[virtual]

Definition at line 46 of file OStreamAudioEncoder.cpp.

References _internal_buffer, _out_fmt_context, _ready_to_encode_frame, and free_pcm_buffer().

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Member Function Documentation

AVStream * OStreamAudioEncoder::create_audio_stream	(	AVFormatContext *	io_fmt_context,
		int	codec_id
	)			[private]

Parameters:

	io_fmt_context	Format context in a fmmpeg fashion.
	codec_id	CodecID in a ffmpeg fashion.

Returns:

New AVStream.

Definition at line 88 of file OStreamAudioEncoder.cpp.

References _num_channels, DEBUG_PRINT, and NULL.

Referenced by encoder_initialize().

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const unsigned char * OStreamAudioEncoder::encode_audio_frame	(	unsigned char *	in_pcm_buffer,
		int	in_pcm_buffer_size,
		int *	out_size
	)

Parameters:

	in_pcm_buffer	PCM data buffer.
	in_pcm_buffer_size	PCM data buffer size.
	out_size	Encoded frame size will be written here.

Returns:

The buffer with encoded data. Its size is written on out_size.

Definition at line 186 of file OStreamAudioEncoder.cpp.

References _audio_stream, _encoded_frame_size, _initialized, _internal_buffer, _internal_buffer_size, _ready_to_encode_frame, DEBUG_PRINT, NULL, read_pcm_buffer(), and write_pcm_buffer().

Referenced by MP3FromPCM::afterGettingFrame1().

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bool OStreamAudioEncoder::encoder_initialize

(

)

[private]

Returns:

true on success, false on insuccess.

Definition at line 115 of file OStreamAudioEncoder.cpp.

References _audio_stream, _encoded_frame_size, _encoding_type, _frame_size, _num_channels, _out_fmt, _out_fmt_context, _ready_to_encode_frame, create_audio_stream(), DEBUG_PRINT, init_pcm_buffer(), MAX_AUDIO_PACKET_SIZE, NULL, open_codec(), and OSTREAM_ENCODING_MP3.

Referenced by OStreamAudioEncoder().

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void OStreamAudioEncoder::free_pcm_buffer

(

)

[private]

Definition at line 241 of file OStreamAudioEncoder.cpp.

References _pcm_internal_buffer, and NULL.

Referenced by ~OStreamAudioEncoder().

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bool OStreamAudioEncoder::init_pcm_buffer

(

int

size

)

[private]

Parameters:

size

Size of the buffer.

Returns:

true on success.

Definition at line 228 of file OStreamAudioEncoder.cpp.

References _pcm_end_ptr, _pcm_internal_buffer, _pcm_read_ptr, and _pcm_write_ptr.

Referenced by encoder_initialize().

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bool OStreamAudioEncoder::open_codec

(

AVStream *

stream

)

[private]

Parameters:

stream

An already initialized stream. AVStream is an ffmpeg struct.

Returns:

true on success, false else.

Definition at line 65 of file OStreamAudioEncoder.cpp.

References DEBUG_PRINT.

Referenced by encoder_initialize().

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int OStreamAudioEncoder::read_pcm_buffer	(	unsigned char *	buf,
		int	buf_size
	)			[private]

Parameters:

	buf	The buffer where to store the data.
	buf_size	Buffer size.

Returns:

0 on success, -1 on insuccess.

Definition at line 247 of file OStreamAudioEncoder.cpp.

References _pcm_end_ptr, _pcm_internal_buffer, _pcm_read_ptr, and _pcm_write_ptr.

Referenced by encode_audio_frame().

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void OStreamAudioEncoder::write_pcm_buffer	(	const unsigned char *	buf,
		int	buf_size
	)			[private]

Parameters:

	buf	The buffer to add.
	buf_size	Buffer size.

Definition at line 275 of file OStreamAudioEncoder.cpp.

References _pcm_end_ptr, _pcm_internal_buffer, and _pcm_write_ptr.

Referenced by encode_audio_frame().

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Member Data Documentation

AVStream* OStreamAudioEncoder::_audio_stream [private]

See also:

ffmpeg doc for this structs

Definition at line 120 of file OStreamAudioEncoder.hh.

Referenced by encode_audio_frame(), and encoder_initialize().

int OStreamAudioEncoder::_encoded_frame_size [private]

It's _encoded_frame_size = _frame_size * 2 * _num_channels;

Definition at line 144 of file OStreamAudioEncoder.hh.

Referenced by encode_audio_frame(), and encoder_initialize().

int OStreamAudioEncoder::_encoding_type [private]

Definition at line 138 of file OStreamAudioEncoder.hh.

Referenced by encoder_initialize().

int OStreamAudioEncoder::_frame_size [private]

E.g. MP3 format.

Definition at line 141 of file OStreamAudioEncoder.hh.

Referenced by encoder_initialize().

bool OStreamAudioEncoder::_initialized [private]

Definition at line 114 of file OStreamAudioEncoder.hh.

Referenced by encode_audio_frame(), and OStreamAudioEncoder().

unsigned char* OStreamAudioEncoder::_internal_buffer [private]

Definition at line 132 of file OStreamAudioEncoder.hh.

Referenced by encode_audio_frame(), OStreamAudioEncoder(), and ~OStreamAudioEncoder().

int OStreamAudioEncoder::_internal_buffer_size [private]

Definition at line 135 of file OStreamAudioEncoder.hh.

Referenced by encode_audio_frame(), and OStreamAudioEncoder().

int OStreamAudioEncoder::_num_channels [private]

Definition at line 150 of file OStreamAudioEncoder.hh.

Referenced by create_audio_stream(), and encoder_initialize().

AVOutputFormat* OStreamAudioEncoder::_out_fmt [private]

See also:

ffmpeg doc for this structs

Definition at line 123 of file OStreamAudioEncoder.hh.

Referenced by encoder_initialize().

AVFormatContext* OStreamAudioEncoder::_out_fmt_context [private]

See also:

ffmpeg doc for this structs

Definition at line 117 of file OStreamAudioEncoder.hh.

Referenced by encoder_initialize(), and ~OStreamAudioEncoder().

unsigned char * OStreamAudioEncoder::_pcm_end_ptr [private]

Definition at line 129 of file OStreamAudioEncoder.hh.

Referenced by init_pcm_buffer(), read_pcm_buffer(), and write_pcm_buffer().

unsigned char* OStreamAudioEncoder::_pcm_internal_buffer [private]

Will be a ring buffer.

Definition at line 126 of file OStreamAudioEncoder.hh.

Referenced by free_pcm_buffer(), init_pcm_buffer(), read_pcm_buffer(), and write_pcm_buffer().

unsigned char* OStreamAudioEncoder::_pcm_read_ptr [private]

Definition at line 129 of file OStreamAudioEncoder.hh.

Referenced by init_pcm_buffer(), and read_pcm_buffer().

unsigned char * OStreamAudioEncoder::_pcm_write_ptr [private]

Definition at line 129 of file OStreamAudioEncoder.hh.

Referenced by init_pcm_buffer(), read_pcm_buffer(), and write_pcm_buffer().

unsigned char* OStreamAudioEncoder::_ready_to_encode_frame [private]

Definition at line 147 of file OStreamAudioEncoder.hh.

Referenced by encode_audio_frame(), encoder_initialize(), OStreamAudioEncoder(), and ~OStreamAudioEncoder().

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

• OStreamAudioEncoder.hh
• OStreamAudioEncoder.cpp

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