frame.h File Reference

Declaration of the mad_frame and mad_header structures, as libmad decoding units, and associated methods. More...

#include "fixed.h"
#include "timer.h"
#include "stream.h"

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Data Structures
struct	mad_header
	MPEG frame header information. More...
struct	mad_frame
	MPEG unit of encoding, and associated context. More...
Defines
#define	MAD_NCHANNELS(header)   ((header)->mode ? 2 : 1)
#define	MAD_NSBSAMPLES(header)
#define	mad_header_finish(header)
	Releases a mad_header structure after usage.
Enumerations
enum	mad_layer { MAD_LAYER_I = 1, MAD_LAYER_II = 2, MAD_LAYER_III = 3 }
enum	mad_mode { MAD_MODE_SINGLE_CHANNEL = 0, MAD_MODE_DUAL_CHANNEL = 1, MAD_MODE_JOINT_STEREO = 2, MAD_MODE_STEREO = 3 }
enum	mad_emphasis { MAD_EMPHASIS_NONE = 0, MAD_EMPHASIS_50_15_US = 1, MAD_EMPHASIS_CCITT_J_17 = 3, MAD_EMPHASIS_RESERVED = 2 }
enum	{   MAD_FLAG_NPRIVATE_III = 0x0007, MAD_FLAG_INCOMPLETE = 0x0008, MAD_FLAG_PROTECTION = 0x0010, MAD_FLAG_COPYRIGHT = 0x0020,   MAD_FLAG_ORIGINAL = 0x0040, MAD_FLAG_PADDING = 0x0080, MAD_FLAG_I_STEREO = 0x0100, MAD_FLAG_MS_STEREO = 0x0200,   MAD_FLAG_FREEFORMAT = 0x0400, MAD_FLAG_LSF_EXT = 0x1000, MAD_FLAG_MC_EXT = 0x2000, MAD_FLAG_MPEG_2_5_EXT = 0x4000 }
enum	{ MAD_PRIVATE_HEADER = 0x0100, MAD_PRIVATE_III = 0x001f }
Functions
void	mad_header_init (struct mad_header *)
	Initializes a newly created mad_header structure.
int	mad_header_decode (struct mad_header *, struct mad_stream *)
	Reads the next frame header from the stream.
void	mad_frame_init (struct mad_frame *)
	Initializes a frame struct.
void	mad_frame_finish (struct mad_frame *)
	Deallocates any dynamic memory associated with frame.
int	mad_frame_decode (struct mad_frame *, struct mad_stream *)
	Decodes a single frame from a bitstream.
void	mad_frame_mute (struct mad_frame *)
	Zeroes all subband values so the frame becomes silent.

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Detailed Description

Declaration of the mad_frame and mad_header structures, as libmad decoding units, and associated methods.

Definition in file frame.h.

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Define Documentation

#define mad_header_finish

(

header

)

Releases a mad_header structure after usage.

nothing

Definition at line 119 of file frame.h.

Referenced by mad_frame_finish().

#define MAD_NCHANNELS

(

header

)

((header)->mode ? 2 : 1)

Definition at line 85 of file frame.h.

Referenced by mad_layer_I(), mad_layer_II(), mad_layer_III(), and mad_synth_frame().

#define MAD_NSBSAMPLES

(

header

)

Value:

((header)->layer == MAD_LAYER_I ? 12 :  \
   (((header)->layer == MAD_LAYER_III &&  \
     ((header)->flags & MAD_FLAG_LSF_EXT)) ? 18 : 36))

Definition at line 86 of file frame.h.

Referenced by mad_header_decode(), and mad_synth_frame().

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Enumeration Type Documentation

anonymous enum

Enumerator:

MAD_FLAG_NPRIVATE_III	number of Layer III private bits
MAD_FLAG_INCOMPLETE	header but not data is decoded
MAD_FLAG_PROTECTION	frame has CRC protection
MAD_FLAG_COPYRIGHT	frame is copyright
MAD_FLAG_ORIGINAL	frame is original (else copy)
MAD_FLAG_PADDING	frame has additional slot
MAD_FLAG_I_STEREO	uses intensity joint stereo
MAD_FLAG_MS_STEREO	uses middle/side joint stereo
MAD_FLAG_FREEFORMAT	uses free format bitrate
MAD_FLAG_LSF_EXT	lower sampling freq. extension
MAD_FLAG_MC_EXT	multichannel audio extension
MAD_FLAG_MPEG_2_5_EXT	MPEG 2.5 (unofficial) extension.

Definition at line 91 of file frame.h.

anonymous enum

Enumerator:

MAD_PRIVATE_HEADER	header private bit
MAD_PRIVATE_III	Layer III private bits (up to 5).

Definition at line 109 of file frame.h.

enum mad_emphasis

Enumerator:

MAD_EMPHASIS_NONE	no emphasis
MAD_EMPHASIS_50_15_US	50/15 microseconds emphasis
MAD_EMPHASIS_CCITT_J_17	CCITT J.17 emphasis.
MAD_EMPHASIS_RESERVED	unknown emphasis

Definition at line 45 of file frame.h.

enum mad_layer

Enumerator:

MAD_LAYER_I	Layer I.
MAD_LAYER_II	Layer II.
MAD_LAYER_III	Layer III.

Definition at line 32 of file frame.h.

enum mad_mode

Enumerator:

MAD_MODE_SINGLE_CHANNEL	single channel
MAD_MODE_DUAL_CHANNEL	dual channel
MAD_MODE_JOINT_STEREO	joint (MS/intensity) stereo
MAD_MODE_STEREO	normal LR stereo

Definition at line 38 of file frame.h.

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Function Documentation

int mad_frame_decode	(	struct mad_frame *	,
		struct mad_stream *
	)

Decodes a single frame from a bitstream.

Definition at line 434 of file frame.c.

References mad_stream::anc_bitlen, mad_stream::anc_ptr, decoder_table, mad_stream::error, mad_header::flags, mad_frame::header, mad_header::layer, mad_bit_finish, mad_bit_init(), mad_bit_length(), MAD_FLAG_INCOMPLETE, mad_header_decode(), MAD_LAYER_III, MAD_RECOVERABLE, mad_stream::next_frame, mad_stream::options, mad_frame::options, mad_stream::ptr, and mad_stream::this_frame.

Referenced by run_sync().

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void mad_frame_finish

(

struct mad_frame *

)

Deallocates any dynamic memory associated with frame.

Definition at line 105 of file frame.c.

References mad_frame::header, mad_header_finish, and mad_frame::overlap.

Referenced by run_sync().

void mad_frame_init

(

struct mad_frame *

)

Initializes a frame struct.

Definition at line 92 of file frame.c.

References mad_frame::header, mad_frame_mute(), mad_header_init(), mad_frame::options, and mad_frame::overlap.

Referenced by run_sync().

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void mad_frame_mute

(

struct mad_frame *

)

Zeroes all subband values so the frame becomes silent.

Definition at line 479 of file frame.c.

References mad_frame::overlap, s, and mad_frame::sbsample.

Referenced by error_default(), and mad_frame_init().

int mad_header_decode	(	struct mad_header *	,
		struct mad_stream *
	)

Reads the next frame header from the stream.

Definition at line 297 of file frame.c.

References mad_header::bitrate, mad_stream::bufend, decode_header(), mad_header::duration, mad_stream::error, mad_header::flags, free_bitrate(), mad_stream::freerate, mad_header::layer, mad_bit_init(), mad_bit_nextbyte(), MAD_BUFFER_GUARD, MAD_ERROR_BUFLEN, MAD_ERROR_BUFPTR, MAD_ERROR_LOSTSYNC, MAD_FLAG_FREEFORMAT, MAD_FLAG_INCOMPLETE, MAD_FLAG_LSF_EXT, MAD_FLAG_PADDING, MAD_LAYER_I, MAD_LAYER_III, MAD_NSBSAMPLES, mad_stream_sync(), mad_timer_set(), mad_stream::next_frame, mad_stream::ptr, mad_header::samplerate, mad_stream::skiplen, mad_stream::sync, and mad_stream::this_frame.

Referenced by mad_frame_decode(), and run_sync().

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void mad_header_init

(

struct mad_header *

)

Initializes a newly created mad_header structure.

Definition at line 70 of file frame.c.

References mad_header::bitrate, mad_header::crc_check, mad_header::crc_target, mad_header::duration, mad_header::emphasis, mad_header::flags, mad_header::layer, mad_timer_zero, mad_header::mode, mad_header::mode_extension, mad_header::private_bits, and mad_header::samplerate.

Referenced by mad_frame_init().