atrac3.c File Reference

ATRAC3 compatible decoder. More...

#include <math.h>
#include <stddef.h>
#include <stdio.h>
#include "libavutil/attributes.h"
#include "libavutil/float_dsp.h"
#include "libavutil/libm.h"
#include "avcodec.h"
#include "bytestream.h"
#include "fft.h"
#include "get_bits.h"
#include "internal.h"
#include "atrac.h"
#include "atrac3data.h"

Go to the source code of this file.

Data Structures
struct	GainBlock
struct	TonalComponent
struct	ChannelUnit
struct	ATRAC3Context

Macros
#define	JOINT_STEREO   0x12
#define	STEREO   0x2
#define	SAMPLES_PER_FRAME   1024
#define	MDCT_SIZE   512
#define	INTERPOLATE(old, new, nsample)   ((old) + (nsample) * 0.125 * ((new) - (old)))

Functions
static void	imlt (ATRAC3Context *q, float *input, float *output, int odd_band)
	Regular 512 points IMDCT without overlapping, with the exception of the swapping of odd bands caused by the reverse spectra of the QMF. More...
static int	decode_bytes (const uint8_t *input, uint8_t *out, int bytes)
static av_cold void	init_imdct_window (void)
static av_cold int	atrac3_decode_close (AVCodecContext *avctx)
static void	read_quant_spectral_coeffs (GetBitContext *gb, int selector, int coding_flag, int *mantissas, int num_codes)
	Mantissa decoding. More...
static int	decode_spectrum (GetBitContext *gb, float *output)
	Restore the quantized band spectrum coefficients. More...
static int	decode_tonal_components (GetBitContext *gb, TonalComponent *components, int num_bands)
	Restore the quantized tonal components. More...
static int	decode_gain_control (GetBitContext *gb, GainBlock *block, int num_bands)
	Decode gain parameters for the coded bands. More...
static int	add_tonal_components (float *spectrum, int num_components, TonalComponent *components)
	Combine the tonal band spectrum and regular band spectrum. More...
static void	reverse_matrixing (float *su1, float *su2, int *prev_code, int *curr_code)
static void	get_channel_weights (int index, int flag, float ch[2])
static void	channel_weighting (float *su1, float *su2, int *p3)
static int	decode_channel_sound_unit (ATRAC3Context *q, GetBitContext *gb, ChannelUnit *snd, float *output, int channel_num, int coding_mode)
	Decode a Sound Unit. More...
static int	decode_frame (AVCodecContext *avctx, const uint8_t *databuf, float **out_samples)
static int	atrac3_decode_frame (AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
static av_cold void	atrac3_init_static_data (void)
static av_cold int	atrac3_decode_init (AVCodecContext *avctx)

Variables
static float	mdct_window [MDCT_SIZE]
static VLC_TYPE	atrac3_vlc_table [4096][2]
static VLC	spectral_coeff_tab [7]
AVCodec	ff_atrac3_decoder

Detailed Description

ATRAC3 compatible decoder.

This decoder handles Sony's ATRAC3 data.

Container formats used to store ATRAC3 data: RealMedia (.rm), RIFF WAV (.wav, .at3), Sony OpenMG (.oma, .aa3).

To use this decoder, a calling application must supply the extradata bytes provided in the containers above.

Definition in file atrac3.c.

Macro Definition Documentation

#define JOINT_STEREO   0x12

Definition at line 51 of file atrac3.c.

Referenced by atrac3_decode_init(), decode_channel_sound_unit(), decode_frame(), and mp3lame_encode_init().

#define STEREO   0x2

Definition at line 52 of file atrac3.c.

Referenced by atrac3_decode_init(), libshine_encode_init(), and mp3lame_encode_init().

#define SAMPLES_PER_FRAME   1024

Definition at line 54 of file atrac3.c.

Referenced by atrac3_decode_frame(), atrac3_decode_init(), decode_spectrum(), and decode_tonal_components().

#define MDCT_SIZE   512

Definition at line 55 of file atrac3.c.

Referenced by imlt().

#define INTERPOLATE	(		old,
			new,
			nsample
	)		((old) + (nsample) * 0.125 * ((new) - (old)))

Definition at line 463 of file atrac3.c.

Referenced by channel_weighting(), and reverse_matrixing().

Function Documentation

static void imlt ( ATRAC3Context *  q, float *  input, float *  output, int  odd_band  )

static

Regular 512 points IMDCT without overlapping, with the exception of the swapping of odd bands caused by the reverse spectra of the QMF.

Parameters

odd_band

1 if the band is an odd band

Reverse the odd bands before IMDCT, this is an effect of the QMF transform or it gives better compression to do it this way. FIXME: It should be possible to handle this in imdct_calc for that to happen a modification of the prerotation step of all SIMD code and C code is needed. Or fix the functions before so they generate a pre reversed spectrum.

Definition at line 123 of file atrac3.c.

Referenced by decode_channel_sound_unit().

static int decode_bytes ( const uint8_t *  input, uint8_t *  out, int  bytes  )

static

Definition at line 149 of file atrac3.c.

Referenced by atrac3_decode_frame().

static av_cold void init_imdct_window ( void  )

static

Definition at line 172 of file atrac3.c.

Referenced by atrac3_init_static_data().

static av_cold int atrac3_decode_close ( AVCodecContext *  avctx )

static

Definition at line 187 of file atrac3.c.

Referenced by atrac3_decode_init().

static void read_quant_spectral_coeffs ( GetBitContext *  gb, int  selector, int  coding_flag, int *  mantissas, int  num_codes  )

static

Mantissa decoding.

Parameters

selector	which table the output values are coded with
coding_flag	constant length coding or variable length coding
mantissas	mantissa output table
num_codes	number of values to get

Definition at line 208 of file atrac3.c.

Referenced by decode_spectrum(), and decode_tonal_components().

static int decode_spectrum ( GetBitContext *  gb, float *  output  )

static

Restore the quantized band spectrum coefficients.

Returns

subband count, fix for broken specification/files

Definition at line 267 of file atrac3.c.

Referenced by decode_channel_sound_unit().

static int decode_tonal_components ( GetBitContext *  gb, TonalComponent *  components, int  num_bands  )

static

Restore the quantized tonal components.

Parameters

components	tonal components
num_bands	number of coded bands

Definition at line 325 of file atrac3.c.

Referenced by decode_channel_sound_unit().

static int decode_gain_control ( GetBitContext *  gb, GainBlock *  block, int  num_bands  )

static

Decode gain parameters for the coded bands.

Parameters

block	the gainblock for the current band
num_bands	amount of coded bands

Definition at line 409 of file atrac3.c.

Referenced by decode_channel_sound_unit().

static int add_tonal_components ( float *  spectrum, int  num_components, TonalComponent *  components  )

static

Combine the tonal band spectrum and regular band spectrum.

Parameters

spectrum	output spectrum buffer
num_components	number of tonal components
components	tonal components for this band

Returns

position of the last tonal coefficient

Definition at line 445 of file atrac3.c.

Referenced by decode_channel_sound_unit().

static void reverse_matrixing ( float *  su1, float *  su2, int *  prev_code, int *  curr_code  )

static

Definition at line 466 of file atrac3.c.

Referenced by decode_frame().

static void get_channel_weights ( int  index, int  flag, float  ch[2]  )

static

Definition at line 528 of file atrac3.c.

Referenced by channel_weighting().

static void channel_weighting ( float *  su1, float *  su2, int *  p3  )

static

Definition at line 541 of file atrac3.c.

Referenced by decode_frame().

static int decode_channel_sound_unit ( ATRAC3Context *  q, GetBitContext *  gb, ChannelUnit *  snd, float *  output, int  channel_num, int  coding_mode  )

static

Decode a Sound Unit.

Parameters

snd	the channel unit to be used
output	the decoded samples before IQMF in float representation
channel_num	channel number
coding_mode	the coding mode (JOINT_STEREO or regular stereo/mono)

Definition at line 572 of file atrac3.c.

Referenced by decode_frame().

static int decode_frame ( AVCodecContext *  avctx, const uint8_t *  databuf, float **  out_samples  )

static

Definition at line 639 of file atrac3.c.

Referenced by atrac3_decode_frame().

static int atrac3_decode_frame ( AVCodecContext *  avctx, void *  data, int *  got_frame_ptr, AVPacket *  avpkt  )

static

Definition at line 734 of file atrac3.c.

static av_cold void atrac3_init_static_data ( void  )

static

Definition at line 774 of file atrac3.c.

Referenced by atrac3_decode_init().

static av_cold int atrac3_decode_init ( AVCodecContext *  avctx )

static

Definition at line 792 of file atrac3.c.

Variable Documentation

float mdct_window[MDCT_SIZE]

static

Definition at line 113 of file atrac3.c.

Referenced by imlt(), and init_imdct_window().

VLC_TYPE atrac3_vlc_table[4096][2]

static

Definition at line 114 of file atrac3.c.

Referenced by atrac3_init_static_data().

VLC spectral_coeff_tab[7]

static

Definition at line 115 of file atrac3.c.

AVCodec ff_atrac3_decoder

Initial value:

= {
    .name             = "atrac3",
    .long_name        = NULL_IF_CONFIG_SMALL("ATRAC3 (Adaptive TRansform Acoustic Coding 3)"),
    .type             = AVMEDIA_TYPE_AUDIO,
    .id               = AV_CODEC_ID_ATRAC3,
    .priv_data_size   = sizeof(ATRAC3Context),
    .init             = atrac3_decode_init,
    .close            = atrac3_decode_close,
    .decode           = atrac3_decode_frame,
    .capabilities     = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1,
    .sample_fmts      = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
                                                        AV_SAMPLE_FMT_NONE },
}

Definition at line 928 of file atrac3.c.