atrac3plusdsp.c File Reference

DSP functions for ATRAC3+ decoder. More...

#include <math.h>
#include "libavutil/float_dsp.h"
#include "avcodec.h"
#include "sinewin.h"
#include "fft.h"
#include "atrac3plus.h"

Go to the source code of this file.

Macros
#define	ATRAC3P_MDCT_SIZE   (ATRAC3P_SUBBAND_SAMPLES * 2)
#define	TWOPI   (2 * M_PI)
#define	DEQUANT_PHASE(ph)   (((ph) & 0x1F) << 6)

Functions
av_cold void	ff_atrac3p_init_imdct (AVCodecContext *avctx, FFTContext *mdct_ctx)
	Initialize IMDCT transform.
av_cold void	ff_atrac3p_init_wave_synth (void)
	Initialize sine waves synthesizer.
static void	waves_synth (Atrac3pWaveSynthParams *synth_param, Atrac3pWavesData *waves_info, Atrac3pWaveEnvelope *envelope, int phase_shift, int reg_offset, float *out)
	Synthesize sine waves according to given parameters.
void	ff_atrac3p_generate_tones (Atrac3pChanUnitCtx *ch_unit, AVFloatDSPContext *fdsp, int ch_num, int sb, float *out)
	Synthesize sine waves for a particular subband.
void	ff_atrac3p_power_compensation (Atrac3pChanUnitCtx *ctx, int ch_index, float *sp, int rng_index, int sb)
	Perform power compensation aka noise dithering.
void	ff_atrac3p_imdct (AVFloatDSPContext *fdsp, FFTContext *mdct_ctx, float *pIn, float *pOut, int wind_id, int sb)
	Regular IMDCT and windowing without overlapping, with spectrum reversal in the odd subbands.
void	ff_atrac3p_ipqf (FFTContext *dct_ctx, Atrac3pIPQFChannelCtx *hist, const float *in, float *out)
	Subband synthesis filter based on the polyphase quadrature (pseudo-QMF) filter bank.

Variables
const uint16_t	ff_atrac3p_qu_to_spec_pos [33]
	Map quant unit number to its position in the spectrum.
const float	ff_atrac3p_sf_tab [64]
const float	ff_atrac3p_mant_tab [8]
static float	sine_table [2048]
	wave table
static float	hann_window [256]
	Hann windowing function.
static float	amp_sf_tab [64]
	scalefactors for quantized amplitudes
static const int	subband_to_powgrp [ATRAC3P_SUBBANDS]
static const float	noise_tab [1024]
static const float	pwc_levs [16]
	Noise level table for power compensation.
static const int	subband_to_qu [17]
	Map subband number to quant unit number.
static const int	mod23_lut [26]
static const float	ipqf_coeffs1 [ATRAC3P_PQF_FIR_LEN][16]
static const float	ipqf_coeffs2 [ATRAC3P_PQF_FIR_LEN][16]

Detailed Description

DSP functions for ATRAC3+ decoder.

Definition in file atrac3plusdsp.c.

Macro Definition Documentation

#define ATRAC3P_MDCT_SIZE   (ATRAC3P_SUBBAND_SAMPLES * 2)

Definition at line 77 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_imdct().

#define TWOPI   (2 * M_PI)

Definition at line 88 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_init_wave_synth().

#define DEQUANT_PHASE

(

ph

)

(((ph) & 0x1F) << 6)

Definition at line 90 of file atrac3plusdsp.c.

Referenced by waves_synth().

Function Documentation

av_cold void ff_atrac3p_init_imdct	(	AVCodecContext *	avctx,
		FFTContext *	mdct_ctx
	)

Initialize IMDCT transform.

Parameters

[in]	avctx	ptr to the AVCodecContext
[in]	mdct_ctx	pointer to MDCT transform context

Definition at line 79 of file atrac3plusdsp.c.

Referenced by atrac3p_decode_init().

av_cold void ff_atrac3p_init_wave_synth

(

void

)

Initialize sine waves synthesizer.

Definition at line 96 of file atrac3plusdsp.c.

Referenced by atrac3p_decode_init().

static void waves_synth ( Atrac3pWaveSynthParams *  synth_param, Atrac3pWavesData *  waves_info, Atrac3pWaveEnvelope *  envelope, int  phase_shift, int  reg_offset, float *  out  )

static

Synthesize sine waves according to given parameters.

Parameters

[in]	synth_param	ptr to common synthesis parameters
[in]	waves_info	parameters for each sine wave
[in]	envelope	envelope data for all waves in a group
[in]	phase_shift	flag indicates 180° phase shift
[in]	reg_offset	region offset for trimming envelope data
[out]	out	receives sythesized data

Definition at line 123 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_generate_tones().

void ff_atrac3p_generate_tones	(	Atrac3pChanUnitCtx *	ch_unit,
		AVFloatDSPContext *	fdsp,
		int	ch_num,
		int	sb,
		float *	out
	)

Synthesize sine waves for a particular subband.

Parameters

[in]	ch_unit	pointer to the channel unit context
[in]	fdsp	pointer to float DSP context
[in]	ch_num	which channel to process
[in]	sb	which subband to process
[out]	out	receives processed data

Definition at line 177 of file atrac3plusdsp.c.

Referenced by reconstruct_frame().

void ff_atrac3p_power_compensation	(	Atrac3pChanUnitCtx *	ctx,
		int	ch_index,
		float *	sp,
		int	rng_index,
		int	sb_num
	)

Perform power compensation aka noise dithering.

Parameters

[in]	ctx	ptr to the channel context
[in]	ch_index	which channel to process
[in,out]	sp	ptr to channel spectrum to process
[in]	rng_index	indicates which RNG table to use
[in]	sb_num	which subband to process

Definition at line 411 of file atrac3plusdsp.c.

Referenced by decode_residual_spectrum().

void ff_atrac3p_imdct	(	AVFloatDSPContext *	fdsp,
		FFTContext *	mdct_ctx,
		float *	pIn,
		float *	pOut,
		int	wind_id,
		int	sb
	)

Regular IMDCT and windowing without overlapping, with spectrum reversal in the odd subbands.

Parameters

[in]	fdsp	pointer to float DSP context
[in]	mdct_ctx	pointer to MDCT transform context
[in]	pIn	float input
[out]	pOut	float output
[in]	wind_id	which MDCT window to apply
[in]	sb	subband number

Definition at line 457 of file atrac3plusdsp.c.

Referenced by reconstruct_frame().

void ff_atrac3p_ipqf	(	FFTContext *	dct_ctx,
		Atrac3pIPQFChannelCtx *	hist,
		const float *	in,
		float *	out
	)

Subband synthesis filter based on the polyphase quadrature (pseudo-QMF) filter bank.

Parameters

[in]	dct_ctx	ptr to the pre-initialized IDCT context
[in,out]	hist	ptr to the filter history
[in]	in	input data to process
[out]	out	receives processed data

Definition at line 598 of file atrac3plusdsp.c.

Referenced by reconstruct_frame().

Variable Documentation

const uint16_t ff_atrac3p_qu_to_spec_pos[33]

Initial value:

= {
      0,    16,   32,   48,   64,   80,   96,  112,
    128,   160,  192,  224,  256,  288,  320,  352,
    384,   448,  512,  576,  640,  704,  768,  896,
    1024, 1152, 1280, 1408, 1536, 1664, 1792, 1920,
    2048
}

Map quant unit number to its position in the spectrum.

To get the number of spectral lines in each quant unit do the following: num_specs = qu_to_spec_pos[i+1] - qu_to_spec_pos[i]

Definition at line 41 of file atrac3plusdsp.c.

Referenced by decode_residual_spectrum(), decode_spectrum(), and ff_atrac3p_power_compensation().

const float ff_atrac3p_sf_tab[64]

Initial value:

= {
    0.027852058,  0.0350914, 0.044212341, 0.055704117,  0.0701828,
    0.088424683, 0.11140823,   0.1403656,  0.17684937, 0.22281647, 0.2807312, 0.35369873,
    0.44563293,   0.5614624,  0.70739746,  0.89126587,  1.1229248, 1.4147949,  1.7825317,
    2.2458496,    2.8295898,   3.5650635,   4.4916992,  5.6591797,  7.130127,  8.9833984,
    11.318359,    14.260254,   17.966797,   22.636719,  28.520508, 35.933594,  45.273438,
    57.041016,    71.867188,   90.546875,   114.08203,  143.73438, 181.09375,  228.16406,
    287.46875,     362.1875,   456.32812,    574.9375,    724.375, 912.65625,   1149.875,
    1448.75,      1825.3125,     2299.75,      2897.5,   3650.625,    4599.5,     5795.0,
    7301.25,         9199.0,     11590.0,     14602.5,    18398.0,   23180.0,    29205.0,
    36796.0,        46360.0,     58410.0
}

Definition at line 51 of file atrac3plusdsp.c.

Referenced by decode_residual_spectrum(), and ff_atrac3p_power_compensation().

const float ff_atrac3p_mant_tab[8]

Initial value:

= {
    0.0,
    0.74801636,
    0.44882202,
    0.32058716,
    0.20400238,
    0.1496048,
    0.07239151,
    0.035619736
}

Definition at line 66 of file atrac3plusdsp.c.

Referenced by decode_residual_spectrum(), and ff_atrac3p_power_compensation().

float sine_table[2048]

static

wave table

Definition at line 92 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_init_wave_synth(), and waves_synth().

float hann_window[256]

static

Hann windowing function.

Definition at line 93 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_generate_tones(), ff_atrac3p_init_wave_synth(), and waves_synth().

float amp_sf_tab[64]

static

scalefactors for quantized amplitudes

Definition at line 94 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_init_wave_synth(), and waves_synth().

const int subband_to_powgrp[ATRAC3P_SUBBANDS]

static

Initial value:

= {
    0, 1, 1, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4
}

Definition at line 244 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_power_compensation().

const float noise_tab[1024]

static

Definition at line 249 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_power_compensation().

const float pwc_levs[16]

static

Initial value:

= {
    3.96875, 3.15625,     2.5,    2.0, 1.59375,   1.25,     1.0, 0.78125,
    0.625,       0.5, 0.40625, 0.3125,    0.25, 0.1875, 0.15625, 0.0
}

Noise level table for power compensation.

Equ: pow(2.0f, (double)(6 - i) / 3.0f) where i = 0...15

Definition at line 401 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_power_compensation().

const int subband_to_qu[17]

static

Initial value:

= {
    0, 8, 12, 16, 18, 20, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32
}

Map subband number to quant unit number.

Definition at line 407 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_power_compensation().

const int mod23_lut[26]

static

Initial value:

= {
    23,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,
    12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 0
}

Definition at line 489 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_ipqf().

const float ipqf_coeffs1[ATRAC3P_PQF_FIR_LEN][16]

static

Definition at line 495 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_ipqf().

const float ipqf_coeffs2[ATRAC3P_PQF_FIR_LEN][16]

static

Definition at line 547 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_ipqf().