DSP functions for ATRAC3+ decoder. More...

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

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. More...

av_cold void	ff_atrac3p_init_wave_synth (void)
	Initialize sine waves synthesizer. More...

static void	waves_synth (Atrac3pWaveSynthParams synth_param, Atrac3pWavesData waves_info, Atrac3pWaveEnvelope envelope, AVFloatDSPContext fdsp, int invert_phase, int reg_offset, float *out)
	Synthesize sine waves according to given parameters. More...

void	ff_atrac3p_generate_tones (Atrac3pChanUnitCtx ch_unit, AVFloatDSPContext fdsp, int ch_num, int sb, float *out)
	Synthesize sine waves for a particular subband. More...

void	ff_atrac3p_power_compensation (Atrac3pChanUnitCtx ctx, AVFloatDSPContext fdsp, int ch_index, float *sp, int rng_index, int sb)
	Perform power compensation aka noise dithering. More...

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. More...

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. More...

Variables
const uint16_t	ff_atrac3p_qu_to_spec_pos [33]
	Map quant unit number to its position in the spectrum. More...

const float	ff_atrac3p_sf_tab [64]

const float	ff_atrac3p_mant_tab [8]

static float	sine_table [2048]
	wave table More...

static float	hann_window [256]
	Hann windowing function. More...

static float	amp_sf_tab [64]
	scalefactors for quantized amplitudes More...

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. More...

static const int	subband_to_qu [17]
	Map subband number to quant unit number. More...

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

◆ ATRAC3P_MDCT_SIZE

#define ATRAC3P_MDCT_SIZE (ATRAC3P_SUBBAND_SAMPLES * 2)

Definition at line 78 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_imdct().

◆ TWOPI

#define TWOPI (2 * M_PI)

Definition at line 89 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_init_wave_synth().

◆ DEQUANT_PHASE

#define DEQUANT_PHASE ( ph ) (((ph) & 0x1F) << 6)

Definition at line 91 of file atrac3plusdsp.c.

Referenced by waves_synth().

Function Documentation

◆ ff_atrac3p_init_imdct()

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 80 of file atrac3plusdsp.c.

Referenced by atrac3p_decode_init().

◆ ff_atrac3p_init_wave_synth()

av_cold void ff_atrac3p_init_wave_synth ( void )

Initialize sine waves synthesizer.

Definition at line 97 of file atrac3plusdsp.c.

Referenced by atrac3p_decode_init().

◆ waves_synth()

static void waves_synth	(	Atrac3pWaveSynthParams *	synth_param,
		Atrac3pWavesData *	waves_info,
		Atrac3pWaveEnvelope *	envelope,
		AVFloatDSPContext *	fdsp,
		int	invert_phase,
		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]	fdsp	ptr to floating-point DSP context
[in]	invert_phase	flag indicating 180° phase shift
[in]	reg_offset	region offset for trimming envelope data
[out]	out	receives sythesized data

Definition at line 125 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_generate_tones().

◆ 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 184 of file atrac3plusdsp.c.

Referenced by reconstruct_frame().

◆ ff_atrac3p_power_compensation()

void ff_atrac3p_power_compensation	(	Atrac3pChanUnitCtx *	ctx,
		AVFloatDSPContext *	fdsp,
		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]	fdsp	pointer to float DSP 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 418 of file atrac3plusdsp.c.

Referenced by decode_residual_spectrum().

◆ ff_atrac3p_imdct()

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 464 of file atrac3plusdsp.c.

Referenced by reconstruct_frame().

◆ ff_atrac3p_ipqf()

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 605 of file atrac3plusdsp.c.

Referenced by reconstruct_frame().

Variable Documentation

◆ ff_atrac3p_qu_to_spec_pos

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 42 of file atrac3plusdsp.c.

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

◆ ff_atrac3p_sf_tab

const float ff_atrac3p_sf_tab[64]

Initial value:

= {
027852058,  0.0350914, 0.044212341, 0.055704117,  0.0701828,
088424683, 0.11140823,   0.1403656,  0.17684937, 0.22281647, 0.2807312, 0.35369873,
44563293,   0.5614624,  0.70739746,  0.89126587,  1.1229248, 1.4147949,  1.7825317,
2458496,    2.8295898,   3.5650635,   4.4916992,  5.6591797,  7.130127,  8.9833984,
318359,    14.260254,   17.966797,   22.636719,  28.520508, 35.933594,  45.273438,
041016,    71.867188,   90.546875,   114.08203,  143.73438, 181.09375,  228.16406,
46875,     362.1875,   456.32812,    574.9375,    724.375, 912.65625,   1149.875,
75,      1825.3125,     2299.75,      2897.5,   3650.625,    4599.5,     5795.0,
25,         9199.0,     11590.0,     14602.5,    18398.0,   23180.0,    29205.0,
0,        46360.0,     58410.0
}

Definition at line 52 of file atrac3plusdsp.c.

Referenced by decode_residual_spectrum(), and ff_atrac3p_power_compensation().

◆ ff_atrac3p_mant_tab

const float ff_atrac3p_mant_tab[8]

Initial value:

Definition at line 67 of file atrac3plusdsp.c.

Referenced by decode_residual_spectrum(), and ff_atrac3p_power_compensation().

◆ sine_table

float sine_table[2048]

static

wave table

Definition at line 93 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_init_wave_synth(), and waves_synth().

◆ hann_window

float hann_window[256]

static

Hann windowing function.

Definition at line 94 of file atrac3plusdsp.c.

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

◆ amp_sf_tab

float amp_sf_tab[64]

static

scalefactors for quantized amplitudes

Definition at line 95 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_init_wave_synth(), and waves_synth().

◆ subband_to_powgrp

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 251 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_power_compensation().

◆ noise_tab

const float noise_tab[1024]

static

Definition at line 256 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_power_compensation().

◆ pwc_levs

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 408 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_power_compensation().

◆ subband_to_qu

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 414 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_power_compensation().

◆ mod23_lut

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 496 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_ipqf().

◆ ipqf_coeffs1

const float ipqf_coeffs1[ATRAC3P_PQF_FIR_LEN][16]

static

Definition at line 502 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_ipqf().

◆ ipqf_coeffs2

const float ipqf_coeffs2[ATRAC3P_PQF_FIR_LEN][16]

static

Definition at line 554 of file atrac3plusdsp.c.

Referenced by ff_atrac3p_ipqf().

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ ATRAC3P_MDCT_SIZE

◆ TWOPI

◆ DEQUANT_PHASE

Function Documentation

◆ ff_atrac3p_init_imdct()

◆ ff_atrac3p_init_wave_synth()

◆ waves_synth()

◆ ff_atrac3p_generate_tones()

◆ ff_atrac3p_power_compensation()

◆ ff_atrac3p_imdct()

◆ ff_atrac3p_ipqf()

Variable Documentation

◆ ff_atrac3p_qu_to_spec_pos

◆ ff_atrac3p_sf_tab

◆ ff_atrac3p_mant_tab

◆ sine_table

◆ hann_window

◆ amp_sf_tab

◆ subband_to_powgrp

◆ noise_tab

◆ pwc_levs

◆ subband_to_qu

◆ mod23_lut

◆ ipqf_coeffs1

◆ ipqf_coeffs2