#include <float.h>
#include <string.h>
#include "libavutil/mathematics.h"
#include "mathops.h"
#include "avcodec.h"
#include "put_bits.h"
#include "aac.h"
#include "aacenc.h"
#include "aactab.h"
#include "aacenctab.h"

Macros
#define	NMR_SFBITS(d)
	AAC encoder NMR scalefactor coder.

#define	NMR_ITERS 14 /* lambda binary-search iters */

#define	NMR_IFINE 9 /* fine-pass lambda iters */

#define	NMR_CITERS 7 /* coarse-pass lambda iters */

#define	NMR_CWARM

#define	NMR_COARSE

#define	NMR_STEP 1 /* fine-pass scalefactor candidate granularity */

#define	NMR_PNS_BITS 9 /* approx cost in bits of signalling PNS */

#define	NMR_PNS_HOLE_FRAC 0.5f

#define	NMR_PNS_HOLE_SPREAD 0.5f

#define	NMR_PNS_HOLE_LAM 20.0f

#define	NMR_RC_K_CBR 0.5f

#define	NMR_RC_ITERS 8 /* lambda bisection iters when clamping an over-cap frame */

#define	NMR_RC_CORR 1.5f

#define	NMR_RC_CAPK 3.0f

#define	NMR_VBR_ANCHOR (-0.75f)

#define	NMR_VBR_TMIN (-3.8f)

#define	NMR_ABR_TMIN (-3.0f)

#define	NMR_ABR_TMAX 2.5f

#define	NMR_ABR_K 0.003f

#define	NMR_ABR_EMA 0.0023f

#define	NMR_ABR_STEP 0.15f

#define	NMR_ABR_HOLD 120

#define	NMR_ABR_BOOT_GAIN 1.2f

#define	NMR_ABR_TOL 0.02f

#define	NMR_ABR_BOOTS 6

#define	NMR_ABR_SETTLE 100

#define	NMR_INFL_HF 0.10f

#define	NMR_CBR_BUF 1536

#define	NMR_SLEW 1.6f

#define	NMR_SLEW_RUN 1.15f /* within short runs */

#define	NMR_RC_CITERS 3 /* corridor coarse-pass iters */

#define	NMR_TRANS_PM 2.0f

#define	NMR_ZERO_STICKY 0.5f

#define	NMR_GROUP_KEEP 0.25f

#define	NMR_HF_TAPER 0.08f

#define	NMR_HF_TAPER_KNEE 8000.0f

#define	NMR_BURST_GAP 10

#define	NMR_BURST_GAIN 8.0f

#define	NMR_SHORT_BOOST 2.0f

#define	NMR_RC_FITERS 4 /* corridor fine-pass iters */

#define	NMR_RC_TRACK 0.1f /* per-frame pull of the corridor centre toward the realized lambda */

#define	NMR_PNS_NDGATE 4.0f

#define	NMR_PNS_MAX_ET 8.0f

#define	NMR_PNS_LAM 100.0f

#define	NMR_PNS_ENTER 0.7f

#define	NMR_PNS_STAY 1.4f

#define	NMR_PNS_ON 8

#define	NMR_PNS_OFF 4

Functions
static float	nmr_solve (AACEncContext s, const float(nd)[NMR_NCAND], const int(nb)[NMR_NCAND], const int blo, const int bnc, int step, const int act, int nact, int destbits, int *chosen, float lo_l, float hi_l, int iters)
	Viterbi over the coding sequence act[0..nact-1] (indices into the per-band curves nd/nb), with lambda binary-searched so the coded size ~ destbits.

static int	nmr_band_curve (AACEncContext s, SingleChannelElement sce, int w, int g, int start, int lo, int step, int maxn, float invthr, float maxval, float nd_row, int nb_row)

static void	nmr_bail_channel (SingleChannelElement *sce)

static int	nmr_setup_channel (AVCodecContext avctx, AACEncContext s, SingleChannelElement sce, NMRSlot t)

static int	nmr_slot_bits (const NMRSlot t, const int(nb)[NMR_NCAND], int step)

static int	nmr_eval_slots (AACEncContext s, NMRSlot const *sl, int nsl, int step, float lam)

static float	nmr_solve_slots (AACEncContext s, NMRSlot const *sl, int nsl, int step, int destbits, float lo_l, float hi_l, int iters)

static float	nmr_nd_stat (AACEncContext s, NMRSlot const *sl, int nsl)

static float	nmr_solve_slots_nd (AACEncContext s, NMRSlot const *sl, int nsl, int step, float target, float lo_l, float hi_l, int iters)

static void	nmr_commit_channel (AACEncContext s, NMRSlot t)

static void	nmr_solve_group (AVCodecContext avctx, AACEncContext s, const float lambda, NMRSlot const sl, int nsl, int chans, int rc_eligible, int rc_global, int rc_rate_frame, int rc_bmax)

static void	search_for_quantizers_nmr (AVCodecContext avctx, AACEncContext s, SingleChannelElement *sce, const float lambda)

Macro Definition Documentation

◆ NMR_SFBITS

#define NMR_SFBITS ( d )

Value:

ff_aac_scalefactor_bits[av_clip((d) + SCALE_DIFF_ZERO, 0, 2*SCALE_MAX_DIFF)]

SCALE_MAX_DIFF

#define SCALE_MAX_DIFF

maximum scalefactor difference allowed by standard

Definition aac.h:94

SCALE_DIFF_ZERO

#define SCALE_DIFF_ZERO

codebook index corresponding to zero scalefactor indices difference

Definition aac.h:95

ff_aac_scalefactor_bits

const uint8_t ff_aac_scalefactor_bits[121]

Definition aactab.c:200

av_clip

#define av_clip

Definition common.h:100

AAC encoder NMR scalefactor coder.

Optimizes the same noise-to-mask objective as the two-loop coder, but with an optimal Viterbi search over scalefactors instead of a heuristic loop. For each coded band the per-scalefactor distortion/bits curve is precomputed, then a trellis over the (window-group, band) coding sequence minimizes sum_g = dist_g(sf_g)/threshold_g + lambda * (spectral_bits_g(sf_g) + scalefactor_differential_bits) with |sf_g - sf_{g-1}| <= SCALE_MAX_DIFF as a constraint, and lambda binary-searched so the coded size meets the per-frame bit budget

Perceptual noise substitution (PNS) is integrated into the same objective: once the trellis settles on its operating lambda, each noise-like band (flagged by mark_pns) is offered a terminal "code as noise" candidate whose cost is nmr_pns + lambda*NMR_PNS_BITS. Because NMR_PNS_BITS is far below a band's spectral bit count, this candidate only wins when lambda is large, i.e. when the encoder is struggling to hold the bitrate. The bits freed by the chosen PNS bands are then re-spent by a second trellis pass over the remaining bands.

Definition at line 58 of file aaccoder_nmr.h.

Referenced by nmr_solve().

◆ NMR_ITERS

#define NMR_ITERS 14 /* lambda binary-search iters */

Definition at line 60 of file aaccoder_nmr.h.

Macros

Functions

Macro Definition Documentation

◆ NMR_SFBITS

◆ NMR_ITERS

◆ NMR_IFINE

◆ NMR_CITERS

◆ NMR_CWARM

◆ NMR_COARSE

◆ NMR_STEP

◆ NMR_PNS_BITS

◆ NMR_PNS_HOLE_FRAC

◆ NMR_PNS_HOLE_SPREAD

◆ NMR_PNS_HOLE_LAM

◆ NMR_RC_K_CBR

◆ NMR_RC_ITERS

◆ NMR_RC_CORR

◆ NMR_RC_CAPK

◆ NMR_VBR_ANCHOR

◆ NMR_VBR_TMIN

◆ NMR_ABR_TMIN

◆ NMR_ABR_TMAX

◆ NMR_ABR_K

◆ NMR_ABR_EMA

◆ NMR_ABR_STEP

◆ NMR_ABR_HOLD

◆ NMR_ABR_BOOT_GAIN

◆ NMR_ABR_TOL

◆ NMR_ABR_BOOTS

◆ NMR_ABR_SETTLE

◆ NMR_INFL_HF

◆ NMR_CBR_BUF

◆ NMR_SLEW

◆ NMR_SLEW_RUN

◆ NMR_RC_CITERS

◆ NMR_TRANS_PM

◆ NMR_ZERO_STICKY

◆ NMR_GROUP_KEEP

◆ NMR_HF_TAPER

◆ NMR_HF_TAPER_KNEE

◆ NMR_BURST_GAP

◆ NMR_BURST_GAIN

◆ NMR_SHORT_BOOST

◆ NMR_RC_FITERS

◆ NMR_RC_TRACK

◆ NMR_PNS_NDGATE

◆ NMR_PNS_MAX_ET

◆ NMR_PNS_LAM

◆ NMR_PNS_ENTER

◆ NMR_PNS_STAY

◆ NMR_PNS_ON

◆ NMR_PNS_OFF

Function Documentation

◆ nmr_solve()

◆ nmr_band_curve()

◆ nmr_bail_channel()

◆ nmr_setup_channel()

◆ nmr_slot_bits()

◆ nmr_eval_slots()

◆ nmr_solve_slots()

◆ nmr_nd_stat()

◆ nmr_solve_slots_nd()

◆ nmr_commit_channel()

◆ nmr_solve_group()

◆ search_for_quantizers_nmr()