G.723.1 compatible encoder. More...

#include <stdint.h>
#include <string.h>
#include "libavutil/channel_layout.h"
#include "libavutil/common.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"
#include "avcodec.h"
#include "celp_math.h"
#include "g723_1.h"
#include "internal.h"
#include "put_bits.h"

Macros
#define	BITSTREAM_WRITER_LE

#define	get_index(num, offset, size)
	Quantize the current LSP subvector. More...

Functions
static av_cold int	g723_1_encode_init (AVCodecContext *avctx)

static void	highpass_filter (int16_t buf, int16_t fir, int *iir)
	Remove DC component from the input signal. More...

static void	comp_autocorr (int16_t buf, int16_t autocorr)
	Estimate autocorrelation of the input vector. More...

static void	levinson_durbin (int16_t lpc, int16_t autocorr, int16_t error)
	Use Levinson-Durbin recursion to compute LPC coefficients from autocorrelation values. More...

static void	comp_lpc_coeff (int16_t buf, int16_t lpc)
	Calculate LPC coefficients for the current frame. More...

static void	lpc2lsp (int16_t lpc, int16_t prev_lsp, int16_t *lsp)

static void	lsp_quantize (uint8_t lsp_index, int16_t lsp, int16_t *prev_lsp)
	Vector quantize the LSP frequencies. More...

static void	iir_filter (int16_t fir_coef, int16_t iir_coef, int16_t src, int16_t dest)
	Perform IIR filtering. More...

static void	perceptual_filter (G723_1_Context p, int16_t flt_coef, int16_t unq_lpc, int16_t buf)
	Apply the formant perceptual weighting filter. More...

static int	estimate_pitch (int16_t *buf, int start)
	Estimate the open loop pitch period. More...

static void	comp_harmonic_coeff (int16_t buf, int16_t pitch_lag, HFParam hf)
	Compute harmonic noise filter parameters. More...

static void	harmonic_filter (HFParam hf, const int16_t src, int16_t *dest)
	Apply the harmonic noise shaping filter. More...

static void	harmonic_noise_sub (HFParam hf, const int16_t src, int16_t *dest)

static void	synth_percept_filter (int16_t qnt_lpc, int16_t perf_lpc, int16_t perf_fir, int16_t perf_iir, const int16_t src, int16_t dest, int scale)
	Combined synthesis and formant perceptual weighting filer. More...

static void	acb_search (G723_1_Context p, int16_t residual, int16_t impulse_resp, const int16_t buf, int index)
	Compute the adaptive codebook contribution. More...

static void	sub_acb_contrib (const int16_t residual, const int16_t impulse_resp, int16_t *buf)
	Subtract the adaptive codebook contribution from the input to obtain the residual. More...

static void	get_fcb_param (FCBParam optim, int16_t impulse_resp, int16_t *buf, int pulse_cnt, int pitch_lag)
	Quantize the residual signal using the fixed codebook (MP-MLQ). More...

static void	pack_fcb_param (G723_1_Subframe subfrm, FCBParam optim, int16_t *buf, int pulse_cnt)
	Encode the pulse position and gain of the current subframe. More...

static void	fcb_search (G723_1_Context p, int16_t impulse_resp, int16_t *buf, int index)
	Compute the fixed codebook excitation. More...

static int	pack_bitstream (G723_1_Context p, AVPacket avpkt)
	Pack the frame parameters into output bitstream. More...

static int	g723_1_encode_frame (AVCodecContext avctx, AVPacket avpkt, const AVFrame frame, int got_packet_ptr)

Variables
AVCodec	ff_g723_1_encoder

Detailed Description

G.723.1 compatible encoder.

Definition in file g723_1enc.c.

Macro Definition Documentation

◆ BITSTREAM_WRITER_LE

#define BITSTREAM_WRITER_LE

Definition at line 40 of file g723_1enc.c.

◆ get_index

#define get_index	(	num,
		offset,
		size
	)

Value:

{                                                                             \
    int error, max = -1;                                                      \
    int16_t temp[4];                                                          \
    int i, j;                                                                 \
                                                                              \
    for (i = 0; i < LSP_CB_SIZE; i++) {                                       \
        for (j = 0; j < size; j++){                                           \
            temp[j] = (weight[j + (offset)] * lsp_band##num[i][j] +           \
                      (1 << 14)) >> 15;                                       \
        }                                                                     \
        error  = ff_g723_1_dot_product(lsp + (offset), temp, size) << 1;      \
        error -= ff_g723_1_dot_product(lsp_band##num[i], temp, size);         \
        if (error > max) {                                                    \
            max = error;                                                      \
            lsp_index[num] = i;                                               \
        }                                                                     \
    }                                                                         \
}

Quantize the current LSP subvector.

Parameters

num	band number
offset	offset of the current subvector in an LPC_ORDER vector
size	size of the current subvector

Definition at line 292 of file g723_1enc.c.

Referenced by lsp_quantize().

Function Documentation

◆ g723_1_encode_init()

static av_cold int g723_1_encode_init ( AVCodecContext * avctx )

static

Definition at line 43 of file g723_1enc.c.

◆ highpass_filter()

static void highpass_filter	(	int16_t *	buf,
		int16_t *	fir,
		int *	iir
	)

static

Remove DC component from the input signal.

Parameters

buf	input signal
fir	zero memory
iir	pole memory

Definition at line 80 of file g723_1enc.c.

Referenced by g723_1_encode_frame().

◆ comp_autocorr()

static void comp_autocorr	(	int16_t *	buf,
		int16_t *	autocorr
	)

static

Estimate autocorrelation of the input vector.

Parameters

buf	input buffer
autocorr	autocorrelation coefficients vector

Definition at line 96 of file g723_1enc.c.

Referenced by comp_lpc_coeff().

◆ levinson_durbin()

static void levinson_durbin	(	int16_t *	lpc,
		int16_t *	autocorr,
		int16_t	error
	)

static

Use Levinson-Durbin recursion to compute LPC coefficients from autocorrelation values.

Parameters

lpc	LPC coefficients vector
autocorr	autocorrelation coefficients vector
error	prediction error

Definition at line 138 of file g723_1enc.c.

Referenced by comp_lpc_coeff().

◆ comp_lpc_coeff()

static void comp_lpc_coeff	(	int16_t *	buf,
		int16_t *	lpc
	)

static

Calculate LPC coefficients for the current frame.

Parameters

buf	current frame
prev_data	2 trailing subframes of the previous frame
lpc	LPC coefficients vector

Definition at line 182 of file g723_1enc.c.

Referenced by g723_1_encode_frame().

◆ lpc2lsp()

static void lpc2lsp	(	int16_t *	lpc,
		int16_t *	prev_lsp,
		int16_t *	lsp
	)

static

< coefficients of the sum and difference polynomials (F1, F2) ordered as f1[0], f2[0], ...., f1[5], f2[5]

Evaluate F1 and F2 at uniform intervals of pi/256 along the unit circle and check for zero crossings.

Definition at line 198 of file g723_1enc.c.

Referenced by g723_1_encode_frame().

◆ lsp_quantize()

static void lsp_quantize	(	uint8_t *	lsp_index,
		int16_t *	lsp,
		int16_t *	prev_lsp
	)

static

Vector quantize the LSP frequencies.

Parameters

lsp	the current lsp vector
prev_lsp	the previous lsp vector

Definition at line 318 of file g723_1enc.c.

Referenced by g723_1_encode_frame().

◆ iir_filter()

static void iir_filter	(	int16_t *	fir_coef,
		int16_t *	iir_coef,
		int16_t *	src,
		int16_t *	dest
	)

static

Perform IIR filtering.

Parameters

fir_coef	FIR coefficients
iir_coef	IIR coefficients
src	source vector
dest	destination vector

Definition at line 366 of file g723_1enc.c.

Referenced by perceptual_filter().

◆ perceptual_filter()

static void perceptual_filter	(	G723_1_Context *	p,
		int16_t *	flt_coef,
		int16_t *	unq_lpc,
		int16_t *	buf
	)

static

Apply the formant perceptual weighting filter.

Parameters

flt_coef	filter coefficients
unq_lpc	unquantized lpc vector

Definition at line 389 of file g723_1enc.c.

Referenced by g723_1_encode_frame().

◆ estimate_pitch()

static int estimate_pitch	(	int16_t *	buf,
		int	start
	)

static

Estimate the open loop pitch period.

Parameters

buf	perceptually weighted speech
start	estimation is carried out from this position

Definition at line 421 of file g723_1enc.c.

Referenced by g723_1_encode_frame().

◆ comp_harmonic_coeff()

static void comp_harmonic_coeff	(	int16_t *	buf,
		int16_t	pitch_lag,
		HFParam *	hf
	)

static

Compute harmonic noise filter parameters.

Parameters

buf	perceptually weighted speech
pitch_lag	open loop pitch period
hf	harmonic filter parameters

Definition at line 494 of file g723_1enc.c.

Referenced by g723_1_encode_frame().

◆ harmonic_filter()

static void harmonic_filter	(	HFParam *	hf,
		const int16_t *	src,
		int16_t *	dest
	)

static

Apply the harmonic noise shaping filter.

Parameters

hf	filter parameters

Definition at line 567 of file g723_1enc.c.

Referenced by g723_1_encode_frame().

◆ harmonic_noise_sub()

static void harmonic_noise_sub	(	HFParam *	hf,
		const int16_t *	src,
		int16_t *	dest
	)

static

Definition at line 577 of file g723_1enc.c.

Referenced by g723_1_encode_frame().

◆ synth_percept_filter()

static void synth_percept_filter	(	int16_t *	qnt_lpc,
		int16_t *	perf_lpc,
		int16_t *	perf_fir,
		int16_t *	perf_iir,
		const int16_t *	src,
		int16_t *	dest,
		int	scale
	)

static

Combined synthesis and formant perceptual weighting filer.

Parameters

qnt_lpc	quantized lpc coefficients
perf_lpc	perceptual filter coefficients
perf_fir	perceptual filter fir memory
perf_iir	perceptual filter iir memory
scale	the filter output will be scaled by 2^scale

Definition at line 596 of file g723_1enc.c.

Referenced by g723_1_encode_frame().

◆ acb_search()

static void acb_search	(	G723_1_Context *	p,
		int16_t *	residual,
		int16_t *	impulse_resp,
		const int16_t *	buf,
		int	index
	)

static

Compute the adaptive codebook contribution.

Parameters

buf	input signal
index	the current subframe index

Definition at line 638 of file g723_1enc.c.

Referenced by g723_1_encode_frame().

◆ sub_acb_contrib()

static void sub_acb_contrib	(	const int16_t *	residual,
		const int16_t *	impulse_resp,
		int16_t *	buf
	)

static

Subtract the adaptive codebook contribution from the input to obtain the residual.

Parameters

buf	target vector

Definition at line 756 of file g723_1enc.c.

Referenced by g723_1_encode_frame().

◆ get_fcb_param()

static void get_fcb_param	(	FCBParam *	optim,
		int16_t *	impulse_resp,
		int16_t *	buf,
		int	pulse_cnt,
		int	pitch_lag
	)

static

Quantize the residual signal using the fixed codebook (MP-MLQ).

Parameters

optim	optimized fixed codebook parameters
buf	excitation vector

Definition at line 776 of file g723_1enc.c.

Referenced by fcb_search().

◆ pack_fcb_param()

static void pack_fcb_param	(	G723_1_Subframe *	subfrm,
		FCBParam *	optim,
		int16_t *	buf,
		int	pulse_cnt
	)

static

Encode the pulse position and gain of the current subframe.

Parameters

optim	optimized fixed CB parameters
buf	excitation vector

Definition at line 931 of file g723_1enc.c.

Referenced by fcb_search().

◆ fcb_search()

static void fcb_search	(	G723_1_Context *	p,
		int16_t *	impulse_resp,
		int16_t *	buf,
		int	index
	)

static

Compute the fixed codebook excitation.

Parameters

buf	target vector
impulse_resp	impulse response of the combined filter

Definition at line 966 of file g723_1enc.c.

Referenced by g723_1_encode_frame().

◆ pack_bitstream()

static int pack_bitstream	(	G723_1_Context *	p,
		AVPacket *	avpkt
	)

static

Pack the frame parameters into output bitstream.

Parameters

frame	output buffer
size	size of the buffer

Definition at line 998 of file g723_1enc.c.

Referenced by g723_1_encode_frame().

◆ g723_1_encode_frame()

static int g723_1_encode_frame	(	AVCodecContext *	avctx,
		AVPacket *	avpkt,
		const AVFrame *	frame,
		int *	got_packet_ptr
	)

static

Compute the combined impulse response of the synthesis filter, formant perceptual weighting filter and harmonic noise shaping filter

Definition at line 1056 of file g723_1enc.c.

Variable Documentation

◆ ff_g723_1_encoder

AVCodec ff_g723_1_encoder

Initial value:

= {
    .name           = "g723_1",
    .long_name      = NULL_IF_CONFIG_SMALL("G.723.1"),
    .type           = AVMEDIA_TYPE_AUDIO,
    .id             = AV_CODEC_ID_G723_1,
    .priv_data_size = sizeof(G723_1_Context),
    .init           = g723_1_encode_init,
    .encode2        = g723_1_encode_frame,
    .sample_fmts    = (const enum AVSampleFormat[]) {
        AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_NONE
    },
}

Definition at line 1192 of file g723_1enc.c.

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ BITSTREAM_WRITER_LE

◆ get_index

Function Documentation

◆ g723_1_encode_init()

◆ highpass_filter()

◆ comp_autocorr()

◆ levinson_durbin()

◆ comp_lpc_coeff()

◆ lpc2lsp()

◆ lsp_quantize()

◆ iir_filter()

◆ perceptual_filter()

◆ estimate_pitch()

◆ comp_harmonic_coeff()

◆ harmonic_filter()

◆ harmonic_noise_sub()

◆ synth_percept_filter()

◆ acb_search()

◆ sub_acb_contrib()

◆ get_fcb_param()

◆ pack_fcb_param()

◆ fcb_search()

◆ pack_bitstream()

◆ g723_1_encode_frame()

Variable Documentation

◆ ff_g723_1_encoder