G.723.1 compatible decoder. More...

#include "libavutil/channel_layout.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"
#include "avcodec.h"
#include "get_bits.h"
#include "acelp_vectors.h"
#include "celp_filters.h"
#include "celp_math.h"
#include "g723_1_data.h"
#include "internal.h"

Data Structures
struct	G723_1_Context

Macros
#define	BITSTREAM_READER_LE

#define	CNG_RANDOM_SEED 12345

#define	normalize_bits_int16(num) normalize_bits(num, 15)

#define	normalize_bits_int32(num) normalize_bits(num, 31)

#define	MULL2(a, b) MULL(a,b,15)
	Bitexact implementation of 2ab scaled by 1/2^16.

#define	iir_filter(fir_coef, iir_coef, src, dest, width)
	Perform IIR filtering.

#define	OFFSET(x) offsetof(G723_1_Context, x)

#define	AD AV_OPT_FLAG_AUDIO_PARAM \| AV_OPT_FLAG_DECODING_PARAM

Functions
static av_cold int	g723_1_decode_init (AVCodecContext *avctx)

static int	unpack_bitstream (G723_1_Context p, const uint8_t buf, int buf_size)
	Unpack the frame into parameters.

static int16_t	square_root (unsigned val)
	Bitexact implementation of sqrt(val/2).

static int	normalize_bits (int num, int width)
	Calculate the number of left-shifts required for normalizing the input.

static int	scale_vector (int16_t dst, const int16_t vector, int length)
	Scale vector contents based on the largest of their absolutes.

static void	inverse_quant (int16_t cur_lsp, int16_t prev_lsp, uint8_t *lsp_index, int bad_frame)
	Perform inverse quantization of LSP frequencies.

static void	lsp2lpc (int16_t *lpc)
	Convert LSP frequencies to LPC coefficients.

static void	lsp_interpolate (int16_t lpc, int16_t cur_lsp, int16_t *prev_lsp)
	Quantize LSP frequencies by interpolation and convert them to the corresponding LPC coefficients.

static void	gen_dirac_train (int16_t *buf, int pitch_lag)
	Generate a train of dirac functions with period as pitch lag.

static void	gen_fcb_excitation (int16_t vector, G723_1_Subframe subfrm, enum Rate cur_rate, int pitch_lag, int index)
	Generate fixed codebook excitation vector.

static void	get_residual (int16_t residual, int16_t prev_excitation, int lag)
	Get delayed contribution from the previous excitation vector.

static int	dot_product (const int16_t a, const int16_t b, int length)

static void	gen_acb_excitation (int16_t vector, int16_t prev_excitation, int pitch_lag, G723_1_Subframe *subfrm, enum Rate cur_rate)
	Generate adaptive codebook excitation.

static int	autocorr_max (const int16_t buf, int offset, int ccr_max, int pitch_lag, int length, int dir)
	Estimate maximum auto-correlation around pitch lag.

static void	comp_ppf_gains (int lag, PPFParam *ppf, enum Rate cur_rate, int tgt_eng, int ccr, int res_eng)
	Calculate pitch postfilter optimal and scaling gains.

static void	comp_ppf_coeff (G723_1_Context p, int offset, int pitch_lag, PPFParam ppf, enum Rate cur_rate)
	Calculate pitch postfilter parameters.

static int	comp_interp_index (G723_1_Context p, int pitch_lag, int exc_eng, int *scale)
	Classify frames as voiced/unvoiced.

static void	residual_interp (int16_t buf, int16_t out, int lag, int gain, int *rseed)
	Peform residual interpolation based on frame classification.

static void	gain_scale (G723_1_Context p, int16_t buf, int energy)
	Adjust gain of postfiltered signal.

static void	formant_postfilter (G723_1_Context p, int16_t lpc, int16_t buf, int16_t dst)
	Perform formant filtering.

static int	sid_gain_to_lsp_index (int gain)

static int	cng_rand (int *state, int base)

static int	estimate_sid_gain (G723_1_Context *p)

static void	generate_noise (G723_1_Context *p)

static int	g723_1_decode_frame (AVCodecContext avctx, void data, int got_frame_ptr, AVPacket avpkt)

Variables
static const AVOption	options []

static const AVClass	g723_1dec_class

AVCodec	ff_g723_1_decoder

Detailed Description

G.723.1 compatible decoder.

Definition in file g723_1.c.

Macro Definition Documentation

#define BITSTREAM_READER_LE

Definition at line 28 of file g723_1.c.

#define CNG_RANDOM_SEED 12345

Definition at line 40 of file g723_1.c.

Referenced by g723_1_decode_frame(), and g723_1_decode_init().

#define normalize_bits_int16 ( num ) normalize_bits(num, 15)

Definition at line 243 of file g723_1.c.

#define normalize_bits_int32 ( num ) normalize_bits(num, 31)

Definition at line 244 of file g723_1.c.

#define MULL2	(	a,
		b
	)	MULL(a,b,15)

Bitexact implementation of 2ab scaled by 1/2^16.

Parameters

a	32 bit multiplicand
b	16 bit multiplier

Definition at line 342 of file g723_1.c.

Referenced by lsp2lpc().

#define iir_filter	(	fir_coef,
		iir_coef,
		src,
		dest,
		width
	)

Value:

{\
    int m, n;\
    int res_shift = 16 & ~-(width);\
    int in_shift  = 16 - res_shift;\
\
    for (m = 0; m < SUBFRAME_LEN; m++) {\
        int64_t filter = 0;\
        for (n = 1; n <= LPC_ORDER; n++) {\
            filter -= (fir_coef)[n - 1] * (src)[m - n] -\
                      (iir_coef)[n - 1] * ((dest)[m - n] >> in_shift);\
        }\
\
        (dest)[m] = av_clipl_int32(((src)[m] << 16) + (filter << 3) +\
                                   (1 << 15)) >> res_shift;\
    }\
}

Perform IIR filtering.

Parameters

fir_coef	FIR coefficients
iir_coef	IIR coefficients
src	source vector
dest	destination vector
width	width of the output, 16 bits(0) / 32 bits(1)

Definition at line 821 of file g723_1.c.

Referenced by formant_postfilter().

#define OFFSET ( x ) offsetof(G723_1_Context, x)

Definition at line 1315 of file g723_1.c.

#define AD AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM

Definition at line 1316 of file g723_1.c.

Function Documentation

static av_cold int g723_1_decode_init ( AVCodecContext * avctx )

static

Definition at line 85 of file g723_1.c.

static int unpack_bitstream	(	G723_1_Context *	p,
		const uint8_t *	buf,
		int	buf_size
	)

static

Unpack the frame into parameters.

Parameters

p	the context
buf	pointer to the input buffer
buf_size	size of the input buffer

Definition at line 110 of file g723_1.c.

Referenced by g723_1_decode_frame().

static int16_t square_root ( unsigned val )

static

Bitexact implementation of sqrt(val/2).

Definition at line 225 of file g723_1.c.

Referenced by comp_ppf_gains(), gain_scale(), and generate_noise().

static int normalize_bits	(	int	num,
		int	width
	)

static

Calculate the number of left-shifts required for normalizing the input.

Parameters

num	input number
width	width of the input, 15 or 31 bits

Definition at line 238 of file g723_1.c.

Referenced by comp_ppf_coeff(), and gain_scale().

static int scale_vector	(	int16_t *	dst,
		const int16_t *	vector,
		int	length
	)

static

Scale vector contents based on the largest of their absolutes.

Definition at line 249 of file g723_1.c.

Referenced by comp_interp_index(), and formant_postfilter().

static void inverse_quant	(	int16_t *	cur_lsp,
		int16_t *	prev_lsp,
		uint8_t *	lsp_index,
		int	bad_frame
	)

static

Perform inverse quantization of LSP frequencies.

Parameters

cur_lsp	the current LSP vector
prev_lsp	the previous LSP vector
lsp_index	VQ indices
bad_frame	bad frame flag

Definition at line 274 of file g723_1.c.

Referenced by g723_1_decode_frame().

static void lsp2lpc ( int16_t * lpc )

static

Convert LSP frequencies to LPC coefficients.

Parameters

lpc	buffer for LPC coefficients

Definition at line 350 of file g723_1.c.

Referenced by lsp_interpolate().

static void lsp_interpolate	(	int16_t *	lpc,
		int16_t *	cur_lsp,
		int16_t *	prev_lsp
	)

static

Quantize LSP frequencies by interpolation and convert them to the corresponding LPC coefficients.

Parameters

lpc	buffer for LPC coefficients
cur_lsp	the current LSP vector
prev_lsp	the previous LSP vector

Definition at line 420 of file g723_1.c.

Referenced by g723_1_decode_frame().

static void gen_dirac_train	(	int16_t *	buf,
		int	pitch_lag
	)

static

Generate a train of dirac functions with period as pitch lag.

Definition at line 443 of file g723_1.c.

Referenced by gen_fcb_excitation().

static void gen_fcb_excitation	(	int16_t *	vector,
		G723_1_Subframe *	subfrm,
		enum Rate	cur_rate,
		int	pitch_lag,
		int	index
	)

static

Generate fixed codebook excitation vector.

Parameters

vector	decoded excitation vector
subfrm	current subframe
cur_rate	current bitrate
pitch_lag	closed loop pitch lag
index	current subframe index

Definition at line 464 of file g723_1.c.

Referenced by g723_1_decode_frame().

static void get_residual	(	int16_t *	residual,
		int16_t *	prev_excitation,
		int	lag
	)

static

Get delayed contribution from the previous excitation vector.

Definition at line 524 of file g723_1.c.

Referenced by gen_acb_excitation().

static int dot_product	(	const int16_t *	a,
		const int16_t *	b,
		int	length
	)

static

Definition at line 537 of file g723_1.c.

Referenced by autocorr_max(), comp_interp_index(), comp_ppf_coeff(), and formant_postfilter().

static void gen_acb_excitation	(	int16_t *	vector,
		int16_t *	prev_excitation,
		int	pitch_lag,
		G723_1_Subframe *	subfrm,
		enum Rate	cur_rate
	)

static

Generate adaptive codebook excitation.

Definition at line 546 of file g723_1.c.

Referenced by g723_1_decode_frame(), and generate_noise().

static int autocorr_max	(	const int16_t *	buf,
		int	offset,
		int *	ccr_max,
		int	pitch_lag,
		int	length,
		int	dir
	)

static

Estimate maximum auto-correlation around pitch lag.

Parameters

buf	buffer with offset applied
offset	offset of the excitation vector
ccr_max	pointer to the maximum auto-correlation
pitch_lag	decoded pitch lag
length	length of autocorrelation
dir	forward lag(1) / backward lag(-1)

Definition at line 583 of file g723_1.c.

Referenced by comp_interp_index(), and comp_ppf_coeff().

static void comp_ppf_gains	(	int	lag,
		PPFParam *	ppf,
		enum Rate	cur_rate,
		int	tgt_eng,
		int	ccr,
		int	res_eng
	)

static

Calculate pitch postfilter optimal and scaling gains.

Parameters

lag	pitch postfilter forward/backward lag
ppf	pitch postfilter parameters
cur_rate	current bitrate
tgt_eng	target energy
ccr	cross-correlation
res_eng	residual energy

Definition at line 616 of file g723_1.c.

Referenced by comp_ppf_coeff().

static void comp_ppf_coeff	(	G723_1_Context *	p,
		int	offset,
		int	pitch_lag,
		PPFParam *	ppf,
		enum Rate	cur_rate
	)

static

Calculate pitch postfilter parameters.

Parameters

p	the context
offset	offset of the excitation vector
pitch_lag	decoded pitch lag
ppf	pitch postfilter parameters
cur_rate	current bitrate

Definition at line 664 of file g723_1.c.

Referenced by g723_1_decode_frame().

static int comp_interp_index	(	G723_1_Context *	p,
		int	pitch_lag,
		int *	exc_eng,
		int *	scale
	)

static

Classify frames as voiced/unvoiced.

Parameters

p	the context
pitch_lag	decoded pitch_lag
exc_eng	excitation energy estimation
scale	scaling factor of exc_eng

Returns: residual interpolation index if voiced, 0 otherwise

Definition at line 748 of file g723_1.c.

Referenced by g723_1_decode_frame().

static void residual_interp	(	int16_t *	buf,
		int16_t *	out,
		int	lag,
		int	gain,
		int *	rseed
	)

static

Peform residual interpolation based on frame classification.

Parameters

buf	decoded excitation vector
out	output vector
lag	decoded pitch lag
gain	interpolated gain
rseed	seed for random number generator

Definition at line 792 of file g723_1.c.

Referenced by g723_1_decode_frame().

static void gain_scale	(	G723_1_Context *	p,
		int16_t *	buf,
		int	energy
	)

static

Adjust gain of postfiltered signal.

Parameters

p	the context
buf	postfiltered output vector
energy	input energy coefficient

Definition at line 846 of file g723_1.c.

Referenced by formant_postfilter().

static void formant_postfilter	(	G723_1_Context *	p,
		int16_t *	lpc,
		int16_t *	buf,
		int16_t *	dst
	)

static

Perform formant filtering.

Parameters

p	the context
lpc	quantized lpc coefficients
buf	input buffer
dst	output buffer

Definition at line 889 of file g723_1.c.

Referenced by g723_1_decode_frame().

static int sid_gain_to_lsp_index ( int gain )

static

Definition at line 957 of file g723_1.c.

Referenced by g723_1_decode_frame().

static int cng_rand	(	int *	state,
		int	base
	)

inlinestatic

Definition at line 967 of file g723_1.c.

Referenced by generate_noise().

static int estimate_sid_gain ( G723_1_Context * p )

static

Definition at line 973 of file g723_1.c.

Referenced by g723_1_decode_frame().

static void generate_noise ( G723_1_Context * p )

static

Definition at line 1027 of file g723_1.c.

Referenced by g723_1_decode_frame().

static int g723_1_decode_frame	(	AVCodecContext *	avctx,
		void *	data,
		int *	got_frame_ptr,
		AVPacket *	avpkt
	)

static

Definition at line 1152 of file g723_1.c.

Variable Documentation

const AVOption options[]

static

Initial value:

= {
    { "postfilter", "postfilter on/off", OFFSET(postfilter), AV_OPT_TYPE_INT,
      { .i64 = 1 }, 0, 1, AD },
    { NULL }
}

Definition at line 1318 of file g723_1.c.

const AVClass g723_1dec_class

static

Initial value:

= {
    .class_name = "G.723.1 decoder",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
}

Definition at line 1325 of file g723_1.c.

AVCodec ff_g723_1_decoder

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_decode_init,
    .decode         = g723_1_decode_frame,
    .capabilities   = CODEC_CAP_SUBFRAMES | CODEC_CAP_DR1,
    .priv_class     = &g723_1dec_class,
}

Definition at line 1332 of file g723_1.c.

Data Structures

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

Function Documentation

Variable Documentation