libavcodec/g723_1.c File Reference

G.723.1 compatible decoder. More...

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

Include dependency graph for libavcodec/g723_1.c:

Go to the source code of this file.

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. More...
#define	iir_filter(fir_coef, iir_coef, src, dest, width)
	Perform IIR filtering. More...
#define	OFFSET(x)   offsetof(G723_1_Context, x)
#define	AD   AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM

Typedefs
typedef struct g723_1_context	G723_1_Context

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. More...
static int16_t	square_root (unsigned val)
	Bitexact implementation of sqrt(val/2). More...
static int	normalize_bits (int num, int width)
	Calculate the number of left-shifts required for normalizing the input. More...
static int	scale_vector (int16_t *dst, const int16_t *vector, int length)
	Scale vector contents based on the largest of their absolutes. More...
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. More...
static void	lsp2lpc (int16_t *lpc)
	Convert LSP frequencies to LPC coefficients. More...
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. More...
static void	gen_dirac_train (int16_t *buf, int pitch_lag)
	Generate a train of dirac functions with period as pitch lag. More...
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. More...
static void	get_residual (int16_t *residual, int16_t *prev_excitation, int lag)
	Get delayed contribution from the previous excitation vector. More...
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. More...
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. More...
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. More...
static void	comp_ppf_coeff (G723_1_Context *p, int offset, int pitch_lag, PPFParam *ppf, enum Rate cur_rate)
	Calculate pitch postfilter parameters. More...
static int	comp_interp_index (G723_1_Context *p, int pitch_lag, int *exc_eng, int *scale)
	Classify frames as voiced/unvoiced. More...
static void	residual_interp (int16_t *buf, int16_t *out, int lag, int gain, int *rseed)
	Peform residual interpolation based on frame classification. More...
static void	gain_scale (G723_1_Context *p, int16_t *buf, int energy)
	Adjust gain of postfiltered signal. More...
static void	formant_postfilter (G723_1_Context *p, int16_t *lpc, int16_t *buf, int16_t *dst)
	Perform formant filtering. More...
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 libavcodec/g723_1.c.

Macro Definition Documentation

#define AD   AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM

Definition at line 1317 of file libavcodec/g723_1.c.

#define BITSTREAM_READER_LE

Definition at line 28 of file libavcodec/g723_1.c.

#define CNG_RANDOM_SEED   12345

Definition at line 41 of file libavcodec/g723_1.c.

Referenced by g723_1_decode_frame(), and g723_1_decode_init().

#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 822 of file libavcodec/g723_1.c.

Referenced by formant_postfilter().

#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 343 of file libavcodec/g723_1.c.

Referenced by lsp2lpc().

#define normalize_bits_int16

(

num

)

normalize_bits(num, 15)

Definition at line 244 of file libavcodec/g723_1.c.

#define normalize_bits_int32

(

num

)

normalize_bits(num, 31)

Definition at line 245 of file libavcodec/g723_1.c.

#define OFFSET

(

x

)

offsetof(G723_1_Context, x)

Definition at line 1316 of file libavcodec/g723_1.c.

Typedef Documentation

typedef struct g723_1_context G723_1_Context

Function Documentation

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 584 of file libavcodec/g723_1.c.

Referenced by comp_interp_index(), and comp_ppf_coeff().

static int cng_rand ( int *  state, int  base  )

inlinestatic

Definition at line 968 of file libavcodec/g723_1.c.

Referenced by generate_noise().

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 749 of file libavcodec/g723_1.c.

Referenced by g723_1_decode_frame().

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 665 of file libavcodec/g723_1.c.

Referenced by g723_1_decode_frame().

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 617 of file libavcodec/g723_1.c.

Referenced by comp_ppf_coeff().

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

static

Definition at line 538 of file libavcodec/g723_1.c.

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

static int estimate_sid_gain ( G723_1_Context *  p )

static

Definition at line 974 of file libavcodec/g723_1.c.

Referenced by g723_1_decode_frame().

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 890 of file libavcodec/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 1153 of file libavcodec/g723_1.c.

static av_cold int g723_1_decode_init ( AVCodecContext *  avctx )

static

Definition at line 86 of file libavcodec/g723_1.c.

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 847 of file libavcodec/g723_1.c.

Referenced by 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 547 of file libavcodec/g723_1.c.

Referenced by g723_1_decode_frame(), and generate_noise().

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 444 of file libavcodec/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 465 of file libavcodec/g723_1.c.

Referenced by g723_1_decode_frame().

static void generate_noise ( G723_1_Context *  p )

static

Definition at line 1028 of file libavcodec/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 525 of file libavcodec/g723_1.c.

Referenced by gen_acb_excitation().

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 275 of file libavcodec/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 351 of file libavcodec/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 421 of file libavcodec/g723_1.c.

Referenced by g723_1_decode_frame().

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 239 of file libavcodec/g723_1.c.

Referenced by comp_ppf_coeff(), and gain_scale().

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 793 of file libavcodec/g723_1.c.

Referenced by g723_1_decode_frame().

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 250 of file libavcodec/g723_1.c.

Referenced by comp_interp_index(), and formant_postfilter().

static int sid_gain_to_lsp_index ( int  gain )

static

Definition at line 958 of file libavcodec/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 226 of file libavcodec/g723_1.c.

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

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 111 of file libavcodec/g723_1.c.

Referenced by g723_1_decode_frame().

Variable Documentation

AVCodec ff_g723_1_decoder

Initial value:

= {
    .name           = "g723_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,
    .long_name      = NULL_IF_CONFIG_SMALL("G.723.1"),
    .capabilities   = CODEC_CAP_SUBFRAMES | CODEC_CAP_DR1,
    .priv_class     = &g723_1dec_class,
}

Definition at line 1333 of file libavcodec/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 1326 of file libavcodec/g723_1.c.

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 1319 of file libavcodec/g723_1.c.