g723_1dec.c File Reference

G.723.1 compatible decoder. More...

#include "libavutil/channel_layout.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"
#include "acelp_vectors.h"
#include "avcodec.h"
#include "celp_filters.h"
#include "celp_math.h"
#include "get_bits.h"
#include "internal.h"
#include "g723_1.h"

Go to the source code of this file.

Macros
#define	BITSTREAM_READER_LE
#define	CNG_RANDOM_SEED   12345
#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

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 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 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)
	Perform 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 g723_1dec.c.

Macro Definition Documentation

#define BITSTREAM_READER_LE

Definition at line 32 of file g723_1dec.c.

#define CNG_RANDOM_SEED   12345

Definition at line 41 of file g723_1dec.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] * 65536) + (filter * 8) +\
                                   (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 507 of file g723_1dec.c.

Referenced by formant_postfilter().

#define OFFSET

(

x

)

offsetof(G723_1_Context, x)

Definition at line 1001 of file g723_1dec.c.

#define AD   AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM

Definition at line 1002 of file g723_1dec.c.

Function Documentation

static av_cold int g723_1_decode_init ( AVCodecContext *  avctx )

static

Definition at line 43 of file g723_1dec.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 68 of file g723_1dec.c.

Referenced by g723_1_decode_frame().

static int16_t square_root ( unsigned  val )

static

Bitexact implementation of sqrt(val/2).

Definition at line 183 of file g723_1dec.c.

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

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 199 of file g723_1dec.c.

Referenced by g723_1_decode_frame().

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 266 of file g723_1dec.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 299 of file g723_1dec.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 347 of file g723_1dec.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 433 of file g723_1dec.c.

Referenced by g723_1_decode_frame().

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

static

Perform 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 478 of file g723_1dec.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 532 of file g723_1dec.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 575 of file g723_1dec.c.

Referenced by g723_1_decode_frame().

static int sid_gain_to_lsp_index ( int  gain )

static

Definition at line 642 of file g723_1dec.c.

Referenced by g723_1_decode_frame().

static int cng_rand ( int *  state, int  base  )

inlinestatic

Definition at line 652 of file g723_1dec.c.

Referenced by generate_noise().

static int estimate_sid_gain ( G723_1_Context *  p )

static

Definition at line 658 of file g723_1dec.c.

Referenced by g723_1_decode_frame().

static void generate_noise ( G723_1_Context *  p )

static

Definition at line 712 of file g723_1dec.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 837 of file g723_1dec.c.

Variable Documentation

const AVOption options[]

static

Initial value:

= {
    { "postfilter", "enable postfilter", OFFSET(postfilter), AV_OPT_TYPE_BOOL,
      { .i64 = 1 }, 0, 1, AD },
    { NULL }
}

Definition at line 1004 of file g723_1dec.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 1011 of file g723_1dec.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   = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1,
    .priv_class     = &g723_1dec_class,
}

Definition at line 1018 of file g723_1dec.c.