qcelpdata.h File Reference

Data tables for the QCELP decoder. More...

#include <stddef.h>
#include <stdint.h>
#include "libavutil/common.h"

Go to the source code of this file.

Classes
struct	QCELPFrame
	QCELP unpacked data frame. More...
struct	QCELPBitmap

Macros
#define	QCELP_OF(variable, bit, len)   {offsetof(QCELPFrame, variable), bit, len}
#define	QCELP_SCALE   8192.
	The final gain scalefactor before clipping into a usable output float.
#define	QCELP_RATE_FULL_CODEBOOK_RATIO   .01
#define	QCELP_RATE_HALF_CODEBOOK_RATIO   0.5
#define	QCELP_SQRT1887   1.373681186
	sqrt(1.887) is the maximum of the pseudorandom white sequence used to generate the scaled codebook vector for bitrate 1/4. More...
#define	QCELP_LSP_SPREAD_FACTOR   0.02
	This spread factor is used, for bitrate 1/8 and I_F_Q, to force LSP frequencies to be at least 80 Hz apart. More...
#define	QCELP_LSP_OCTAVE_PREDICTOR   29.0/32
	Predictor coefficient for the conversion of LSP codes to LSP frequencies for 1/8 and I_F_Q. More...
#define	QCELP_BANDWIDTH_EXPANSION_COEFF   0.9883
	Initial coefficient to perform bandwidth expansion on LPC. More...

Typedefs
typedef struct QCELPFrame	QCELPFrame
	QCELP unpacked data frame.
typedef struct QCELPBitmap	QCELPBitmap
typedef uint16_t	qcelp_vector[2]

Detailed Description

Data tables for the QCELP decoder.

Author

Reynaldo H. Verdejo Pinochet

Remarks

FFmpeg merging spearheaded by Kenan Gillet

Development mentored by Benjamin Larson

Macro Definition Documentation

QCELP_BANDWIDTH_EXPANSION_COEFF

#define QCELP_BANDWIDTH_EXPANSION_COEFF   0.9883

Initial coefficient to perform bandwidth expansion on LPC.

Note

: 0.9883 looks like an approximation of 253/256.

TIA/EIA/IS-733 2.4.3.3.6 6

QCELP_LSP_OCTAVE_PREDICTOR

#define QCELP_LSP_OCTAVE_PREDICTOR   29.0/32

Predictor coefficient for the conversion of LSP codes to LSP frequencies for 1/8 and I_F_Q.

TIA/EIA/IS-733 2.4.3.2.7-2

QCELP_LSP_SPREAD_FACTOR

#define QCELP_LSP_SPREAD_FACTOR   0.02

This spread factor is used, for bitrate 1/8 and I_F_Q, to force LSP frequencies to be at least 80 Hz apart.

TIA/EIA/IS-733 2.4.3.3.2

QCELP_SQRT1887

#define QCELP_SQRT1887   1.373681186

sqrt(1.887) is the maximum of the pseudorandom white sequence used to generate the scaled codebook vector for bitrate 1/4.

TIA/EIA/IS-733 2.4.8.1.2