Osmocom GMR-1 AMBE vocoder private header. More...

#include <stdint.h>

Data Structures
struct	ambe_raw_params
	AMBE encoded frame raw parameters. More...

struct	ambe_subframe
	AMBE subframe parameters. More...

struct	ambe_synth
	AMBE synthesizer state. More...

struct	ambe_decoder
	AMBE decoder state. More...

Macros
#define	AMBE_RATE 8000
	AMBE sample rate (Hz)

#define	M_PIf (3.141592653589793f)
	Value of pi as a float.

Enumerations
enum	ambe_frame_type { AMBE_SPEECH , AMBE_SILENCE , AMBE_TONE }
	AMBE possible frame types. More...

Functions
void	ambe_decode_init (struct ambe_decoder *dec)
	Initializes decoder state. More...

void	ambe_decode_fini (struct ambe_decoder *dec)
	Release all resources associated with a decoder. More...

int	ambe_decode_frame (struct ambe_decoder dec, int16_t audio, int N, const uint8_t *frame, int bad)
	Decodes an AMBE frame to audio. More...

int	ambe_decode_dtx (struct ambe_decoder dec, int16_t audio, int N)
	Generates audio for DTX period. More...

void	ambe_frame_unpack_raw (struct ambe_raw_params rp, const uint8_t frame)
	Unpack a frame into its raw encoded parameters. More...

void	ambe_frame_decode_params (struct ambe_subframe sf, struct ambe_subframe sf_prev, struct ambe_raw_params *rp)
	Decodes the speech parameters for both subframes from raw params. More...

void	ambe_subframe_expand (struct ambe_subframe *sf)
	Expands the decoded subframe params to prepare for synthesis. More...

float	cosf_fast (float angle)
	Fast Cosinus approximation using a simple table. More...

float	sinf_fast (float angle)
	Fast Sinus approximation using a simple table. More...

void	ambe_fdct (float out, float in, int N, int M)
	Forward Discrete Cosine Transform (fDCT) More...

void	ambe_idct (float out, float in, int N, int M)
	Inverse Discrete Cosine Transform (iDCT) More...

void	ambe_fdft_fc (float out_i, float out_q, float *in, int N, int M)
	Forward Discrete Fourrier Transform (float->complex) More...

void	ambe_idft_cf (float out, float in_i, float *in_q, int N, int M)
	Inverse Discret Fourrier Transform (complex->float) More...

void	ambe_synth_init (struct ambe_synth *synth)
	Initialized Synthesizer state. More...

void	ambe_synth_enhance (struct ambe_synth synth, struct ambe_subframe sf)
	Apply the spectral magnitude enhancement on the subframe. More...

void	ambe_synth_audio (struct ambe_synth synth, int16_t audio, struct ambe_subframe sf, struct ambe_subframe sf_prev)
	Generate audio for a given subframe. More...

int	ambe_decode_tone (struct ambe_decoder dec, int16_t audio, int N, const uint8_t *frame)
	Decodes an AMBE tone frame. More...

Variables
const uint8_t	ambe_hpg_tbl [48][4]
	Number of harmonics per group for a given L (starts at L=9)

const float	ambe_gain_tbl [256][2]
	Gain (subframe 0, subframe 1)

const uint16_t	ambe_v_uv_tbl [64]
	V/UV decisions (subframe 0 = low byte. MSBs = low freq)

const float	ambe_prba12_tbl [128][2]
	PRBA[1:2].

const float	ambe_prba34_tbl [64][2]
	PRBA[3:4].

const float	ambe_prba57_tbl [128][3]
	PRBA[5:7].

const float	ambe_hoc0_tbl [128][4]
	HOC for 1st frequency block.

const float	ambe_hoc1_tbl [64][4]
	HOC for 2nd frequency block.

const float	ambe_hoc2_tbl [64][4]
	HOC for 3rd frequency block.

const float	ambe_hoc3_tbl [64][4]
	HOC for last frequency block.

const float	ambe_sf0_interp_tbl [4]
	Interpolation ratios for subframe 0 magnitude prediction.

const float	ambe_sf0_perr14_tbl [64][4]
	Prediction Error [1:4] for subframe 0.

const float	ambe_sf0_perr58_tbl [32][4]
	Prediction Error [5:8] for subframe 0.

Detailed Description

Osmocom GMR-1 AMBE vocoder private header.

Data Structures

Macros

Enumerations

Functions

Variables

Detailed Description