sspmod_snr_norm.c File Reference

Normalisation of dynamic range of filterbank energies. More...

Functions
int	spr_snr_norm_setup (SprSspInfo *Info, const char **descript, void *aux_info)
int	spr_snr_norm_process (SprSspInfo *Info, const void *frame_in, void *frame_out)
void	spr_snr_norm_reset (SprSspInfo *Info, SprSspStatus *action)
void	spr_snr_norm_free (SprSspInfo *Info)

Detailed Description

Normalisation of dynamic range of filterbank energies.

The masking algorithm adds a 'constant' to each of the frequency channels in the input file. The 'constants' are adapted depending on the measured dynamic range. The goal is a normalisation of the dynamic range in each frequency band.

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[snr_norm]
nfr <number>
Number of frames used for initial mask-values (constants) calculation. Set it to -1 if all frames should be used. Default 100. Overruled if a file with constants is given.
spdet_in <copy/move> <buf_name>
Name of the second input stream (named buffer). Speech detection information (1 or 0)
snr_t <number>
Target dynamic range (SNR), default 30 dB.
snr_m <number>
Minimum dynamic range (SNR), default 10 dB.
const_down <number>
Decrease exponential weight for constants, default 0.05.
const_up <number>
Increment (absolute) for constants, default 1500.
const_min <number>
Minimum value of constants, default 1000.
const_max <number>
Maximum value of constants, default 1.0e9.
min_up <number>
increase smoothing weight for minima, default 0.02.
max_down <number>
Decrease smoothing weight for maxima, default 0.02.
file <fname>
Starting constants are given in a file.

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Author

Tom Claes

Date

17 August 1995