AMR pre-processing functions


Functions

static void apply_ir_filter (float *out, const AMRFixed *in, const float *filter)
 Circularly convolve a sparse fixed vector with a phase dispersion impulse response filter (D.6.2 of G.729 and 6.1.5 of AMR).
static const float * anti_sparseness (AMRContext *p, AMRFixed *fixed_sparse, const float *fixed_vector, float fixed_gain, float *out)
 Reduce fixed vector sparseness by smoothing with one of three IR filters.

Function Documentation

static const float* anti_sparseness ( AMRContext p,
AMRFixed fixed_sparse,
const float *  fixed_vector,
float  fixed_gain,
float *  out 
) [static]

Reduce fixed vector sparseness by smoothing with one of three IR filters.

Also know as "adaptive phase dispersion".

This implements 3GPP TS 26.090 section 6.1(5).

Parameters:
p the context
fixed_sparse algebraic codebook vector
fixed_vector unfiltered fixed vector
fixed_gain smoothed gain
out space for modified vector if necessary

Definition at line 724 of file amrnbdec.c.

Referenced by amrnb_decode_frame().

static void apply_ir_filter ( float *  out,
const AMRFixed in,
const float *  filter 
) [static]

Circularly convolve a sparse fixed vector with a phase dispersion impulse response filter (D.6.2 of G.729 and 6.1.5 of AMR).

Parameters:
out vector with filter applied
in source vector
filter phase filter coefficients
out[n] = sum(i,0,len-1){ in[i] * filter[(len + n - i)len] }

< filters at pitch lag*1 and *2

Definition at line 677 of file amrnbdec.c.

Referenced by anti_sparseness().


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