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EQ FIR: Add check and removal for trailing zeros in filter coefficients 

This patch adds removing of extra zeros in the FIR coefficients. The
zeros can happen in some responses due to fixed point quantization of
very small values. The zero taps consume DSP resources for nothing so
better to clean them out for EQ configuration data.

Signed-off-by: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>
This commit is contained in:
Seppo Ingalsuo 2018-09-19 16:36:22 +03:00
parent d77beaf8bd
commit c43666d6f0
1 changed files with 18 additions and 2 deletions
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20
tune/eq/eq_fir_blob_quant.m
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@ -44,15 +44,31 @@ if nargin < 2
bits = 16;
end
%% Quantize
[bq, shift] = eq_fir_quantize(b, bits);
nb = length(bq);
%% Check trailing zeros
nf = length(bq);
nz = nf;
while bq(nz) == 0
nz = nz - 1;
end
if nz < nf
nb = nz + 1;
fprintf(1,'Note: Filter length was reduced to %d -> %d due to trailing zeros.\n', ...
nf, nb);
bq = bq(1:nb);
else
nb = nf;
end
%% Make length multiple of four (optimized FIR core)
mod4 = mod(nb, 4);
if mod4 > 0
pad = zeros(1,4-mod4);
bqp = [bq pad];
nnew = length(bqp);
fprintf(1,'Note: Filter length was %d, padded length into %d,\n', nb, nnew);
fprintf(1,'Note: Filter length was %d, padded length into %d.\n', nb, nnew);
else
nnew = nb;
bqp = bq;