FreeCalypso > hg > gsm-codec-lib
view libgsmefr/convolve.c @ 477:4c9222d95647
libtwamr encoder: always emit frame->mode = mode;
In the original implementation of amr_encode_frame(), the 'mode' member
of the output struct was set to 0xFF if the output frame type is TX_NO_DATA.
This design was made to mimic the mode field (16-bit word) being set to
0xFFFF (or -1) in 3GPP test sequence format - but nothing actually depends
on this struct member being set in any way, and amr_frame_to_tseq()
generates the needed 0xFFFF on its own, based on frame->type being equal
to TX_NO_DATA.
It is simpler and more efficient to always set frame->mode to the actual
encoding mode in amr_encode_frame(), and this new behavior has already
been documented in doc/AMR-library-API description in anticipation of
the present change.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Sat, 18 May 2024 22:30:42 +0000 |
parents | 8de2f0f9bd78 |
children |
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/************************************************************************* * * FUNCTION: Convolve * * PURPOSE: * Perform the convolution between two vectors x[] and h[] and * write the result in the vector y[]. All vectors are of length L * and only the first L samples of the convolution are computed. * * DESCRIPTION: * The convolution is given by * * y[n] = sum_{i=0}^{n} x[i] h[n-i], n=0,...,L-1 * *************************************************************************/ #include "gsm_efr.h" #include "typedef.h" #include "namespace.h" #include "basic_op.h" #include "no_count.h" #include "sig_proc.h" void Convolve ( Word16 x[], /* (i) : input vector */ Word16 h[], /* (i) : impulse response */ Word16 y[], /* (o) : output vector */ Word16 L /* (i) : vector size */ ) { Word16 i, n; Word32 s; for (n = 0; n < L; n++) { s = 0; move32 (); for (i = 0; i <= n; i++) { s = L_mac (s, x[i], h[n - i]); } s = L_shl (s, 3); y[n] = extract_h (s); move16 (); } return; }