FreeCalypso > hg > gsm-codec-lib
annotate libgsmefr/residu.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> |
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date | Sat, 18 May 2024 22:30:42 +0000 |
parents | de9dc80c1312 |
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rev | line source |
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1 /************************************************************************* |
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2 * |
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3 * FUNCTION: Residu |
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4 * |
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5 * PURPOSE: Computes the LP residual. |
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6 * |
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7 * DESCRIPTION: |
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8 * The LP residual is computed by filtering the input speech through |
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9 * the LP inverse filter A(z). |
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10 * |
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11 *************************************************************************/ |
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12 |
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13 #include "gsm_efr.h" |
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14 #include "typedef.h" |
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15 #include "namespace.h" |
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16 #include "basic_op.h" |
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17 #include "no_count.h" |
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18 #include "sig_proc.h" |
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19 |
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20 /* m = LPC order == 10 */ |
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21 #define m 10 |
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22 |
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23 void Residu ( |
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24 Word16 a[], /* (i) : prediction coefficients */ |
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25 Word16 x[], /* (i) : speech signal */ |
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26 Word16 y[], /* (o) : residual signal */ |
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27 Word16 lg /* (i) : size of filtering */ |
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28 ) |
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29 { |
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30 Word16 i, j; |
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31 Word32 s; |
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32 |
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33 for (i = 0; i < lg; i++) |
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34 { |
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35 s = L_mult (x[i], a[0]); |
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36 for (j = 1; j <= m; j++) |
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37 { |
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38 s = L_mac (s, a[j], x[i - j]); |
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39 } |
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40 s = L_shl (s, 3); |
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41 y[i] = round (s); move16 (); |
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42 } |
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43 return; |
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44 } |