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annotate dev/gsm0611-silence-fr.c @ 183:452c1d5a6268

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libgsmefr BFI w/o data: emit zero output after decoder reset In real-life usage, each EFR decoder session will most likely begin with lots of BFI frames before the first real frame arrives. However, because the spec-defined home state of the decoder is speech rather than CN, our regular logic for BFI w/o data would have to feed pseudorandom noise to the decoder (in the "fixed codebook excitation pulses" part), which is silly to do at the beginning of the decoder session right out of reset. Therefore, let's check reset_flag_old, and if we are still in the reset state, simply emit zero output.
author Mychaela Falconia <falcon@freecalypso.org>
date Tue, 03 Jan 2023 00:12:18 +0000
parents 61cb83bd11ec
children e4ca04586118
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1 /*
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2 * This program is meant to be run only once by the developer - it uses
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3 * libgsm function gsm_implode() to transform the idle frame of GSM 06.11
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4 * (3GPP TS 46.011) from the table format given in the spec into
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5 * libgsm/RTP format.
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6 */
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7
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8 #include <stdio.h>
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9 #include <stdlib.h>
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10 #include <string.h>
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11 #include <strings.h>
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12 #include <gsm.h>
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14 static const gsm_signal lar_params[8] = {42, 39, 21, 10, 9, 4, 3, 2};
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15 static const gsm_signal subframe_params[17] =
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61cb83bd11ec GSM 06.11 silence frame: it's Nc=40 first, then bc=0
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16 {40, 0, 1, 0, 3, 4, 3, 4, 4, 3, 3, 3, 3, 4, 4, 3, 3};
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17
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18 main(argc, argv)
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19 char **argv;
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20 {
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21 gsm state;
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22 gsm_signal params[76];
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23 gsm_byte frame[33];
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24 unsigned n;
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25
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26 /* gsm_implode() requires dummy state */
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27 state = gsm_create();
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28 if (!state) {
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29 fprintf(stderr, "gsm_create() failed!\n");
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30 exit(1);
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31 }
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32 /* gather params */
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33 bcopy(lar_params, params, sizeof(gsm_signal) * 8);
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34 bcopy(subframe_params, params + 8, sizeof(gsm_signal) * 17);
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35 bcopy(subframe_params, params + 25, sizeof(gsm_signal) * 17);
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36 bcopy(subframe_params, params + 42, sizeof(gsm_signal) * 17);
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37 bcopy(subframe_params, params + 59, sizeof(gsm_signal) * 17);
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38 /* generate frame */
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39 gsm_implode(state, params, frame);
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40 /* print the frame */
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41 for (n = 0; n < 33; n++) {
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42 printf("0x%02X,", frame[n]);
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43 if (n == 4 || n == 11 || n == 18 || n == 25 || n == 32)
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44 putchar('\n');
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45 else
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46 putchar(' ');
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47 }
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48 exit(0);
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49 }