FreeCalypso > hg > gsm-codec-lib
view amrefr/encode-r.c @ 604:54f0f1b74c25
libgsmhr1 TFO: require BFI=0 and SID=0 for homing
In order for a received frame to be recognized as DHF, we need
not only the correct bit pattern, but also BFI=0 and SID=0.
The BFI=0 requirement should be obvious, while the SID=0 requirement
is needed only for HR codec. With FR and EFR, SID classification
comes from the payload bits and no separate check is needed -
but in HR we get an out-of-band SID ternary flag. When SID=1,
no payload bits are used at all; when SID=2, we use only the first
33 bits of the payload. Therefore, it is proper to conditionalize
DHF acceptance on SID=0.
We already implemented this logic in the just finished full decoder;
now bring TFO code into agreement.
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Thu, 04 Dec 2025 19:40:35 +0000 |
| parents | 0c4e1bc06740 |
| children |
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/* * amrefr-encode-r is a counterpart to gsmefr-encode-r, implementing * "alternative EFR" by way of libtwamr. Unlike standard gsmefr-encode-r, * there is no -d option and no DTX support in this version. */ #include <stdio.h> #include <stdint.h> #include <stdlib.h> #include <string.h> #include <strings.h> #include "../libgsmefr/gsm_efr.h" #include "../libtwamr/tw_amr.h" #include "../libtest/roberead.h" main(argc, argv) char **argv; { FILE *inf, *binf; struct amr_encoder_state *state; int16_t pcm[160]; struct amr_param_frame amr_frame; uint8_t efr_frame[EFR_RTP_FRAME_LEN]; int rc; if (argc != 3) { fprintf(stderr, "usage: %s input.robe output.gsmx\n", argv[0]); exit(1); } inf = fopen(argv[1], "r"); if (!inf) { perror(argv[1]); exit(1); } binf = fopen(argv[2], "w"); if (!binf) { perror(argv[2]); exit(1); } state = amr_encoder_create(0, 0); if (!state) { perror("amr_encoder_create()"); exit(1); } for (;;) { rc = robe_get_pcm_block(inf, pcm); if (!rc) break; amr_encode_frame(state, MR122, pcm, &amr_frame); amr_dhf_subst_efr2(&amr_frame, pcm); EFR_params2frame(amr_frame.param, efr_frame); fwrite(efr_frame, 1, sizeof efr_frame, binf); } fclose(binf); exit(0); }
