FreeCalypso > hg > gsm-codec-lib
view libgsmfrp/good_frame.c @ 123:92fdb499b5c3
doc/EFR-library-API article written
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Sat, 10 Dec 2022 22:01:14 +0000 |
parents | 4812e00bc100 |
children | f081a6850fb5 |
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/* * In this module we implement preprocessing of received good frames. */ #include <stdint.h> #include <string.h> #include "gsm_fr_preproc.h" #include "internal.h" void gsmfr_preproc_good_frame(struct gsmfr_preproc_state *st, gsm_byte *frame) { int sid; /* always set correct magic */ frame[0] = 0xD0 | frame[0] & 0x0F; /* now classify by SID */ sid = gsmfr_preproc_sid_classify(frame); switch (sid) { case 0: /* good speech frame */ memcpy(&st->speech_frame, frame, sizeof(gsm_frame)); st->rx_state = SPEECH; return; case 1: /* invalid SID frame */ if (st->got_valid_sid) { st->rx_state = COMFORT_NOISE; gsmfr_preproc_gen_cn(st, frame); } else { st->rx_state = NO_DATA; memcpy(frame, &gsmfr_preproc_silence_frame, sizeof(gsm_frame)); } return; case 2: /* valid SID frame */ st->got_valid_sid = 1; memcpy(st->sid_prefix, frame, 5); st->sid_xmaxc[0] = ((frame[6] & 0x1F) << 1) | (frame[7] >> 7); st->sid_xmaxc[1] = ((frame[13] & 0x1F) << 1) | (frame[14] >> 7); st->sid_xmaxc[2] = ((frame[20] & 0x1F) << 1) | (frame[21] >> 7); st->sid_xmaxc[3] = ((frame[27] & 0x1F) << 1) | (frame[28] >> 7); st->rx_state = COMFORT_NOISE; gsmfr_preproc_gen_cn(st, frame); return; } }