FreeCalypso > hg > gsm-codec-lib
view miscutil/gsmx-to-tw5a.c @ 605:63f774192906
gsmhr_decoder_twts002_in(): set BFI=1 SID=1 for invalid SID
When a received TW-TS-002 RTP payload indicates invalid SID,
which of the 3 possible BFI/SID combinations should we pass to
our internal ETSI-based speech decoder or TFO engine?
Our original code passed BFI=0 SID=1, but upon further reflection,
BFI=1 SID=1 is a better choice. In the corner case where received
invalid SID is fed to a full decoder in homed state, setting BFI=1
allows that decoder to emit zeros on PCM and stay homed, instead of
launching into full decoding.
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Thu, 04 Dec 2025 21:01:46 +0000 |
| parents | 5595293e4f29 |
| children |
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/* * This program converts FR/EFR speech recordings from gsmx binary format * into more formally standardized TW-TS-005 Annex A format. * * FR and EFR frames are written in basic format (no TEH); * BFI marker records are converted into TW-TS-001 No_Data frames. */ #include <stdio.h> #include <stdint.h> #include <stdlib.h> #include <string.h> #include <strings.h> #include "../libgsmfr2/tw_gsmfr.h" #include "../libgsmefr/gsm_efr.h" #include "../libtest/binreader.h" #include "../libtest/tw5writer.h" main(argc, argv) char **argv; { FILE *binf, *outf; unsigned frame_index; uint8_t frame[BINFILE_MAX_FRAME]; int rc; if (argc != 3) { fprintf(stderr, "usage: %s input.gsmx output.hex\n", argv[0]); exit(1); } binf = fopen(argv[1], "r"); if (!binf) { perror(argv[1]); exit(1); } if (strcmp(argv[2], "-")) { outf = fopen(argv[2], "w"); if (!outf) { perror(argv[2]); exit(1); } } else outf = stdout; for (frame_index = 0; ; frame_index++) { rc = binfile_read_frame(binf, frame); if (rc < 0) { fprintf(stderr, "error: garbage in %s after %u frames\n", argv[1], frame_index); exit(1); } if (!rc) break; switch (frame[0] & 0xF0) { case 0xB0: fprintf(outf, "%02X\n", 0xE6 | frame[1] & 1); break; case 0xC0: emit_hex_frame(outf, frame, EFR_RTP_FRAME_LEN); break; case 0xD0: emit_hex_frame(outf, frame, GSMFR_RTP_FRAME_LEN); break; } } exit(0); }
