FreeCalypso > hg > gsm-codec-lib
view miscutil/efr2amr.c @ 183:452c1d5a6268
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 | 41f1ae68d253 |
children |
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/* * Our gsm-efr2amr utility reads in an EFR speech recording in our * extended-libgsm file format and converts it to AMR, inserting * an AMR NO_DATA frame in the place of every BFI in the input * but NOT performing any special handling or even detection of * EFR SID frames. */ #include <stdio.h> #include <stdint.h> #include <stdlib.h> #include <string.h> #include <strings.h> #include "../libtest/binreader.h" extern const uint8_t amr_122_bit_order[244]; static const char amr_file_hdr[] = "#!AMR\n"; main(argc, argv) char **argv; { char *infname, *outfname; FILE *inf, *outf; int wrong_flag; uint8_t frm_in[BINFILE_MAX_FRAME], frm_out[32]; unsigned bit_a, bit_n, outlen; int rc, bfi; if (argc == 3 && argv[1][0] != '-') { wrong_flag = 0; infname = argv[1]; outfname = argv[2]; } else if (argc == 4 && !strcmp(argv[1], "-w")) { wrong_flag = 1; infname = argv[2]; outfname = argv[3]; } else { fprintf(stderr, "usage: %s [-w] input.gsmx output.amr\n", argv[0]); exit(1); } inf = fopen(infname, "r"); if (!inf) { perror(infname); exit(1); } outf = fopen(outfname, "w"); if (!outf) { perror(outfname); exit(1); } fwrite(amr_file_hdr, 1, 6, outf); for (;;) { rc = binfile_read_frame(inf, frm_in); if (rc < 0) { fprintf(stderr, "error: garbage in %s\n", infname); exit(1); } if (!rc) break; if (frm_in[0] == 0xBF) bfi = 1; else if ((frm_in[0] & 0xF0) == 0xC0) bfi = 0; else { fprintf(stderr, "error: %s is not in EFR codec format\n", infname); exit(1); } if (bfi) { frm_out[0] = 0x78; outlen = 1; } else { frm_out[0] = 0x3C; frm_out[31] = 0; for (bit_a = 0; bit_a < 244; bit_a++) { if (wrong_flag) bit_n = bit_a; else bit_n = amr_122_bit_order[bit_a]; msb_set_bit(frm_out + 1, bit_a, msb_get_bit(frm_in, 4 + bit_n)); } outlen = 32; } fwrite(frm_out, 1, outlen, outf); } fclose(outf); exit(0); }