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
line wrap: on
line source

/*
 * 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);
}