view miscutil/efr2amr.c @ 122:b33f2168fdec

doc/EFR-rationale article written
author Mychaela Falconia <falcon@freecalypso.org>
date Sat, 10 Dec 2022 08:51:01 +0000
parents 41f1ae68d253
children
line wrap: on
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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);
}