view efrtest/rec2etsi.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 bd832a456339
children
line wrap: on
line source

/*
 * This program reads in an EFR session recording in our binary format
 * (presumably obtained by converting from an RTP capture on the network
 * side or from a Calypso DSP readout on the mobile side) and converts
 * it into ETSI *.dec format, to be fed to ETSI decoder test program.
 *
 * The output from this program is in the local machine's native byte order.
 */

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include "../libgsmefr/gsm_efr.h"
#include "../libtest/binreader.h"

static void
frame2bits(frame, bits)
	uint8_t *frame;
	uint16_t *bits;
{
	unsigned nb, byte, mask, bit;

	for (nb = 0; nb < 31; nb++) {
		byte = *frame++;
		for (mask = 0x80; mask; mask >>= 1) {
			if (byte & mask)
				bit = 1;
			else
				bit = 0;
			*bits++ = bit;
		}
	}
}

main(argc, argv)
	char **argv;
{
	FILE *binf, *outf;
	uint8_t frame[BINFILE_MAX_FRAME];
	uint16_t bits[250];
	int rc;

	if (argc != 3) {
		fprintf(stderr, "usage: %s input.gsmx output.dec\n", argv[0]);
		exit(1);
	}
	binf = fopen(argv[1], "r");
	if (!binf) {
		perror(argv[1]);
		exit(1);
	}
	outf = fopen(argv[2], "w");
	if (!outf) {
		perror(argv[2]);
		exit(1);
	}
	for (;;) {
		rc = binfile_read_frame(binf, frame);
		if (rc < 0) {
			fprintf(stderr, "error: garbage in %s\n", argv[1]);
			exit(1);
		}
		if (!rc)
			break;
		if (frame[0] == 0xBF) {
			bits[3] = 1;			/* BFI */
			bzero(bits + 4, 245 * 2);
			bits[249] = frame[1] & 1;	/* TAF */
		} else if ((frame[0] & 0xF0) == 0xC0) {
			frame2bits(frame, bits);
			bits[248] = EFR_sid_classify(frame);
			bits[249] = 0;			/* TAF */
		} else {
			fprintf(stderr,
				"error: %s is not in EFR codec format\n",
				argv[1]);
			exit(1);
		}
		fwrite(bits + 3, 2, 247, outf);
	}
	fclose(outf);
	exit(0);
}