view efrtest/etsi-enc-common.c @ 478:936a08cc73ce

doc/AMR-library-API: describe the decoder
author Mychaela Falconia <falcon@freecalypso.org>
date Sun, 19 May 2024 21:32:31 +0000
parents 51678b070c7a
children
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/*
 * This C module holds some functions that have been split off from
 * etsi-enc.c, with the goal of making it easier to build both
 * standard-EFR and AMR-EFR versions of the ETSI-format EFR encoder.
 */

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

read_input(inf, pcm, filename_for_errs, big_endian)
	FILE *inf;
	int16_t *pcm;
	char *filename_for_errs;
{
	uint8_t file_bytes[320], *sp;
	int cc;
	unsigned n;

	cc = fread(file_bytes, 2, 160, inf);
	if (cc == 0)
		return 0;
	if (cc != 160) {
		fprintf(stderr, "error: short read from %s\n",
			filename_for_errs);
		exit(1);
	}
	sp = file_bytes;
	for (n = 0; n < 160; n++) {
		if (big_endian)
			pcm[n] = (sp[0] << 8) | sp[1];
		else
			pcm[n] = sp[0] | (sp[1] << 8);
		sp += 2;
	}
	return 1;
}

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

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

void
emit_output(outf, bits, nbits, big_endian)
	FILE *outf;
	uint8_t *bits;
	unsigned nbits;
{
	unsigned n;

	for (n = 0; n < nbits; n++) {
		if (big_endian) {
			putc(0, outf);
			putc(bits[n], outf);
		} else {
			putc(bits[n], outf);
			putc(0, outf);
		}
	}
}