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/******************************************************************************
*
* Copyright 2022 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************/
#include <stdint.h>
#include "lc3bin.h"
/**
* LC3 binary header
*/
#define LC3_FILE_ID (0x1C | (0xCC << 8))
struct lc3bin_header {
uint16_t file_id;
uint16_t header_size;
uint16_t srate_100hz;
uint16_t bitrate_100bps;
uint16_t channels;
uint16_t frame_10us;
uint16_t rfu;
uint16_t nsamples_low;
uint16_t nsamples_high;
};
/**
* Read LC3 binary header
*/
int lc3bin_read_header(FILE *fp,
int *frame_us, int *srate_hz, int *nchannels, int *nsamples)
{
struct lc3bin_header hdr;
if (fread(&hdr, sizeof(hdr), 1, fp) != 1
|| hdr.file_id != LC3_FILE_ID)
return -1;
*nchannels = hdr.channels;
*frame_us = hdr.frame_10us * 10;
*srate_hz = hdr.srate_100hz * 100;
*nsamples = hdr.nsamples_low | (hdr.nsamples_high << 16);
fseek(fp, SEEK_SET, hdr.header_size);
return 0;
}
/**
* Read LC3 block of data
*/
int lc3bin_read_data(FILE *fp, int nchannels, void *buffer)
{
uint16_t nbytes;
if (fread(&nbytes, sizeof(nbytes), 1, fp) < 1
|| nbytes > nchannels * LC3_MAX_FRAME_BYTES
|| nbytes % nchannels
|| fread(buffer, nbytes, 1, fp) < 1)
return -1;
return nbytes / nchannels;
}
/**
* Write LC3 binary header
*/
void lc3bin_write_header(FILE *fp,
int frame_us, int srate_hz, int bitrate, int nchannels, int nsamples)
{
struct lc3bin_header hdr = {
.file_id = LC3_FILE_ID,
.header_size = sizeof(struct lc3bin_header),
.srate_100hz = srate_hz / 100,
.bitrate_100bps = bitrate / 100,
.channels = nchannels,
.frame_10us = frame_us / 10,
.nsamples_low = nsamples & 0xffff,
.nsamples_high = nsamples >> 16,
};
fwrite(&hdr, sizeof(hdr), 1, fp);
}
/**
* Write LC3 block of data
*/
void lc3bin_write_data(FILE *fp,
const void *data, int nchannels, int frame_bytes)
{
uint16_t nbytes = nchannels * frame_bytes;
fwrite(&nbytes, sizeof(nbytes), 1, fp);
fwrite(data, 1, nbytes, fp);
}
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