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