1 /****************************************************************************** 2 * 3 * Copyright 2022 Google LLC 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at: 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 ******************************************************************************/ 18 19 #include <stdint.h> 20 #include "lc3bin.h" 21 22 23 /** 24 * LC3 binary header 25 */ 26 27 #define LC3_FILE_ID (0x1C | (0xCC << 8)) 28 29 struct lc3bin_header { 30 uint16_t file_id; 31 uint16_t header_size; 32 uint16_t srate_100hz; 33 uint16_t bitrate_100bps; 34 uint16_t channels; 35 uint16_t frame_10us; 36 uint16_t rfu; 37 uint16_t nsamples_low; 38 uint16_t nsamples_high; 39 }; 40 41 42 /** 43 * Read LC3 binary header 44 */ 45 int lc3bin_read_header(FILE *fp, 46 int *frame_us, int *srate_hz, int *nchannels, int *nsamples) 47 { 48 struct lc3bin_header hdr; 49 50 if (fread(&hdr, sizeof(hdr), 1, fp) != 1 51 || hdr.file_id != LC3_FILE_ID) 52 return -1; 53 54 *nchannels = hdr.channels; 55 *frame_us = hdr.frame_10us * 10; 56 *srate_hz = hdr.srate_100hz * 100; 57 *nsamples = hdr.nsamples_low | (hdr.nsamples_high << 16); 58 59 fseek(fp, SEEK_SET, hdr.header_size); 60 61 return 0; 62 } 63 64 /** 65 * Read LC3 block of data 66 */ 67 int lc3bin_read_data(FILE *fp, int nchannels, void *buffer) 68 { 69 uint16_t nbytes; 70 71 if (fread(&nbytes, sizeof(nbytes), 1, fp) < 1 72 || nbytes > nchannels * LC3_MAX_FRAME_BYTES 73 || nbytes % nchannels 74 || fread(buffer, nbytes, 1, fp) < 1) 75 return -1; 76 77 return nbytes / nchannels; 78 } 79 80 /** 81 * Write LC3 binary header 82 */ 83 void lc3bin_write_header(FILE *fp, 84 int frame_us, int srate_hz, int bitrate, int nchannels, int nsamples) 85 { 86 struct lc3bin_header hdr = { 87 .file_id = LC3_FILE_ID, 88 .header_size = sizeof(struct lc3bin_header), 89 .srate_100hz = srate_hz / 100, 90 .bitrate_100bps = bitrate / 100, 91 .channels = nchannels, 92 .frame_10us = frame_us / 10, 93 .nsamples_low = nsamples & 0xffff, 94 .nsamples_high = nsamples >> 16, 95 }; 96 97 fwrite(&hdr, sizeof(hdr), 1, fp); 98 } 99 100 /** 101 * Write LC3 block of data 102 */ 103 void lc3bin_write_data(FILE *fp, 104 const void *data, int nchannels, int frame_bytes) 105 { 106 uint16_t nbytes = nchannels * frame_bytes; 107 fwrite(&nbytes, sizeof(nbytes), 1, fp); 108 109 fwrite(data, 1, nbytes, fp); 110 } 111