68 lines
2.5 KiB
C
68 lines
2.5 KiB
C
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/**
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* @file adts.h
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* @brief
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* @author licaibiao
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* @version 1.0
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* @date 2023-12-06
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*
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* @copyright Copyright (c) 2023-2030 liwen01 Technology Co., Ltd
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*
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*/
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#ifndef __AdtsHeader__adts__
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#define __AdtsHeader__adts__
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#include <stdio.h>
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#include <stdint.h>
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/*
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* ADTS 全称: Audio Data Transport Stream. 是 AAC音频的传输流格式.
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* ADTS头中相对有用的信息包括: 采样率, 声道数, 帧长度. 每一个带ADTS头信息的AAC流都会清晰的告诉解码器他需要的这些信息.
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* 一般情况下ADTS的头信息都是7个字节, 分为两部分: 前28bit是 adts_fixed_header, 后28bit是 adts_variable_header.
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*/
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typedef struct adts_fixed_header {
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unsigned short syncword: 12;
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unsigned char id: 1;
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unsigned char layer: 2;
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unsigned char protection_absent: 1;
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unsigned char profile: 2;
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unsigned char sampling_frequency_index: 4;
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unsigned char private_bit: 1;
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unsigned char channel_configuration: 3;
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unsigned char original_copy: 1;
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unsigned char home: 1;
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} adts_fixed_header; // length : 28 bits
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typedef struct adts_variable_header {
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unsigned char copyright_identification_bit: 1;
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unsigned char copyright_identification_start: 1;
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unsigned short aac_frame_length: 13;
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unsigned short adts_buffer_fullness: 11;
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unsigned char number_of_raw_data_blocks_in_frame:2;
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} adts_variable_header; // length : 28 bits
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// 设置adts固定的一部分
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extern void set_fixed_header(adts_fixed_header *header);
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// 设置adts可变的一部分
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extern void set_variable_header(adts_variable_header *header, const int aac_raw_data_length);
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// 解析buff中的adts固定部分头信息
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extern void get_fixed_header(const unsigned char buff[7], adts_fixed_header *header);
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// 解析buff中的adts可变部分头信息
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extern void get_variable_header(const unsigned char buff[7], adts_variable_header *header);
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// 将adts头信息转化为一个64位的整数, PS: 前面8位空着
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extern void convert_adts_header2int64(const adts_fixed_header *fixed_header, const adts_variable_header *variable_header, uint64_t *header);
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// 将adts头信息转化为一个7字节的buff
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extern void convert_adts_header2char(const adts_fixed_header *fixed_header, const adts_variable_header *variable_header, unsigned char buffer[7]);
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extern void aac_dsi_to_adts(uint8_t *dsi, uint8_t *adts, uint32_t aac_data_length);
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#endif /* defined(__AdtsHeader__adts__) */
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