ZLMediaKit/src/Extension/AAC.cpp
2019-06-28 16:12:39 +08:00

130 lines
4.8 KiB
C++

/*
* MIT License
*
* Copyright (c) 2016-2019 xiongziliang <771730766@qq.com>
*
* This file is part of ZLMediaKit(https://github.com/xiongziliang/ZLMediaKit).
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "AAC.h"
namespace mediakit{
void writeAdtsHeader(const AACFrame &hed, uint8_t *pcAdts) {
pcAdts[0] = (hed.syncword >> 4 & 0xFF); //8bit
pcAdts[1] = (hed.syncword << 4 & 0xF0); //4 bit
pcAdts[1] |= (hed.id << 3 & 0x08); //1 bit
pcAdts[1] |= (hed.layer << 1 & 0x06); //2bit
pcAdts[1] |= (hed.protection_absent & 0x01); //1 bit
pcAdts[2] = (hed.profile << 6 & 0xC0); // 2 bit
pcAdts[2] |= (hed.sf_index << 2 & 0x3C); //4bit
pcAdts[2] |= (hed.private_bit << 1 & 0x02); //1 bit
pcAdts[2] |= (hed.channel_configuration >> 2 & 0x03); //1 bit
pcAdts[3] = (hed.channel_configuration << 6 & 0xC0); // 2 bit
pcAdts[3] |= (hed.original << 5 & 0x20); //1 bit
pcAdts[3] |= (hed.home << 4 & 0x10); //1 bit
pcAdts[3] |= (hed.copyright_identification_bit << 3 & 0x08); //1 bit
pcAdts[3] |= (hed.copyright_identification_start << 2 & 0x04); //1 bit
pcAdts[3] |= (hed.aac_frame_length >> 11 & 0x03); //2 bit
pcAdts[4] = (hed.aac_frame_length >> 3 & 0xFF); //8 bit
pcAdts[5] = (hed.aac_frame_length << 5 & 0xE0); //3 bit
pcAdts[5] |= (hed.adts_buffer_fullness >> 6 & 0x1F); //5 bit
pcAdts[6] = (hed.adts_buffer_fullness << 2 & 0xFC); //6 bit
pcAdts[6] |= (hed.no_raw_data_blocks_in_frame & 0x03); //2 bit
}
string makeAdtsConfig(const uint8_t *pcAdts){
if (!(pcAdts[0] == 0xFF && (pcAdts[1] & 0xF0) == 0xF0)) {
return "";
}
// Get and check the 'profile':
unsigned char profile = (pcAdts[2] & 0xC0) >> 6; // 2 bits
if (profile == 3) {
return "";
}
// Get and check the 'sampling_frequency_index':
unsigned char sampling_frequency_index = (pcAdts[2] & 0x3C) >> 2; // 4 bits
if (samplingFrequencyTable[sampling_frequency_index] == 0) {
return "";
}
// Get and check the 'channel_configuration':
unsigned char channel_configuration = ((pcAdts[2] & 0x01) << 2)
| ((pcAdts[3] & 0xC0) >> 6); // 3 bits
unsigned char audioSpecificConfig[2];
unsigned char const audioObjectType = profile + 1;
audioSpecificConfig[0] = (audioObjectType << 3) | (sampling_frequency_index >> 1);
audioSpecificConfig[1] = (sampling_frequency_index << 7) | (channel_configuration << 3);
return string((char *)audioSpecificConfig,2);
}
void makeAdtsHeader(const string &strAudioCfg,AACFrame &adts) {
uint8_t cfg1 = strAudioCfg[0];
uint8_t cfg2 = strAudioCfg[1];
int audioObjectType;
int sampling_frequency_index;
int channel_configuration;
audioObjectType = cfg1 >> 3;
sampling_frequency_index = ((cfg1 & 0x07) << 1) | (cfg2 >> 7);
channel_configuration = (cfg2 & 0x7F) >> 3;
adts.syncword = 0x0FFF;
adts.id = 0;
adts.layer = 0;
adts.protection_absent = 1;
adts.profile = audioObjectType - 1;
adts.sf_index = sampling_frequency_index;
adts.private_bit = 0;
adts.channel_configuration = channel_configuration;
adts.original = 0;
adts.home = 0;
adts.copyright_identification_bit = 0;
adts.copyright_identification_start = 0;
adts.aac_frame_length = 7;
adts.adts_buffer_fullness = 2047;
adts.no_raw_data_blocks_in_frame = 0;
}
void getAACInfo(const AACFrame &adts,int &iSampleRate,int &iChannel){
iSampleRate = samplingFrequencyTable[adts.sf_index];
iChannel = adts.channel_configuration;
}
Sdp::Ptr AACTrack::getSdp() {
if(!ready()){
WarnL << "AAC Track未准备好";
return nullptr;
}
return std::make_shared<AACSdp>(getAacCfg(),getAudioSampleRate());
}
}//namespace mediakit