2018-10-30 14:59:42 +08:00
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/*
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2020-04-04 20:30:09 +08:00
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* Copyright (c) 2016 The ZLMediaKit project authors. All Rights Reserved.
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2018-10-30 14:59:42 +08:00
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*
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* This file is part of ZLMediaKit(https://github.com/xiongziliang/ZLMediaKit).
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*
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2020-04-04 20:30:09 +08:00
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* Use of this source code is governed by MIT license that can be found in the
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* LICENSE file in the root of the source tree. All contributing project authors
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* may be found in the AUTHORS file in the root of the source tree.
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2018-10-30 14:59:42 +08:00
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*/
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#include "AAC.h"
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namespace mediakit{
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void writeAdtsHeader(const AACFrame &hed, uint8_t *pcAdts) {
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pcAdts[0] = (hed.syncword >> 4 & 0xFF); //8bit
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pcAdts[1] = (hed.syncword << 4 & 0xF0); //4 bit
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pcAdts[1] |= (hed.id << 3 & 0x08); //1 bit
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pcAdts[1] |= (hed.layer << 1 & 0x06); //2bit
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pcAdts[1] |= (hed.protection_absent & 0x01); //1 bit
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pcAdts[2] = (hed.profile << 6 & 0xC0); // 2 bit
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pcAdts[2] |= (hed.sf_index << 2 & 0x3C); //4bit
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pcAdts[2] |= (hed.private_bit << 1 & 0x02); //1 bit
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pcAdts[2] |= (hed.channel_configuration >> 2 & 0x03); //1 bit
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pcAdts[3] = (hed.channel_configuration << 6 & 0xC0); // 2 bit
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pcAdts[3] |= (hed.original << 5 & 0x20); //1 bit
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pcAdts[3] |= (hed.home << 4 & 0x10); //1 bit
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pcAdts[3] |= (hed.copyright_identification_bit << 3 & 0x08); //1 bit
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pcAdts[3] |= (hed.copyright_identification_start << 2 & 0x04); //1 bit
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pcAdts[3] |= (hed.aac_frame_length >> 11 & 0x03); //2 bit
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pcAdts[4] = (hed.aac_frame_length >> 3 & 0xFF); //8 bit
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pcAdts[5] = (hed.aac_frame_length << 5 & 0xE0); //3 bit
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pcAdts[5] |= (hed.adts_buffer_fullness >> 6 & 0x1F); //5 bit
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pcAdts[6] = (hed.adts_buffer_fullness << 2 & 0xFC); //6 bit
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pcAdts[6] |= (hed.no_raw_data_blocks_in_frame & 0x03); //2 bit
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}
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string makeAdtsConfig(const uint8_t *pcAdts){
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if (!(pcAdts[0] == 0xFF && (pcAdts[1] & 0xF0) == 0xF0)) {
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return "";
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}
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// Get and check the 'profile':
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unsigned char profile = (pcAdts[2] & 0xC0) >> 6; // 2 bits
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if (profile == 3) {
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return "";
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}
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// Get and check the 'sampling_frequency_index':
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unsigned char sampling_frequency_index = (pcAdts[2] & 0x3C) >> 2; // 4 bits
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if (samplingFrequencyTable[sampling_frequency_index] == 0) {
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return "";
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}
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// Get and check the 'channel_configuration':
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unsigned char channel_configuration = ((pcAdts[2] & 0x01) << 2)
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| ((pcAdts[3] & 0xC0) >> 6); // 3 bits
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unsigned char audioSpecificConfig[2];
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unsigned char const audioObjectType = profile + 1;
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audioSpecificConfig[0] = (audioObjectType << 3) | (sampling_frequency_index >> 1);
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audioSpecificConfig[1] = (sampling_frequency_index << 7) | (channel_configuration << 3);
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return string((char *)audioSpecificConfig,2);
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}
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void makeAdtsHeader(const string &strAudioCfg,AACFrame &adts) {
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uint8_t cfg1 = strAudioCfg[0];
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uint8_t cfg2 = strAudioCfg[1];
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int audioObjectType;
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int sampling_frequency_index;
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int channel_configuration;
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audioObjectType = cfg1 >> 3;
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sampling_frequency_index = ((cfg1 & 0x07) << 1) | (cfg2 >> 7);
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channel_configuration = (cfg2 & 0x7F) >> 3;
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adts.syncword = 0x0FFF;
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adts.id = 0;
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adts.layer = 0;
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adts.protection_absent = 1;
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adts.profile = audioObjectType - 1;
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adts.sf_index = sampling_frequency_index;
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adts.private_bit = 0;
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adts.channel_configuration = channel_configuration;
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adts.original = 0;
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adts.home = 0;
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adts.copyright_identification_bit = 0;
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adts.copyright_identification_start = 0;
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adts.aac_frame_length = 7;
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adts.adts_buffer_fullness = 2047;
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adts.no_raw_data_blocks_in_frame = 0;
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}
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void getAACInfo(const AACFrame &adts,int &iSampleRate,int &iChannel){
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iSampleRate = samplingFrequencyTable[adts.sf_index];
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iChannel = adts.channel_configuration;
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}
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2019-06-28 16:12:39 +08:00
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Sdp::Ptr AACTrack::getSdp() {
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if(!ready()){
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WarnL << "AAC Track未准备好";
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return nullptr;
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}
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return std::make_shared<AACSdp>(getAacCfg(),getAudioSampleRate());
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}
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2018-10-30 14:59:42 +08:00
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}//namespace mediakit
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