/* * Copyright (c) 2016 The ZLMediaKit project authors. All Rights Reserved. * * This file is part of ZLMediaKit(https://github.com/xiongziliang/ZLMediaKit). * * Use of this source code is governed by MIT license that can be found in the * LICENSE file in the root of the source tree. All contributing project authors * may be found in the AUTHORS file in the root of the source tree. */ #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 << getCodecName() << " Track未准备好"; return nullptr; } return std::make_shared(getAacCfg(),getAudioSampleRate()); } }//namespace mediakit