ZLMediaKit/src/Extension/AACRtmp.cpp

/*
 * Copyright (c) 2016 The ZLMediaKit project authors. All Rights Reserved.
 *
 * This file is part of ZLMediaKit(https://github.com/xia-chu/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 "AACRtmp.h"
#include "Rtmp/Rtmp.h"

namespace mediakit{

static string getAacCfg(const RtmpPacket &thiz) {
    string ret;
    if (thiz.getMediaType() != FLV_CODEC_AAC) {
        return ret;
    }
    if (!thiz.isCfgFrame()) {
        return ret;
    }
    if (thiz.buffer.size() < 4) {
        WarnL << "bad aac cfg!";
        return ret;
    }
    ret = thiz.buffer.substr(2);
    return ret;
}

void AACRtmpDecoder::inputRtmp(const RtmpPacket::Ptr &pkt) {
    if (pkt->isCfgFrame()) {
        _aac_cfg = getAacCfg(*pkt);
        onGetAAC(nullptr, 0, 0);
        return;
    }

    if (!_aac_cfg.empty()) {
        onGetAAC(pkt->buffer.data() + 2, pkt->buffer.size() - 2, pkt->time_stamp);
    }
}

void AACRtmpDecoder::onGetAAC(const char* data, size_t len, uint32_t stamp) {
    auto frame = FrameImp::create();
    frame->_codec_id = CodecAAC;

    //生成adts头
    char adts_header[32] = {0};
    auto size = dumpAacConfig(_aac_cfg, len, (uint8_t *) adts_header, sizeof(adts_header));
    if (size > 0) {
        frame->_buffer.assign(adts_header, size);
        frame->_prefix_size = size;
    } else {
        frame->_buffer.clear();
        frame->_prefix_size = 0;
    }

    if(len > 0){
        //追加负载数据
        frame->_buffer.append(data, len);
        frame->_dts = stamp;
    }

    if(size > 0 || len > 0){
        //有adts头或者实际aac负载
        RtmpCodec::inputFrame(frame);
    }
}

/////////////////////////////////////////////////////////////////////////////////////

AACRtmpEncoder::AACRtmpEncoder(const Track::Ptr &track) {
    _track = dynamic_pointer_cast<AACTrack>(track);
}

void AACRtmpEncoder::makeConfigPacket() {
    if (_track && _track->ready()) {
        //从track中和获取aac配置信息
        _aac_cfg = _track->getAacCfg();
    }

    if (!_aac_cfg.empty()) {
        makeAudioConfigPkt();
    }
}

void AACRtmpEncoder::inputFrame(const Frame::Ptr &frame) {
    if (_aac_cfg.empty()) {
        if (frame->prefixSize()) {
            //包含adts头,从adts头获取aac配置信息
            _aac_cfg = makeAacConfig((uint8_t *) (frame->data()), frame->prefixSize());
        }
        makeConfigPacket();
    }

    if(!_aac_cfg.empty()){
        auto rtmpPkt = RtmpPacket::create();
        //header
        uint8_t is_config = false;
        rtmpPkt->buffer.push_back(_audio_flv_flags);
        rtmpPkt->buffer.push_back(!is_config);

        //aac data
        rtmpPkt->buffer.append(frame->data() + frame->prefixSize(), frame->size() - frame->prefixSize());

        rtmpPkt->body_size = rtmpPkt->buffer.size();
        rtmpPkt->chunk_id = CHUNK_AUDIO;
        rtmpPkt->stream_index = STREAM_MEDIA;
        rtmpPkt->time_stamp = frame->dts();
        rtmpPkt->type_id = MSG_AUDIO;
        RtmpCodec::inputRtmp(rtmpPkt);
    }
}

void AACRtmpEncoder::makeAudioConfigPkt() {
    _audio_flv_flags = getAudioRtmpFlags(std::make_shared<AACTrack>(_aac_cfg));
    auto rtmpPkt = RtmpPacket::create();

    //header
    uint8_t is_config = true;
    rtmpPkt->buffer.push_back(_audio_flv_flags);
    rtmpPkt->buffer.push_back(!is_config);
    //aac config
    rtmpPkt->buffer.append(_aac_cfg);

    rtmpPkt->body_size = rtmpPkt->buffer.size();
    rtmpPkt->chunk_id = CHUNK_AUDIO;
    rtmpPkt->stream_index = STREAM_MEDIA;
    rtmpPkt->time_stamp = 0;
    rtmpPkt->type_id = MSG_AUDIO;
    RtmpCodec::inputRtmp(rtmpPkt);
}

}//namespace mediakit