gstrtpreceiver.h

//
// Created by consti10 on 09.04.24.
//

#ifndef FPVUE_GSTRTPRECEIVER_H
#define FPVUE_GSTRTPRECEIVER_H

#include <gst/gst.h>
#include <thread>
#include <memory>
#include <vector>
#include <functional>

/**
 * @brief Uses gstreamer and appsink to expose the functionality of receiving and parsing
 * rtp h264, h265 and mjpeg.
 */
class GstRtpReceiver {
public:
    /**
     * The constructor is delayed, remember to use start_receiving()
     */
    explicit GstRtpReceiver(int udp_port,int codec);
    virtual ~GstRtpReceiver();
    // Depending on the codec, these are h264,h265 or mjpeg "frames" / frame buffers
    // The big advantage of gstreamer is that it seems to handle all those parsing quirks the best,
    // e.g. the frames on this cb should be easily passable to whatever decode api is available.
    typedef std::function<void(std::shared_ptr<std::vector<uint8_t>> frame)> NEW_FRAME_CALLBACK;
    void start_receiving(NEW_FRAME_CALLBACK cb);
    void stop_receiving();
private:
    std::string construct_gstreamer_pipeline();
    void loop_pull_samples();
    void on_new_sample(std::shared_ptr<std::vector<uint8_t>> sample);
private:
    // The gstreamer pipeline
    GstElement * m_gst_pipeline=nullptr;
    NEW_FRAME_CALLBACK m_cb;
    int m_video_codec;
    int m_port;
    // appsink
    GstElement *m_app_sink_element = nullptr;
    bool m_pull_samples_run;
    std::unique_ptr<std::thread> m_pull_samples_thread=nullptr;
};


#endif //FPVUE_GSTRTPRECEIVER_H