GstVideoReceiver.h

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#pragma once
 
#include <QtCore/QLoggingCategory>
#include <QtCore/QMutex>
#include <QtCore/QQueue>
#include <QtCore/QThread>
#include <QtCore/QTimer>
#include <QtCore/QWaitCondition>
 
#include <glib.h>
#include <gst/gstelement.h>
#include <gst/gstpad.h>
 
#include "VideoReceiver.h"
 
Q_DECLARE_LOGGING_CATEGORY(GstVideoReceiverLog)
 
typedef std::function<void()> Task;
 
/*===========================================================================*/
 
class GstVideoWorker : public QThread
{
    Q_OBJECT
 
public:
    explicit GstVideoWorker(QObject *parent = nullptr);
    ~GstVideoWorker();
    bool needDispatch() const;
    void dispatch(Task task);
    void shutdown();
 
private:
    void run() final;
 
    QWaitCondition _taskQueueUpdate;
    QMutex _taskQueueSync;
    QQueue<Task> _taskQueue;
    bool _shutdown = false;
};
 
/*===========================================================================*/
 
typedef struct _GstElement GstElement;
 
class GstVideoReceiver : public VideoReceiver
{
    Q_OBJECT
 
public:
    explicit GstVideoReceiver(QObject *parent = nullptr);
    ~GstVideoReceiver();
 
public slots:
    void start(uint32_t timeout) override;
    void stop() override;
    void startDecoding(void *sink) override;
    void stopDecoding() override;
    void startRecording(const QString &videoFile, FILE_FORMAT format) override;
    void stopRecording() override;
    void takeScreenshot(const QString &imageFile) override;
 
private slots:
    void _watchdog();
    void _handleEOS();
 
private:
    GstElement *_makeSource(const QString &input);
    GstElement *_makeDecoder(GstCaps *caps = nullptr, GstElement *videoSink = nullptr);
    GstElement *_makeFileSink(const QString &videoFile, FILE_FORMAT format);
 
    void _onNewSourcePad(GstPad *pad);
    void _onNewDecoderPad(GstPad *pad);
    bool _addDecoder(GstElement *src);
    bool _addVideoSink(GstPad *pad);
    void _noteTeeFrame();
    void _noteVideoSinkFrame();
    void _noteEndOfStream();
    bool _unlinkBranch(GstElement *from);
    void _shutdownDecodingBranch();
    void _shutdownRecordingBranch();
    void _logDecodebin3SelectedCodec(GstElement *decodebin3);
 
    bool _needDispatch();
    void _dispatchSignal(Task emitter);
 
    static gboolean _onBusMessage(GstBus *bus, GstMessage *message, gpointer user_data);
    static void _onNewPad(GstElement *element, GstPad *pad, gpointer data);
    static void _wrapWithGhostPad(GstElement *element, GstPad *pad, gpointer data);
    static void _linkPad(GstElement *element, GstPad *pad, gpointer data);
    static gboolean _padProbe(GstElement *element, GstPad *pad, gpointer user_data);
    static gboolean _filterParserCaps(GstElement *bin, GstPad *pad, GstElement *element, GstQuery *query, gpointer data);
    static GstPadProbeReturn _teeProbe(GstPad *pad, GstPadProbeInfo *info, gpointer user_data);
    static GstPadProbeReturn _videoSinkProbe(GstPad *pad, GstPadProbeInfo *info, gpointer user_data);
    static GstPadProbeReturn _eosProbe(GstPad *pad, GstPadProbeInfo *info, gpointer user_data);
    static GstPadProbeReturn _keyframeWatch(GstPad *pad, GstPadProbeInfo *info, gpointer user_data);
 
    GstElement *_decoder = nullptr;
    GstElement *_decoderValve = nullptr;
    GstElement *_fileSink = nullptr;
    GstElement *_pipeline = nullptr;
    GstElement *_recorderValve = nullptr;
    GstElement *_source = nullptr;
    GstElement *_tee = nullptr;
    GstElement *_videoSink = nullptr;
    GstVideoWorker *_worker = nullptr;
    gulong _teeProbeId = 0;
    gulong _videoSinkProbeId = 0;
 
    static constexpr const char *_kFileMux[FILE_FORMAT_MAX + 1] = {
        "matroskamux",
        "qtmux",
        "mp4mux"
    };
};