gstreamer+qt5实现简易视频播放器

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文章目录

前言
一、安装环境
- 1.QT5
- 2.gstreamer
二、代码
- 1.Windows实现
三、测试效果
总结

前言

最近在研究mpp，通过gstreamer实现了硬解码，但是我在想我可能需要一个播放器，我之前学过qt5所以就选择了qt5来结合gstreamer开发一个简单的播放器。今天的环境基于Windows，后续会把Linux的也补上的。

注意：基于QT5，我觉得因为全平台特性，可能QT5比MFC还是有优势，代码只需要小改就可以轻松移植。

一、安装环境

本身不需要特殊配置就支持N卡硬解码，A卡和I卡可能要借助VAAP，我手上没有设备，暂未研究。所以显卡驱动和芯片组驱动就不说了肯定都是要装的。

1.QT5

这个不介绍了，网上找找就好了。

2.gstreamer

Windows11安装并使用Gstreamer-1.0

二、代码

代码很简单，没有特别做UI，只实现了视频硬解码、播放和音频播放功能。

1.Windows实现

代码只能跑在Windows上因为播放组件是需要区分WIndows和Linux甚至MacOS的。

Gstreamer_Player.pro

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++17

# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

SOURCES += \
    main.cpp \
    mainwindow.cpp

HEADERS += \
    mainwindow.h

FORMS += \
    mainwindow.ui

# 添加GStreamer和Glib库
unix {
    PKGCONFIG += gstreamer-1.0 gstreamer-video-1.0 glib-2.0 gstvideo-1.0
}

# 如果你使用的是Windows，请添加以下内容，并调整路径
win32 {
    INCLUDEPATH += E:/gstreamer/1.0/msvc_x86_64/include/gstreamer-1.0
    INCLUDEPATH += E:/gstreamer/1.0/msvc_x86_64/include/glib-2.0
    INCLUDEPATH += E:/gstreamer/1.0/msvc_x86_64/lib/glib-2.0/include
    
    LIBS += -LE:/gstreamer/1.0/msvc_x86_64/lib -lgstreamer-1.0 -lgobject-2.0 -lglib-2.0 -lgstvideo-1.0
}

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <gst/gst.h>
#include <gst/video/videooverlay.h>

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private slots:
    void on_playButton_clicked();

private:
    Ui::MainWindow *ui;
    GstElement *pipeline;
};

#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QMessageBox>
#include <QFileDialog>

//代码只有Windows系统才执行
#ifdef Q_OS_WIN
#include <windows.h>
#include <dwmapi.h>
#endif

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    gst_init(nullptr, nullptr);

    pipeline = gst_pipeline_new("pipeline");
    GstElement *source = gst_element_factory_make("filesrc", "source");
    GstElement *demuxer = gst_element_factory_make("decodebin", "demuxer");
    GstElement *videoconvert = gst_element_factory_make("videoconvert", "videoconvert");
    GstElement *videosink = gst_element_factory_make("d3dvideosink", "videosink");
    GstElement *audioconvert = gst_element_factory_make("audioconvert", "audioconvert");
    GstElement *audioresample = gst_element_factory_make("audioresample", "audioresample");
    GstElement *audiosink = gst_element_factory_make("autoaudiosink", "audiosink");

    //这一句可以合并，因为都是必须创建成功的
    if (!pipeline || !source || !demuxer || !videoconvert || !videosink || !audioconvert || !audioresample || !audiosink) {
        QMessageBox::critical(this, "Error", "Failed to create GStreamer elements.");
        return;
    }

    gst_bin_add_many(GST_BIN(pipeline), source, demuxer, videoconvert, videosink, audioconvert, audioresample, audiosink, nullptr);
    gst_element_link(source, demuxer);

    g_signal_connect(demuxer, "pad-added", G_CALLBACK(+[](GstElement *demuxer, GstPad *new_pad, gpointer user_data) {
                         GstElement *pipeline = GST_ELEMENT(user_data);
                         GstPad *videoconvert_sink_pad = gst_element_get_static_pad(gst_bin_get_by_name(GST_BIN(pipeline), "videoconvert"), "sink");
                         GstPad *audioconvert_sink_pad = gst_element_get_static_pad(gst_bin_get_by_name(GST_BIN(pipeline), "audioconvert"), "sink");
                         GstPadLinkReturn ret;

                         GstCaps *new_pad_caps = gst_pad_get_current_caps(new_pad);
                         GstStructure *new_pad_struct = gst_caps_get_structure(new_pad_caps, 0);
                         const gchar *new_pad_type = gst_structure_get_name(new_pad_struct);

                         if (g_str_has_prefix(new_pad_type, "video/x-raw")) {
                             ret = gst_pad_link(new_pad, videoconvert_sink_pad);
                         } else if (g_str_has_prefix(new_pad_type, "audio/x-raw")) {
                             ret = gst_pad_link(new_pad, audioconvert_sink_pad);
                         } else {
                             ret = GST_PAD_LINK_OK;
                         }

                         if (GST_PAD_LINK_FAILED(ret)) {
                             g_printerr("Type is '%s' but link failed.\n", new_pad_type);
                         } else {
                             g_print("Link succeeded (type '%s').\n", new_pad_type);
                         }

                         gst_object_unref(videoconvert_sink_pad);
                         gst_object_unref(audioconvert_sink_pad);
                         gst_caps_unref(new_pad_caps);
                     }), pipeline);

    gst_element_link_many(videoconvert, videosink, nullptr);
    gst_element_link_many(audioconvert, audioresample, audiosink, nullptr);

    GstBus *bus = gst_element_get_bus(pipeline);
    gst_bus_add_signal_watch(bus);
    g_signal_connect(bus, "message::error", G_CALLBACK(+[](GstBus *bus, GstMessage *msg, gpointer user_data) {
                         GError *err;
                         gchar *debug_info;
                         gst_message_parse_error(msg, &err, &debug_info);
                         g_printerr("Error received from element %s: %s\n", GST_OBJECT_NAME(msg->src), err->message);
                         g_printerr("Debugging information: %s\n", debug_info ? debug_info : "none");
                         g_clear_error(&err);
                         g_free(debug_info);
                     }), nullptr);
    gst_object_unref(bus);

    WId winId = ui->videoWidget->winId();
    gst_video_overlay_set_window_handle(GST_VIDEO_OVERLAY(videosink), winId);
}

MainWindow::~MainWindow()
{
    gst_element_set_state(pipeline, GST_STATE_NULL);
    gst_object_unref(pipeline);
    delete ui;
}

void MainWindow::on_playButton_clicked()
{
    QString filename = QFileDialog::getOpenFileName(this, "Open Video File", "", "Video Files (*.mp4 *.avi *.mkv)");
    if (filename.isEmpty())
        return;

    gst_element_set_state(pipeline, GST_STATE_READY);
    g_object_set(G_OBJECT(gst_bin_get_by_name(GST_BIN(pipeline), "source")), "location", filename.toStdString().c_str(), nullptr);
    gst_element_set_state(pipeline, GST_STATE_PLAYING);
}

main.cpp

#include "mainwindow.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}