QMediaPlayer。如何使用多音频播放视频？

Question

有一个包含两个音频曲目的视频文件：

  Duration: 01:05:09.12, start: 0.000000, bitrate: 2781 kb/s
    Stream #0:0: Video: mpeg4 (Advanced Simple Profile) (XVID / 0x44495658), yuv420p, 720x400 [SAR 1:1 DAR 9:5], 1998 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc
    Stream #0:1: Audio: ac3 ([0] [0][0] / 0x2000), 48000 Hz, 5.1(side), fltp, 384 kb/s
    Stream #0:2: Audio: ac3 ([0] [0][0] / 0x2000), 48000 Hz, 5.1(side), fltp, 384 kb/s

使用以下代码进行播放：

self.player = QMediaPlayer()
self.player.setMedia(QMediaContent(QUrl.fromLocalFile(fileName)))
self.player.play()

播放视频和第一首音频曲目。如何切换到第二个音轨

Answer 1

正如@musicamante在评论中指出的，解决方案是访问QMediaStreamsControl，但PyQt5不公开它

相反，PySide2将其公开，解决方案是使用shiboken2进行强制转换：

import os

from PySide2 import QtCore, QtWidgets, QtMultimedia, QtMultimediaWidgets

import shiboken2


class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        video_widget = QtMultimediaWidgets.QVideoWidget()
        self.player = QtMultimedia.QMediaPlayer(
            self, QtMultimedia.QMediaPlayer.VideoSurface
        )
        file = os.path.join(os.path.dirname(os.path.realpath(__file__)), "test5.mkv")
        self.player.setMedia(
            QtMultimedia.QMediaContent(QtCore.QUrl.fromLocalFile(file))
        )
        self.player.setVideoOutput(video_widget)
        self.player.play()
        self.setCentralWidget(video_widget)

        control = self.player.service().requestControl(
            "org.qt-project.qt.mediastreamscontrol/5.0"
        )
        qptr = shiboken2.getCppPointer(control)[0]
        self.qcontrol = shiboken2.wrapInstance(qptr, QtMultimedia.QMediaStreamsControl)
        self.resize(640, 480)

    def contextMenuEvent(self, event):
        menu = QtWidgets.QMenu()
        group = QtWidgets.QActionGroup(menu)
        group.setExclusive(True)
        index = 0
        for i in range(self.qcontrol.streamCount()):
            t = self.qcontrol.streamType(i)
            if t == QtMultimedia.QMediaStreamsControl.AudioStream:
                action = menu.addAction("Audio-{}".format(index))
                action.setCheckable(True)
                if self.qcontrol.isActive(i):
                    action.setChecked(True)
                action.setData(i)
                menu.addAction(action)
                index += 1
        action = menu.exec_(self.mapToGlobal(event.pos()))
        if action is not None:
            i = action.data()
            self.qcontrol.setActive(i, True)


if __name__ == "__main__":
    import sys

    app = QtWidgets.QApplication(sys.argv)
    w = MainWindow()
    w.show()
    sys.exit(app.exec_())

在pyqt5的情况下，应使用sip和以下代码：

import os

from PyQt5 import QtCore, QtWidgets, QtMultimedia, QtMultimediaWidgets

import sip


class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        video_widget = QtMultimediaWidgets.QVideoWidget()
        self.player = QtMultimedia.QMediaPlayer(
            self, QtMultimedia.QMediaPlayer.VideoSurface
        )
        file = os.path.join(os.path.dirname(os.path.realpath(__file__)), "test5.mkv")
        self.player.setMedia(
            QtMultimedia.QMediaContent(QtCore.QUrl.fromLocalFile(file))
        )
        self.player.setVideoOutput(video_widget)
        self.player.play()
        self.setCentralWidget(video_widget)

        control = self.player.service().requestControl(
            "org.qt-project.qt.mediastreamscontrol/5.0"
        )
        self.qcontrol = sip.cast(control, QtMultimedia.QMediaStreamsControl)
        self.resize(640, 480)

    def contextMenuEvent(self, event):
        menu = QtWidgets.QMenu()
        group = QtWidgets.QActionGroup(menu)
        group.setExclusive(True)
        index = 0
        for i in range(self.qcontrol.streamCount()):
            t = self.qcontrol.streamType(i)
            if t == QtMultimedia.QMediaStreamsControl.AudioStream:
                action = menu.addAction("Audio-{}".format(index))
                action.setCheckable(True)
                if self.qcontrol.isActive(i):
                    action.setChecked(True)
                action.setData(i)
                menu.addAction(action)
                index += 1
        action = menu.exec_(self.mapToGlobal(event.pos()))
        if action is not None:
            i = action.data()
            self.qcontrol.setActive(i, True)


if __name__ == "__main__":
    import sys

    app = QtWidgets.QApplication(sys.argv)
    w = MainWindow()
    w.show()
    sys.exit(app.exec_())

但正如QMediaStreamsControl所指出的，PyQt5中不可用，因此解决方案是公开它，为此，您必须：

1. 下载PyQt5源代码：https://pypi.python.org/packages/source/P/PyQt5/PyQt5-5.14.2.tar.gz

2. 在PyQt5源代码的“sip/qtmedia”文件夹中创建文件qmediastreascontrol.sip

   qmediastreascontrol.sip

   class QMediaStreamsControl : QMediaControl
   {
   %TypeHeaderCode
   #include <qmediastreamscontrol.h>
   %End
   
   public:
       enum StreamType { 
           UnknownStream, 
           VideoStream, 
           AudioStream, 
           SubPictureStream, 
           DataStream 
       };
   
       virtual ~QMediaStreamsControl();
       virtual int streamCount() = 0;
       virtual QMediaStreamsControl::StreamType streamType(int streamNumber) = 0;
       virtual QVariant metaData(int streamNumber, const QString &key) = 0;
       virtual bool isActive(int streamNumber) = 0;
       virtual void setActive(int streamNumber, bool state) = 0;
   
   signals:
       void streamsChanged();
       void activeStreamsChanged();
   
   protected:
   %If (Qt_5_6_1 -)
       explicit QMediaStreamsControl(QObject *parent /TransferThis/ = 0);
   %End
   %If (- Qt_5_6_1)
       QMediaStreamsControl(QObject *parent /TransferThis/ = 0);
   %End
   };
   

3. 将%Include qmediastreamscontrol.sip添加到文件sip/qtmedia/qtmediamod.sip的末尾

4. 使用修改后的源代码编译并安装PyQt5

总之：

• 如果使用pyside2，解决方案很简单

• 如果使用pyqt5，则必须修改其源代码、编译并安装。希望通过@musicamante报告类QMediaStreamsControl在pyqt5的未来版本中公开