問(wèn)題描述

有一個(gè)包含兩個(gè)音軌的視頻文件:

There is a video file with two audio tracks:

  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

用這段代碼玩它:

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

播放視頻和第一個(gè)音軌.Н如何切換到第二個(gè)音軌?

Video and first audio track is played. Нow to switch to the second audio track?

推薦答案

正如@musicamante 在評(píng)論中指出的那樣，解決方案是訪問(wèn) QMediaStreamsControl 但 PyQt5 沒(méi)有公開它.

As @musicamante points out in the comments, the solution is to access the QMediaStreamsControl but PyQt5 does not expose it.

相反，PySide2 確實(shí)公開了它，解決方案是使用 shiboken2 進(jìn)行投射:

Instead PySide2 does expose it and the solution is to cast using shiboken2:

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 的情況下，您應(yīng)該使用 sip 和以下代碼:

In the case of pyqt5 you should use sip with the following code:

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，因此解決方案是公開它，為此您必須:

But as pointed out by QMediaStreamsControl is not available in PyQt5, so a solution is to expose it and for this you must:

1. 下載 PyQt5 源碼:https://pypi.python.org/packages/source/P/PyQt5/PyQt5-5.14.2.tar.gz

2. 在 PyQt5 源代碼的sip/QtMultimedia"文件夾中創(chuàng)建文件 qmediastreamscontrol.sip.

1. Download PyQt5 source code: https://pypi.python.org/packages/source/P/PyQt5/PyQt5-5.14.2.tar.gz

2. Create the file qmediastreamscontrol.sip in "sip/QtMultimedia" folder of the PyQt5 source code.

qmediastreamscontrol.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
};