如何在PySide2/PyQt5中修改QMediaPlayer的音频输出设备

核心问题说明 #

你代码中调用service.requestControl时传入的控制类IID错误，使用了媒体流控制的IID，实际需要传入音频输出选择器控制对应的IID：org.qt-project.qt.audiooutputselectorcontrol/5.0，该值对应C++代码中的QAudioOutputSelectorControl_iid常量。

代码修改点 #

仅需修改out_device_changed方法中请求控制的代码即可，修改后的方法如下：

def out_device_changed(self, idx):
    service = self.player.service()
    if service:
        # 替换为正确的音频输出选择器IID
        out = service.requestControl("org.qt-project.qt.audiooutputselectorcontrol/5.0")
        if out:
            out.setActiveOutput(self.out_combo.currentText())
            service.releaseControl(out)
        else:
            print("无法获取音频输出控制，请检查Qt Multimedia后端配置")

完整可运行代码 #

import sys
from PySide2 import QtMultimedia
from PySide2.QtCore import QUrl, Qt
from PySide2.QtMultimedia import QMediaPlayer, QMediaContent
from PySide2.QtWidgets import (QPushButton, QSlider, QHBoxLayout, QVBoxLayout,
                               QFileDialog, QStyle, QApplication, QDialog, QComboBox)


class Window(QDialog):
    def __init__(self):
        super().__init__()

        self.out_combo = QComboBox()
        mode = QtMultimedia.QAudio.AudioOutput
        devices = QtMultimedia.QAudioDeviceInfo.availableDevices(mode)
        for item in [(dev.deviceName(), dev) for dev in devices]:
            self.out_combo.addItem(item[0], item[1])
        self.out_combo.currentIndexChanged.connect(self.out_device_changed)

        openBtn = QPushButton('Open file')
        openBtn.clicked.connect(self.open_file)

        self.playBtn = QPushButton()
        self.playBtn.setEnabled(False)
        self.playBtn.setIcon(self.style().standardIcon(QStyle.SP_MediaPlay))
        self.playBtn.clicked.connect(self.play_file)

        self.slider = QSlider(Qt.Horizontal)
        self.slider.setRange(0, 0)
        self.slider.sliderMoved.connect(self.set_position)

        hor_layout = QHBoxLayout()
        hor_layout.setContentsMargins(0, 0, 0, 0)
        hor_layout.addWidget(openBtn)
        hor_layout.addWidget(self.playBtn)
        hor_layout.addWidget(self.slider)

        ver_layout = QVBoxLayout()
        ver_layout.addWidget(self.out_combo)
        ver_layout.addLayout(hor_layout)

        self.setLayout(ver_layout)

        self.player = QMediaPlayer(None, QMediaPlayer.VideoSurface)

        self.player.stateChanged.connect(self.mediastate_changed)
        self.player.positionChanged.connect(self.position_changed)
        self.player.durationChanged.connect(self.duration_changed)

        self.show()

    def open_file(self):
        file_name, _ = QFileDialog.getOpenFileName(self, "Open file")
        if file_name != '':
            self.player.setMedia(QMediaContent(QUrl.fromLocalFile(file_name)))
            self.playBtn.setEnabled(True)

    def play_file(self):
        if self.player.state() == QMediaPlayer.PlayingState:
            self.player.pause()
        else:
            self.player.play()

    def mediastate_changed(self, state):
        if self.player.state() == QMediaPlayer.PlayingState:
            self.playBtn.setIcon(self.style().standardIcon(QStyle.SP_MediaPause))
        else:
            self.playBtn.setIcon(self.style().standardIcon(QStyle.SP_MediaPlay))

    def position_changed(self, position):
        self.slider.setValue(position)

    def duration_changed(self, duration):
        self.slider.setRange(0, duration)

    def set_position(self, position):
        self.player.setPosition(position)

    def out_device_changed(self, idx):
        service = self.player.service()
        if service:
            out = service.requestControl("org.qt-project.qt.audiooutputselectorcontrol/5.0")
            if out:
                out.setActiveOutput(self.out_combo.currentText())
                service.releaseControl(out)
            else:
                print("无法获取音频输出控制，请检查Qt Multimedia后端配置")


app = QApplication(sys.argv)
window = Window()
sys.exit(app.exec_())

注意事项 #

• 该方案在Windows 7/10/11 + PySide2 5.15.x版本下验证可用
• 若仍无法获取控制对象，确认Qt Multimedia使用默认DirectShow后端，部分自定义后端不支持音频输出选择控制
• 切换输出设备时无需暂停播放，可实时切换生效

内容的提问来源于stack exchange，提问作者noEmbryo