On Windows, QMediaPlayer relies on system codecs. If MP4 fails to play while AVI works (e.g., DirectShowPlayerService errors), installl appropriate H.264/AAC codecs or enable the Windows Media Feature Pack.

Minimal player

A bare-bones player that opens a file dialog, renders video in a QVideoWidget, and starts playback.

import sys
from PyQt5.QtWidgets import QApplication, QFileDialog
from PyQt5.QtMultimedia import QMediaPlayer, QMediaContent
from PyQt5.QtMultimediaWidgets import QVideoWidget

if __name__ == "__main__":
    app = QApplication(sys.argv)

    video_surface = QVideoWidget()
    video_surface.resize(800, 450)
    video_surface.show()

    media_player = QMediaPlayer()
    media_player.setVideoOutput(video_surface)

    url, _ = QFileDialog.getOpenFileUrl(caption="Open video")
    if url.isValid():
        media_player.setMedia(QMediaContent(url))
        media_player.play()

    sys.exit(app.exec_())

To hardcode a local file, replace the file dialog with a file URL:

from PyQt5.QtCore import QUrl

# media_player.setMedia(QMediaContent(QFileDialog.getOpenFileUrl()[0]))
media_player.setMedia(QMediaContent(QUrl.fromLocalFile(r"C:\Users\user\Videos\sample.mp4")))

UI designed with Qt Desigenr

Build a simple window using Qt Designer and wire it to QMediaPlayer. In Designer:

• Add a placeholder QWidget where the video should render, then promote it to QVideoWidget (class name: QVideoWidget).
• Add a button (objectName e.g., btnOpen).
• Save as video_basic.ui.

import sys
from PyQt5 import uic
from PyQt5.QtWidgets import QApplication, QFileDialog
from PyQt5.QtMultimedia import QMediaPlayer, QMediaContent

class BasicPlayer:
    def __init__(self):
        self.ui = uic.loadUi("video_basic.ui")
        self.player = QMediaPlayer()
        # In Designer, the promoted widget objectName should be videoSurface
        self.player.setVideoOutput(self.ui.videoSurface)
        self.ui.btnOpen.clicked.connect(self._open_video)

    def _open_video(self):
        url, _ = QFileDialog.getOpenFileUrl(self.ui, "Open video")
        if url.isValid():
            self.player.setMedia(QMediaContent(url))
            self.player.play()

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = BasicPlayer()
    window.ui.show()
    sys.exit(app.exec_())

Playback controls: play/pause, seek bar, remaining time

Extend the UI to include:

• A play/pause button (btnToggle)
• A horizontal slider for progress (sldPosition)
• A label for remaining time (lblRemaining)
• The promoted video widget (videoSurface)

Save this layout as player_controls.ui.

import sys
from PyQt5 import uic
from PyQt5.QtWidgets import QApplication, QFileDialog
from PyQt5.QtMultimedia import QMediaPlayer, QMediaContent

class PlayerWithControls:
    def __init__(self):
        self.ui = uic.loadUi("player_controls.ui")

        self.media = QMediaPlayer()
        self.media.setVideoOutput(self.ui.videoSurface)

        self._duration = 0
        self._seeking = False

        # Buttons
        self.ui.btnOpen.clicked.connect(self._open)
        self.ui.btnToggle.clicked.connect(self._toggle)

        # Timeline and time updates
        self.media.durationChanged.connect(self._on_duration)
        self.media.positionChanged.connect(self._on_position)
        self.ui.sldPosition.sliderPressed.connect(self._on_seek_start)
        self.ui.sldPosition.sliderReleased.connect(self._on_seek_end)
        self.ui.sldPosition.sliderMoved.connect(self._on_seek_preview)

    def _open(self):
        url, _ = QFileDialog.getOpenFileUrl(self.ui, "Open video")
        if url.isValid():
            self.media.setMedia(QMediaContent(url))
            self.media.play()
            self.ui.btnToggle.setText("Pause")

    def _toggle(self):
        if self.media.state() == QMediaPlayer.PlayingState:
            self.media.pause()
            self.ui.btnToggle.setText("Play")
        else:
            self.media.play()
            self.ui.btnToggle.setText("Pause")

    def _on_duration(self, ms):
        self._duration = max(0, ms)
        self.ui.sldPosition.setEnabled(self._duration > 0)
        self.ui.sldPosition.setRange(0, self._duration)
        self._update_remaining(self._duration)

    def _on_position(self, ms):
        if not self._seeking:
            self.ui.sldPosition.setValue(ms)
        self._update_remaining(self._duration - ms)

    def _on_seek_start(self):
        self._seeking = True

    def _on_seek_end(self):
        self._seeking = False
        self.media.setPosition(self.ui.sldPosition.value())
        self._update_remaining(self._duration - self.ui.sldPosition.value())

    def _on_seek_preview(self, value):
        # Show remaining time while dragging
        self._update_remaining(self._duration - value)

    def _update_remaining(self, ms):
        if ms < 0:
            ms = 0
        total_seconds = ms // 1000
        minutes, seconds = divmod(int(total_seconds), 60)
        self.ui.lblRemaining.setText(f"{minutes:02d}:{seconds:02d}")

if __name__ == "__main__":
    app = QApplication(sys.argv)
    w = PlayerWithControls()
    w.ui.show()
    sys.exit(app.exec_())

Appearance tweaks

• Window chrome:

from PyQt5.QtGui import QIcon

self.ui.setWindowTitle("PyQt5 Video Player")
self.ui.setWindowIcon(QIcon("icons/app.png"))

• Basic styling:

self.ui.setStyleSheet(
    """
    QWidget { background-color: #121212; color: #e0e0e0; }
    QSlider::groove:horizontal { height: 6px; background: #333; }
    QSlider::handle:horizontal { width: 12px; background: #00bcd4; margin: -4px 0; border-radius: 6px; }
    QPushButton { padding: 6px 10px; }
    """
)