QFileDialog open multiple files and set MIME filter

Question

How can I use a QFileDialog to open multiple videos at once and apply a MIME filter at same time? Current code:

file_dialog = QFileDialog(self)

AVI = "video/x-msvideo"
MP4 = "video/mp4"

is_windows = sys.platform == "win32"
if not mime_types:
    mime_types = self.video_widget.get_supported_mime_types()
    if is_windows and AVI not in mime_types:
        mime_types.append(AVI)
    elif MP4 not in mime_types:
        mime_types.append(MP4)

mime_types.insert(0, "application/octet-stream")
file_dialog.setMimeTypeFilters(mime_types)

file_dialog.setDirectory(QStandardPaths.writableLocation(QStandardPaths.MoviesLocation))

if file_dialog.exec() != QDialog.Accepted:
    return
print(file_dialog.selectedFiles())