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Playing videos from the streaming server

Playing videos from the streaming server


The Opencast streaming server of the RWTH Aachen University uses the Paella Player to play videos. The player offers a number of controls to adjust the playback speed and video quality, call up subtitles or chapter marks or zoom into the video.

The controls are available partly in the image, partly above the timeline.

Videos uploaded as presentations also have a slide/frame navigation automatically generated from the video file.


Table of contents

1. Controls in the picture
2. Controls below the timeline

3. Slide navigation


1. Controls in the picture

  • Play-Button in Video At the top left of the picture, there is a semi-transparent play button.
  • Zoom-Buttons in Video At the top centre of the video image, there are two semi-transparent buttons that allow you to zoom in or out of the video. When zooming into the video, the currently visible section within the overall picture is displayed in the upper right corner of the video image. You can move the visible section by dragging the video image.
    Preview of the visible section of the video
  • Button for picture in picture You move the mouse over the video image, a button is displayed for a few seconds on the right side of the image to activate the picture-in-picture view. When you activate it, the video is displayed in a reduced size in the lower right corner of the screen and always continues to run in the foreground, even when you switch from the browser to other applications. Clicking the icon to exit the Picture-in-Picture mode Button for closing picture in picture will return you to normal play mode.

2. Controls below the timeline

  • Play-Button in Video Play video
  • Button for going backwards in video Go back 5 seconds in the video
  • Button for skipping 5 sec in video Skip 5 seconds in the video
  • Button for adjusting play speed Adjust playback speed: 0.75x, 1x (default), 1.25x, 1.5x, 1.75x, 2x, 2.25x, 2.5x, 2.75x, 3x
  • Button for volume level Adjust volume level with slider (appears when clicked)
  • Button for zooming Show zoom option: zoom in, zoom out, return to default
  • Button for automatic adjustment of video quality Adjust video quality: 720p, 1080p, auto (adjusts automatically starting with 360p)
  • Button to call metadata Call up metadata. The field "Ansichten" also shows how often the video has been watched. Only one click per current session in RWTHmoodle is counted. If a person plays the video several times during a session, only one view is counted. The number of views is only clicked counts. They do not give any indication of how long the video has been playing. You can find detailed information on this in the Usage statistics for the course room.

    Screenshot of the metadata
  • Button for full-screen mode Start full-screen mode
  • Button for customize video layouts Customize video layout: If a presenter and a presentation video have been uploaded, you can set here whether only one of the two videos should be shown in the foreground, both videos next to each other or both videos picture-in-picture. The button is only displayed if two videos have been uploaded.
    • Possible layouts Possible layouts: Presenter in the foreground, Presentation in the foreground, Presenter and presentation side by side.
    • Side by side layout Nächste Folie Slide If the "side by side" layout is selected, two arrows appear in the presentation video to jump to the previous or next slide.
    • Button for two videos in picture and picture If the "side by side" layout is selected, the option to display the two videos picture-in-picture also appears. One of the videos will be displayed in front of the other in a reduced size. With the circle symbol, you can swap the position of the videos, i.e. which of the two videos should be displayed large in the background and which small in the foreground.
  • Button for searching in video Search in the video
  • Button for slide navigation Call up the slide timeline to navigate to the appropriate slide
    slide navigation window
  • Button for subtitles Subtitles or chapters, if uploaded as WebVTT file
    Screenshot of the chapter navigation


When playing videos on Macintosh notebooks with the Safari web browser, there is choppy video playback. In this case, the video sometimes jumps back for a short moment. When using a smartphone or iPad with Safari, these delays do not occur.

3. Slide navigation

For videos uploaded as presentations, Opencast automatically generates a slide/frame navigation from the video file. The timeline shows the slide changes and makes it easy to jump between the sections.

Screenshot of the frame navigation


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last changed on 09/29/2022

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GNU General Public License 3
This work is licensed under a GNU General Public License