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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 to adjust the video layout.

The controls are available partly in the image, partly below the timeline. The player can also be controlled via keyboard shortcuts.

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
  4. Keyboard shortcuts

1. Controls in the picture

  • Start the video: By clicking the play button in the center of the screen, you start the video.

Play button in the picture

  • Button for picture-in-picture-view in the picture Activate picture-in-picture-view: If you move the mouse over the video image after starting the video, a button is displayed for a few seconds on the right-hand side of the image with which you can activate the picture-in-picture view. When activated, the video is displayed in a reduced size at the bottom right of the screen and continues to run in the foreground, even if you switch from the browser to other applications. Click on the button to exit picture-in-picture mode Button to exit picture-in-picture mode to return to normal playback mode.
  • Button to jump to next or previous slide Jump to the previous or next slide: For videos that have been uploaded as presentation videos, you can jump to the next or previous slide by clicking on the forward or back button.

2. Controls below the timeline

  • Play button Play
  • Pause button Pause
  • Rewind button Rewind 5 seconds
  • Forward button Forward 5 seconds
  • Button to adjust playback speed Adjust playback speed: 0.75x, 1x (default), 1.25x, 1.5x, 1.75x, 2x, 2.25x, 2.5x, 3x
  • Loudspeaker button Set volume to mute or unmute by clicking the button or adjust volume by slider
  • Settings button View and adjust settings, if applicable
    • Video description and data
    • Adjust video quality: auto, 854x480, 1280x720, 1920x1080
    • Transcriptions (only for presentation videos)
    • Overview of the keyboard shortcuts
  • Fullscreen mode button Start fullscreen mode
  • Video layout button Adjust video layout: If a presenter and a presentation video have been uploaded, you can set here whether only one of the two videos or both videos should be displayed.

Video layout menu

  • Possible layouts if both videos (i.e. presenter and presentation) are to be displayed: Presenter in the foreground, presentation in the foreground, presenter and presentation next to each other. You can perform these and other settings by clicking the buttons in the picture:
    • Switch button Use the switch button to move the videos to the other side.
    • Maximize button Use the maximize button to bring the respective video to the foreground.
    • Dual stream button Use the dual stream button to display both videos side by side in the same size.
    • Close button Use the close button to close a video.
  • Captions and chapters button Display captions or chapters, if uploaded als WebVTT file
  • Search button for captions and chapters Search in the video's captions or chapters, if uploaded als WebVTT file

Search field for chapters

  • Slide timeline button Display slide timeline for presentation videos: This way, you can quickly navigate to the appropriate slide.

Slide timeline of a presentation video

  • Replay button Replay video

3. Slide navigation

For videos that have been uploaded as a presentation, Opencast automatically generates a slide/frame navigation from the video file. The timeline shows the slide changes, making it easier to jump between sections.

Timeline of a presentation video


4. Keyboard shortcuts

Videos from the Opencast streaming server can also be controlled via the following keyboard shortcuts:

  • Toggle play/pause: Key "K"/Space
  • Toggle audio mute: Key "M"
  • Rewind (10 seconds): Key "J"/Arrow left
  • Forward (10 seconds): Key "L"/Arrow right
  • Toggle fullscreen: Key "F"
  • Exit fullscreen: Key "F"/Key "Esc"
  • Toggle captions: Key "C"
  • Volume up (10%): Arrow up
  • Volume down (10%): Arrow down
  • Decrease playback speed (0.75x, 1x, 1.25x, 1.5x, 1.75x, 2x, 2.25x, 2.5x): Key "U"
  • Increase playback speed (1x, 1.25x, 1.5x, 1.75x, 2x, 2.25x, 2.5x): Key "O"


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last changed on 01/17/2024

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