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Speaker preparations

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So you have been invited to present a talk or workshop at DiVOC or another remote event? On this page, we provide information to help you optimally prepare for your session in technical terms.

To get started, you will need to be clear about whether you will be streaming a talk as a single speaker (live or possibly as a recording followed by a live interactive Q&A), or whether several persons will be presenting together. Depending on this either a set-up with OBS studio (single speaker) or via BigBlueButton (multiple speakers) will be the right choice.

If your contribution is not to be streamed (and possibly recorded) but is meant to be a self-organised session, then please check How to self-organise a session? for recommendations on simple set-ups.

Important: we will be doing a rehearsal of 30 to 60 minutes' length with you several days ahead of the event, in order to address any technical questions and practice the sequence of your session. Please mark your calendar for one or two proposed rehearsal time slots now.

Audio and video

Headset and microphone

It is of paramount importance for all participants to have the best possible audio quality. The better the microphone you are using and the more closely-placed that microphone to your mouth is, the more clearly listeners will be able to hear you. Gaming head sets usually work really well, but USB head sets may provide good results as well. Bluetooth-connected head sets have been reported to frequently fail after a few minutes; if the Bluetooth connection to the head set breaks during the talk, this will cause an irritating and unnecessary interruption, so we urge you to please use a cable-connected head set. Simple phone head sets with a microphone integrated into the cable usually provide inferior audio quality, and those microphones also frequently scratch and rustle at clothing, causing unwanted background noises. The VOC provides a list of recommendations for head sets.

Video camera

Good-quality video is great to have. If you have the option to feed an external HD camera's video into your computer, then that would be the preferred solution. Simple USB cameras can typically provide reasonable video, too. The integrated camera of a laptop may do fine as well, if it provides as least 720p (1280×720).


The vast majority of cameras produce better-quality images if light levels are high. Prepare the room from which you are planning to stream well ahead of the session and take care to set up ample illumination for your face and torso. The background should be about as bright as yourself. You should absolutely avoid having light shine directly into the camera lens. The camera should be pointed at a wall or shelf, not a window. If a window is within the field of view, try to minimise daylight and reflections in the window pane using curtains.

Check the overall video image quality, ideally at the same time of day as your talk, on one of the days preceeding your session.

Talk by a single speaker

A standard talk would follow this sequence for a session: a herald introduces your upcoming talk, then gives the stage to you. You present your talk, showing your slides and if applicable demos on your computer. Your talk will be followed by a questions and answers part: the herald reads selected questions and passes them on to you to answer. The herald wraps up the session with closing remarks.

The technical set-up for this is as follows: both you and the herald will send their audio and video signals via OBS studio. Consequently, you need to have OBS studio installed and configured on your computer. Both sets of signals will be received by the video operations center (VOC) and fed into the outgoing stream broadcast.

In order to execute the session seamlessly, it is necessary for the VOC, herald and yourself to be able to communicate without delays. On the one hand hand, the herald and you must be able to pass the speaker role back and forth between each other, and on the other hand VOC will be giving you instructions, or simply reminders about the timing. The mumble system will be used for this type of communication, mumble being a system that allows for low-latency audio transmissions that you will also need to have installed and configured.

During your talk, you cannot expect to make any use of the stream as delivered to the general audience. That is because depending on the set-up, the stream will be lagging behind your input by up to two minutes. Consequently, you cannot wait to receive any instructions from the herald via the stream. Therefore, it is important to work with mumble with its very low latency.

Workshop or talk with multiple participants or speakers

For scenarios where multiple contributors are to be seen and heard simultaneously or in rapid succession, we provide a BigBlueButton room where all contributors and the herald meet. Video and audio will then be received by an additional „silent“ participant who routes the signals into the outgoing stream.

TODO: Ton über BBB und/oder Mumble? Sind alle im Mumble? - check German page for updates!

Technical set-up


Please install the mumble client on the computer that you will be using for streaming or for participation in a BigBlueButton room. We will be communicating to you in due time to which server we expect you to connect.

For the duration of the session, please set your mumble client to continuous transmission. Do not mute or deafen yourself. We will take appropriate precautions to avoid any distractions during your talk as much as possible. It will be necessary, however, for us to be able to reach out to you directly, without you having to monitor a text chat or similar in parallel to your talk.

OBS studio

OBS studio is rather complex software. Fortunately, OBS can be configured such that it will be possible to create a perfectly acceptable video stream with it even if you have little previous experience using it.

We will be sending you the necessary files to configure your OBS for streaming in due time. In particular, this will include three scenes: a full-frame view of your camera, a full-screen view of your desktop or your presentation program in full-screen mode, and a split screen including your presentation slides or demo and your camera frame. During the rehearsal, we will assist you in optimally setting all of this up.

Streaming and encoding parameters

To generate the stream, you will need to set a couple of parameters:

We will communicate the actual streaming URL to you during the rehearsal.


We will open a room on a dedicated server for you and communicate the URL to you in due time. Please see about forwarding the URL to all contributing participants. We will coordinate with you how to configure the room to determine who can participate, whether participants will need a code to join, whether participants will be muted upon joining, whether a moderator will have to approve participants in order to join, and whether all participants will have a moderator role.

Sequence of a session

15 minutes to go

VOC, herald and contributors meet in mumble and the respective stream or BBB room have been started.

Together, we conduct a quick technical check-up and rehearse the start sequence (introduction by herald, beginning of the talk by speaker).

We check the latency of herald and speaker(s): both should have the same latency with respect to the VOC. If necessary we attempt to adjust the codec parameters.

1 minute to go

VOC, herald and contributors get ready for their cue. By default, there will be radio silence on all channels. Anyone but the VOC, herald and contributors will have left the mumble channel by this time.

The talk

VOC plays the intro jingle then gives herald and speaker(s) their cue to start.

The herald introduces the session, the contributors deliver their talk or workshop.

If needed, the VOC informs you in case audio or video are not working as intended. In the worst case, the stream will have to be interrupted to troubleshoot and start over.

10 minutes and 5 minutes before the projected end of the session, VOC gives timing reminders.

Questions and Answers

The herald will do a short transition following the end of your talk („I am looking forward to your questions!“). Depending on the time left, the herald will then present the speaker(s) with questions selected from the Q&A pad, giving the speaker(s) the opportunity to reply.

VOC will give a pointer when the time runs out („last question“).

The herald finishes with some concluding remarks.

VOC plays the outro jingle and stops the stream (switching to break mode). VOC announces to herald and speaker(s) when their audio cannot be heard in the stream anymore.

howto/en/speakerinnenvorbereitung.txt · Zuletzt geändert: 2020/09/30 18:38 von stb