Advice for presenters

This is the reference documentation for advice for presenters for events recorded by the DebConf video team. If you think something should be included here, don’t hesitate to Contact us or to make a merge request on the git repository for this documentation.

All event-related advice should instead be added on their respective wiki page.

Display Output

We use a 16:9 resolution, 1280x720. Our old limitation of 1024x768 resolution and 4:3 aspect ratio no longer applies. Slides that have a 4:3 aspect ratio will be pillar-boxed. This means if your presentation is not 16:9, it will be displayed between black bars.

Our video capture system uses HDMI. The video team has adaptors to some other formats:

  • micro-HDMI

  • mini-HDMI

  • DVI

  • DP

  • mini-DP

  • USB-C (thunderbolt compatible)

  • VGA (best-effort, via unreliable adapters)

The VGA-to-HDMI adapters are on a best-effort basis. Those are known to be somewhat unreliable and you are encouraged to test your laptop with them prior to your talk, in order to check whether they are an option.

If your laptop doesn’t have one of the above mentioned digital ports, it’s up to you to bring an adapter and, ideally, test it before bringing it to DebConf.

Presenters are strongly encouraged to test if their setup works correctly with our video equipment before their session, either in one of the video team volunteer training sessions or in breaks between talks. Attempting to fix stuff five minutes before your presentation is not fun!

As a last resort, desktop systems are present as part of the videoteam setup, so if you have your talk in PDF format, it can be presented via the desktop system.


If your USB-C port uses Thunderbolt, you may need to update your thunderbolt firmware to get video to work.

xrandr hints

720p VGA mode

One of these should work to get 720p video over VGA:

xrandr --newmode 720p60 74.25  1280 1390 1430 1650 720 725 730 750 +HSync +VSync
xrandr --newmode 720p60-2 74.25 1280 1392 1448 1650 720 722 728 750

Substitute the mode that works better appropriately in:

xrandr --addmode VGA-1 720p60
xrandr --output VGA-1 --mode 720p60

This should make VGA only laptops work with the Opsis capture board using a VGA-to-HDMI adaptor.

Mirroring at non-native LCD resolution

This should work:

xrandr --output LVDS-1 --scale-from 1280x720 --output HDMI-1 --same-as LVDS-1

Publishing your slides

Please publish your slides in the appropriate DebConf share repository.

Alternatively you can email your presentation the videoteam mailing list and it will be added to the repository (eventually).


Debian presentation templates for various architectures, and archives of previous talks can be found on the main Debian wiki.


To get your slides to the right aspect ratio, you can use this snippet in your beamer template:



If possible, bring something to drink during the talk. We normally try to have water bottles at the speaker’s desk, but can’t guarantee anything.

Presenting remotely or online (Jitsi)

For presenting without physically travelling to DebConf, we use Jitsi, a Web-based video conferencing platform.

Do a test call in Jitsi at least a day before your talk. Make sure that you can see and hear others, and that they can see and hear you. If you’ll be presenting a BoF from weak hardware or behind a slow uplink, try to have a test call with multiple participants, to ensure the available CPU and bandwidth are adequate.

In live talks, anyone speaking in the Jitsi room will be broadcast and recorded as part of the talk, so keep the link private.

In pre-recorded talks, the Jitsi room will be “live” during the introduction and during the Q&A session, but not while the pre-recorded video is playing. The video director will be in the room and will count you down (“going live in 5, 4, 3, 2…”) when the video stream is about to switch from the recording to broadcasting Jitsi. The switch will happen around a minute before the end of the recording is seen on the stream.

While in Jitsi, keep an eye on the Jitsi chat pane (on the left; press C to open it). The video team may use that to communicate with you without distracting viewers.

During Q&A, you need not share your desktop to Jitsi; it’s better if you leave your camera running, assuming you have a camera, so your face can be seen in the video. The etherpad can be grabbed to the video independently (through a cloud machine that has the pad open in a headless GUI environment).

When going through the pad, do so in order, so it’s easier for the video team to keep the relevant part of the pad in the frame. If your session has a talkmeister, they’ll manage that for you.

During BoF sessions, press R in Jitsi to raise your hand, and press P to see who has their hand raised. Remember to unraise your hand afterwards.