This page contains tips for preparing your talk. (Target date: November 4) If you have any questions, concerns, or suggestions please feel free to write to one our organizational mailing lists: the public list, or the private list, depending on the nature of the matter you would like to discuss.

Note: being part of a wiki, this page is subject to change (including by you!); so please check back every now and again for any changes and updates.

We'll bring up the web-based upload service at some point. Let us know at if you're already ready to go!

Guidelines for conduct

Please review our guidelines for conduct when preparing your talk to make sure we’re all on the same page and strive to make the event a great experience for all. If you’re not sure whether your talk or presentation style meets the guidelines laid out in the guidelines for conduct, we’d be happy to help. You can email Sacha Chua at to chat more about this.

Recording your talk

To help EmacsConf 2023 run smoothly, please prerecord your talk, and plan to upload your video(s) by November 4 to allow us enough time to do any needed processing (e.g. format or codec conversion) in preparation for the event. Please consider submitting a prerecording as early as possible so that we can see if volunteers can caption your video to make it more accessible and searchable.

To make it easier for organizers and attendees to correctly pronounce your name, please start your video with something along the lines of:

"Hi! I’m ${NAME} and I’ll be talking about ${TOPIC}."


To record your video, you could use any of the following pieces of free software, depending on your needs:

If you decide to use OBS, please make sure to verify the window-capture options. Most notably, there is a “Swap red and blue” option that is necessary for some setups, and it's easy to miss it.

You might find the following free software programs useful for editing your video recordings:

Per GNU Project’s Guide to Formats, we prefer to receive prerecorded videos in formats unencumbered by software patents, such as video/webm (WebM-encoded video files, with .webm file extension) and video/ogg (video files encoded with the Theora video codec, encapsulated in an Ogg transport layer, with .ogg or .ogv file extension). However, if for one reason or another you are unable to send us your prerecorded video in one of the above formats, you may submit them in other common formats, like MPEG-4 (.mp4), and we will convert them to our preferred formats on your behalf.

Prepare recorded video in 720p (1280px by 720px) or higher, in the WebM format if possible.

Audio quality

Audio quality can go a long way in making your talk enjoyable to watch. Consider the background noise in the room that you are using to record, and see if you can temporarily turn off things for your recording. Start by recording a separate video with at least 5 seconds of quiet in the same room in which you plan to do your main recording. You can listen to it to see how quiet things are, and figure out if there are other things you can turn off such as fans or other computers. When you upload your talk, you can also include your latest silence recording so that we can use it to reduce noise in your video.

If you have an external microphone or a headset, try recording the audio through that so that you can reduce the sound of the computer itself. If you have a smartphone, that might also be a good way to record audio that you can then combine with your video afterwards. Some people find that draping a blanket over their head (including the microphone under the blanket) can help reduce echo, which can be a good excuse to make a blanket fort. (It's for EmacsConf!)

Many speakers prefer to record and edit the audio until they're happy with how it fits in the time, and then add the slides or videos afterwards. It might be easier than trying to do both the audio and the video in one go.


The talks will be broadcast with a resolution of 1280x720px (720p), so it may help to switch to that size before you record. Please make sure your text will be easy to read. You can change the font-size in your Emacs. (Maybe M-x customize-face default and set the height to 150 or 180?) If you are capturing a single window, you can also resize it before you record.

We recommend using dark text on a light background for your recording, as this can be easier to see especially for people who are visually impaired. Themes with more contrast are easier to read than low-contrast ones. If you use a dark theme with your Emacs, you can change to a lighter one with M-x customize-theme (look for those with a -light suffix). The modus-themes-load-operandi command from the modus-themes package can be a good option.


If you would like to compress your video before uploading, the following shell script may be useful:

ffmpeg -y -i "$1" -c:v libvpx-vp9 -b:v 0 -crf $Q -an -row-mt 1 -tile-columns 2 -tile-rows 2 -cpu-used $CPU -g 240 -pass 1 -f webm -threads $CPU /dev/null &&
ffmpeg -y -i "$1" -c:v libvpx-vp9 -b:v 0 -crf $Q -c:a libopus -row-mt 1 -tile-columns 2 -tile-rows 2 -cpu-used $CPU -pass 2 -g 240 -threads $CPU "$2"

If you put it in a file called, you can execute it from the command line with something like sh input-file.webm output-file.webm. It will compress the file in two passes. During the first pass, the frame count will increase, but the speed will be 0. After the first pass, it will display proper progress information.


We ask that speakers who plan to participate in live Q&A sessions schedule a short tech-check in the weeks leading to the conference; this is to ensure that you can perform all the common tasks you’d need such as sharing your screen or toggling your microphone.

We use BigBlueButton for our video-conferencing needs, and a quick way to familiarize yourself with it is to run it in a test room: Tiling window managers and multi-monitor setups can be a little tricky, so it's good to figure out a setup that works for you. If there are things you'd like to confirm by having another person in the meeting, such as audio quality, please feel free to get in touch with us and we’ll sort things out together.

Thank you so much for helping with EmacsConf 2023!

Frequently-asked questions

Can I present live?

Tech issues kept happening during EmacsConf 2023, so we’d really prefer that all talks have prerecorded videos. There will be time for live questions and answers, though, so if you can record a short video covering your main points, you might be able to go into more detail in live Q&A.

I have so much I want to share. Can I record a longer video?

The conference program has so many interesting talks. We wish we could fit everything in at full length! (Maybe EmacsConf month?) Please think of your video as a short teaser that can get people interested and point them to where they can find out more. You can email links and other notes to add to the wiki page for your talk. If you’d like to record a longer video in addition to the short one for the main conference, please feel free to send us that too.

Additionally, even though it is tempting, please refrain from speaking super quickly or fast-forwarding your recording to make it fit within the format. Trimming out the silences and the filler words can help sometimes, but a better solution for you might be to condense your talk to the essentials, then write, record, and edit your voice-over. Once you've figured out how to use the time, you can record your video to go along with it. Don't sweat being a few minutes over or under, that's cool.

Feel free to send some questions for the host to ask you during the Q&A so that you can address extra points that didn't make it into the video.

I can’t figure out how to record the video. Can I just present the talk?

We might be able to help you record your talk using the BigBlueButton web conferencing system before the conference. Please email with some times that might work for you and we’ll see if a volunteer can meet up with you to record it.

Do I need to follow some visual guidelines for the presentation?

  • Dark text on a light background is more legible than the opposite (especially for people who are visually impaired), and more contrast is better than a low-contrast theme. This stands for both your slides and your Emacs theme.
  • If you think your fonts might be too small in your slides or in Emacs, they might very well be. You can change the font-size in your Emacs, but you can also play with the size of the captured window during your recording.
  • Try to minimize the screen-flashes that occur when you switch between windows, especially if their themes do not cohere (light-to-dark and the reverse). If you can edit your recording, fades and other transitions are a neat solution to this problem.

How do I show my keystrokes on screen?

In Emacs, you can use interaction-log.el (in MELPA) to display the keystrokes and the commands they run in a separate buffer. For a system-wide solution, you can look into screenkey.

I’m not used to talking to myself. Can I present the talk to someone?

We might be able to help you record your talk using the BigBlueButton web conferencing system before the conference. Please email with some times that might work for you and we’ll see if a volunteer can meet up with you to record it.

Can I see the other proposed talks?

Once we’ve emailed the speakers about their acceptance, we’ll put up the talk wiki pages. That way, you can see what else is going on in the conference and maybe coordinate with other speakers in order to minimize overlap and maximize awesomeness.

What if there are lots of great questions during Q&A and it's already time for the next talk?

The stream will move on to the next talk, but people can join the BigBlueButton meeting room and keep chatting with you for as long as you want to keep going. You can also continue answering questions on the collaborative pad or IRC, and we’ll copy questions and answers onto the wiki page afterwards so that you can answer them in your own time after the event.

More questions?

Please email We’d love to hear from you.

Thanks for contributing to EmacsConf 2023!