This page contains notes and tips for our speakers on preparing their talks and presentations. Please read through the list and consider it while preparing your talk. If you have any questions, concerns, or suggestions please feel free to write to one of the organizers directly (e.g., or 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.

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 2021 run smoothly, please prerecord your talk, and send us your video(s) by November 7 at the latest (three weeks before the conference), 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}."

Please upload your prerecording(s) (and script/notes if any) via FTP to the FTP server we have set up with the following details:

  • host:
  • username: anonymous
  • port: 21
  • folder: upload-here

To upload your recording and any accompanying material to the above FTP server, you can use your FTP client of choice. For instance, FileZilla, a free/libre user-friendly application with a graphical user interface. On deb-based GNU/Linux distributions such as Trisquel you can install FileZilla by running sudo apt install filezilla in a terminal. Otherwise, you can download FileZilla from their project website.

You can also use a command-line interface with ftp:

$ ftp 21
> anonymous
> passive
> cd upload-here
> send /local/path/to/file.ext file.ext  # Don't forget the 2nd arg!
# Ctrl-D to exit

If you get a 500 Illegal PORT command. command, try passive or quote pasv to switch to passive mode before sending your file.

If connection fails on the first try, please check to make sure the details are exactly as described above; and if the issue persists, please email so we can look into it.

If you have a script or notes for your talk, please include it as well so that we could use it to help us with the captioning of your talk. You can also send us additional information to include on the wiki page for your talk, such as a PDF or links to other pages or additional videos. If you need help, please email

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

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 try to 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.

The conference broadcast will most likely be in 720p (1280px x 720px, progressive) using the WebM video format. The closer to this format submitted video files arrive in, the easier it will be to process and upload them.


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 -aq-mode 2 -an -tile-columns 0 -tile-rows 0 -frame-parallel 0 -cpu-used 8 -auto-alt-ref 1 -lag-in-frames 25 -g 240 -pass 1 -f webm -threads 8 /dev/null &&
ffmpeg -y -i "$1" -c:v libvpx-vp9 -b:v 0 -crf $Q -c:a copy -tile-columns 2 -tile-rows 2 -frame-parallel 0 -cpu-used -5 -auto-alt-ref 1 -lag-in-frames 25 -pass 2 -g 240 -threads 8 "$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:

If this is your first time at EmacsConf or if you run into any problems, please get in touch with us and we'll sort things out together! In those cases, since we'll need to schedule a 1-on-1 tech-check with you, we ask that you email the closest volunteer to your timezone in the list below (or zaeph if none of the timezones is a good fit). You can also visit us at #emacsconf-org on Libera.

We will likely schedule those 1-on-1 tech-checks with you on Saturdays or Sundays, but we would be happy to try and work out another time if that doesn't work for you.

Volunteer Email IRC Nick Timezone
Leo Vivier <> zaeph CET (UTC+1)
Wanna help out? You can add your name and contact-info here! <your@email>
Corwin Brust <> corwin US/Central (UTC-6)
Amin Bandali <> bandali US/Eastern (UTC-5)
Yuchen Pei <> Australia/Eastern (UTC+11)
Case Duckworth <> acdw US/Central (UTC-6)

If you'd like to help out with the tech-checks, feel free to add your name and email to the above list and email <> to plan the logistics.

Thank you so much for helping with EmacsConf 2021!

Frequently-asked questions

Can I present live?

Tech issues kept happening during EmacsConf 2020, so we'd really prefer that all talks have prerecorded videos. There might be time for live questions and answers over a web conference, 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.

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 November 7. 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.

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 November 7. 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 all 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 we run out of time?

You can continue answering questions on the collaborative pad or IRC, and we'll copy questions and answers onto the wiki page afterwards. You can also answer questions on the wiki page even after the event.

An extended live demo or Q&A session might be possible if someone volunteers to broadcast it on an alternative stream. If you or a volunteer is interested in helping with this, please feel free to contact us at

More questions?

Please email We'd love to hear from you.

Thanks for contributing to EmacsConf 2021!