Ubicomp/ISWC’21 is a virtual conference. Each paper author will have a chance to present their work through a pre-recorded video and an online Q&A session following the presentation of their work. This page outlines information for all presenters to help them prepare and present their work at the conference.

Specifying preferred time slots for presenting your work

In order to accommodate attendees from anywhere in the world, we expect all authors to present their work twice at different time points during the day. This will allow better visibility of your work, and allow participants to attend your presentation at a suitable time within the day. The available time slots for paper presentations are indicated in blue in the diagram below:


Details about how to select appropriate time slots will be emailed to all contact authors in July 2021.

If you have not received this email, please contact the program chairs:
For ISWC notes/briefs:

Material for presenting your work

You are expected to prepare a pre-recorded presentation of your work for the main conference. This should be a 6 min video, and it will be shown during the conference. There is also an option to provide additional material if you want to allow the audience to engage more thoroughly with your work.

Required material for IMWUT Papers & ISWC Notes:

  • Pre-recorded video of your presentation – duration 6 mins – size < 200MB

Required material for ISWC Briefs:

  • Pre-recorded video of your presentation – duration 1 mins – size < 40MB

Optional material for IMWUT Papers & ISWC Notes:

  • Teaser video – 30secs – size < 20MB
  • Extended video presentation that attendees have the option to watch – duration < 20 mins – uploaded and shared through a Youtube link.
  • Extended slide deck that attendees can explore (PDF format) – size < 50MB

Uploading the material for your presentation can be done through this online form (detailed instructions will be announced later on). When submitting your material please ensure that you use the correct paper ID and full title of your paper as indicated in the email that is sent to the contact authors by the end of July 2021. The deadline for uploading all the materials is due on 15 August, 2021. For the accepted papers in the May 2021 cycle and the ISWC notes/briefs, the deadline is due on 29 August, 2021.

If you have not received this email, please contact the program chairs:

Where to submit? (PCS)

All materials must be submitted via PCS. We created a NEW PCS submission link for each paper. Please check yours at  

Your IMWUT paper should be found under the category name of “UbiComp/ISWC 2021 Papers Video Presentations.”  This PCS link is different from your original IMWUT paper submission. If your paper is missing, please let the program chairs know. 

Please note that we set the presenter as the contact author, and only the contact author can modify your submission.  

Video presentation – Technical Requirements

Acknowledgement: The technical requirements information shown here are kindly shared with Ubicomp/ISWC by the ACM CHI’21 organisers. (Original page).

The following technical requirements apply to all video submissions at UBICOMP/ISWC. Please note that videos that do not adhere to these guidelines may not be processed. It is your responsibility to ensure these requirements are met.


The file names should have only alphabets and numeric characters with no spaces or special characters.


  • Resolution must be at precisely 1080p (1920 x 1080)
  • All videos must be encoded as an MP4 using the H.264 codec.
  • Videos must be in a 16:9 aspect ratio.
  • Accompanying closed caption file in .srt or .sbv format.

File Size

For Video Presentations: up to 200MB

For Teaser Video: up to 30MB

For extended Video Presentations: no size requirements – submitted as YouTube link.

Handbrake provides good compression results and is available for OSX, Windows and Ubuntu.

Encoding to MPEG-4/H.264 (.mp4)

All the videos should use MPEG-4 encoding using the H.264 codec (file format .mp4). Most video editing software (such as iMovie, Adobe Premiere, Camtasia, and Final Cut Pro) provides an exporting option to MPEG-4/H.264. There are also a number of free encoding solutions you can use:

  • x264 can encode any video into H.264.
  • For Windows users, Freemake Video Converter and Handbrake both provide good results.
  • For OSX users, we recommend Handbrake and other free converters available through the Apple App Store (e.g. Miro Video Converter).
  • For Linux users, FFmpeg is a well-known transcoding solution.

Important: Encode your video using square pixels for the pixel aspect ratio to avoid your movie looking stretched when projected.

Note: We do not endorse or are responsible for the use of any of the software mentioned in this guide.

If you compress your video with unusual software or codecs you risk the possibility that reviewers will not be able to watch your video. UBICOMP/ISWC does not accept software applications or digital video clips requiring a specific computing platform or additional software to play. Before submitting, we also invite you to check the compliance of your file using the Video Checker. You can also upload your video to Youtube (private) and check that it plays correctly.

General Guidelines

Presentation Format (Video Presentations only)

  • Recommended: full-screen screencast of the slides, with a picture-in-picture video of the presenter.
  • Acceptable Alternatives: full screen of slides with audio of speaker or slides and speaker video side-by-side.
  • Other presentation formats can be used (e.g., include a short demo in the presentation), keeping in the spirit of what kind of presentation you would have delivered at the conference.

See A Remote Video Presentation Guide for more details.

Opening Title

You must include the Title, Authors of the work and affiliations at the beginning of the video, either as a title shot or as an overlay text. Make sure that you leave the title for long enough of a duration to be read (up to 10 seconds for Video Presentations, and up to 4 seconds for Teaser Video).


All pre-recorded conference presentation videos must be closed captioned. Allow time to prepare this, especially if using an AI-based service. Submit a closed-captioning file in .srt or .sbv format with the video. Here are two examples of closed captioning done well: Example 1, Example 2.

YouTube provides free tools for generating closed captions (instructions for using YouTube), either starting from a transcript of the dialog (recommended), or using their automated speech recognition and correcting the result. YouTube will add the timings to sync it to the audio. Download the .sbv or .srt file and delete your video when you are finished.

If you use automatic speech recognition, or other AI-based captioning tools (e.g., it is essential to review your closed captions and correct any errors.

Accessibility Considerations

In addition to providing closed captions, use the tips for creating an accessible presentation in this 5 minute video. Remember that some people will not be able to see your slides, so the presentation should be understandable from the script alone. 


Please avoid using effects in your video that could trigger an adverse reaction. For example, flashing lights can induce seizures for people with photosensitive epilepsy. Avoid using animations (simple appear/disappear is ok), unsteady camera work, flashing strobe lights, loud sounds, or repetitive alarms. If you include components, such as police car lights and sirens, consider warning viewers at the start of the video or right before the content so they can look away or mute their computers. The Trace Center offers an analysis tool to help authors assess whether their video is safe for people with photosensitive epilepsy (

Third-party material and Copyright

Authors retain copyright to videos, but ACM requires that you sign an agreement allowing ACM to distribute the material. For IMWUT papers, please fill in this template and upload the signed agreement via PCS. The authors of ISWC notes/briefs must agree with the audio/video release when signing the ACM e-rights forms for their camera-ready submission, so that they can present their work at Ubicomp/ISWC 2021.

It is very important that you have the rights to use all the material that is contained in your submission, including music, video, images, etc. Attaining permissions to use video, audio, or pictures of identifiable people or proprietary content rests with the author, not the ACM or the CHI conference. You are encouraged to use Creative Commons content, for example music available at ccMixter or Newgrounds. If you need to use copyrighted protected work, you are required to review and comply with ACM’s Copyright and Permission Policy and ACM’s Requirements about 3rd party material. In addition, YouTube’s copyright education website provides useful information on reusing 3rd party material.

Note: You will be asked to confirm that you agree with these policies on the final submission form.


Optional videos (i.e., teaser and longer videos) may be uploaded to YouTube. YouTube will show advertisements with videos that contain monetized audio content, regardless of what copyright is associated with that content. To ensure that your video can show without advertisements, we recommend that you upload your video to YouTube in advance before submission, set to “private”, to check whether it is used for monetization.

Sanity check

Please ensure that content is appropriate in terms of rights and taste, does not contain inappropriate language, viewpoints or imagery and is unlikely to cause offence to any individuals or groups either present at the conference or beyond.


  • Selecting time slots for presentation :
    31 July 2021
  • Submitting pre-recorded video presentations:
    16 August 2021

For IMWUT papers accepted through the May cycle and ISWC Notes:

  • Selecting time slots for presentation:
    13 August 2021
  • Submitting pre-recorded video presentation:
    29 August 2021

For ISWC Briefs:

  • Submitting pre-recorded video presentation:
    29 August 2021