Community Review: BEP044 - Stimuli

[scott-huberty]

Note

This discussion will stay locked until 12:01 AM EST (UTC-5) on Monday, November 2, 2026 (05:01 UTC), when the review period opens.

We are pleased to announce the community review period for BIDS Extension Proposal (BEP) 044! We have developed this extension to standardize how stimulus files, their metadata, and their annotations are stored and referenced in BIDS datasets.

BEP044 extends the BIDS standard to store stimulus files in a dataset-level /stimuli directory, named with a stim-<label> entity and media suffixes (audio, image, video, audiovideo). Stimuli are described in a stimuli.tsv catalog, annotations of time-varying stimuli are stored as stim-<label>_annot-<label>_events.tsv files, and events.tsv files reference stimuli through a stim_id column. A new Media Files appendix, shared with BEP047, defines the supported audio, image, and video formats and their technical metadata. Per-subject stimulus recordings, such as a screen capture of what a participant saw, are stored next to that participant's data using the stim-<label> entity. Existing datasets that reference stimuli through stim_file remain valid.

• The draft specification may be found here, with the most significant changes in the "Stimuli" section and the "Media Files" appendix.
• The proposed changes may be found at the bids-specification PR #2022. To view the source difference, click the Files changed tab.
• Example datasets are being proposed here, which are at these links:
  • stimuli_basic
  • stimuli_subject
  • stimuli_timevarying
• The necessary BIDS validator changes are in the bids-validator PR #445 as well.

Procedure

Review period

Community review is open from November 2 - November 13, 2026.

Voting

This discussion is a poll, which you can vote in once and cannot change your response. Therefore, please vote once you are satisfied that your answer will not change.

If you vote "No", you may create a thread to explain your reasoning or send a private email to bids.maintenance [at] gmail.com so that your position can be fully understood.

How to review

Use threads in this discussion to request clarification or changes to the BEP. Each independent topic or proposed change should have its own thread. Please review existing threads and consider adding comments to those, if your topics are already being discussed. If your concerns are adequately represented by an existing comment or comments, consider using the 👍🏻 reaction button to indicate agreement in place of extending the discussion.

Where possible, propose the specific text you would like to see added or removed.

For minor issues, such as typos, feel free to make code suggestions only, using the suggest feature on the BEP044 pull request. These suggestions may be accepted or rejected without discussion, so do not make substantial proposals in this way.

Finalization

Once the review period is finished, the BEP leads and maintainers will consider the entire discussion, identify outstanding points to be resolved, and work toward finalizing the BEP. Community members may be asked to participate in this process to provide the necessary expertise.

Before being merged, the BEP will be integrated into the BIDS validator, and the examples must pass the validator.

A BIDS standard version v1.12 release is anticipated in January 2027, regardless of the conclusion of this specific BEP.

If, for any reason, a critical issue is found after the BEP is merged, the BEP will be reverted while the issues are addressed. At the discretion of the BIDS steering group and maintainers group, depending on the scope of changes, a new community review period may be opened.