The missing deliverable is often the timeline

An agent gives you an MP4 with attractive animated words. Another gives you a subtitle file. Both may describe the task as complete, but neither response tells you whether the captions match the final edit, can be revised, or work where you intend to publish.

For a product demonstration, ask for a caption handoff, not merely a captioned video. The handoff should connect the approved wording, the video version, the timing data and each delivery format. This prevents a common operational mistake: correcting the transcript while accidentally shipping an older render.

Methodology and intended audience

This guide is for creators and developers who use video-editing skills to produce narrated demos, interviews or explainers. We reviewed W3C accessibility guidance, the browser text-track reference and FFmpeg's subtitle-filter documentation on September 12, 2026.

The delivery checks below are our proposed editorial workflow. We did not render a clip, test a hosting platform or certify an accessibility implementation. The objective is to specify evidence a reviewer can inspect before publication, rather than rank transcription models by unmeasured accuracy.

Separate correct wording from attractive styling

Captions need to communicate relevant speech and non-speech audio, with timing aligned to the soundtrack. W3C warns that automatic captions require accuracy review; an omitted negative can reverse meaning. Treat transcription as a draft, not an approval. W3C caption guidance

Our suggested review order is wording first, timing second, styling last. For a software demo, create a small terminology sheet containing product names, command names and any unusual abbreviations. Compare these against the actual narration. Do not silently replace what the speaker said with a stronger marketing claim.

Record unresolved phrases separately. A reviewer should be able to say that a passage needs clarification without blocking unrelated typography work. Conversely, an attractive animation should never close an unresolved wording issue.

Choose the delivery format before rendering

A browser text track references a WebVTT file associated with the media element. It can carry a language, a human-readable label and a track kind; multiple language tracks are possible. The browser reference also describes origin requirements for externally hosted track files. MDN text-track reference

A burned-in delivery is different. FFmpeg's subtitles filter draws text onto the video image using libass, with build requirements and font-related options documented explicitly. A successful subtitle export does not establish that the rendering environment has those capabilities. FFmpeg subtitles filter

Use this decision rule:

For a site player with selectable captions, request the timed-text file and verify the player's actual track controls.
For a destination requiring visible text in the picture, request a separate burned-in export.
For future revisions or translations, preserve the editable caption source even when the public delivery is burned in.

SRT may be useful in an editing workflow, but do not assume every destination accepts every format. Make the destination's accepted format an explicit requirement. Keep the clean master as a separate artifact so you do not need to remove text from already rendered pixels.

Create a version-bound delivery receipt

For each package, we recommend a short receipt containing the following information:

The exact video filename and content hash.
The caption source filename, language and review state.
The export format and intended destination.
The editor's name or role and the date of the wording review.
Any timing, pronunciation or translation questions still open.
Which playback checks actually happened, rather than checks merely requested.

Use clear states such as draft transcript, wording reviewed, timing reviewed and destination checked. These are proposed workflow labels, not existing OpenAgentSkill certification badges.

The receipt should describe one specific release. If the video changes, reopen the affected timing checks. If only a typo changes, regenerate whichever outputs contain that typo and record their new filenames. Do not overwrite the previous approved package before the replacement is checked.

Try one deliberate edit before trusting the pipeline

Here is a suggested acceptance exercise, not a test we performed. Start with a short non-sensitive demo that contains an opening title, a product name and a sentence near the end. Approve its captions, then remove a section from the middle of the video.

Ask the agent to produce a revised delivery package. Check whether it identifies that timing after the cut may need adjustment. Inspect the caption around the edit and the final spoken sentence. A pipeline that only changes the text file's name has not demonstrated that it can maintain synchronization.

Next, change the product name in the caption source. Compare the sidecar file and rendered delivery. The same correction should appear wherever intended; a mismatch exposes disconnected export paths.

Finally, inspect the intended presentation size. Check line breaks, contrast and whether text covers a meaningful control or diagram. For a selectable track, also verify that captions can actually be enabled. A file existing in a folder is not evidence of usable playback.

Limitations and the next practical step

This checklist does not replace full accessibility evaluation or a complete viewing of the final release. Sampling around edits can find timeline problems, but it cannot guarantee that every cue is correct. Translation needs its own language review, and destination behavior can differ from local playback.

The OpenAgentSkill directory can help you shortlist editing workflows. Ask each candidate to produce the same handoff package before comparing visual styles. For another artifact-level review pattern, see our editable PPTX handoff checklist.

The useful completion claim is specific: these captions were reviewed against this video and checked in this destination. That is far more actionable than a generic message saying the video is ready.