What is Video Alt Text?
Video alt text concisely describes a video’s essential visual subject or purpose for people who cannot perceive it. Because HTML video lacks an alt attribute, the description appears in nearby accessible content or player metadata.
How Video Alt Text works
A textual alternative for video communicates the visual purpose or essential information that surrounding prose, dialogue, and captions do not already provide. Its scope depends on context: a decorative loop may need no additional description, while a silent demonstration may need a concise explanation or a fuller transcript. Since the media element has no image-style alt field, authors must deliberately associate or position the text. This accessibility copy is prepared with player metadata and editorial review.
Key facts
- 1An accessible name for the player identifies the control or title but does not necessarily describe the video’s visual content; naming and content alternatives solve separate problems.
- 2Captions represent speech and important sounds, whereas a visual description conveys actions, appearance, diagrams, or on-screen changes that cannot be inferred from the audio.
- 3Nearby descriptive text can be programmatically associated with the player through an accessible description, but duplicate visible and hidden copies may cause screen readers to announce it twice.
When Video Alt Text matters
Provide a description when visuals convey information that dialogue or captions omit. Without one, screen-reader users may miss the video’s purpose even when playback controls are accessible.
Common use cases for metadata
These examples cover metadata broadly, not specifically Video Alt Text.
- Filtering files by dimensions, duration, codec, MIME type, language, or detected content.
- Building catalogs with searchable descriptions, rights, locations, and relationships.
- Driving output paths, transformation parameters, moderation, and retention rules.
Working with metadata
This guidance covers metadata broadly, not just Video Alt Text.
A metadata reader parses known structures and can derive additional properties from the encoded content. The workflow then validates and normalizes fields before using them for search, routing, naming, filtering, or access decisions.
Metadata can be embedded in a file, stored beside it, or derived during analysis. Track its source and normalization rules, and decide which fields are authoritative, searchable, privacy-sensitive, or safe to copy into derivatives.
What you gain
- Structured metadata makes media searchable, filterable, and automatable.
- Technical properties let workflows choose valid transformations before processing.
- Provenance and rights fields support governance throughout an asset’s lifecycle.
What it costs
- Copying all metadata preserves context but can leak private or obsolete information.
- Derived labels scale classification but carry confidence limits and model bias.
- Rigid schemas improve consistency while making novel or vendor-specific fields harder to retain.
Before production
- 1Distinguish supplied metadata from values detected or derived during processing.
- 2Normalize units, time zones, encodings, and controlled vocabularies at ingestion.
- 3Remove sensitive fields before exposing files or metadata to another audience.