diagnostic · one of 36 free, no counter
Media
What video and audio is on this page, and is any of it captioned?
Media is the heaviest thing on most pages that have any, and the settings that decide the cost - preload, autoplay, a poster frame that is a full-size JPEG - are attributes nobody looks at twice. Captions are the other reading: a video without them is inaccessible, and an embed’s tracks live in a document this side cannot read, so an embed is never counted as uncaptioned.
Reach it Press ⌘ + K on any tab and type media. Ctrl + K on Windows and Linux
in the panel · free, no counter
What this actually is
video, audio and their poster frames, downloadableOn any page with a player, before shipping a hero video, and as an accessibility check. The download links are also the practical way to get a poster frame out of a page.
Asked about this diagnostic
4 of themWhy is a YouTube embed not marked as uncaptioned?
Because its tracks are inside a document on another origin that nothing here can read. Marking it uncaptioned would be a claim made from an absence of evidence.
What counts as a caption track?
captions and subtitles. A descriptions or chapters track is a different thing and counting it would inflate the reading.
Does preload="auto" matter?
On a page with one video, rarely. On a page with six, it is the whole page weight - the browser starts fetching all of them before anybody presses play.
Can I download the video itself?
The source URLs are listed, and a poster is directly downloadable. Whether a stream can be saved depends on how it is served, which is the site’s decision rather than ours.
how to use media
- Open Media to list every video and audio element with its sources.
-
Read
preload,autoplayand the poster's size - the three settings that decide the cost. - Check the tracks. Captions and subtitles only, so an empty column is an accessibility finding.
- Download a poster frame straight from the row when you need one.
70 of these · no host permissions · three free audits