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Comment by devmonk | Hacker News Reader

Wow. :( "I'm confused. Why would you (a blind user) want to know what the poster frame is? How does it affect you?"

That is pretty bad.

I think they need a group of people with disabilities to review all of the specs. There have to be many more issues like this lurking (that those with disabilities could probably already point me to).

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  Wow. :( "I'm confused. Why would you (a blind user) want to
  know what the poster frame is? How does it affect you?"

There are real needs and perceived needs. Trying to understand the potential use cases is not bad in any way.

You're probably right, and I sure hope that's what he's doing. I have to admit it did come across pretty bad when I read it though :)

I think it probably sounded that way due to the editorializing of the headline. If instead it had read "Editor of HTML5 tries hard to gain a better understanding of potential use cases facing people with disabilities" you might have read it differently.

Note that this is not a question of providing an alt text for e.g. an image of a movie poster on IMDB.

The 'poster' in this case is specifically a single image preview for a video shown before the video starts playing. According to the spec "typically one of the first non-blank frames".

It can be compared with e.g. a low resolution preview of a high-resolution image, as was used in the early days of the web. It is definitely not obvious that it would make sense to have an alternative text specifically for the lo-res preview as distinct from the alt text for the image itself.

Note that the video element already support an alternative text description - its just the single-frame preview which doesn't support a separate text.

I think Ians questioning of this feature is completely valid.

The only objection I can think of is that the poster can be intended to convey meaning. If this meaning is entirely lost without an alt text, then the lack of an alt text for the poster is an oversight.

But then again the use of colors in an image conveys meaning. That does not mean that there should be alt texts for each color channel. The alternative content should be provided at a level that makes sense if you don't have access to the specific media.

The HTML5 spec specifically addresses accessibility for video like this:

To make video content accessible to the blind, deaf, and those with other physical or cognitive disabilities, authors are expected to provide alternative media streams and/or to embed accessibility aids (such as caption or subtitle tracks, audio description tracks, or sign-language overlays) into their media streams. (http://www.whatwg.org/specs/web-apps/current-work/multipage/...)

This is much more sensible that providing an alt text for the first frame in the video.

The standard should support an accessible version of what is staticly and dynamically displayed in the browser to a non-disabled person. If a non-disabled person will always see that frame on load, that frame needs an accessible way of making sense of that frame.

That ignores the content/presentation distinction which is essential for providing real accessibility.

If you have a <video> element, you can control what frame is displayed before the video is played, by inserting a <poster> element into it. If the page author doesn't explicitly specify a poster frame, the browser is free to choose a frame to display.

The person who filed the bug is (effectively) saying "if the page author specifies a poster frame, it should be possible to add alt text. If the page author uses the default poster frame, it should be impossible to add alt text."

I believe the question Hixie was getting at was "why would you (a blind user) care about an explicitly-set poster frame but not a default poster frame?" which, I think, is reasonable.

That line of questioning may sound offensive but, I think, Ian is trying to separate what the user "want" and what the user "need."

I thought the same thing at first, but this post provides an alternate thought: http://news.ycombinator.com/item?id=1742913

A non-sighted user hasn't managed to get to a video without somehow navigating their way there. The people replying to the tracker seem to be under the assumption that a non-sighted user will just mystically be presented with a video and not know what it is all about. I can't imagine a case where this is likely.

Navigating their way there gives them context to what the video will be (in the use case that the video is on a blank page). If the page contains textual content then the user will get context from the text. If the video is completely unrelated to location context or to page-level context then the content will be of little to no interest, so providing an alt description adds no real-world value.

Also note that unless the video has audio captioning then the entire video is of little to no interest. Imagine watching something like Lost in Translation with no visual input and no descriptive captioning.

I can not only imagine cases like that, I've encountered those cases. Picture a blog with multiple embedded videos, presented without comment.

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