Re: Why is there no alt attribute associated with the poster attribute on a video element (or, what's the accessible name calculation on a video element

Silvia writes:

> In essence: the poster is a visual summarisation of the video.

Actually,  the poster  is  WAS ENVISIONED TO BE a visual summarisation of
the video, by the former HTML5 editor, who also demonstrated on multiple
occasions that he knew nothing of the accessibility space: the needs, the
users, their user experience, etc. and he frequently demonstrated his lack
of empathy in that regard.

The reality is that the content author can point that @poster attribute to
ANY graphic image URI, including interstitials and/or 'placeholder' slides
(which may or may not contain "burned in" text intended for the end-user) a
reality that some engineers simply refuse to accept as a possibility.

Breaking this down:

<video src="file.mp4"   <!-- this is a visual asset that requires a text
alternative, AKA an AccessibleName. Given its complexity, it also needs an
AccessibleDescription -->

           poster="image.png">    <!-- this is a DIFFERENT visual asset
that also *potentially *requires a text alternative, AKA an AccessibleName
-->





> You only need one summary in text.


Respectfully, you are wrong. I do not know where or how you arrive at this
assertion, but it is simply and clearly wrong:

*Success Criterion 1.1.1 Non-text Content (Level A)**:*
*All non-text content* that is presented to the user has a text alternative
that serves the equivalent purpose... (JF: ALL, not some)

The text alternative is not a "summary", it is an alternative to the visual
representation. Any time there is an image with text burned into it the
textual alternative is not a summarization of that text: it must be
faithfully and accurately replicated in text that can be processed by
machine (i.e. a screen reader).

Evidence for all of this was also brought forward "back in the day", along
with multiple impassioned and detailed explanations about this topic by
daily screen reader users. Please, listen to the end users - they know
better than a sighted engineer will ever understand what they need and want.

JF

On Fri, May 15, 2020 at 5:18 PM Silvia Pfeiffer <silviapfeiffer1@gmail.com>
wrote:

> There were lengthy discussions about this back in the day - you should be
> able to Google them.
>
> In essence: the poster is a visual summarisation of the video. The video's
> alt tag is a text summarisation of the video. You only need one summary in
> text.
>
> Hope this helps.
>
> Best regards,
> Silvia.
>
>
> On Fri, May 15, 2020, 12:59 AM thrishma reddy <thrishmareddy@gmail.com>
> wrote:
>
>> Hello,
>>
>> I was wondering if there was ever any solution to the question asked here
>> - https://github.com/w3c/html/issues/1431 (Why is there no alt attribute
>> associated with the poster attribute on a video element (or, what's the
>> accessible name calculation on a video element)?
>>
>>
>> Thanks,
>> Thrishma
>>
>>

-- 
*​John Foliot* | Principal Accessibility Strategist | W3C AC Representative
Deque Systems - Accessibility for Good
deque.com
"I made this so long because I did not have time to make it shorter." -
Pascal