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

Hi Thrisma,

Hmm.... you're right - it only has a "title" attribute.
FWIW, I think it should have an explicit "alt" attribute.

Just my 2c worth though.

Cheers,
Silvia.


On Mon, May 18, 2020 at 8:02 AM thrishma reddy <thrishmareddy@gmail.com>
wrote:

> Hi Silvia,
>
> Thanks for your reply. So when you say alt attribute for the video do you
> mean it looks like the below example?
>
> Example  -
>
> <video width="320" height="240" poster="/images/w3schools_green.jpg"
> controls *alt="Bear catching a fish in a river"*>
>    <source src="moviea.mp4" type="video/mp4">
>    <source src="movaie.ogg" type="video/ogg">
>    Your browser does not support the video tag.
> </video>
>
> There is no example of the video's alt attribute that I could find on the
> internet.
>
> I agree with you that there should be only one alternative field
> describing the video. The poster  image is the visual summary and the alt
> attribute is the textual summary of the video. There is no need to have an
> alt attribute for the poster image as it's only purpose is to be a visual
> summary of the video. This is true only when there exists an alt attribute
> for the <video> tag as shown in the above example. Otherwise, the poster
> property needs to have an alt attribute.
>
> Another question for you- When the source of an image is broken we display
> the alt text of the <img> tag. Does the alt property (if present) for the
> <video> tag do the same?
>
> Thanks,
> Thrishma
>
> On Sun, May 17, 2020 at 4:56 PM Silvia Pfeiffer <silviapfeiffer1@gmail.com>
> wrote:
>
>> Hey John,
>>
>> That's all a possibility, yes.
>>
>> So if your poster has different content from the video, your alt text
>> should include the poster description, too, because it's supported by
>> accessibility software. Introducing another attribute would require all
>> accessibility software to be updated with two text alternatives for one
>> element, which becomes very confusing very fast.
>>
>> Hope that helps.
>>
>> Best regards,
>> Silvia.
>>
>> On Sun, May 17, 2020, 11:17 PM John Foliot <john.foliot@deque.com> wrote:
>>
>>> 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
>>>
>>>
>>>
>>>