[whatwg] Apple Proposal for Timed Media Elements

Maciej Stachowiak mjs at apple.com
Wed Apr 4 19:58:10 PDT 2007

On Apr 4, 2007, at 7:31 PM, Vladimir Vukicevic wrote:

> Maciej Stachowiak wrote:
>> CSS Timed Media Module proposal - http://webkit.org/specs/  
>> Timed_Media_CSS.html
> Some feedback on my initial reading..  the CSS properties specified  
> seem like a good set that will cover most common functionality.   
> Some comments about the spec, though:

Thanks for reading over this part.

> 1. 'media-loop-count' is an awkward name, especially with "The  
> default value of 1 means the item will play through once but will  
> not loop."  We went through this with APNG, and ended up renaming  
> that member.  I would suggest 'media-play-count' instead -- that  
> way there is no ambiguity with what the number means.

We considered 'media-repeat-count' instead of 'media-loop-count', but  
that turned out to be more confusing. We really wanted all the  
looping-related properties to have consistent naming, and I don't  
think 'play' would work in the other places mentioned.

> 2. The descriptions for 'media-loop-start-time' and 'media-loop-end- 
> time' don't match; start-time says "sets the time at which the  
> media item begins playing after looping", and end-time says "sets  
> the time at which the media item loops for the second and  
> subsequent repetitions".
> I would suggest that start-time says "sets the time index at which  
> the media item starts playing for the second and subsequent  
> repetitions", and that end-time says "sets the time index at which  
> the media item ends playing for the second and subsequent  
> repetitions."  The language for end-time is still a little awkward,  
> since "ends playing" could imply that it simply stops playing (and  
> does not loop), but it's clearer than before.

I think the language might have ended up actually defining it wrong.  
The intent of 'media-loop-end-time' is that this is the point where  
you end where repeating, but on the last iteration you go all the way  
to 'media-end-time'. So if 'media-loop-count' has a value of 3, the  
three repetitions would go as follows:

media-start-time                                    ===>       media- 
                           media-loop-start-time   ===>       media- 
time                                    ===>       media-end-time

I'll update the spec.

> 3. 'media-timing' I would get rid of completely; while a shorthand  
> would be useful, I don't think that media-timing as specified  
> really works. Shorthands for properties such as 'background' are  
> understandable on their own; 'media-timing: playing 0s -0.5s 2 2s  
> -4s 1' is very opaque.    If it's still desirable, I would remove  
> the setting of start/end times and change the volume shorthand to  
> only accept the symbolic names; e.g. 'media-timing: playing high  
> 4;'... but I think that removing the shorthand entirely would be  
> preferable.

I'll reply in more detail about media-timing in a later message.


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