[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-
loop-end-time
media-loop-start-time ===> media-
loop-end-time
media-loop-start-
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.
Regards,
Maciej
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