[whatwg] Assigning media resources represented as DOM objects to a media element

[Robert O'Callahan]

On Sun, Feb 17, 2013 at 8:43 AM, Glenn Maynard <glenn at zewt.org> wrote:

> On Fri, Feb 15, 2013 at 2:10 PM, Robert O'Callahan <robert at ocallahan.org>wrote:
>
> Even if you get past that, you still have the problem that revoked URLs
>> are useless. It's impossible to do something equivalent to video2.src =
>> video1.src (which works today).
>>
>
> True, though cloneNode() should definitely work.  On the other hand,
> .innerHTML works with blob URLs if the URL is still in scope, but would
> never work here (not something I use often, but I guess some people still
> do).
>

cloneNode() won't work for autorevoked URLs, because it is defined to only
clone attributes and children, not internal state (with a few exceptions
for Web compatibility). (Don't tell me that it shouldn't work that way; I
argued that long ago and lost :-).) innerHTML-based cloning would work in
the same cases cloneNode() would: i.e. not at all for autorevoked URLs or
srcObject.


>  Also, getting access to the underlying source object is a valuable
>> feature, especially for MediaStream and MediaSource objects which have
>> interesting APIs on them.
>>
>
> I don't know anything about those, but you can always stash a reference to
> an object on the img, even if img doesn't care about it.  "img.src =
> URL.createBlobURL(blob); img.xActualBlob = blob;"  It's not as nice as
> having them tied together, but it's not terrible.
>

Yes, you can work around not having an API for this, if you control both
the setting and the getting. It's still a workaround.

I think the stakes are not that high here. Lack of srcObject can be worked
around in most cases. On the other hand adding srcObject is not a big
burden --- I don't think it needs to be added to every resource-loading
element. It's useful for media elements, maybe <img>, and dubiously
<iframe> (all of which already have multiple ways to specify the resource
to load).

Rob
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