[whatwg] Stream API Feedback

[Leandro Graciá Gil]

I have two more questions about the Stream API:


   1. Are GeneratedStream objects supposed to stop when they go out of
   scope?
   2. Should StreamRecorder objects keep alive the Stream objects that
   created them? Is there a use case where this should not be the case?


On 17 March 2011 19:50, Philip Jägenstedt <philipj at opera.com> wrote:

> On Thu, 17 Mar 2011 17:51:08 +0100, Olli Pettay <Olli.Pettay at helsinki.fi>
> wrote:
>
>  On 03/17/2011 06:31 PM, Philip Jägenstedt wrote:
>>
>>> On Thu, 17 Mar 2011 16:48:40 +0100, Olli Pettay
>>> <Olli.Pettay at helsinki.fi> wrote:
>>>
>>>  On 03/17/2011 03:11 PM, Lachlan Hunt wrote:
>>>>
>>>>> On 2011-03-16 19:29, Olli Pettay wrote:
>>>>>
>>>>>> Perhaps navigator.getUserMedia("audio,video", success, error);
>>>>>> could return an url to the device in the success callback, and that
>>>>>> url
>>>>>> could be then set to video.src.
>>>>>>
>>>>>
>>>>> The creation of a URL is unnecessary indirection. It's easier to avoid
>>>>> creating special URLs entirely, and instead assign the the Stream
>>>>> object
>>>>> directly to video.src.
>>>>>
>>>>
>>>>
>>>> The type of .src is string.
>>>> Assigning a different type of object to it
>>>> is quite strange.
>>>>
>>>> Also, if getUserMedia would return just an URL, browser wouldn't need
>>>> to create any stream object (unless someone then want to stream
>>>> from <video> to PeerConnection).
>>>>
>>>
>>> Sure, but instead one would have to mint URLs and keep a mapping between
>>> those URLs and the streams that they actually represent. If people copy
>>> those URLs around, how long are they supposed to work for? Consider this
>>> scenario:
>>>
>>> function getStreamURL() {
>>> var s;
>>> // code that sets s to a new Stream object for the default camera or
>>> something
>>> return s.url;
>>> }
>>> var url = getStreamURL();
>>> /* garbage collector? */
>>> document.querySelector('video').src = url;
>>>
>>
>> I'd assume stream url would be handled like
>> urls created using createObjectURL.
>> It could be then revoked.
>>
>
> I wasn't aware of this API, it's in
> http://www.w3.org/TR/FileAPI/#dfn-createObjectURL for reference.
>
> That API has an explicit revokeObjectURL to solve the lifetime issue, but
> there's no such thing for the Stream API.
>
>
> --
> Philip Jägenstedt
> Core Developer
> Opera Software
>