W3C home > Mailing lists > Public > public-html-media@w3.org > June 2012

Re: [MSE] Moving Media Source methods into a separate object.

From: Aaron Colwell <acolwell@google.com>
Date: Mon, 18 Jun 2012 13:36:17 -0700
Message-ID: <CAA0c1bAjqmvXNBo5WCEGGe+_GJpq6FHRnGgkbDSgZsh4jTdzSg@mail.gmail.com>
To: David Dorwin <ddorwin@google.com>
Cc: public-html-media@w3.org
Hi David,

comments inline...

On Sat, Jun 16, 2012 at 8:07 PM, David Dorwin <ddorwin@google.com> wrote:

>> Associating the MediaSource with a <video> would be similar to
>> LocalMediaStream.
>> 1. Create a MediaSource object.
>> 2. Use createObjectURL() to get a blob URL for the MediaSource object.
> Does this imply overloading createObjectURL() to accept a MediaSource
> object?

[acolwell] Yes.

> A new URL is created every time createObjectURL() is called, so one might
> have multiple URLs pointing to the same MediaSource object. Does this
> pose any problems?

[acolwell] Yes multiple URLs pointing to a single instance could be
possible. I believe this is possible with MediaStream. I'm not aware of any

> Does it make sense to just add getURL() to MediaSource instead?

[acolwell] We could do that. I was just trying to be consistant with what
MediaStream does. I assume they had a good reason to go this route instead
of using a getURL() approach.

> 3. Assign the blob URL to HTMLMediaElement.src.
> What happens if the URL is associated with multiple HTMLMediaElements?
> Sharing data might be nice, but what are the implications for
> implementations?

[acolwell] So initially I was assuming that a MediaSource would only be
associated with a single HTMLMediaElement. The basic idea is that an
HTMLMediaElement can only accept a MediaSource blob URL if the MediaSource
is in the "closed" state. If it receives a URL for a MediaSource that isn't
"closed" then it just triggers a MEDIA_ERR_SRC_NOT_SUPPORTED error. If we
decide later that there is a strong use case for associating multiple
HTMLMediaElements with a single MediaSource then we can specify new
Received on Monday, 18 June 2012 20:36:47 UTC

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