[whatwg] HTMLMediaElement buffered/bufferedBytes

Silvia Pfeiffer silviapfeiffer1 at gmail.com
Tue Jun 10 03:35:13 PDT 2008

I think this all makes sense.
+1 from me.


On Tue, Jun 10, 2008 at 8:24 PM, Philip Jägenstedt <philipj at opera.com> wrote:
> Hi,
> I'm currently implementing more of <audio> and <video> (in Opera) and
> will probably have quite a lot of questions/comments during the coming
> months. If this is not the best place for such discussion, please point
> out where I need to be.
> Today's issue:
> The name of the buffered/bufferedBytes attributes imply that these
> ranges are buffered on disk or in memory, so that they will not have to
> be re-downloaded. However, the description reads "the ranges of the
> media resource, if any, that the user agent has downloaded, at the time
> the attribute is evaluated."
> This is not the same things, as we will not be able to buffer large
> files on memory-limited devices. Instead, we might only buffer 1 MB of
> data around the current playback point, or some other scheme.
> I would suggest that buffered/bufferedBytes be taken to mean exactly
> what they sound like by changing the description to something like:
> (differences marked *like this*)
> The buffered attribute must return a static normalized TimeRanges object
> that represents the ranges of the media resource, if any, that the user
> agent has *buffered*, at the time the attribute is evaluated.
> Note: Typically this will be a single range anchored at the zero point,
> but if, e.g. the user agent uses HTTP range requests in response to
> seeking, then there could be multiple ranges. *There is no guarantee
> that all buffered ranges will remain buffered, due to storage/memory
> constraints or other reasons.*
> The intention is that only ranges which are actually internally buffered
> should be exposed in the buffered/bufferedBytes ranges, whereas the
> current phrasing implies that all ranges which have at some point been
> downloaded/buffered should be included.
> Admittedly, this makes the attributes useless for determining how much
> of the resource has been downloaded, but if this is needed I might
> suggest the attributes downloaded/downloadedBytes instead. The
> usefulness of the buffered attribute (in my current interpretation) is
> not obvious to me at all, I would appreciate some use cases if possible.
> --
> Philip Jägenstedt
> Opera Software

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