[whatwg] Limiting the amount of downloaded but not watched video

Zachary Ozer zach at longtailvideo.com
Mon Jan 17 14:01:06 PST 2011

On Mon, Jan 17, 2011 at 9:08 PM, Chris Pearce <chris at pearce.org.nz> wrote:
> On 18/01/2011 8:05 a.m., Zachary Ozer wrote:
>> What no one has mentioned so far is that the real issue isn't the
>> network utilization or the memory capacity of the devices, it's
>> bandwidth cost.
>> The big issue for publishers is that they're incurring higher costs
>> when using the<video>  tag, which is a disincentive for adoption.
> I assume you're comparing to the bandwidth usage of flash? Does flash allow
> developers to control how the media is downloaded on the client? What
> mechanisms does it provide? Maybe we can do something similar?

There are a bunch:

* backBufferLength : Number - [read-only] The number of seconds of
previously displayed data that currently cached for rewinding and

* backBufferTime : Number - Specifies how much previously displayed
data Flash Player tries to cache for rewinding and playback, in

* bufferLength : Number - [read-only] The number of seconds of data
currently in the buffer.

* bufferTime : Number - Specifies how long to buffer messages before
starting to display the stream.

* bufferTimeMax : Number - Specifies a maximum buffer length for live
streaming content, in seconds.

* bytesLoaded : uint - [read-only] The number of bytes of data that
have been loaded into the application.

* bytesTotal : uint - [read-only] The total size in bytes of the file
being loaded into the application.

See http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/net/NetStream.html

> Can this not be implemented on the server side? If you know the media has an
> average playback rate of X KB/s, can the server reliably throttle its
> transmission at 1.5X?

I suppose it could be implemented server side, but it's not currently
part of the HTTP spec (so far as I'm aware). That would *really*
hinder adoption.

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