[whatwg] Possible alternative to specifying a codec for the <video> tag

[Krzysztof Żelechowski]

Dnia 23-12-2007, N o godzinie 13:08 +0000, David Gerard pisze:
> On 23/12/2007, Robert (Jamie) Munro <rjmunro at arjam.net> wrote:
> 
> > How could we do that? The codec is usually a relatively small download
> > download compared to the video itself. If we could suggest a way for
> > codecs to be provided alongside the videos by the content providers,
> > this /may/ be a way forward. Hypothetically, you could do video by
> > adding better binary file handling to Javascript, and painting on the
> > canvas, but good performance is unlikely.
> 
> 
> Arbitrary executable downloads didn't work out well with ActiveX, and
> "Download codec to view this!" is already a vector for malware.

That would not be an arbitrary download; it would be a download of _the_
codec.  
The executable code must not be enclosed in the content envelope (unless
the envelope is generated on the fly by the server depending on the user
agent; I think it would be a cumbersome thing to do).
Arbitrary active extensions can request services from the operating
system; the code to be executed should not be allowed to.  It could be
allowed to request services from the browser only; if that is set up
correctly, the decoder will be as safe as the browser is, even if it is
a piece of broken malware.  Thus we would need the browser to be a
direct show* engine provider for the decoder and the decoder would be
allowed to access its own memory only and call its own functions and the
functions explicitly provided by the browser.  Is this feasible?
Who would be in charge of wrapping the decoder for all the various
browser implementations out there?  Because each of them can provide a
different interface to the decoder. 
The publishers?  And what if some browser vendor decides to issue an
incompatible update?  I doubt the publishers are able to follow the
technology that closely; they probably have something else to do. 
The decoder engine vendors?  They should be able to this but their
consent, or at least their opinion, is required in this case.
And, last but not least: can we expect the opposing browser vendors to
offer the direct show engine and allow the decoder to run without much
user intervention?  Because if not, this solution would be very weak.
What do you think?
Chris
*(Note: DirectShow, IIRC, is a video-related trademark owned by
Microsoft.  I used it here because of lack of a better expression.)