[mythtv] WinTV PVR-250 (hardware mpeg encoder)

[Dan Conti]

On Thu, 9 Jan 2003, Dr. J. S. Pezaris wrote:
>
> I think the larger point is being missed here.  With a low horsepower CPU,
> you can think about small, low-power, fanless Myth implementations.  A
> larger CPU requires a bigger, noisier fan, and a bigger, noisier power
> supply, and a bigger, more expensive chassis.  The catch is that a low
> horsepower CPU requires hardware support for at least one of
> encoding/decoding, if not both.  The recently released VIA EPIA
> motherboards (with equivalent of 500 MHz Pentium III processors) are
> screaming to be built into a Myth box (TV out, network and video on-board,
> digital/analog audio out, fanless, small, and inexpensive), but they don't
> have the horsepower to do real-time software encode/decode on video
> streams.

Actually i was wondering about that, whether or not shared video memory
systems would be able to handle, for example, real time decoding and
display of an mpeg2 stream. It seems like the memory bus would be quickly
saturated. I have onboard video myself, but dont have the magically
impossible to find asus tv-out adapter for it.

> I know it's possible to work really hard and get a decent-looking
> desktop-sized case with a heavy-hitting processor that is reasonably quiet,
> but the solutions quickly become expensive.  I don't see having separate
> encode and decode boxes being very interesting as there are already
> commercial one-chassis attractive and quiet implementations (like TiVo)
> that work just fine for much of MythTV's functionality and aren't that
> pricey.  Having an encoder farm networked to a series of display clients is
> all well-and-good for the small number of people for whom that solution is
> interesting.  I suspect that far, far more people will want something like
> I've described: a small, attractive, silent (or nearly so) one-box
> solution.

One distinction here is that you are discussing details of
commercialization and mass market adoption; this kinds of details may not
even be in mind for the people working on mythtv. Personally i have
already purchased a HTPC case and all the silencing goodies, and have no
need for a box as you described above.

Even in that market, however, there are merits to seperation of the
receiver/display device and the backend (storage). It may be 10 years away
but the eventual target is for the standard home to have a headless PC for
storage and cheap devices (like you describe above, but without hard
drives) that talk to services on said PC. But that is not today nor
tomorrow, and probably not here. :)

> In sum: I think suporting harware encoding/decoding in MythTV is not just a
> good idea, but a critical one.

I personally agree with this, but my motives are different; the machine i
plan on using for myth isn't dedicated, it runs various other services,
and i'd hate to have video jerkyness while watching tv because someone is,
say, checking out a picture from my website, or because i'm copying
pictures off my cf card. But the flipside is that i have quiet fans and
can buy the $50 faster processor, so again, it probably wont ever matter
for me, and (per a previous quote) that same sort of logic is used by
those working on things. :)

> That's my two cents.
>
>        - pz.
>
> --
> John Pezaris, Ph.D.
> pz@hms.harvard.edu
>
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