[mythtv-users] Telly

Joseph A. Caputo jcaputo1 at comcast.net
Wed Jul 16 14:11:56 EDT 2003


> -----Original Message-----
> From: mythtv-users-bounces at snowman.net
> [mailto:mythtv-users-bounces at snowman.net]On Behalf Of Ray Olszewski
> Sent: Wednesday, July 16, 2003 12:30 PM
> To: Discussion about mythtv
> Subject: RE: [mythtv-users] Telly
>
>
> Josept -- I can't tell from what you wrote if you and I are
> disagreeing or
> not. Mostly, we are not (on the details, I mean), but here is where I am
> confused:
>
> At 12:01 PM 7/16/2003 -0400, Joseph A. Caputo wrote:
> [...]
> >...recording is done 'off-line', in such a way as can be
> >handled by a Via C3 processor.
>
> What does "off-line" mean in this context?
>
> Are you saying that the video is initially recorded, uncompressed, to a
> scratch file, then encoded at less than real-time after recording is
> completed? Honestly, I find it hard to believe that they are taking this
> approach with only 80 GB of hard-disk space in the standard box.
> (If I just
> did the math right, uncompressed captures, at 320x240x16-bit-color-NTSC
> take about 17 GB/hour ... not physically impossible with an 80 GB
> drive in
> the system, but not really practical for a consumer product either.
>
> Or are you saying that a Via C3 can handle software encoding (at some
> plausible image size and color depth) if it is not simultaneously
> displaying to the screen?
>
> Or are you saying something else?
>
> How they are doing timed recording (not recording, or lack
> thereof, of live
> TV) seems to me the key to deducing what hardware is involved. I
> can't tell
> myself a believable story for how they are doing timed recording
> with this
> hardware if it does not include a hardware encoder ... but perhaps I'm
> overlooking some plausible setup.

Well, the specs on their web page indicate for graphics "Integrated 2D/3D
graphics with MPEG decoder" and for TV Tuner, simply "NTSC standard".  That,
coupled with the fact that timeshifting of LiveTV is explicitly *not* a
feature, is pretty good evidence that they're not doing real-time encoding.
So, why not?  If they have a hardware encoder (and we know they have a
hardware decoder), then the box is certainly powerful enough, so there must
be some other reason for not doing realtime/timeshifting encoding.  I have a
hard time believing this is the case.  So, I'm assuming they *don't* have
hardware encoding, which begs the question:  is the VIA C3 powerful enough
to do full NTSC resolution realtime encoding?  The answer is that I don't
know for sure because I don't have one.  A 1GHz Epia M-10000 might, *just*
have enough juice.  Actually, now that I think about it, if it *can* do
realtime encoding, you could probably watch it at the same time by either
viewing the 'live' stream (overlay direct from the tuner card) or by relying
on the hardware MPEG decoding, so that playback doesn't really take any
extra CPU (well, minimal).  So, *if* the box can do realtime encoding, then
the omission of TV-timeshifting features must have been a business, rather
than a technical, decision.  Either way, I don't think the Telly has a
hardware encoder.  But you're right in that it is a bit ridiculous to think
that they'd be caching a couple of hours' worth of uncompressed video at a
time.  I just threw that out there because I wasn't sure if the VIA C3 could
handle realtime encoding, and in the absence of a hardware encoder, that
would be the only other plausible (although clumsy) explanation.

I guess we'll  have to wait for someone to get their hands on one of these
to know the real scoop.

-JAC



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