[mythtv] dvd revisited (and remoted)

Henk Poley mythtv-dev@snowman.net
Mon, 16 Dec 2002 15:24:58 +0100

> Van: Thor Johnson <thormj@ieee.org>
>> [mailto:mythtv-dev-admin@snowman.net]On Behalf Of Henk Poley
>>> Van: Ray <maillists@sonictech.net>
>>>> On Sat, Dec 14, 2002 at 10:23:45AM +0100, Henk Poley wrote:
>>>>> That DOES sound great but I don't think it is practical unless you
>>>>> have the server recompress the DVD before shipping it over the
>>>>> ethernet (not that should be much of a barrier since cpu is getting
>>>>> cheaper every day).
>>>> Recompressing DVD (and no scaling) to DivX in realtime takes a P2400
>>>> HyperThreading.  But I guess it should take less when doing it in a
>>>> lower resolution.  The Videolan.org guys seem to be able to do it.
>>> I'm probably missing something but low to medium end Athlons are
>>> already compressing 640x480 TV captures with Myth so DVD resolution
>>> shouldn't be that much harder.
>> Could also be some Intel sponsored 'benchmark' I read.  Don't know at
>> what resolution DVD works.  btw, I know it's pretty useless to reencode
>> at a higher resolution than your (..analog..) TV set can display.
> Why do we need to decompress->recompress for dvd->remote viewer?
> How about we just pipe the commands & mpeg2 stream back and forth?
> If you need to overlay something, have it done on the frontend...

On ethernet there's not really a problem, no.

But AFAIK, we were (also) talking about WiFi, the "11Mbit/s" is at
hardware-level. The frequencyband used is open (not licenced) so you have
quite some 'noise'. The maximum data throughput is about half that,

MPEG2 (at 2GB/hr) -> ~4.55Mbit/s but there's some overhead, and you don't
want to be at the 'edge' since there can be more interference now and then
(microwave etc.)

DivX gives good performance at half that bitrate... Thus recompression...

Yup, there is faster WiFi (22Mbit and 54MBit) but tests I've seen suggest
that current 54MBit solutions only connect at ridiculous near distances of
3-4 meters. More than that and there won't even be a connection. But things
can change quickly in computerland.

 	Henk Poley <><