[mythtv-users] HDTV - PVR: Does it work?
ian at duckland.org
Wed Jan 21 01:45:43 EST 2004
On Tue, 2004-01-20 at 20:37, Brandon Beattie wrote:
> 1080i is the highest bandwidth HDTV stream at 19.6Mb/s. A full ATSC
> stream can be up to 45Mb/s but this is only if you save all the
> subchannels(Which would have to be maxed out) Most atsc streams are
> 14-25Mb/s that I see on my 11 HD stations. The HDTV streams come
> through as transport streams (MPEG2-TS) which contain redundant
> information for i frames in the mpeg codec just incase some data is lost
> in transmission. Douglas and others have already taken a few steps to
> remove this and turn the mpeg2-ts into mpeg2-ps (No redundant data such
> as used for DVD's). This cuts off some useless bandwidth once the
> stream is received. (About 10-20% with little CPU usage). So the end
> answer is you shouldn't push more than about 20-25Mb/s from the backend
> to the frontend for watching a HD show. a 100Mb/s connection is plenty.
Uhhh... 20-25MB/s is impossible on 100Mb. Even 100 FullDuplex...
100 Megabits = around 12MB/sec fully utilized. I've never seen more
than 11MB/sec. And that was with a crossover cable...
Ian Forde, RHCE, CCSE, SCNA, SCDME
ian at duckland.org / ian at cytben.com
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