[mythtv-users] Semi-OT: HD Questions

[Graham Wood]

On Tue, May 16, 2006 at 09:47:18AM -0500, Ivan Kowalenko wrote:
> MPEG-2 and H.264. That is, I mean, with the BBC doing its HD trials  
> with H.264, how is it that existing HDTVs will know what to do with  
> it? Has H.264 compatibility been around for a while? Shouldn't H.264  
> in HD (even interlaced) require a marked increase in processing power  
> to decode and scale (assuming your TV runs at a resolution lower than  
> the signal)?
There is a difference between decoding and displaying.  My HDTV has a built-in freeview 
decoder that can handle the MPEG2 data streams - but doesn't know enough to do H.264.  As 
opposed to that, the two HDMI connectors are transmitting an un-encoded data stream, so the 
electronics just need to chuck them straight at the pixels - no decoding required, 
regardless of how the stream arrived at my STB.

> Third, what is the minimum requirement for an HD back-end? I'm  
> guessing not much, since the stuff is already encoded, but then  
> again. There really hasn't been a lot of documentation that I can  
> find about this (then again, I could just be looking in all the wrong  
> places).
The data stream for HDTV is comparable (in the cases I've seen) in bandwidth to that of high
quality standard definition DVB - since the algorithms are better.  If all you are using the
backend for is transfering the data to disk and back again (e.g. no re-encoding or anything)
then the reqs for HDTV are comparable to that of an SDTV with a hardware encoder.

Graham