[opendtv] Re: 720P = 540i ?

  • From: Jeroen Stessen <jeroen.stessen@xxxxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Wed, 4 May 2005 16:32:33 +0200


Donald Koeleman wrote: 
> At wich of the four business divisions :-) ? 

Dunno. "Home" probably. San Jose CA. And it's not funny. 

> And what do you guys think of this dscaler project, 

Watching it. Interesting work of amateurs, not necessarily 
with a negative meaning to the word amateurs. After all, a 
"pro" is mostly still an amateur, but with a paycheck...  ;-) 

> and how do you score on this one:
http://www.dscaler.com/dtv-vs-windvd/Passion_Of_Mind_WinDVD_Showdown.htm ? 

> I can tell you that after scrolling up and down, between the images 
> I did rather poorly;-).

I saved the 2 images, and the file names were a bit tell-tale. 

Then I toggled between them in ACDSee, and the most obvious 
difference is in the picture width ! Very strange, how can 
two renderers extract a 720x480 image from the same DVD, with a 
different picture width ? At least one of them must have been 
scaling, without being asked. We see that all too often, that 
video players on a PC apply scaling multiple times. Must have 
something to do with square and non-square pixels. I notice 
with delight that on this year's WinHec it has been mentioned 
that in Longhorn they will delete a lot of these unnecessary 
cascaded operations: scaling, color space conversion, amplitude 
stretching (16..235 to 0..255), all for a better TV-out quality. 

But what other difference am I supposed to see ? There doesn't 
seem to be much of challenging motion that would reveal the 
quality of de-interlacers or of frame-rate up-converters. 
There's enough difference in the textures that at least one of 
these pictures might look "funny" when it moves. Who knows, 
compared to a plain DVD player connected to an interlaced display 
both of these computer players might perform very badly, only 
in different ways. On the basis of this data I can not tell. 

I'm off for a long weekend now, so please don't expect any 
more messages from me until next Monday. 

-- Jeroen 

| From:     Jeroen H. Stessen   | E-mail:  Jeroen.Stessen@xxxxxxxxxxx |
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