[opendtv] Re: HDMI issues
- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Mon, 27 Feb 2006 10:23:23 -0500
Jeroen Stessen wrote:
>> According to The Perfect Vision, p.43 in print version or
>> p.31 at
>> http://www.avguide.com/servlet/download/2485.pdf?download=3Dyes
>
> I can't download that because I am not registered. And
> generally I wish to keep it that way.
You can opt out of spam. Seems to be okay.
>> HDMI outputs are typically less accurate and more
>> distorted than component video outputs, in a survey of
>> DVD players. See under the heading "Surprising Results."
>
> Can you please define "component video outputs" ? Are
> those SD interlaced (480i), SD progressive (480p), or HD
> up-converted (720p or 1080i) ??
Since they mention the upconversion issue separately, i.e. that
upconversion in the player *also* offers no benefits in all cases except
for the Krell, I would have to conclude that TPV is telling us that
component outputs at 480i, 480p, 720p or 1080i are generally better than
attempting to use the HDMI interface, in the case of DVD players.
On the other hand, I don't find this very surprising. There's no reason
to assume that going through potentially two separate rescaling steps,
one in the DVD player to upconvert from 480i, the second in the display
to convert to whatever that display's native format is, should be better
than just letting the display do this one time. No?
(BTW, I discovered that the Philips DVDR 75/17 doesn't accept 480p,
720p, or 1080i component inputs for recording, even though the player
does output progressive scan. The Accurian doesn't have a 480i component
out option to try. :( Probably an advantage in some ways, given all the
glitches I noticed with component video sync during the Olympics,
between the HD content and the SD ads.)
> Because, if the analog outputs are SD and the HDMI output is
> HD, then a conversion should have been done from Y'CbCr
> Rec.601 to Y'CbCr Rec.709. It's in the Gamma Sutra:
> http://www.poynton.com/DVAI/DVAI_TOC_full.html#26
> If either the source or the display forgets this distinction
> between SD and HD formats (thank you ATSC...) then a lot will
> go wrong.
Sounds reasonable. But remember that they also mention image distortion
being a problem with HDMI, e.g. circles looking like ellypses. So it's
more than just a color shift problem. Maybe this is a problem of screens
with oddball aspect ratios that don't rescale whatever comes in from
HDMI correctly. Growing pains, perhaps.
Bert
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