Re: HP dreamcolor screen, any opinions?
Re: HP dreamcolor screen, any opinions?
- Subject: Re: HP dreamcolor screen, any opinions?
- From: "J. Raimar Kuhnen" <email@hidden>
- Date: Fri, 22 Aug 2008 21:32:28 +0200
- Thread-topic: HP dreamcolor screen, any opinions?
Hi,
DVI is - from the beginning - able to run up to 48bit on double link, but
there has been no consumer level implementation of this feature. Even with
4MP resolution (30"-2560x1600), a Dual-Link DVI Interface only uses 268 of
the available 330Mz bandwith. A Single-Link Interface on the other hand can
drive the typical 2.3MP (1920x1200) only in 8bit, as the maximum 165Mhz
bandwith is fully occupied by 2.3Mp@8bit (In fact, to drive 2.3MP over
165Mhz one has to reduce the blanking signal).
If more than 8bits have to be decoded, the second link is used for the less
significant bits but must still use the same data format than the first
link. Especially in the medical market, one can find display and graphic
adapter configurations that support 10bit or even more bits (which are
needed for a smooth DICOM compliant gradation curve and perfect detail on
digital X-rays).
In case of graphic cards, one has to differ between a 10bit RAMDAC and 10bit
output on the graphics cards. The 10bit RAMDAC is used to convert the
digital graphics data to the analogue output (like VGA, Component or
sVideo). For DVI, the 10bit RAMDAC is not used in any case. The DVI-signal
is transferred via the TMDS Protocol.
Both HDMI and Display Port do support higher bitdepth - that´s maybe their
major advantage and the main idea that drives the development. HDMI reaches
340Mhz bandwith from version 1.3 on and does theoretically support high
resolutions with high bitdepth. But the majority of the HDMI implementations
only support up to 1080p or sometimes HD+ (WUXGA - 1920x1200). No higher
resolutions or higher bitdepth.
Display port can make use of up to four main links with 165Mhz or 270Mhz
bandwith equivalent to DVI. That means that display port is able - just like
DualLink DVI or HDMI - to drive 4MP (2560x1600) at 10bit or WUXGA
(1920x1200) at 12bit. HDMI can also drive 48bit at WUXGA (1920x1200). Unlike
HDMI - Display Port is not compatible to DVI. Although one can use the
display port to "tunnel" DVI-data.
But - having a HDMI or DP connector does not make the system automically
10/12/16bit capable. The software driver and operatig system has to support
it. Consumer level Mac OS and Windows drivers are still limited to 8bit. As
far as i know, the Matrox Parhelia card only the uses the 10bit with a
special Photoshop plugIn - no global support. Plus: only if the full number
of links in the interfaces and transmitter/receiver chips are implemented,
the full bandwith and bit depth can be used.
I hope that helps a bit.
Raimar
am 22.08.2008 2:24 Uhr schrieb email@hidden unter
email@hidden:
> Von: Klaus Karcher <email@hidden>
> Datum: Thu, 21 Aug 2008 19:05:10 +0200
> An: colorsync-users <email@hidden>
> Cc: <email@hidden>
> Betreff: Re: HP dreamcolor screen, any opinions?
>
>> Roger Breton wrote:
>>> In case this got bounced, here's a reply from HP's Proofing Product
>>> Manager about the DreamColor monitor...
>>>
>>> Andrew Page wrote:
>>>> To the 10-bit question that's come up, you do need a 10-bit
>>>> enabled card and software. The "easiest" way to implement the
>>>> 10-bit path for is through 10 bit, or floating point, textures in
>>>> the OpenGL path. DisplayPort is the recommended path to get 10
>>>> bit data into the card.
>
> Klaus Karcher wrote:
>> AFAIK there is no graphics card with DisplayPort for the Mac yet
>> unfortunately.
>>
>> Anyway, the card vendors claim to support 10 bits per channel already
>> in a more or less roundabout way (see references below). In theory it
>> should be possible to transmit 10 bits per channel over dual-link
>> DVI. [...]
>
> hmm ... is there really no one who can comment on this topic?
>
> Klaus
_____________________________
J.Raimar Kuhnen-Burger
Master of Art (Farbkommunikation)
Diplom Designer (Farbe)
Kunst- und Medienwissenschaftler
Milchberg 26
D-31177 Harsum
Tel./Fax.05127-931006
www.concolori.de
Skype: jrkuhnen
iChat: jrkuhnen
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