HDMI or VGA?

[wexfordpress]

Both my flat screen monitor and my computer have capability to run
either
VGA or HDMI connection. What if any are the advantages to switch to
HDMI?

John Culleton

[Michael Black]

I don't know, but since one is much more recent than the other, surely
there is an advantage. Since you have the capability, and all it will
cost you is the HDMI cable (I bought one at a dollar store for 3.00), I
can't see why you don't bother going HDMI.

It would be different if your video card or your monitor didn't do HDMI,
because then it would cost you to change.

Michael

[mike]

If it ain't broke, count your blessings, don't fix it.

http://www.h-online.com/open/features/HDCP-and-HDMI-747051.html

[David Brown]

Use HDMI, as it will give you a far better quality picture. With VGA,
the signal is turned into analogue for the cable, then back to digital
within the screen. That gives you loses in the colour resolution, and
challenges with synchronisation (such as missing a few columns of pixels
at the side of the screen). HDMI is digital all the way, and you get
the best picture your graphics card and screen can show.

[J G Miller]

On Tuesday, April 30th, 2013, at 08:54:49h +0200, David Brown wrote:

> HDMI is digital all the way, and you get the best picture your
> graphics card and screen can show.

Actually, if DVI output on the graphics card and DVI input on the
screen are avalable, that will give the best picture a graphics card
and screen can show because the maximum resolution and refresh rate
is limited by which version of HDMI is being used.

See the table at

<http://en.wikipedia.org/wiki/Hdmi>

[Måns Rullgård]

J G Miller <mil...@yoyo.ORG> writes:

> On Tuesday, April 30th, 2013, at 08:54:49h +0200, David Brown wrote:
>
>> HDMI is digital all the way, and you get the best picture your
>> graphics card and screen can show.
>
> Actually, if DVI output on the graphics card and DVI input on the
> screen are avalable, that will give the best picture a graphics card
> and screen can show because the maximum resolution and refresh rate
> is limited by which version of HDMI is being used.

HDMI and DVI are essentially the same thing. HDMI merely specifies a
few required modes the display must support and a few standard optional
modes. A display is free to support additional modes as well, and many
do.

The difference you're probably thinking of is that most HDMI outputs are
single-link whereas dual-link DVI is common. Dual-link is required for
very high resolutions. The actual rule is to use dual-link with TMDS
clocks above 165MHz for DVI, 340MHz for HDMI 1.3a. This means a single
HDMI 1.3a link can support higher resolutions than a single DVI link.

Most displays have no need for high clock rates and consequently have
only single-link inputs. Unless you require dual-link, DVI and HDMI are
equivalent, though you may prefer the smaller HDMI connector.

--
M�ns Rullg�rd
ma...@mansr.com

[J G Miller]

On Tuesday, April 30th, 2013, at 13:24:52h +0100, Måns Rullgård wrote:

> The difference you're probably thinking of is that most HDMI outputs are
> single-link whereas dual-link DVI is common. Dual-link is required for
> very high resolutions.

I was thinking specifically about people who have bought 120 Hz refresh
rate monitors (usually with 3d capabalities) and have complained that with
HDMI (version 1.3 that is) the best they can get is 60 Hz, but with a DVI-D
cable they could get the 120 Hz rate on the monitor for which they had paid.

[Måns Rullgård]

J G Miller <mil...@yoyo.ORG> writes:

> On Tuesday, April 30th, 2013, at 13:24:52h +0100, M�ns Rullg�rd wrote:
>
>> The difference you're probably thinking of is that most HDMI outputs are
>> single-link whereas dual-link DVI is common. Dual-link is required for
>> very high resolutions.
>
> I was thinking specifically about people who have bought 120 Hz refresh
> rate monitors (usually with 3d capabalities) and have complained that with
> HDMI (version 1.3 that is) the best they can get is 60 Hz, but with a DVI-D
> cable they could get the 120 Hz rate on the monitor for which they had paid.

3D support was added in HDMI 1.4, so that's hardly surprising.

[David Brown]

As pointed out by another poster, DVI and HDMI are basically the same
thing. There are some limitations and differences between the pixel
clock rates, refresh rates, resolutions, colour resolutions, etc.,
between different versions of the interfaces. So if you have
particularly high requirements, you want the fastest version of each
interface.

But the OP was asking specifically for VGA or HDMI - HDMI is
indisputably the correct answer. If the choice had been DVI or HDMI,
the answer would probably have been "it doesn't matter" - a graphics
card that supports both interfaces will typically support the same
speeds and resolutions on both.

[Hermann Riemann]

David Brown schrieb:

> HDMI is digital all the way, and you get
> the best picture your graphics card and screen can show.

I think displayport is better because 30 bpp instead
of 24 bpp used by HDMI and DVI.

--
http://www.Herman-Riemann.de

[Måns Rullgård]

Hermann Riemann <nospam...@hermann-riemann.de> writes:

> David Brown schrieb:
>
>> HDMI is digital all the way, and you get the best picture your
>> graphics card and screen can show.
>
> I think displayport

Displayport is still not widely available.

> is better because 30 bpp instead of 24 bpp used by HDMI and DVI.

HDMI 1.3a supports 30 bpp.

[Hermann Riemann]

Måns Rullgård schrieb:

> Displayport is still not widely available.

Some graphic cards and monitors now have displayport.

> HDMI 1.3a supports 30 bpp.

yes- by definition, how by hardware?

--
http://ww.Hermann-Riemann.de

[Måns Rullgård]

Hermann Riemann <nospam...@hermann-riemann.de> writes:

> M�ns Rullg�rd schrieb:

>
>> Displayport is still not widely available.
>
> Some graphic cards and monitors now have displayport.

Mine don't, not even the graphics cards I bought less than a week ago.
You have to actively look for it. It is not ubiquitous.

>> HDMI 1.3a supports 30 bpp.
>
> yes- by definition, how by hardware?

As well as Displayport devices do. The truth is you'll be hard pressed
to find a display able to render even 8 bits per component accurately,
let alone 10.

[Hermann Riemann]

Måns Rullgård schrieb:

> You have to actively look for it.

yes.

> The truth is you'll be hard pressed
> to find a display able to render even 8 bits per component accurately,
> let alone 10.

I have made some color experiments using C and SDL.
the values of single colors (r g b) in range[0:0x0F](dez: 0:16)
is hard to see,
but in range [0x0F0:0x0FF] (dez: 240:255) a bit may be seen.

I think, some graphic programs may use 4 pixel
instead of one to get the 2 bits,
or spread more precisison of color over more pixels.

--
http://www.Hermann-Riemann.de

[Henrik Carlqvist]

On Fri, 03 May 2013 19:28:31 +0200, Hermann Riemann wrote:
> I have made some color experiments using C and SDL. the values of single
> colors (r g b) in range[0:0x0F](dez: 0:16) is hard to see,
> but in range [0x0F0:0x0FF] (dez: 240:255) a bit may be seen.

Usually the human eye is capable of detecting the least significant bit
differences in about 7-bit color images.

In your test case above you are able to detect least significant bit
changes in 8-bit color images. But, as you write, you are only able to
see those changes in a small part of the color scales.

If you adjust your gamma correction curves to give a steeper curve for
the dark colors where you now are unable to spot least bit differences
and a more flattened curve for the bright colors you will probably not be
able to note those changes anymore. Most monitors have settings for gamma
curves.

regards Henrik
--
The address in the header is only to prevent spam. My real address is:
hc351(at)poolhem.se Examples of addresses which go to spammers:
root@localhost postmaster@localhost

[David Brown]

On 03/05/13 20:47, Henrik Carlqvist wrote:
> On Fri, 03 May 2013 19:28:31 +0200, Hermann Riemann wrote:
>> I have made some color experiments using C and SDL. the values of single
>> colors (r g b) in range[0:0x0F](dez: 0:16) is hard to see,
>> but in range [0x0F0:0x0FF] (dez: 240:255) a bit may be seen.
>

It is actually in these low ranges that there is a benefit in 10-bit
colour on a screen - but only if the screen is mostly dark, and the room
is mostly dark. Your eyes adjust to the dark and you can discern
smaller shades of near-black. There is therefore some point in 10-bit
colour for dark scenes in films - but little point on a computer screen.

Of course, 10-bit colour can be useful to people working with
professional level photography, DTP, and so on, where accurate colour
matching is important - and worth paying for.

And 10-bit (or more) colour is good in the source, such as digital
photographs, because it allows more accurate manipulation and changes
without losing resolution. But you don't need it in the output device.

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Don't you get 2Mpix limit for hdmi of any ilk?

though i wonder how common 4m+ monitors are anyway