Forums > Jitter

[ot] decklink onair

September 13, 2006 | 9:01 pm

http://www.decklink.com/products/intensity/on-air/

‘Blackmagic On-Air 2.0 combines a real time HD mixing console when
used with two Intensity boards plugged into Apple Mac Pro systems for
a complete live television production studio.’

How feasible is the option of using two Intensity cards with jitter,
for doing for instance realtime mixing of those two HDMI sources ?

best,

Gideon


September 13, 2006 | 9:31 pm

On Sep 13, 2006, at 2:01 PM, Gideon Kiers wrote:

> How feasible is the option of using two Intensity cards with
> jitter, for doing for instance realtime mixing of those two HDMI
> sources ?

I can’t speak from experience, but I would imagine as long as they
provide QT input components for these cards, that you should be to
use jit.qt.grab and be able to transport this data to the GPU) and
mix the HD sources with jit.gl.slab without much problem. If you have
a chance to test, let us know your findings.

Thanks,
Joshua


September 13, 2006 | 9:41 pm

I havent tested those specific cards, but I know Decklink and AJA
cards work with jit.qt.grab (and GEMs pix_video) without any issues,
and provide the whole visible video image, every scanline you want.

v a d e //

http://www.vade.info
abstrakt.vade.info

On Sep 13, 2006, at 5:31 PM, Joshua Kit Clayton wrote:

>
> On Sep 13, 2006, at 2:01 PM, Gideon Kiers wrote:
>
>> How feasible is the option of using two Intensity cards with
>> jitter, for doing for instance realtime mixing of those two HDMI
>> sources ?
>
> I can’t speak from experience, but I would imagine as long as they
> provide QT input components for these cards, that you should be to
> use jit.qt.grab and be able to transport this data to the GPU) and
> mix the HD sources with jit.gl.slab without much problem. If you
> have a chance to test, let us know your findings.
>
> Thanks,
> Joshua


September 13, 2006 | 9:46 pm

Ok, would be a v interesting option if it works. The other question
is if it would be possible to access the HDMI output of the cards ?

best,

On 13-sep-2006, at 23:31, Joshua Kit Clayton wrote:

> I can’t speak from experience, but I would imagine as long as they
> provide QT input components for these cards, that you should be to
> use jit.qt.grab and be able to transport this data to the GPU) and
> mix the HD sources with jit.gl.slab without much problem. If you
> have a chance to test, let us know your findings.
>
> Thanks,
> Joshua

—————————

Gideon G. Kiers MA/IMM

mobile.: +31 6 16614770
studio.: +31 10 4143745
fax….: +31 84 7559757
home…: +31 10 4112603
iceland: +354 6626132

dlf@telcosystems.net
http://www.telcosystems.net

Stadhoudersweg 49B
3038 EE Rotterdam
the Netherlands

—————————


September 13, 2006 | 10:21 pm

On Sep 13, 2006, at 2:46 PM, Gideon Kiers wrote:

> Ok, would be a v interesting option if it works. The other question
> is if it would be possible to access the HDMI output of the cards ?

Again, if they expose a QT video output component, it should work
with jit.qt.videoout. There’s nothing DV specific to that object.
Note that I doubt that you would be able to address it as an OpenGL
display, so it might not be suitable for many purposes aside from
simple disk playback.

Btw, for people looking to record DVI output from their computers,
this sounds like a promising option (DVI->HDMI converter box-
>Decklink Intensity), relatively low-cost as compared to many of the
other RGB frame grabbing options out there.

-Joshua


September 13, 2006 | 10:34 pm

On 14-sep-2006, at 0:21, Joshua Kit Clayton wrote:

> Again, if they expose a QT video output component, it should work
> with jit.qt.videoout. There’s nothing DV specific to that object.
> Note that I doubt that you would be able to address it as an OpenGL
> display, so it might not be suitable for many purposes aside from
> simple disk playback.

Indeed. The Onair software does seem to be able to do this, mix 2
inputs to 1 output, not through openGL probably.

> Btw, for people looking to record DVI output from their computers,
> this sounds like a promising option (DVI->HDMI converter box-
> >Decklink Intensity), relatively low-cost as compared to many of
> the other RGB frame grabbing options out there.

Exactly. Allthough I’m not 100% sure the Intensity card will be able
to deal with this DVI->HDMI conversion properly in f.i. a 1080p
resolution. I’ve sent a mail to the Decklink people, will post their
reply if I get any.

best,


September 14, 2006 | 2:56 pm

As allways, things are a bit more complicated, here’s the blackmagic
answer :

=== HDMI output to DVI input

The HDMI standard provides backward compatibility for DVI signals so
you can
use and adapter on a DVI port to output to a HDMI display.

However DVI computer monitors expect 8-bit RGB signals, and DVI
signals are
always 8-bit RGB. HDMI signals are most commonly 8-bit YUV but could
also be
RGB and could also be 10 or 12-bit in the latest HDMI 1.3 specification.

We are currently unaware of any cameras or DVD players which output
anything
other than 8-bit YUV through their HDMI port. If you were to attach a
simple
HDMI-to-DVI cable to these devices, they would fail to work with a DVI
display.

Furthermore, DVI computer displays typically work at one frequency
which is
usually 60 Hz. This contrasts with NTSC and PAL signals which are
29.97 and
25 Hz respectively and are therefore incompatible with DVI computer
displays
although they should work with DVI TV’s which support multiple
frequencies.

In order to guarantee that a HDMI signal can be displayed on a DVI
computer
monitor, such as an Apple 23" or Dell 24" display, the signal would
need to
undergo colorspace conversion from YUV to RGB and then pulldown
processing
would need to be performed on the video frame rate to adapt it to the
60 Hz
rate expected by the display. If the HDMI signal was anything other than
8-bit, it would also need to be adapted to 8-bit. I’m sure there are
probably expensive convertors which do this but it would make more sense
just to use a HDMI display which supports multiple frequencies.

DVI does not support audio. HDMI supports video and audio.

=== DVI output to HDMI input

"Does this mean that we can connect the Intensity card to the regular
DVI-D output of the graphics card of a second machine, which would be
sending out in a 1920 x 1080 resolution ? Have you tested this option
in your labs ?"

We thought of that but so far have been unable to find a graphics
card which
outputs at standard TV resolutions such as 1920 x 1080, 1280 x 720,
720 x
486 and 720 x 576. If we could find one, then I would expect we could
capture it with Intensity using a DVI to HDMI adapter on the graphics
card
output.

If you aware of such a graphics card, please let us know the brand
and model
as we’d love to get one and test it. I realize you can directly
connect a
big screen TV to the DVI output of computers but if you check the
resolution
being used, it will not be a TV resolution.

On 14-sep-2006, at 0:21, Joshua Kit Clayton wrote:

> Btw, for people looking to record DVI output from their computers,
> this sounds like a promising option (DVI->HDMI converter box-
> >Decklink Intensity), relatively low-cost as compared to many of
> the other RGB frame grabbing options out there.


September 14, 2006 | 3:42 pm

Hello,

Maybe using converter boxes ?

CP-261H / PC/HD with Audio to HDMI Format Converter

http://tinyurl.com/jcnyg

CP-267 / HDMI to DVI converter w/Digital Audio

http://tinyurl.com/zdptz

Bertrand

2006/9/14, Gideon Kiers

:
> As allways, things are a bit more complicated, here’s the blackmagic
> answer :
>
> === HDMI output to DVI input
>
> The HDMI standard provides backward compatibility for DVI signals so
> you can
> use and adapter on a DVI port to output to a HDMI display.
>
> However DVI computer monitors expect 8-bit RGB signals, and DVI
> signals are
> always 8-bit RGB. HDMI signals are most commonly 8-bit YUV but could
> also be
> RGB and could also be 10 or 12-bit in the latest HDMI 1.3 specification.
>
> We are currently unaware of any cameras or DVD players which output
> anything
> other than 8-bit YUV through their HDMI port. If you were to attach a
> simple
> HDMI-to-DVI cable to these devices, they would fail to work with a DVI
> display.
>
> Furthermore, DVI computer displays typically work at one frequency
> which is
> usually 60 Hz. This contrasts with NTSC and PAL signals which are
> 29.97 and
> 25 Hz respectively and are therefore incompatible with DVI computer
> displays
> although they should work with DVI TV’s which support multiple
> frequencies.
>
> In order to guarantee that a HDMI signal can be displayed on a DVI
> computer
> monitor, such as an Apple 23" or Dell 24" display, the signal would
> need to
> undergo colorspace conversion from YUV to RGB and then pulldown
> processing
> would need to be performed on the video frame rate to adapt it to the
> 60 Hz
> rate expected by the display. If the HDMI signal was anything other than
> 8-bit, it would also need to be adapted to 8-bit. I’m sure there are
> probably expensive convertors which do this but it would make more sense
> just to use a HDMI display which supports multiple frequencies.
>
> DVI does not support audio. HDMI supports video and audio.
>
> === DVI output to HDMI input
>
> "Does this mean that we can connect the Intensity card to the regular
> DVI-D output of the graphics card of a second machine, which would be
> sending out in a 1920 x 1080 resolution ? Have you tested this option
> in your labs ?"
>
> We thought of that but so far have been unable to find a graphics
> card which
> outputs at standard TV resolutions such as 1920 x 1080, 1280 x 720,
> 720 x
> 486 and 720 x 576. If we could find one, then I would expect we could
> capture it with Intensity using a DVI to HDMI adapter on the graphics
> card
> output.
>
> If you aware of such a graphics card, please let us know the brand
> and model
> as we’d love to get one and test it. I realize you can directly
> connect a
> big screen TV to the DVI output of computers but if you check the
> resolution
> being used, it will not be a TV resolution.
>
> On 14-sep-2006, at 0:21, Joshua Kit Clayton wrote:
>
> > Btw, for people looking to record DVI output from their computers,
> > this sounds like a promising option (DVI->HDMI converter box-
> > >Decklink Intensity), relatively low-cost as compared to many of
> > the other RGB frame grabbing options out there.
>


September 14, 2006 | 3:53 pm

yes, interesting. allthough i believe the problem is more the
resolution possibilities of the graphics card, then the converter
(for dvi to hdmi/intensity) ?

On 14-sep-2006, at 17:42, bertrand wrote:

> CP-261H / PC/HD with Audio to HDMI Format Converter
> http://tinyurl.com/jcnyg


September 14, 2006 | 7:59 pm

Hola,
I’m looking for a some advicer in the general
direction of manipulating live DV input to look
something close to atomic microscope imagery.
I’ve come up with a few "not-so-great’ patches using
Video->Nurbs patch as a starting point.
These are using existing footage but not live..
Any ideas?
All the best,
Stuart Smith


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