[PD] system requirements video

[marius schebella]

hi cgc,

thank you, for your posting, I think i am coming along now

-) Operating system Linux
-) video pack GEM, maybe pdp, ...
-) video source DV camera or analog camera coming via capture card
(composite?)
-) HD, RAM It should be possible to load the pre-recorded media into the
RAM. (3-5 minutes for each of the five files). I have not checked, if there
is a RAM video player at all!
-) CPU I know that 800 MHz with a G4 are something different than with a
Pentium. Still, I am glad to read that a lot is done by the hardware
(graphic card) and an average PC with 1GHz+ should do it.
latency actually is of importance, since the video should be like a mirror
to the performer. but some ms are ok.
I think all my questions are answered, only if there is a preferred graphic
card, to be used?

Marius.

----- Original Message ----- 
From: <cgc at humboldtblvd.com>
To: "marius schebella" <marius.schebella at chello.at>
Cc: <PD-list at iem.at>
Sent: Monday, September 08, 2003 8:31 PM
Subject: Re: [PD] system requirements video


> Quoting marius schebella <marius.schebella at chello.at>:
>
> > Hi,
> >
> > what hardware requirements do I need to process live-video? I want to
> > mix
> > the data of a live video input with realtime processed videos and need
> > a
> > quality which is high enough to be displayed an a wall by a video
> > beamer
> > (600*800 ???). Do I only need a faster graphic-card (mine has 16MB), or
> > also
> > a fast cpu, RAM, etc.? (Some concrete suggestions of models/types of
> > cards,
> > how fast exactly?). Another calculation I need to process is adding 5
> > (or 6)
> > pre-recorded videos into one in real time using parts of the videos,
> > and/or
> > overlays.
> >
>
> We need more information to accurately answer your question.  Can you
specify
> the following:
>
> - Operating system
> - video package (GEM/gridflow/pdp)
> - live video source (DV/webcam/capture card)
> - type of video card
> - CPU, RAM ,HD
> - birth date, drivers license or other state issued ID number, favorite
color ;)
>
> In general the faster stuff you have and the more of it the better.  There
> aren't any absolute specs for any of this so you'll have to scale
accordingly,
> but here's a few general comments:
>
> - We have been getting very good results with DV camera input using GEM on
OSX.
>  any recent G4 800mhz+ will grab the input and display it on screen.
>
> - scaling the video is 'free' using GEM since it's done entirely in
hardware.  i
> think pdp has gl scaling and possibly other hardware accelerations.
>
> - using openGL you can use the video card to composite multiple clips with
alpha
> blending
>
> - playing multiple clips will put a big strain on the hard drive.  the
best
> solution is to have multiple drives for the video and RAID if possible.
>
> - resolution of the CPU based capture and processing varies with speed and
type
> of CPU.  Under 800mhz is probably limited to 320x240 for decent frame
rates,
> while 1ghz+ boxes should be able to do 640x480.  various optimizations
like SSE
> and Altivec and hardware acceleration also impact the final throughput
greatly.
>
> > And how big would latency be with those patches?
> >
>
> Depending on the OS, capture device and machine, it could be as low as a
few ms.
>  One of the GEM devs Daniel Heckenberg wrote a paper on OSx as a low
latency
> real-time video capture system.  In general long latencies in visual data
is not
> as off-putting as audio ones.  If the delay gets too long then just set up
some
> trippy rave style feedback system and put your brain in neutral for
awhile.
>
> > Greetings, Marius.
> >
> > ps.: an additional (but off topic) question, what is the difference
> > between
> > video, movie and film in this context?
>
> There's not really any difference in this context.  In GEM video is live
> capture, films and movies are clips on the hard drive.  In Quicktime the
term
> movie is used to describe objects containing a mixture of video, audio,
text and
> interactive elements.
>
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