🚀 go-pugleaf

In article <1992Nov12.150556.25771@mintaka.lcs.mit.edu> duda@brokaw.lcs.mit.edu (Andrzej Duda) writes:
>We are looking for a frame grabber card for live TV input. We want to
>digitize it in real-time without compression with the resolution from
>320x240x16 to 160x120x16 at 10fps and store to disk. The card should
>be for Sparc (or for PC eventually). According to my information neither
>VideoPix, RasterOps nor Parallax can do it. Any suggestions?
>

For my experience both the Parallax XVideo and the RasterOps SparcCard TC
can be used for your tasks. I've run a small program on our Sparc2 equipped
with a Parallax XVideo board to see what's possible (to get good performance
values the framebuffer was mapped into memory which allows direct read access).

An image of 240x180 pixels (24 bit/pixel) can be read from the card, converted
to 16 bit (5/5/5 RGB) and written to disk in 65-71 msec. This was measured with
the tmp filesystem in the swap partition. With the normal filesystem one can't
get similiar values, there's too much overhead from the flesystem (from six
successive frames three were grabbed, converted, and written in 67-70 msec each;
one needed 150-170 msec and the other two needed 200-240 msec). This results
in a mean value of about 130 msec /frame. I'd call this worst case.

We experienced similiar access rates for reading from the framebuffer of
the RasterOps card. Therefore I think that the performance of both cards
will not be significantly different. The greatest performance bottleneck for
storing uncompressed video is be the filesystem - if you use it; you might
try using a raw partition instead. The UNIX filesystem probably has it's
advantages, but there is anything else but support for continuous media. 


-edgar-

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Edgar Ostrowski

phone:  +49 30 314-25985
e-mail: ostrowski@prz.tu-berlin.dbp.de
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