On Mon, 13 Dec 2004, Dik Takken wrote:
> Since my computer (Athlon 1400) is too slow to capture high quality, full
> res MJPEG video, I consider buying a hardware MJPEG capture card. There
Hmmm, I didn't think cpu speed mattered all that much for 'capture'
purposes but rather the speed of the I/O (disc) subsystem mattered
a great deal. For full frame high quality the data rates are such
that you probably need to splice/raid-0 two drives together.
An Athlon 1400 is probably too slow for the filtering + encoding
phase of the process though (unless you're very patient ;)).
> is lots of info in the archives about a lot of famous MJPEG cards, but
> most of them are no longer sold in the shop around the corner.
Exactly - MJPEG is essentially "yesterday's technology" and the main
source of MJPEG cards today is E-Bay or used equipment dealers.
I believe Linux Media Labs still sells MJPEG cards - but at $430 or
so (last I checked) they're considerably more expensive than a
DV conversion box plus a (very inexpensive) IEEE1394 card.
> So, I'm looking for a decent hardware MJPEG capture card that is currently
> available in computer stores. If MJPEG is still the best choice today,
It's not. Much newer methods have become available. For recording
from TV there are the Hauppauge cards (PVR-250 and PVR-350) that will
produce an MPEG stream directly with no encoding on your system. THe
downside of that is, of course, you do not have the chance to do
any filtering (denoising for example).
I do not know if the PVR-250 (or 350) can be used as a general
purpose capture/encoding device (if a VHS deck can be attached) or if
it's limited to signals received via the TV tuner section of the
card.
> that is. I have seen new (external) capture devices that can convert
> analog video directly to DV and stream it directly to your harddisk. How
> good/bad is the quality of these devices? Say I want to process the video
Depends which one you get - not all analog to DV conversion units
are equal. The Canopus product line is highly regarded (it's neither
the most expensive nor the cheapest). I have a Canopus ADVC100
which is currently selling (in the US) for about $250 (less if you
shop around a little). The newer model, the ADVC300, has hardware
denoising and a TBC (Time Base Corrector) builtin (and is a more
expensive at around $470).
> after capturing and re-encode to MPEG2, does DV offer sufficient image
> quality to do this or is an MJPEG capture card a better choice? Do
Most assuredly the quality is excellent. It's what most of the
camcoders use these days (DVCAM and DVCPRO are the "pro" versions
and are used by movie makers and the broadcaset industry).
I think the quality of DV is better - I know it's produced far
better movies than the Bt878 based card ever did.
Another advantage is that you don't have to resample the video from
square pixels to video pixels. Capturing at 640x480 (or 640x576) and
then doing a quality resampling to 704xN for placement on a DVD adds
extra time to the workflow (and any time of conversion/scaling at
best will not degrade the image - it won't improve it!).
> external capture devices have a big advantage compared to internal capture
> cards?
As was mentioned in another reply - you can take the conversion box
from machine to machine, don't have to open the system (and the
IEEE1394 devices are "hot pluggable" - you don't need to
powerdown/reboot
to change them). And you can easily add more disk space to the
system by using external discs that have a IEEE1394 interface.
I recommend taking a look at the Canopus (http://www.canopus.com)
line - the models 100 and 300 are the main ones to look at (no need
to explore the 500 and 1000 unless you want to see what the "pro"s
are using :)).
Maybe others who have switched over to the DV (using kino and dvgrab)
will jump in at this point with their tales.
Cheers,
Steven Schultz
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