On Thu, 9 Aug 2001 11:46:49 +0300, Timchenko Maxim
<[log in to unmask]> posted article
<[log in to unmask]>, which
said:

> > quality is going to be better.  Of course, C-Band analog source is
> > always the best that can be had, no matter what the so-called experts
> "C-Band analog source" - please explain

C-Band, or Big Ugly Dish (BUD).  It was the thing to have to get hundreds of
channels in the middle of nowhere, or where no cable services was offered,
and before the small dish services like DirecTV and Dish Network came along.
DirecTV and Dish Network both compress their video signals with MPEG2
compression technologies.  Satellites in the Clarke belt only have 32
transponders, so they can only transmit 32 analog channels.  DirecTV came
along and compressed these channels so you can now get about 8 channels on
each transponder with MPEG2 compression.  Ideally the compression would not
be so great as to result in any noticeable effects, but the more channels
they have on one transponder, the more compressed they are.  Since C-Band
signals are uncompressed, they are the best quality that can be had.
However, some people were not too good at aiming their C-Band dishes so they
had "sparklies".  Most people who tout DirecTV and Dish or other DBS
services as "the best in broadcast quality" are remembering the infamous
sparklies that could result from not having a perfectly aimed C-Band dish,
or from using a C-Band dish that was too small.  With a digital signal, you
either get the picture or you don't.  There is no possibility of a "bad"
picture.  Your aim can be off just a little and your signal strength will
drop, but this does not affect picture quality.  However, the better your
aim on the DBS dish (DirecTV, Dish) the more resistence your gear will have
to "rain fade"... that loss of picture that results when the rain or clouds
are so heavy that the signal from the satellite cannot get to your back yard
dish.  Sometimes very heavy storms go over Cheyenne, Wyoming, where the Dish
Network uplink center is located, and it results in a loss of service for
the entire country until the storm passes.

> > Actually I have not found that CPU speed affects video quality at
> > all.  Hard drive speed is where you get better quality due to the
> > fact that you won't drop frames.  When I had a 4800 RPM drive in my
>
> If you want to compress on the fly with MP43 or DivX (which are the ones I
> use to get great video with little disk space) you'd be surprised how much
> CPU power it takes. Not on-the-fly, my 800-MHz system encodes 512x384 DivX
>  at 12-15fps. Badly-written capture drivers may also require a lot of CPU
> power (like FlyVideo's capture driver on Windows 2000... aargh!)

I would like to capture directly to MPEG, but with this VIA chipset and
SoundBlaster Live problem, I always get crackles in the audio track when
capturing directly to MPEG with PowerVCR. :-(

> If you use a less computation-expensive [or simply better-optimized :) ]
> codec (Wavelets, Morgan MJPEG) you need less CPU power. If you capture
> uncompressed only, you don't need a fast CPU, but then you're limited to
> capturing 5-15 min. chunks because of 2Gb file size limit, and you're
> obligated to have a fast drive.

Mostly all I ever want to capture is small bits, like commercials or music
videos.  BTUYV cuts the file size by around 2.5 times, I think.

> > I capture 24-bit 320x240 and it only takes about 5 minutes of video
> > to hit 2 gigs, IIRC.
>
> If your card allows, capture YUV12 instead. Little loss in terms of
> picture quality, but less bits per pixel. VirtualDub allows to "spill"
> long capture into several files transparently, so that you don't have to
> stop the capture every 5min to enter a new file name...

I've not had much luck using VirtualDub.  It locked up my old PC and it
locked up the new one I built.  Then again, I didn't download the latest
version.  I'm using an older version, I imagine.  I may check into it later.
:-)

Ethan

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