EnigmA Amiga Run 1997 July/EnigmA AMIGA RUN 20 (1997)(G.R. Edizioni)(IT)[!][issue 1997-07 & 08][EAR-CD IV].iso/lightwave/lwmlist/96.lightwave-0215/[e-mail] _Wed Feb 21 05:53:35 1996.msg

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Subject: Re:Non-Linear edition and Animation Playback
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>How about MiroVIDEO DC20 PCI ?
>And FPS 60 from FAST ?
>
>I can do "S-VHS 3CCD camera quality"(Broadcast quality) with the MiroVideo?
>I'm thinking to editing commercials with 15", 30" or 45" and playback my
>Lightwave animations. I will use a S-VHS deck and, some times, Betacam SP
>deck. It depends, how client we are produce?

> FPS 60 from FAST ?

Its an ISA card. That pretty nuch tells you everything you need to know.
(i.e. low-cpu-to-card-bandwidth == low-quality).

The Electronic Mailbox Fast FPS60 FAQ says ...

 Q: What resolution does the FPS/60 capture at?
 A: The FPS/60 captures at 320x480, 30 frames per second and output quality
    is 640x480, full screen and full motion.
 Q: What compression ratios does the FPS/60 capture video at?
 A: The FPS/60 has freely selectable compression ratios from 9:1 through 75:1.

> MiroVIDEO DC20 PCI ?

I can only go from miro's web site and other advertising literature since
I've not found any reviews yet. But here goes ...

  A high quality hard drive controller card is critical for maximum
  performance. The following controllers are recommended for use
  with the miroVIDEO DC20:

  Adaptec  - AHA/2940 AHA/2940W AHA/3940 AHA/3940W
  Buslogic - BT-946C BT-956C

  A number of manufacturers are offering "AV" drives, or drives tuned
  for audio/video applications. Look for 3.5 inch hard drives rated at
  7200 RPM. Also, embedded servo drives which eliminate problems
  associated with thermal recalibration of drive heads can support
  higher sustained data transfer rates. Fast Wide SCSI drives are
  preferred because they provide the maximum data bandwidth.

  Hard drives meeting the desired specifications include:

  Micropolis 4211 AV-2.1 gigabytes
  Micropolis 3243 AV-4 gigabytes
  Micropolis 1991-9 gigabytes
  Quantum Atlas family
  Quantum Fireball 1280-1.3 gigabytes
  Quantum Grand Prix XP34280-4.3 gigabytes
  Quantum Grand Prix XP32140-2.1 gigabytes
  Seagate Barracuda2 - 2HP-2 gigabytes
  Seagate Elite 2 HP-3 gigabytes

  The miroVIDEO DC20 captures video in CCIR601 SQ Pixel YUV 4:2:2
  (16 million colors, square pixel). For NTSC video (the US standard),
  it captures at 640 x 480 pixels at 30 frames per second. This results
  in a video data rate of 18.6 megabytes per second of uncompressed video.
  For PAL video, capture is 768 x 576 pixels at 25 frames per second or
  22.3 megabytes per second, uncompressed.

  With the Motion-JPEG compression scheme the higher the compression
  ratio, the more data is lost. A recent test by several Hollywood
  video production professionals produced the following M-JPEG compression
  guidelines:

   4:1 -  6:1  Broadcast
   8:1 - 12:1  Professional
  14:1 - 20:1  Consumer
  25:1 - 40:1  Multimedia

Other information that I've seen says that the card has a 128KB buffer
for each frame. This gives a minimum compression ratio of 5:1 with a
corresponding data rate of 3.75MB/s.

Interestingly, one of miro's product comparison cards says that the much
more expensive Targa 2000 card has the same maximum data rate of 3.75MB/s.
I can't find any TrueVision documentation to confirm or deny this figure.

For comparison, DPS's PVR FAQ mentions its highest-quality setting gives a
frame size of 230KB, which means its minimum compression ratio is 3:1 with
a corresponding data rate of 6.75 MB/s, although it is displaying 720x480
rather than the 640x480 of the miro DC20.

In a message last month David Norris ([e-mail]) said ...

> I tried the Miro DC20, which uses the system's hard drive, but just
> couldn't get the performance out of it; sooner or later it would drop
> a frame or two when I sneezed.  I couldn't reliably get more than 2Mb/s
> out of this board, which translates into pretty crappy video.

Unfortunately David didn't mention his hard-drive controller and drive,
so noone can really guess whether they were his system's bottleneck.

I haven't actually seen one of these things working, so I can't say what
the actual quality is like, but I'm sure that the professionals here
with PVRs will advise you to go in that direction instead. If I were a
paying client, I would probably agree with them.

As an enthusiastic amateur however, I must say that the DC20 at $900 looks
to be an interesting (to me) alternative to a $1600 PVR.

Good luck,

John.