Panasonic NV-W1
Martin Blatter
**** Panasonic NV-W1 (AG-W1) ****
A review by Peter Simeon
The Panasonic NV-W1 (AG-W1, name in the USA) is a VCR which has the
capability to convert any TV signal to any other. It supports PAL,
NTSC, PAL-M, SECAM and MESECAM.
The VCR can Play any VHS-Tape (also LP/EP) and is S-VHS playback
compatible. You cannot record S-VHS and there are no Y/C-connectors.
It has HIFI-Stereo sound. I have read that Panasonic had to develop a
new Audio head to be able to support both PAL and NTSC HIFI-Stereo. The
NV-W1 has no Tuner. You can only record TV programs if your TV has a
video out connector or if you have a separate tuner.
There are two video/audio in and two video/audio out connectors. All
connectors are RCA jacks.
When you play a VHS-Tape the VCR automatically detects what TV-System
is used. You can then select "through" or another TV-System for the
output. if you select "through" the NV-W1 acts like a normal Multi-System
VCR and the TV has to be also Multi-System. If you select another
TV-System for the output the converter is activated.
You can also use the NV-W1 as converter without playing a tape. There
is a switch which selects the Input system. You can connect a LaserDisc
player to the input and a PAL-TV or a PAL-S-VHS VCR to the output.
The resolution of the converter is still better than VHS. So if you
use an external S-VHS for recording LaserDiscs you get a better result.
If you want to record the input signal with the NV-W1 you can again
select what system to use. (eg. You can make a Secam-Copy of a
NTSC-LaserDisc).
The record and playback quality of VHS Tapes is excellent. The resolution
compared to a 4 years old JVC was visibly better. Unfortunately there is
only AGC for HIFI-Stereo audio. The Quality of S-VHS Tapes is not so good.
The picture is a bit noisy and of course you loose resolution because
there are no Y/C-outputs.
The Quality of the conversion of the NV-W1 is great. If the Number
of scan lines is the same (eg. NTSC-PAL-M or PAL-SECAM) only the color
encoding is converted. This kind of conversion is perfect. We converted
SECAM Satellite Signals to PAL. Because PAL is superior to SECAM the
recorded PAL picture is better than when recorded in SECAM. We could not
test the quality of NTSC-PAL-M, because we had no TV which was PAL-M
compatible. A normal PAL TV does not decode color because the color
carrier frequency is 3.58 Mhz for PAL-M and 4.43 MHz for all other PAL
systems.
For the NTSC-PAL or PAL-NTSC conversion the NV-W1 uses a digital video
memory. This is the most complicated conversion. PAL and NTSC signals
are quite different. The three main differences are:
1) Color encoding
2) Number of scan lines (PAL 625, NTSC 525)
3) Number of frames (PAL 50 Hz, NTSC 60 Hz)
1) is not very difficult to convert. A simple device could convert NTSC to
60 Hz PAL or PAL to 50 Hz NTSC. 60 Hz PAL and 50 Hz NTSC are not used
formats, but all PAL TVs would display 60 Hz PAL.
2) This is more difficult to convert. You have to insert or delete lines.
In professional converters usually two scanlines are processed together
to produce a new scanline. If you convert from NTSC to PAL you get
a picture which has less resolution than a standard PAL picture.
3) This is the most difficult problem. You have to adjust the number of
frames. Because you have to kill 10 frames if you go from NTSC to PAL
you get a motion which is no longer smooth. Professional converters
often interpolate a new frame out of two frames. Fast moving scenes
become very unsharp.
The digital video memory is divided into two parts: one for luminance,
the other for chrominance. The converter processes luminance and chrominace
separately. To adjust the number of lines it always processed two lines at
once. To solve the 50/60 Hz problem it reads and writes asynchronous to/from
the video memory. The only problem is that some frames are "cut". The first
half of a frame is taken from one frame and the second half from the next
frame. This looks like this if you look at a vertical moving object:
||| <- This part is from 1st frame
|||
||| <- This part is from 2nd frame
|||
This effect is only visible in fast moving sceenes. I prefer this to the
method of interpolating two frames together. The picture is always perfectly
sharp. The Quality of the conversion is better than many professional
conversions seen on TV. We converted a VHS-Tape with computer animations
(The Amiga World Animation Video Vol. 1) and some Movies from LaserDisc.
This frame "cut" effect never very annoying. I had to watch about 10
minutes before I found out how the NV-W1 solves the 50/60 Hz problem.
Sometimes you see a some motions which are not smooth. This is caused by
loosing some frames. Even if it is asynchronous, some frames are missing.
But there is NO possibility to solve this problem perfectly.
We also converted a PAL LaserDisc to NTSC. Here the same asynchronous
effect happens. The resolution is a good as NTSC can be. You see immediatly
that the signal does no longer flicker (because it is now 60 Hz).
There are two things the NV-W1 can't handle:
1. PAL 60 Hz with 4.43 MHz color carrier frequency. We generated this using
an Amiga in NTSC mode with a RGB-PAL converter. (Probably the opposite,
Amiga in PAL mode with a RGB-NTSC converter, is also not possible).
2. NTSC with a color carrier frequency of 4.43 MHz. Some Multi-System
VCRs can supply such a signal.
The NV-W1 is available now in Switzerland about $3500. The converter is
really good enough for home video. Unfortunately the VCR is not S-VHS.
I would buy it if it were S-VHS. But I expect a S-VHS version. Two facts
lead to this conclusion:
1. The Luminance/Chrominance memory
2. A Panasonic employee told me last year at the FERA (Electronic Fair
in Zurich) that it is only a marketing issue that the NV-W1 has only
VHS.
I also heard some rumours that there will be separate converters.
If you want a converter now, or if you can get it cheap, go for the NV-W1
now. If you can wait, it's probably better to wait for a S-VHS version.
--
Peter Simeon cbmehq!cbmswi!mighty!astra!pe...@cbmvax.commodore.com
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Martin A. Blatter bla...@gorgo.ifi.unizh.ch (University of Zurich)