VIDEO CAMERA 1996

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MIXED EMOTIONS

 

INTRO

Video mixers are the ultimate post-production tool but most movie-makers can only dream of owning one. Now, maybe, Video Tech will be making some of those dreams come true....

 

COPY

Until you’ve actually played around with a video mixer it’s difficult to see what all the fuss is about, but it only takes a moment to get hooked! The facility to mix or wipe between two images might not seem that important, after all editing and other post production effects are now so accessible, and it’s possible to create professional-looking video movies with just a few inexpensive gadgets. Nevertheless a mix or wipe from one source to another cannot be achieved any other way, and it is the one effect that has remained stubbornly out of reach of most video movie-makers due to the high cost of the equipment. It’s been over eight years since the first ‘domestic’ mixers from Panasonic appeared but in all that time the official ticket price of new mixers has never dipped below £1000.

 

Video Tech have broken the log-jam with the VMX410. This fully-featured 2-channel digital vision mixer/processor and 4-channel audio mixer, designed and built in the UK, is now reaching the shops where it will be selling for just under £800. By any reckoning that’s still quite a lot of money, but when you see what it can do, and compare it with the competition, it might just look like a bargain!

 

The relatively high cost of digital vision mixers, including the VMX410, can be directly attributed to the complex circuitry needed to combine two free-running video sources. Mixing one video signal with another depends on one of the inputs being temporarily stored in a digital memory, and read out again, so that it is in perfect synchronisation with the other one. That’s no mean feat, and Video Tech have had to use some heavy-duty technology in order to do it.

 

Interestingly the front-end digital conversion chips in the VMX410 are the same as those used on some rival mixers but the rest of the circuitry, including the main effects processor, are all home-grown. This is a no-compromise design. The cost-savings are not a result of any corner-cutting but a welcome spin-off from the computer and multi-media industries, where the increased supply of specialised digital video processing microchips has driven prices down.  

 

Once a video signal has been converted into digital data you can do all sorts of interesting things with it. In the case of the VMX410 that includes:

 

* 60 wipe patterns, with 4 stages of edge sharpness

* glitch-free switching between channels

* wipe or mix to each or both input channels or one of 10 background colours

* picture-in-picture (PIP)

* five different sizes of PIP sub-screen, positionable anywhere on the screen

* PIP screen ‘window’ through which the second input channel can be viewed

* plain or bordered PIP screen

* chroma and  luminance keying

* positive/negative chroma and luma switching

* brightness, contrast, saturation and detail adjustment

* colour/mono switching

* digital still frame (frame or field mode)

* colour re-registration

* timebase correction

 

Some of those features might be unfamiliar and deserve a little explanation. Colour re-registration can correct small alignment errors that occur on recordings made on some VCRs and camcorders, where colours appear to be displaced. The 410 can shift colours vertically by up to 3 TV lines, and horizontally in seven 100nS steps, which should be enough to get most recordings back into shape.

 

Video signals piped through the ‘A’ channel  can be treated to a dose of timebase correction. This regenerates weak or degraded synchronisation pulses, which comes in handy when dealing with noisy or wonky source material. In fact the timebase corrector on this device is unusually versatile and can even lock on to video signals where the synch pulses are missing.   

 

Chrominance and luminance keying can be used to create the familiar ‘weather man’ effect, where the subject -- shot against a coloured background -- is superimposed on top of an image coming from the second input channel. The system used on the VMX410 is very flexible and can be adjusted to key to almost any colour or brightness level. These are selected by placing a moving cursor over a nominated section of the picture.

 

The video processor facility has four memories, so picture adjustments on channel A can be stored and quickly changed to suit different inputs. The still frame works in field or frame mode. Frame stored images give the highest quality but if there’s any movement in the scene this will show up as a judder, in which case the field mode can be selected, for a rock solid, though slightly less well defined picture.

 

Wipe and mix effects can be controlled manually, from the left hand fader (the one on the right is for audio), or triggered automatically, with a programmable transition lasting up to 8 seconds.  

 

Several additional facilities can be generated by combining various effects modes. Some of them, like ‘feedback’ produce a  tunnel of PIP screens of ever diminishing size will have sci-fi enthusiasts in raptures. That’s just a quick run-through of what it can do, we’d need rather more space than is available to do all of the effects justice, so on now to more mundane matters.

 

The two input channels can handle either composite or S-Video configured signals, or a combination of the two, converting between one format and the other. The quoted bandwidth is in the order of 500-lines, which means it can comfortably accommodate video inputs from the latest digital camcorders. By the way, did we mention it has an audio mixer as well? This has four input channels, including one for a microphone, and there’s a headphone monitor socket, with variable output.

 

Several effects and processor settings can be triggered externally, using the mixer’s GPI (general purpose interface) socket. Video Tech thoughtfully provide full details of the control protocols, for those who may wish to use it with other items of post-production equipment.

 

The whole caboodle is housed inside a neat-looking sloping console, with all of the input and output sockets on the back panel. The various effect and option buttons are laid out logically, with LED displays showing which modes have been selected. At first this approach appears a tad cumbersome, and it has to be said that moving from one option to another can involve a fair amount of button prodding, but you quickly get used to it. One word of warning though, the unit comes with a crib-sheet, detailing all of the various wipe patterns, don’t loose it otherwise you’ll be lost...

 

PERFORMANCE

Normally we expect to find a few rough edges on ‘domestic’ video mixers but the VMX410 has one of the cleanest repertories of effects we’ve seen, with impressively few tell-tale signs of the digital processing taking place. Transitions are very smooth, with no instability at the changeover points. Colours are noiseless and uniform, and PIP screens have none of the digital artefacts commonly seen on other types of processor. However, top honours go to the chroma key facility, which compares very favourably with professional systems. With care, and good, even lighting it’s possible to get almost perfect superimposition’s, with none of the whiskery edges that usually give the game away. Low-band and S-Video signals passed through the processor without any additional noise and colours remained unaffected.

 

The audio mixer is a bog-standard design, the VU meters are a useful touch, but really there’s not a lot to say except that it works well, the faders are smooth and progressive, and (so far) noiseless.

 

VERDICT

Apparently Video Tech have been working on a video mixer for several years. We’ve known about the VMX410 for a while, but it sounded too good to be true. Launch dates kept on being put back so we’ve been loath to say anything about it until we saw one in the flesh. Well, it’s here now and it has definitely been well worth the wait. Performance is outstanding, equal to or better than anything else we’ve seen in the past eight years, and the very attractive price must put it at the top of any ambitious video-maker wish-list. We just hope Video Tech can make enough of them to satisfy demand. Recommended

 

THE RIVALS

This is a small market and the VMX410 has few serious rivals, at least as far as performance and facilities are concerned. The main competition comes from the excellent Videonics MX1 and if you shop around you can pick one up for around £1100. Panasonic have just launched the WJ-AVE55 production mixer, it looks very well specified with several interesting effects, but we haven’t had a chance to fully evaluate it yet, but the list price of £1100 rules it out as a direct competitor. We liked Vivanco’s VM-500 (see April VC), but again the price at £1200 is quite a lot more than the VMX410. If funds are limited then it’s well worth a trawl through the ads for the ageing and relatively unsophisticated Panasonic WJ-AVE5 which we’ve seen selling for less than £500; it’s bigger brother the AJ-AVE7 has been advertised for just £700, though if you’ve managed to scrape together that much we’d strongly suggest you try to find another £100 for a VMX410.

 

SPECIFICATIONS

Make/model:                 Video Tech VMX410

Typical price:                 £800

Features:                      2-channel vision mixer with timebase corrector & 4-channel audio mixer

Effects:             60-wipe patterns and fade/mix to background colour or second input,  chroma and luma keying, picture in picture (PIP), freeze, video processing with 4 setting memory (contrast,  saturation, brightness, pos/neg), auto fade (variable speed), colour re-registration,

Sockets:                       AV in/out  (phono & S-Video), headphone & microphone (jack), external control (mini DIN), DC Power in 

Dimensions:                  410 x 70 x 265 mm

 

PERFORMANCE

Effects definition         excellent

Effect  stability         very good

Audio mixing         very good

 

VC RATINGS

Value for money         *****

Ease of use                      ****

Performance                     *****

Features                        *****

---end---

Ó R. Maybury 1996 0904

 

 


 

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