VIDEO CAMERA 1996

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MIXED BLESSING

 

INTRO

If you like the idea of desktop video, but don’t fancy poking around inside your PC then how about this digital video mixer from Vivanco, the latest addition to their MovieBox range

 

COPY

PC-based editing and post-production was never going to be easy, it’s the nature of the beast, but Vivanco have been doing their best to tame the technology and make it more approachable, with the MovieBox system. Unlike most other forms of desktop video, MovieBox does not use plug-in cards. That should please a lot of PC owners, who either do not relish the idea of tinkering around inside their equipment, or their PCs have simply run out of spare expansion slots.

 

MovieBox is based around a trio of devices, that plug into the computer’s serial, parallel and monitor sockets. We’ve already looked at MovieCutBox, which is the system edit controller (see VCR September 95), now it’s the turn of MovieMixBox, a 2-channel digital video mixer/processor plus 3-channel audio mixer. Incidentally, the third component is MovieGenBox, a PC genlock, that allows computer generated graphics, titles and images to be mixed with video from MixBox; look out for a full review soon.

 

Whilst the three units were designed to work together, they can still work as stand-alone devices, though clearly some functions -- that depend on other components -- will be unavailable. MixBox comes in two parts, the hardware and software. The electronics are housed inside a slim metal cabinet, that carries all of the AV inputs and outputs. The software is on a single 3.5-inch diskette. Our test sample also came with a ‘lite’ version of Movie Titler, a useful title generator program, though this will mainly be of interest to system users with a GenBox.

 

MixBox has two input channels, that can handle either composite or S-Video feeds, or a mixture of both. The channels are designated ‘M’, for master and ‘E’ for effects, the master channel remains in analogue form and is used to synchronise the second channel and the output, so it must always be present. The E channel is digitised, it is the one where all of the effects are carried out and is normally supplied by the second video source, though it can be sourced from the PC in the form of an image file. The computer communicates with MixBox via a parallel interface cable (supplied), this plugs into the PC’s LPT-1 port, (normally used for a printer).

 

Software installation is carried out from inside Windows. The disk loads from Program Manager in the usual way; it only takes a couple of minutes to sort itself out. The set-up defaults should suit most machines but if for any reason the PC uses a different parallel port or interrupt it’s a simple enough matter to change the settings, using the configure option on a drop-down menu. The only other preliminary is to select the appropriate signal inputs, which means choosing between composite or S-Video inputs, and deciding which input is going to be the master channel. Once that’s done MixBox is ready to go.

 

The desktop display is split into five areas. At the top there’s the signal routing plan, next to that there’s the video processor section. This uses virtual sliders for setting the brightness, saturation, contrast plus red, blue and green colour levels for both channels. The bottom half of the screen is taken up with the audio mixing and tone control sliders on the left hand side, and the master mix/wipe controls on the right. Drop-down control sliders are used to set chromakey and lumakey levels, and strobe speed.

 

At switch-on MixBox is configured for a basic 2-channel cross-fade. This can be carried out manually, by clicking and moving the slider control with the mouse pointer, or automatically, by double clicking on the ‘autotake’ button. The speed can be continuously varied using a second small slider. There’s a ‘bump’ option, which gives the effect a cute little judder as it terminates. Autotake proved to be rather unreliable, and the software was demonstrably the root cause of several system crashes on one of our test machines (workhorse 486/33 8Mb, Win 3.1 etc.). It worked okay on others, we never did find out why.  

 

Effects are selected from the toolbar at the top of the screen, either from the menu or icons. The basic options are cross-fade, wipe and move. Additional facilities include chromakey, lumakey, strobe and freeze. The freeze mode works as a frame-grabber, these can be saved as bitmap files (also gif, JPEG, pcx, tga and tiff formats), which can used as stills on the E channel.

 

The software comes with a choice of 22 wipe patterns. We suspect they should all be available immediately but on our sample they had to be loaded one by one from system files. This wasn’t explained in the instructions. It took a while to figure it out and several more minutes to load them all. Once installed, a simple double-click on chosen wipe in the selection window changes the pattern, and the icon is shown in the ‘Take’ window. In addition to the wipes provided MixBox comes with an extra program called MovieEditMix. This allows user to create their own custom cross-fades. It’s not the easiest piece of software to get to know, and devising a transition can take rather a long time, but for those with the patience and perseverance it could prove quite useful.

 

The audio mix section is reasonably straightforward, and the provision of tone controls is a definite bonus. Sound settings on both E and M channels can be stored and the wipe/fade control can be set to audio only or audio and video.

 

PERFORMANCE

Synchronisation is good, the processed output signal is stable and largely free of jitter. There is some evidence of the digital processing taking place. A small amount of pixellation is sometimes evident on static scenes though the processor is largely transparent; there’s only a negligible increase in noise and no significant loss of resolution on composite or S-Video inputs.

 

Transitions (wipes, fades etc.) occur in 64 steps, so there is a very slight pulsation as the image changes. This can be quite noticeable on a slow manual cross-fade or wipe, unless you’ve got a very steady hand. The changeover is quite clean though, and effect edges on wipes are sharp and well defined. The choice of effects should be more than enough to suit most users.

 

The chroma and luma key facilities work reasonably well, though the degree of control is fairly coarse and the best results are obtained when the subject and single colour background are brightly lit. It can involves a fair amount of trial and error -- especially chromakey -- but with care, it is possible to create some quite respectable effects.

 

The audio section performs very well indeed, again there’s no additional noise and the fader action is very smooth.

 

SUMMARY

Apart from those few glitches we mentioned previously, that concerned one test machine, MixBox is generally easy to use and combined with the other two parts of the system, forms a competent PC-based post production set-up. At just under £1000 MixBox is a fairly expensive piece of kit, though until recently that would have been competitive with stand-alone mixers, assuming you already had a PC. However, the price of digital mixers has been falling recently and the cheapest ones currently sell for less than £800, and that includes at least one model with a much wider range of effects and facilities than MixBox. However, compared with other desktop video products MixBox and the MovieBox system as a whole stacks up reasonably well against the competition. It’s certainly worth thinking about as an alternative to systems that use plug-in cards, which can be notoriously difficult to install and configure. For that reason alone it might appeal to movie-makers new to the joys of PC ownership, taking their first tentative dip into the sometimes murky waters of desktop video.

 

SPECIFICATIONS

Make/model:                 Vivanco PCV 4000 Movie Mix Box

Typical price:                 £999

System requirements     IBM PC or compatible, 386 or higher plus MS Windows 3.1 or higher

Features:                      2-channel vision mixer/processor & 3-channel audio mixer

Effects:             fade, 6 move effects, 22 wipe patterns, chroma and luma keying, video processing (contrast,  saturation, brightness RGB levels), strobe, freeze, auto fade (variable speed), Movie Edit Mix software (creates custom wipe & fade effects), Movie Titler (creates custom titles)

 

Sockets:                       AV in/out  (phono & S-Video), PC Parallel (25 pin sub-D), DC Power in (5-pin DIN) 

Dimensions:                  414 x 55 x 130 m

 

PERFORMANCE

Effects definition         good

Effect  stability         average

Audio mixing         good

 

VC RATINGS

Value for money         ***

Ease of use                      ****

Performance                     ****

Features                        ***

---end---

Ó R. Maybury 1996 2305

 

 

 

 

 


 

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