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GTH Electronics ACE Converter

Is it a standards convertor? Is it a time-base convertor? Is it an aspect ratio convertor?
Well, actually, it is all three and a bit more besides. Robert Scarfe reports:

This may look like a typical black box which just happens to be beige. But I've put it through its paces and it is multi-functional and comes highly recommended.
        The niggles are positively trivial and what it can do for the money is startlingly impressive. It is a great product at an amazingly good price although it is fairly complex to use and not a toy for technophobes.
        What you get for just 299 is a time-base corrector, international standards converter and aspect ratio converter all in a neat box, approximately 8" wide and 4 " high. Other features are control over video output, including saturation, colour balance and sharpness. It can also output colour bar test patterns.
        Its outputs are more comprehensive than its inputs and other boxes on the market offer added options. But, bear in mind, you would need to buy multiple broadcast quality products costing several thousand pounds in total to achieve all the features of this single unit with a greater choice of connections.
        The ACE inputs S-video via the usual four pin mini din and composite with a phono socket. It outputs composite S-video, RGB and component via the SCART socket, plus there is stereo audio in and out via phonos.
        But it is the ACE features that are important, and this review is about how I rated them.

International Standards Conversion
It converts in and out of NTSC and PAL and, unusually especially considering the low price, inputs and outputs SECAM. It also handles pseudo PAL and every other permutation you can think of, including South American PAL.
        I was greatly impressed with the conversion quality and did a side-by-side comparison with our own broadcast Prime Image Penta II which cost around 5000. It comes a surprisingly close second. The only quality differences are quite subtle, mainly noticeable in pans when converting PAL to NTSC. There was noticeable judder and horizontal shimmering but no converter is totally transparent, regardless of cost.
        For the vast majority of footage, especially if it does not contain an enormous amount of movement or detailed graphics, you would barely notice the conversion. One thing I did observe was that NTSC to PAL was subjectively better than the reverse. The SECAM conversion in all directions is also excellent.
        This unit blows converter-type VCRs such as the W1 right out of the water.

Aspect Ratio Conversion
This feature comes right near the end of the manual, almost as if it were an afterthought. But in my opinion it could prove its most useful benefit and probably justifies the 300 asking price on this feature alone.
        That is because if you are shooting and editing your programmes in 16x9 you need to output it in a variety of formats so it looks equally good when it has to be viewed on a conventional 4x3 TV.
        It is no good sending customers a full height or anamorphic viewing tape ie one stretched out in a vertical direction. With this unit you can output in letter box, 14x9 and full screen 4x3. You can do the reverse by pillar boxing conventional 4x3 source material to fit within a 16x9 frame.
        There is a little bit of degradation in this mode because it involves zooming the central part of the image, but it is fairly transparent up to 14x9. Zooming up to full 16x9 means you start to lose lower third straps, but 14x9 is a good compromise used by most of the broadcasters and is perfectly acceptable.
        This aspect ratio conversion is superior to most DVEs because they can generally only reduce image width and height. This feature requires zooming beyond the maximum frame size and this unit does it well.
        This mode is engaged by holding in the output type button for two seconds on power-up. Keeping the button depressed for five seconds causes the unit to toggle between letter-box and pillar box. The PAL button then functions as a zoom in the horizontal direction or vertical and horizontal direction.
        This can be confusing initially but I have included some illustrations of pillar boxing and letter-boxing for you to see how it works. A test-card initially is quite useful to enable you to play with the unit and see what it does on widescreen and conventional TVs. That is better than experimenting with conventional footage, as it is sometimes difficult to see what you are trying to achieve.

Pillarboxing: (GTH Note: All shown on 4:3 screen. Pillarboxed images display correctly on a 16:9 screen.)
4:3 Test Card Electronic Source
4:3 Test Card Electronic Source
4:3 Pillarboxed to 16:9, No Zoom
4:3 Pillarboxed to 16:9, No Zoom
  
4:3 Pillarboxed to 16:9, Zoomed up to 14:9
4:3 Pillarboxed to 16:9, Zoomed up to 14:9
4:3 Pillarboxed to 16:9, Zoom to Full Width
4:3 Pillarboxed to 16:9, Zoom to Full Width

Letterboxing: (GTH Note: All shown on 4:3 screen. This is why the original 16:9 image is stretched vertically.)
16:9 Anamorphic Test Card Source
16:9 Anamorphic Test Card Source
 
  
16:9 Letterboxed to 4:3, Zoomed up to 14:9
16:9 Letterboxed to 4:3, Zoomed up to 14:9
16:9 Letterboxed to 4:3, Zoom to Full Height
16:9 Letterboxed to 4:3, Zoom to Full Height

Time-base Correction with Colour Positioning Feature
This corrects the one line drop in chroma when playing back VHS tape. You are able to shift it up to four lines if you are dealing with tapes which have been subjected to multiple copying, as a VHS recorder shifts the colour down by one line each time it is recorded.
        Without time-base correction after multiple copying, on things like captions the registration would be wrong and the colour filling each letter would be lower than its outline. You have also got horizontal shift, plus or minus to deal with horizontal bleed.
        No further comments: the ACE unit does what it says on the box.

Colour Controls
Unusually, this unit has full colour correction on all three RGB channels which means you have infinite scope for correcting white balance errors plus placing a colour cast to create a visual effect like warmth on a sunset image. Used in conjunction with the saturation control, this can enhance the creativity of your work.
        My experimentation included creating a highly saturated yellowish image which would lend itself to creative commercials. There is also a video invert option, which is quite useful for copying photographic negatives to video. The colour controls are useful to optimise the colour balance of the final output and achieve natural skin tones.

Widescreen Signalling Option P
This was a unit submitted for review where the audio and manual buttons have been substituted for 16x9 and letterbox. What this feature does is include a data packet in line 23 which the widescreen TV detects. It then instigates change of mode.
        What that means is that a widescreen TV can automatically display your material in its intended format without the TV viewer needing to adjust the set. A combination of out or in on the two re-purposed buttons will put a widescreen switching signal either 4x3 full-screen, 14x9 letterbox, 16x9 full-screen anamorphic or 16x9 letterbox.
        Incidentally, on some older TVs or monitors with under-scan there is noticeable data on line 23 at the top of the screen, but most modern equipment blanks it out see fig X. Most people with widescreen cameras may already have noticed this line. The Widescreen signalling option P is a useful additional feature.

There Must be Something Wrong With it
One criticism of this unit generally is that most buttons have dual functions and it can be difficult to see which mode you are in as there is no status display to tell you. Adding one would be an improvement and make a complex and multi-functional unit easier to operate.
        A good example is the component output which irritatingly re-sets every time the unit is switched on - and also the same switch is used for the letter-box pillar box function.
        Also on power-up the unit adopts a default condition which, if you used it purely for aspect ratio conversion for example, would be annoying and time-consuming as you would have to go through all the button configurations each time you started to use it. But GTH told me they were already on it. You can order your convertor to default at start-up to whichever mode you use most ie aspect ratio conversion. It's all on their website.
        A potential product enhancement though hardly to be expected at this price-point would be a genlock input, which would be handy if you were using the unit upstream of any routers or genlocked edit suites. In other words, this unit is intended purely as a device between two sources but could be developed much further.
        Another minor gripe is the lack of RGB or component input, ie DVD players etc.

And Finally ...
I like the fade feature which works simultaneously on both video and audio. You can use this when duplicating programmes with a clock and/or colour bars on the front with audio tone. There is a customary three seconds of black before the start of programme. The moment the colour bars disappear, hit the fade button and, by the time it has faded up (2.5 seconds approx), your programme comes up smoothly and your VHSs have an elegant black pre-roll without showing the bars from the master tape.
        As a by-product of all its other features, this unit blanks out any VITC and Macrovision signals in the vertical interval period, which means you could use it to rip off copy-protected material. That is obviously a reprehensible practice which I and the IOV condemn universally and absolutely. (GTH Note: We have a strict policy on this. See FAQs)

Robert Scarfe F.Inst.V. Abacus Television

Institute of Videography FOCUS Magazine, May 2003

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