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HINTS & TIPS

 

SHORT CHANGED?

Where can I find reviews on the regional differences between DVDs? I buy most of my DVDs from Play.com and try to compare the Region 1 edition to the Region 2 and I notice most R1 discs have a longer running time. Is there a technical reason for this or do R1 titles generally have more content?

Simon Hunt

 

A

There are two explanations; the first is good old-fashioned editing and censorship, which we’ll come back to in a moment. The second reason is subtler and has to do with the way movies are transferred to video. Film is shot at 24 frames per second (fps) but the PAL video system we use in the UK operates at 25fps so during the movie to video transfer for Region 2 discs the film is speeded up slightly (by 4%). The soundtrack is corrected for pitch and in general you won’t notice a thing, except that the movie will now be typically 4 to 6 minutes shorter than the original. (The conversion process for movies to NTSC video is quite different; see Getting Started).

 

Hollywood studios, mindful of the significant cultural and religious differences in overseas markets sometimes produce several different versions of a movie. Producers, and Directors occasionally make late changes following audience reaction to a movie’s release on DVD in the US and then there are the cuts imposed or suggested by our own British Board of Film Classification (BBFC), so one way or another it’s not surprising that what we end up with may be different to the R1 release. Incidentally, it works both ways and British movies shown in US cinemas and released on DVD are often hacked about -- nudity bad, violence good -- and there are several instances of UK films featuring strong regional accents being shown with subtitles. For a more detailed comparison of R1 and R2 titles have a look at http://www.dvdcompare.org.uk/comparisons/

 

 

 

PANNING PANASONIC

I own a Panasonic TX32PS1 TV and am not entirely happy with it. During panning shots, particularly with lighter backgrounds, the screen itself seems almost dirty. Also some parts of the screen seem to be lighter or darker than others, and you can see a faint line where the two are separated. It happens on TV broadcasts, video and even DVD playback though the screen is full of rich colours you can't really see it. Is this a fault specific to Panasonic or is this to be expected on any make?

Rob Woodhouse

 

A

TVs with flat screen picture tubes employ a variety of video processing circuits to compensate for the difficulty of producing a perfectly shaped picture on a 16:9 widescreen display. It’s mostly to do with the velocity of the electron beam which flits back and forth on the inside of the screen. Because the screen is flat and wide the beam has to travel further – compared with older types of tube, which have slightly curved screens – so the beam has to be sped up as it moves across the outer thirds of the screen and unless the intensity of the beam is very carefully controlled it can affect the brightness. It’s a juggling act and for the most part manufacturers get it about right and the screen appears uniformly bright but if the alignment is off, even by a small amount you may notice slight variations.  It also doesn’t help that the brightness of very flat screens can be affected by ambient lighting, especially if there’s strong light, from a window for example, striking the screen at a shallow angle. If repositioning the TV doesn’t help and the effects are as severe as you suggest then it may well need some adjustment.

 

 

QUICK TIP

Subtle picture faults, like small variations in screen brightness are extremely annoying but it can be difficult to convince dealers that they’re worth investigating. To avoid embarrassment, before you insist on a visit from a service engineer make sure that you can adequately demonstrate the effect. It’s no good relying on a TV broadcast, Sodd’s Laws says that you won’t be able to see it when the engineer is there, so prepare a small selection of DVDs or make some recordings on tape that clearly show the problem.

 

 

 

AUDIO ANGST

I recently changed from Freeview to cable in an attempt to improve signal quality and increase the number of channels. This seems to have worked fine, however, a more worrying side effect of the change emerged the first time I switched on the TV after installation - no surround-sound from Telewest broadcasts.

 

The problem is that the Pace digibox has no audio-out jacks, a situation I find to be quite absurd. The original Philips ON Digital receiver had audio outs that connected to my AV amp and this gave me fantastic surround. But here I am with a more modern digibox with no capability to link to my AV receiver. Is there any way to connect to the AV receiver? Or do I tell Telewest to get stuffed and go back to Freeview?

Gordon Robertson

 

A

It sounds as though you have been issued with one of the new DiTV4000 cable boxes, which, probably for reasons of economy, does not have the separate stereo audio outputs that were a feature of the earlier DiTV1000 and DiTV2000 models. These sockets carry standard stereo sound and you will get 4-channel analogue surround sound from TV programmes and movies with Dolby Surround soundtracks. On the DiTV4000 the stereo output is still there but it’s confined to the SCART sockets and there are various ways you can extract it and pipe it into your AV receiver. One solution is to hook the cable box up to the TV via you VCR using a SCART lead (assuming it’s a stereo model) and connect its stereo output to the AV amp; the only problem with this is the VCR will have to be left switched on. If your TV has a set of stereo outputs they can be connected to the amp, otherwise you can use a SCART to SCART lead with stereo audio ‘breakout’ cables; Maplin has one (part no VA23A) which you can order from www.maplin.co.uk for £9.99.

 

 

QUICK TIP

Telewest, in common with most other cable TV companies do not as yet provide their subscribers with anything other than the basic stereo soundtrack from the original transmissions, which may or may not contain an embedded 4-channel Dolby Surround soundtrack. However, the capacity to supply high quality multi-channel digital surround sound does exist because they distribute TV channels using the same MPEG 2 system employed by satellite broadcasters -- used to carry 5.1 sound on some of the movie channels -- but this would involve a considerable investment in infrastructure and a new generation of cable receivers.

 

 

 

SPLIT PERSONALITY

I have a Toshiba 28Z07B TV, which has three SCARTs but only one with RGB video. I have my Panasonic Sky digibox connected with a good quality SCART cable to my Scan SC2000 DVD player. This is then connected to the TV via a SCART cable and picture quality was very good. I then decided to upgrade to Sky+ and I envisaged that the same connectivity would be okay, and I could take advantage of RGB connection in the same way. However, if I select RGB from the set-up with Sky+, I get a 'smeared' picture. I have spoken with Sky who assures me the specification should be identical but can offer no advice.

Steve Thompson

 

A

One possible explanation is the Sky + box is experiencing an interaction with the Macrovision anti-piracy signals generated by your DVD player. Macrovision is designed to prevent VCRs making illicit recordings of DVDs; since the Sky+ box is also a recording device its automatic gain control (AGC) and colour processing circuitry may also be affected by the ‘spoiler’ signals coming from the DVD. Assuming that the picture from the digibox is okay when it is connected directly to the TV’s SCART socket (otherwise there may be a fault) then the solution is to split the input to the TV using a SCART switcher box, so that both devices can share the RGB SCART socket. There are a fair number of these devices on the market so it is important to choose carefully. You are looking for one with auto or remote switching, so you don’t have to keep getting up out of your chair, and you should make sure that all of the sockets are fully wired for RGB signals. You’ll find a selection of suitable models at the following web sites:

http://www.euronetwork.co.uk/acatalog/SwitchBoxes.html

http://www.beststuff.co.uk/av_hubs_and_splitters.htm

http://www.av-sales.com/html/quintro.html

 

 

QUICK TIP

We probably shouldn’t be telling you this but on some DVD players it is possible to switch off the Macrovision anti-piracy system in a hidden service menu, in much the same way as you can ‘hack’ some models for all region playback. Clearly it is not something we can condone but it would be one solution to the problem of connecting a DVD player and VCR to TVs with only one SCART socket. Details of Macrovision hacks often appear alongside region code hacks on web sites such as: http://www.dvdrhelp.com/dvdhacks.php

 

 

 

GETTING A BUZZ

I've recently bought the Mordaunt-Short 500 THX Declaration speaker package. I'm very happy with it, but I've got one problem: My centre speaker is placed on top of my TV (Panasonic) and as soon as I turn it on, I hear a constant hum emanating from the centre. It has the same tone as I hear in the back of my TV, only louder. According to the MS website, the centre is magnetically shielded. If the 504 is shielded properly, how can this hum get into the speaker and, maybe more importantly, can it harm the speaker?

Micha Rentier, Holland

 

A

You are confusing magnetic shielding with radio frequency (RF) screening. In the former the magnet surrounding the speaker’s voice coil is encased in a metal alloy shield (on some speakers there is also a second magnet), and these measures are designed to neutralise the speaker’s magnetic field, which can affect the nearby TV screen. If a thin metal plate inside the picture tube becomes magnetised this can result in areas of colour ‘staining’ in the picture. RF screening is a quite different kettle of fish and this is meant to prevent high frequency interference coming from the TV feeding back into the amplifier through unscreened cables and components. Unfortunately speaker cables are normally unprotected and the speaker itself is very difficult to screen so you should try moving the speaker further away from the TV – a couple of inches should do the trick -- and shorten or re-route the cables.

 

QUICK TIP

The average CRT-based TV is brim full of electronic circuits that radiate quite significant levels of RF interference that can be picked up by sensitive equipment several tens of metres away -- that’s how TV detector vans work. You can easily demonstrate the effect by holding an AM radio near your TV. Fortunately it drops off quickly the further away you get and it’s not usually a problem as most signal carrying cables are effectively screened but it is still a good idea to keep them all as far away from the TV as possible  

 

 

 

GETTING CREATIVE

I have a couple of questions regarding the Creative Labs Digital 5500 package, which you reviewed in issue 112 of Home Entertainment. If I connect my Sky digibox to the stereo line input of the decoder will I get Dolby Pro-Logic sound? Can the decoder unit be placed horizontally?

Roy Scott

 

A

Sorry, we forgot to mention in the review that in addition to its digital coaxial and optical bitstream connections the Digital 550 does indeed have a normally configured set of stereo line input sockets on the back. So the answer to your first question is yes. If you connect them, via a stereo phono-to-phono cable to your Sky satellite receiver box you will get full-blown Dolby Pro Logic surround from all speakers, assuming of course that it’s there to begin with on the TV programme or movie soundtrack that you are watching (try it with the Simpsons, this almost always has a Dolby Surround soundtrack). There’s good news on question two and as far as we can see there is nothing to stop you mounting the amplifier module horizontally, it even has some little rubber feet on the base so Creative Labs clearly have no problem with its orientation. However, as you may have noticed from the photograph all of the front panel labelling is arranged so it can be read when the unit is stood on end in the vertical position; that’s hardly a problem, but it could look a bit odd, or quite funky, depending on your perspective. 

 

 

 

MAKING LIGHT WORK

I'm thinking of buying a Sony KP-41DS1 rear projection TV, but I have been told that the bulbs in rear projection TVs only last about two years and cost approximately £400 to replace. Is this the case?

Jim Williams

 

A

Your informant is mostly correct and replacement lamps for video projectors can be expensive, £300 to £400 is not unusual. Video projector lamp operating lives typically range between 1000 and 4000 hours, which could equate to two years or less under some circumstances (see Getting Started), however, none of this applies to the KP-41DS1 as this is a CRT-based projector. Inside the box there’s a trio of high intensity picture tubes, which beam onto the inside of the screen through a set of lenses and mirrors. Because the tubes are driven hard they also have a limited life, compared with the 8 to 10 year lifespan of a normal TV picture; unlike projector bulbs they rarely burn out completely but over time the light output does decrease. Understandably video projector manufacturers are reluctant to quote life expectancy figures, they have no way of knowing how it will be used, but as a general rule you can expect CRT projection tubes to last between 10,000 and 15,000 hours, before the light output falls too low or they suffer permanent ‘burn-in’. Replacement costs are quite high, you can expect to pay between £300 to £400 per tube – remember there are three of them -- and that doesn’t include fitting costs, but with ‘normal’ use you should get four or five years use out of it before you start to notice a reduction in brightness.

 

 

QUICK TIP

There are two other video projector technologies besides high-intensity CRT. In an LCD projector a bright light is shone through a single colour or three monochrome LCD elements; these are similar to the LCD screens used in pocket TVs. The most recent type of video projector uses a technique called DLP (digital light processing). This is based on a microchip covered in a matrix of pivoting ‘micromirrors’, which represent a video display. The mirrors reflect light from a lamp through a series of rotating filters to create a colour image.

 

 

TRICKY FLICKER

I recently purchased a Toshiba 36ZP38 36in TV and have noticed a flickering across the picture horizontally (lines that are lighter in colour than the picture). This is noticeable usually when there is a head and shoulders shot of a person with a medium-to-light coloured plain background. I have read in your magazine that TVs with 32in screens and above are prone to flicker but I am not sure whether this is what I am experiencing, or whether being a 100Hz TV I should not be experiencing this flicker anyway. If I arrange for the TV to be exchanged they will charge me if the TV proves to be okay so I would be grateful for your advice.

David Peace

 

A

Screen flicker is an inherent problem with the 625-line 50Hz PAL video system but the effect tends to be fairly subjective. It doesn’t bother some people but drives others mad and it definitely becomes more noticeable on larger screens, which is why we prefer 100Hz displays on screens 32-inches and above. The faster 100Hz screen refresh rate shouldn’t produce any perceptible flicker though early sets did sometimes have problems displaying fast moving objects, which could appear jerky or blurred. It sounds as though your TV has a problem and you certainly shouldn’t be able to distinguish individual picture lines. It’s hard to say at this distance what type of fault this could be but just in case you are being overly sensitive or have some unique and as yet unrecorded visual defect, without prompting, ask a member of your family or a friend is they can see anything wrong with the picture and if they spot the flickering lines then make your call to the dealer.

 

 

 

GETTING STARTED 1 – 3:2 PULLDOWN

Transferring movies to PAL DVD and videotape is a relatively straightforward process and involves speeding up the projector slightly, from 24 frames per second to the 25 fps (50 fields per second) of PAL video but it’s much harder to transfer movies to NTSC video. That’s because the NTSC system operates at 30fps (60 fields per second) and speeding up movie footage by 25% would be intolerable. To overcome the problem a system known as ‘3:2 Pulldown’ has been developed

 

It’s quite involved but basically it means stretching four frames of movie film to fit into five frames of video. This means creating two new fields of video but you can’t simply repeat a frame as this would make any motion on the screen look jerky, so the new frame (which comprises two fields) has to be constructed from the successive four movie frames.

 

This is how it works. Movies are transferred to video on a telecine converter; as each movie frame of film passes through it is electronically scanned. The first frame, which we’ll call frame A is scanned three times, to produce three video fields, next up is frame B and this is scanned twice, to produce two video fields, then comes frame C and this is scanned three times, and frame D is scanned twice, (notice the pattern 3,2,3,2), the sequence is then repeated so over the course of four movie frames ten fields or five frames of video are created. Clear as mud eh…

 

 

GETTING STARTED 2 – PROJECTOR LAMP LIFE  

Before you buy a video projector your should know that there is a hidden cost in the shape of replacement lamps. These aren’t your ordinary 60-watt light bulbs, or even the sort of high output Halogen lamps that you find in slide and cine-projectors, but fancy Metal Halide lamps that are mounted in their own sub-assemblies with integral reflectors. In most cases you’ll see little change from around £300 to £400.

 

These lamps have a typical life expectancy of 1000 to 2000 hours though some recent ‘UHP’ types  (Ultra High Performance – a proprietary brand made by Philips), may be rated at between 4000 and 6000 hours. However these figures are normally based on fairly conservative usage of three to five hours per day; lamps that are used for longer periods will normally have shorter lives.  The quoted figures also depend on the projector being used in a clean dust-free environment and treated very carefully to avoid mechanical shock while they are on, and immediately after they are switched off, while they are still extremely hot and therefore still very fragile. 

 

Environmental conditions are important as airborne contaminants can lead to overheating, through clogging of the filters in the projector’s cooling system. A build up of dirt and dust on the fan can also cause problems, by slowing it down and reducing its efficiency.

 

To prolong the life of a projector lamp it is important to follow the manufacturer’s instructions to the letter, which usually means not moving the projector for at least twenty minutes after it has been switched off. You should also clean or replace the filters according to the service intervals in the instruction manual, and possibly more often if it is used in a smoky or dusty atmosphere.

 

 

---end---

 

Ó R. Maybury 2003, 0307

 

 

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