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Home Entertainment Blog Archive

Brought to you by your friendly, opinionated, Home Entertainment and Technology writer, Stephen Dawson

Here I report, discuss, whinge or argue on matters related to high fidelity, home entertainment equipment and the discs and signals that feed them. Since this Blog is hand-coded (I like TextPad), there are no comments facilities. But feel free to email me at scdawson [at] hifi-writer.com. I will try to respond, either personally or by posting here emails I consider of interest. I shall assume that emails sent to me here can be freely posted by me unless you state otherwise.

This archive is for an uncertain period commencing Thursday, 9 September 2004

Philips hobbles performance of DVD+R/+RW DVD recorders - Monday, 18 October 2004, 9:14 am

Some time back I mentioned the aspect ratio limitations of the DVD+VR recording format, as used by consumer DVD+R/RW DVD recorders. I took the opportunity to draw this to the attention of Philips Electronics -- the inventor and controller of DVD+VR and DVD+R/RW technology, and shortly before I went overseas, received a reply. It is one that I consider very disappointing. Before getting to it, here's the issue.

Each Title on a DVD (whether commercially available pre-recorded ones, or made on a recorder) is marked with the aspect ratio of the content of that Title. The two principal alternatives are 16:9 or 4:3. This item of information is very important to DVD players, because it affects how the DVD player delivers the picture to the TV. Remember, in the DVD player's setup menu you have to specify your TV's aspect ratio. Specify it incorrectly, and the picture will be distorted. The following table shows the effect that this setting has upon the picture, depending upon the 'flag' marking the aspect ratio for the particular Title.

Display Device Aspect Ratio
4:3 16:9
DVD Title Aspect Ratio 4:3 Picture unaltered Picture unaltered*
16:9 Vertical height of picture reduced from 576 to 432 pixels (PAL), or from 480 to 360 (NTSC)** Picture unaltered
* A few DVD players will reformat the picture by shrinking the picture width by 25% and inserting black bars to either side. Most rely on the display device to adjust for the narrower picture.
**Some DVDs will be reformatted, if the DVD player is set to '4:3 pan and scan' rather than '4:3 letterbox', by cropping a central portion from the widescreen image. But DVDs so encoded remain rare.

Notice that in only one of the four combinations is the picture reformatted: when it's an anamorphic widescreen picture (ie. 16:9 format) being shown on a 4:3 TV. If it were not reformatted, then the image would seem tall and narrow. The reformatting is performed in one of two ways: either omitting every fourth horizontal scan line (the cheap and nasty way), or by generating three new scan lines from each group of four source ones (producing a somewhat smoother result).

But here's the problem: if the DVD player does not know that the source picture is in 16:9 format, then it will not reformat it for a 4:3 TV. And there is no way of forcing the image to display correctly (except for those few 4:3 TVs that also have a 16:9 display mode).

Consumer DVD+R/+RW recorders alway record everything with the Title aspect ratio flag set to 4:3. Instead, the aspect ratio of the source is flagged within the video stream under the DVD+VR specification. But this is a proprietary flag, recognised only by DVD+R/+RW recorders. It is not recognised by regular DVD players.

Now here is the reply to my query from the Philips 'technical team in Singapore':

It is not the DVD+VR specification that needs changing but the DVD-Video specification!

The DVD+VR standard correctly handles the widescreen flag in real-time, as you can notice when you play back a widescreen recording on the DVD+RW recorder itself. It's just because the DVD-Video format specifies that the aspect ratio has to be constant throughout a 'title' (recording) that regular DVD-Video players cannot handle the real-time switching of this.

The DVD+RW disc therefore contains different flags: One for DVD-Video players that is constant, the other that DVD-Video players ignore but DVD+RW recorders respect and maintain. This one can change within the recording.

It is not expected though that the DVD-Video standard will be changed at this point.

The arrogance of this is rather breath-taking. The claim is that the DVD Video specification is defective because it fails to allow aspect ratio switching within a Title. Perhaps, but I've been trying to think of a circumstance in which one would need this. For sure, different Titles on a single DVD may need to be in different aspects, but not different scenes within one Title.

Except for one thing. Philips is a European company. Some analogue TV broadcasts in Europe use the PALPlus TV system, which provides for aspect ratio switching (it uses a flag) on the fly. So, yes, I can see that Philips had a legitimate issue to address. And so the ability of DVD+R/+RW recordings to change aspect ratio within a Title when played back on a DVD+R/+RW recorder is useful. But this is an additional feature above the standard DVD Video specification. It is not an excuse to hobble the implementation of the standard DVD Video features in such a way that causes DVD+R/+RW recordings to be incompatible with certain equipment combinations.

Consider: in my office I record a widescreen digital TV program onto a DVD+R disc. I then take it into the house for my family to watch, using a 4:3 TV and a regular DVD player. Because the Philips DVD recorder insists on flagging the Title at a 4:3 aspect ratio under the DVD Video specification, this equipment combination displays the picture distorted. This, incidentally, is by no means a rare equipment combination. In fact, most DVD players in Australia are connected to 4:3 TVs.

This problem could be solved simply by allowing the user to specify the official DVD aspect ratio flag for each Title, as permitted by some DVD-R/-RW recorders. The default could be left at 4:3 for those users who do not wish to be troubled by this level of technical involvement. It's worth noting that Sony DVD recorders, which support DVD-R, DVD-RW and DVD+RW discs, permit the aspect ratio to be set for Titles -- but only on DVD-R and DVD-RW discs. So even on this multi-format recorder, adherence to the DVD+VR specification limits capability.

Aladdin DVD appears - with THX Optimizer - Saturday, 16 October 2004, 10:06 pm

Setup panel on 'Aladdin' DVD The Region 2/4 DVD of the 1992 Disney animated feature Aladdin was released a few days ago. This provides another opportunity for people to set up their audio systems and display devices properly, thanks to the inclusion of the THX Optimizer on this DVD.

Just insert Disc 1, wait for the main menu to appear, then choose 'Setup'. You will see the THX Optimizer icon. Select this, and work through the system. There's a good chance both your picture and surround performance will be improved.

Most DVD movies have subtitles, of course, for the hearing impaired. This one, though, comes with 'Descriptive Audio' for the visually impaired. Basically, a pleasant male voice describes the action as it takes place. Normally, rather pointless I would have thought, I can see its point with a musical such as this. The default audio is something called 'English 5.1 Disney Enhanced Home Theatre Mix'. There's also a standard 5.1 mix. Not sure what the difference is yet. (Nice of Disney to spell 'Theatre' correctly for the PAL version.)

It also has a couple of commentary tracks and, excellently, runs these at a mere 96 kilobits per second in mono (1.0). Why waste hi-fi bitrate levels for mere commentary, detracting from the picture quality? Both the 5.1 tracks run 448kb/s, and the 'Descriptive Audio' track uses a further 192kb/s.

Weird scenes in the muslcal mind - Saturday, 16 October 2004, 11:53 am

Weird scenes in the muslcal mind

One of my favourite LPs, way back when I was at school, was The Doors' Weird Scenes Inside the Gold Mine. This was a two LP best-of compilation of previously released tracks, plus one otherwise not-existing track. I recall taking this to school once ... but not the vlnyl LP.

Oh no. No way would I take vinyl there. Vinyl was precious. To be played only on turntables with good quality cartridges tracking two or less grams.

No. What I took to school was an audio cassette recording I had made.

Now, normally I was careful to make sure that each track fitted properly onto the tape. But, for reasons I have no hope of recalling some three decades later, I did permit one track to only partially record, terminated prematurely by the end of the recordable section of the tape.

I write of this all these years later, prompted by listening to the offending track a few days ago some 35,000 feet above the central Australian desert on an MP3 player.

As it happens, the cassette of which I've been writing was stolen at school, which is to say, during or before 1975. Since then I imagine I've heard said track more than a hundred times (it's 'Take It As It Comes' from the band's self-titled first album). Yet still, as that point in the track approaches, I find myself mentally bracing for the anticipated flutter as the cassette player's head runs over the end-join to the tape lead-out. Strange how these things stick.

Singapore Electronics - Saturday, 16 October 2004, 11:46 am

Well, I'm back. My absence was due to a family trip, to Bangkok, London, Paris and Singapore. Got home this morning. Many interesting moments, although only some of relevance here.

Way back in 1972 my father was posted for a time in Singapore, back when it was still Third World, but up and coming fast. It was supposed to be a short posting, so the rest of us stayed here in Australia, but I took the opportunity to acquire my first stereo system. I researched the options available, and issued instructions, and my very limited funds from a part-time job, to him: I wanted a 10 watt per channel Kenwood amplifier. It seemed the best value for money.

He wrote back some weeks later that he'd bought me something else. Sucked in, I thought. The amp he'd bought was from a then unknown brand, Rotel. The RA-810 was rated at 40 watts per channel. I didn't believe it, but later it was reviewed in Australian HI-FI (for which I write these days) and the tests revealed the specification to be conservative. It measured 55 watts per channel. That was incredibly powerful for those days.

Now, of course, Singapore is an economic powerhouse and nobody's conception of Third World. I explored only a small part of Sim Lim Square, a huge mall full of electronics shops. Many computers, digital still and video cameras, and home entertainment shops. I soon noticed that home theatre receivers were much less expensive than here. All brands. For example, in one high quality shop -- Alpha Audio -- the Denon AVR-3805 (link to PDF) was priced at $SING1,450, which works out to $AUS1,208. RRP here: $2,499. Guess what. Buy a budget airfare, fly over, buy one, bring it back and you'll still be ahead (although without warranty support). May have to pay 10% GST on entry, although you can get your 5% Singapore GST back at the airport.

Then all you have to do is change the power plug. Singapore runs on 230 volts.

I made only one significant purchase there: the NAD PP-2 phono preamplifier. $SING150, or $AUS125.

That which has not been, and will still not be for a while - Wednesday, 22 September 2004, 9:20 pm

As usual, I've been neglecting this Blog. I plead a high workload. In the past seven days I have submitted 16,500 words to my various editors.

I shall be adding nothing here for three more weeks. Sorry. But let us hope my absence fills me up with interesting ideas.

In the meantime, you can read my review of a stack of sub-two kilogram projectors in the current issue of Australian Personal Computer, and subwoofers and satellites in the current issue of Sound and Image.

PAL-60 is good? - Wednesday, 22 September 2004, 9:10 pm

Aaron writes:

I'm an avid reader on consumer electronics especially DVD-related standards and to say that your feature on PAL-Progressive Scan and Analog to digital DVD-conversion and their fallacies was an eye-opener would be to put it modestly. Fantastically well-written and documented, this teaches a layman not to get swung by general opinions on new DVD-standards just because they seem to look so cool!

Also Stephen it would be great if you could shed light on PAL-60 that is touted as a holy grail of sorts by purists for the console manufacturers. I mean I have seen PAL-60 on both, PS2 and the XBox and they are definitely stunnning. But how is PAL-60 enabled? Is it from the game-software developers end? And if it is, how exactly does it influence a Multi-region picture tube. For example, I played a demo DVD of Transformers on the PS2 which didn't have PAL-60 as video option and the picture trully sucked. In the sense that the screen wasn't aligned properly and also the view-area was far smaller than the full-screen picture that I got in the retail title of the same game that boasted of PAL-60. Would be of mighty interest to console afficonados who have to worry abt a lot of things apart from the console to get a plesant gaming experience so to speak!

My response:
Thanks for the kind comments.

I don't know why people would rave about PAL-60. It is really just an interchange format, a hybrid love-child of PAL and NTSC.

Technically PAL just stands for the colour coding scheme, although it has also come to mean the 625 lines per frame/25 frames per minute TV system widely used here and in Europe.

PAL-60 is NTSC (525 lines per frame/30 frames per second -- which means 60 fields per second, thus the '60') with the NTSC colour encoding scheme replaced with the PAL colour encoding scheme. It exists because:

  • it used to require equipment worth many tens of thousands of dollars to covert the resolution and frame rate of NTSC to PAL
  • it's fairly easy to convert the colour schemes from one format to the other
  • many older PAL TVs could support the NTSC resolution and frame rate, but not the colour coding scheme.
Consequently it made sense for VCR makers in PAL countries to include a circuit to change the colour scheme on NTSC tapes to the PAL colour scheme. And that's what PAL 60 is: NTSC with the slightly superior PAL colour.

So why would anyone create PS2 games in PAL-60 from scratch? My guess is as a form of region coding. Most modern Australian and European TVs can play both NTSC and PAL-60 material okay. Few US TVs can play either PAL or PAL-60. The direction of video and DVD sales has been from the US to the rest of the world, not the reverse.

Now the advantage of PAL-60 to a games vendor is that he doesn't have to change anything in the game. The frame rates and resolution remain the same as the US NTSC version. All that changes is the colour encoding, and it is the player that determines how the colour is actually wrapped around the analogue luminence signal. So if a player wraps a PAL colour signal around an NTSC luminence signal, you have PAL-60. So the discs work fine for most Australian users, don't work for most US users, and require very little extra work from the games developer.

PAL-60 could possibly be better in one respect than regular PAL for games: it is less susceptible to flicker. But the cost is somewhat lower resolution than regular PAL.

Aaron seems pretty emphatic about the quality of PAL-60, though, so am I missing something?
Forthcoming: Twin Tuner High Definition PVR from Strong - Thursday, 9 September 2004, 11:20 am

Yesterday I had a long chat with Trevor Young of Strong Technologies, which currently sells the SRT-5390 digital TV receiver/Personal Video Recorder. He says that the company has a number of new products forthcoming, including a high definition TV receiver within a couple of months. But the most exciting project is likely to appear early next year -- as early as January, he hopes.

This will be a high definition receiver with personal video recorder built in. From what he tells me, this will have everything. Two HD tuners so you can record two different programs at once, or record one and watch another one. Of course, it will record SD programs as well. DVI output for high quality connection to projectors and plasma displays. The hard disk size has not yet been finalised, but will be at least 160GB. And price is planned to be $1,199.

If this works well, this would have to be the dream digital TV receiver.