Hehe.
RTFM and POS I know.
What’s IDTS?
[quote=“sandman”]except when they say the TV can handle PAL, they must be using a different definition of “handle” to the one I’m used to, because the picture’s absolute crap.[/quote]This you didn’t tell me, what telly do you have ? I have a little telly I bought in HK 10 years ago, and it has menu options for PAL/NTSC/AUTO, it’s left on AUTO obviously.
Hehe.
RTFM and POS I know.
What’s IDTS?[/quote]
It Does That Sometimes.
There is a perfectly simple explanation for all this. Your device will output PAL or NTSC coded content to the matching output device, and the switch selects for that. However, your device is not capable of any conversion between PAL and NTSC, which would require more expense to build, obviously. The difference between NTSC and PAL are three things: resolution or field size (I believe vertical resolution mainly… PAL has a few more lines), refresh rate or scan rate (PAL: 50fps, NTSC 59.97fps), and color modulation (different offset frequencies). Your device’s behavior, when set to PAL and outputting to an NTSC TV, is consistent with this set of differences. It is scrolling vertically because the field size is wrong. It should also be playing faster, although conditions are such that you can’t tell. The color is missing because it is modulated to a higher frequency, so on a really high end TV, you’ll see polka-dot artifacts that were meant to be color. Sound plays because it’s coded the same way in either standard.
An actual conversion is not straightforward. The refresh rate is the killer. To get NTSC output (broadcast standard used in Taiwan), 10 frames need to be made up every second. How the device does that completely determines quality – some just repeat frames every so often, resulting in jerky motion. And since it’s for TV, the discs may even be encoded in interlaced mode, which means even more horibble performance if the interpolation is done poorly. A better naive conversion, imho, should just be to resample the sound (much simpler) and play the original frames at 20% faster rate. The picture quality will be better but you know… it’s really not acceptable for a commercial device. The best would be to have an NTSC/PAL dual mode TV then no conversion would be necessary. I’m surprised your friend’s dual mode TV produces bad quality. It’s probably because the TV only has the number of lines for NTSC as somebody mentioned earlier and so it tries some form of resampling of the larger PAL picture frame to get it to fit on screen – bad idea unless done in a sophisticated way. That would also make a stupid dual mode TV. It’s more like an NTSC TV with a PAL kludge.
Now you already know your disc content is coded in PAL, so… how to get it to work at home. My suggestion is to re-encode it on the computer to NTSC. There are free tools to do this and the conversion quality can be as good as such a conversion can be. Better yet, just watch it on the computer. Computers don’t care about PAL/NTSC at all. You are free to hook your computer up to the TV, too. If your computer has such a connection (S-video is the simplest way), it will have a built-in NTSC modulator for your TV – that is, unless you bought your graphics card from the UK, in which case it would be PAL again! 
Thanks zeugumite. I think you explained it pretty well. The computer stuff, though, is way too complicated for this moron – actually, I don’t even have a computer, although my wife has a laptop.
And I also found out the reason for the NTSC/PAL switch is the same reason the device has a 110v/220v selector awitch – its so the device can be used in other countries.
So probably the easiest thing to do would just be to bring the device and the DVD back with me next time I visit the UK and plug it into me da’s telly. Except he’s not that keen on the Pogues.
There is a perfectly simple explanation for all this. Your device will output PAL or NTSC coded content to the matching output device, and the switch selects for that. However, your device is not capable of any conversion between PAL and NTSC, which would require more expense to build, obviously. The difference between NTSC and PAL are three things: resolution or field size (I believe vertical resolution mainly… PAL has a few more lines), refresh rate or scan rate (PAL: 50fps, NTSC 59.97fps), and color modulation (different offset frequencies). Your device’s behavior, when set to PAL and outputting to an NTSC TV, is consistent with this set of differences. It is scrolling vertically because the field size is wrong. It should also be playing faster, although conditions are such that you can’t tell. The color is missing because it is modulated to a higher frequency, so on a really high end TV, you’ll see polka-dot artifacts that were meant to be color. Sound plays because it’s coded the same way in either standard.
An actual conversion is not straightforward. The refresh rate is the killer. To get NTSC output (broadcast standard used in Taiwan), 10 frames need to be made up every second. [/quote]
PAL is 25fps (frames per second) and NTSC is 29.97fps, or rarely, 30fps. Or do you mean 10 fields? If sandman’s watching a film originally shot at 24fps and rendered into PAL at 25fps (1 for 1 frames) then he’ll get a much better experience by watching it on PAL on a PAL TV or on a computer. I hate NTSC films because often the judder created during the telecine is very noticeable. (The conversion from film’s 24fps to NTSC’s 29.97fps)
Play the film 20% faster? Anyway, a better way to do it would be to insert a US$60,000 Snell & Wilcox real-time converter betwixt DVD player and telly, or buy a multisystem telly in the first place. The built-it converters just add frames. That’s all, but often it’s enough, and it’s usually better than a software conversion unless you are prepared to get into motion sensing algorithms and are running a Cray supercomputer. TEMPenc can do a wee bit of motion sensing, and my computer only takes between 7 and 25 hours to do a high quality conversion.
Whilst it will appear on the computer as if the computer doesn’t care, the MPEG-2 algorithm does code this information into file. As you zeugmite points out MPEG-2 for DVDs is normally interlaced for telly, and indeed I always thought MPEG-2 by its very nature is either PAL or NTSC, as it was set up specifically to create DVDs to play in DVD players for standard interlaced CRT televisions. I mean the whole sequencing of the fields and the field types are created with interlaced fields in mind. I have never seen a non-interlaced MPEG-2 source so I don’t know. A computer conversion producing an NTSC coded DVD from a PAL source is at the mercy of the software used to do the conversion and how much time you are prepared to give the conversion.
But would this conversion be any better than the conversion the DVD player is doing? Or not doing. Why is there a switch on the back of the DVD player if there is no converter built into the DVD player? This goddam switch is at the heart of the whole problem.
If there is no converter built in, and a PAL disc is loaded, then the output will be PAL as there is no converter to convert to NTSC. The switch at the back will do nothing. The television will show a black and white picture with hideous banding.
If there is no converter built in, and an NTSC disc is loaded, then the output will be NTSC as there is no converter to convert to PAL (not that you’d want to as I never saw a PAL TV that couldn’t handle NTSC). The switch at the back will do nothing. I have no idea what would happen, but I assume there might be PAL TVs out there without NTSC tuners
So what does the switch do? I think it does this:
When switched to PAL, it outputs in PAL. If the disc is NTSC, it is converted by the onboard MPEG chip from NTSC to PAL. If the disc is PAL, it is just passed directly on to the telly.
When switched to NTSC, it outputs in NTSC. If the disc is PAL, it is converted by the onboard MPEG chip from PAL to NTSC . If the disc is NTSC, it is just passed directly on to the telly.
This is the only scenario that makes sense.
So if sandman wants to watch a PAL disc on his 1930s technology Taiwanese television then he should set the switch to NTSC or annex the Sudetenland.
(Errors and ommissiiosooonnss excepted. I’m in a awful hurry to get out of the orifice.)
If I set the switch to NTSC I get a message on the TV saying “PAL disc loaded.” If I set it to PAL I get the sound and the hideous banding. But I’ve been saved by a potato afficionado.
Sorry, I do mean fields.
As for the switch, I think it’s just as sandman says, it’s so you can use it in different countries. There is no conversion capability. When the switch is in a position that doesn’t match the source format, the DVD player complains, as sandman describes. Basically, it’s a complaint about NOT being able to convert.
Then it is clear as daylight. The NTSC/PAL switch let the DVD player read either PAL or NTSC disc, and will out-put same signal as the disc format. Play from the PC or Converterbox between the player and the TV seems like the only alternative (but maybe not good enough…)
Well the only answer then is to get drunk. BTW, my NT$2,000 Datong DVD player wot I bought nearly 2 years ago (and I suspect any modern DVD player) will convert on the fly and do an OK job unless it’s footie or fast moving stuff. So it should be fine for your Best of Lawn Bowls 1940-67.
Here is a picture of a PAL TV on sale in Taiwan.
tkec.com.tw/tkec/product/sho … id=060512#
29" JVC. NT$19k. Bit pricey. Likely to be far cheaper in HK, where all TVs are multi-standard, they have 220 Volts, and a decent sandwich shop in every MTR station. And bitter. And pork pies. And the rule of law. Building regulations. A police force. Foreigner-friendly government. All right, all right, I’m going.