Y'know, I always thought the crap on the disks about PAL/NTSC was just
that, but my home cinema buff colleagues were insistent, so I just shut
up, but it always struck me as insane to tie the disks to a TV system.
"The road to Paradise is through Intercourse."
The uk.transport FAQ; http://www.huge.org.uk/transport/FAQ.html
> PAL is made up of 25 frames, or images per second, with 525 scan lines
> NTSC is made up of 30 frames, or images per second, with 625 scan lines
Right sort of idea but....
PAL is made up of 25 frames, or images per second, with *625* scan lines
NTSC is made up of 30 frames, or images per second, with *525* scan lines
(and with both these each frame is displayed in two separate fields
which are interlaced at either 50Hz (PAL) or 60Hz (NTSC) )
Errr - not necessarily ;-)
The DVD contains information that will instruct the player to render the
digital data stream into an appropriate format. The actual data held on
the disc can be format agnostic.
The problem with NTSC/PAL colour incompatibility is usually only
observed with a composite or RF modulated video signal. This is because
the chroma sub carrier information is positioned differently in an NTSC
broadcast signal, and does not have a "swinging colour burst" like PAL.
Hence the TVs failure to decode the chroma information correctly. If
your TV has a RGB compatible input the whole thing gets much simpler.
Colour information in a video signal is not carried on "extra lines" as
such - so fewer lines does not equal no colour. Also since PAL has a
higher resolution than NTSC this would not support the argument!
A second and more important point is that when a DVD player is connected
via a RGB connection you are no longer dealing with either PAL or NTSC
video as such. RGB does not use a colour encoding scheme at all - the
colour information is directly represented by the three R, G, & B wires.
Normally if you play a region 1 DVD, the player will output its RGB
signal at the same scan rates as those used for NTSC broadcast. If your
TV has RGB but is not capable of syncing to a 60Hz 525 line signal then
you may also have a problem (although complete lack of picture or a
rolling picture is more likely)
John Rumm wrote:
pardon me for replying to my own post... having read what I wrote I
realalise that I do not write quite what I thought! ;-)
The word "format" was perhaps a little "fuzzy" for the pedantry of this
I should have added that while the colour transmission system of the
actual data on the disc does not *have* to be encoded specifically for a
given region - the digitisation is usually performed at a resolution and
frame rate that matches that used in the target market.
So for example a region 1 DVD will be encoded for 30/60 Hz field/frame
rate. The player however could output this in true NTSC, or as PAL60
(Its much harder for a player to change the frame rate of a disc however
unless it includes a standards converter)
Er, no, sorry, if you read what was posted the original poster is correct.
The regional coding is part of the operating system of the DVD which is
purely in the digital domain. It matters not one jot whether it is to be
replayed on a machine that delivers it in PAL or NTSC - that encoding is
done in software and/or by the modulator.
Are you sure about this?
I've only ever played dvds on my computer via WinDVD and this has always
shown Region 1 DVDs to be NTSC and Region 2 PAL.
e.g. the disc currently in the drive is listed in the WinDVD info box as
Type: Interlaced MPEG2
Bitrate: 8.000 Mbps
Framerate: 25.000 Hz
Aspect ratio: 16x9
Dave Cunningham dave at upsilon org uk
PGP KEY ID: 0xA78636DC
It would have been more illuminating to have had the results from a Region 1
disc too :-)
Anyway, as Dave says, the DVD contains digital data in MPEG format. PAL and
NTSC describe the RF transmission method, not the source encoding. However,
one would naturally expect the encoding to reflect the intended use:
On a region 0 DVD I have, it states it is NTSC, not both
You still haven't explained what is actually on the DVD, apart from saying
The mpeg stream on the DVD has to have a FPS and a reolution
if it is for a PAL system it is 720x576 @ 25 FPS
If it is for an NTSC system it is 720x480 @ 29.97 FPS
Do you agree with this?
I'm not sure on the relevance of this post. I've given data showing the
encoding of the raw MPEG streams on both R1 and R2 discs & these seems
to follow NTSC and PAL resolutions and frame rates.
If a dvd disc was simply encoded in some base form and transcoded by the
player then why do multiregion dvd players output NTSC or PAL depending
on the region of the disc rather than simply transcoding to PAL or NTSC
If OTOH, your point is that NTSC and PAL are RF transmission methods (as
John has said) and aren't used to describe encoding methods then you
certainly haven't made it very clearly and are IMHO being a little
Dave Cunningham dave at upsilon org uk
PGP KEY ID: 0xA78636DC
Pedantry should be assumed on Usenet ;-)
I know that my multi-region DVD player produces some form of NTSC-alike
output with R1 discs, because the geometry is different and can be seen to
change when accessing the tv menu and fiddling with the 60Hz settings. Of
course, it could be no more than PAL at 60Hz. I can't detect any obvious
quality differences between R1 and R2 discs, and certainly don't have
versions of the same disc to compare anyway.
The link I posted earlier from www.mpeg.org seems to suggest quite strongly
that the frame rate of the encoded mpeg stream is the intended rate. As
such, it is probably a good thing that R1 discs carry an NTSC logo if they
are encoded at 30Hz (or seemingly 29.97 as the Yanks seem to have come up
0.1% short somehow), even if it is strictly technically meaningless. If my
TV did not have some 60Hz capability, would I have to rely on my DVD player
to drop frames to get down to 25Hz frame rate, assuming it could ?
[Okay, just checked the DVD manual. For output, it has PAL/Auto. on Auto,
the TV must be multi-standard. I changed it to PAL and tried to play an R1
disc. Up popped a message saying it wasn't a PAL disc. Not quite the
correct terminology, but I see what it meant.]
I don't think I've made myself clear. These might well be the common rates
used on most PAL and NTSC, but this is due to history, not a fundamental.
They don't. They will output a native screen resolution and size etc, but
this is nothing to do with PAL or NTSC.
They're not just transmission systems - they used to be part of the entire
chain from camera output onwards. But this was many years ago with quality
equipment. The PAL 'footprint' caused many problems in production and was
dispensed with as soon as was practical. It only really exists now for the
final stage of transmitter to receiver if things are being done correctly.
*Rehab is for quitters
Dave Plowman email@example.com London SW 12
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