DVDs and NTSC/PAL

> Actually, it's more of a request for a clarification. I was under the
> impression that there was, ultimately, no such thing as an NTSC or
> PAL DVD ‹
> I understood that DVDs stored their video data in the same way
> regardless of
> the broadcast modulation system that would be used to play them back.

While I can't offer any real technical expertise on this, I'm fairly
certain this is not the case.

Without going into too much pointless detail, the BBC has developed a
device to "unpick" the conversion from PAL to NTSC on older recordings
(to avoid having to convert them back to the PAL standard by
traditional means, with the resulting loss in quality), and it's being
used for the first time on a forthcoming R2 PAL "Doctor Who" release.
There's been some discussion as to what the results will be when the
remastered PAL recording is converted to NTSC (for an eventual R1 DVD
release).

It sounds like a good idea in theory -- but no, as far as I know, this
is not the way it's done.

BRIAN/bpearcecloud9.net
<http://www.redjacketpress.com>

First post here... Hope it works.

The MPEG 2 content on a DVD is formatted in PAL or NTSC. It is quite difficult to successfully convert video from PAL to NTSC or visa-versa. Try http://www.nattress.com/standardsConversion.htm for a conversion plug-in for Final Cut Pro. http://www.creativecow.net/show.php?forumid=86&page=/articles/solorio_marco/std_converter_rev/index.html for a review.

High Definition video, while coming in many different formats from an acquisition standpoint, e.g D5, HDCAM, DVCPRO HD, does not have any relationship with PAL/NTSC.

Hope this helps,

Tom Kershaw

Posted by bigstevemac on 07:13am Oct 26, 2004:
>I was under the impression that there was, ultimately, no such thing
>as an NTSC or PAL DVD - I understood that DVDs stored their video
>data in the same way regardless of the broadcast modulation system
>that would be used to play them back.

Kind of depends what you mean by "in the same way". The compression
schemes are the same but the formats differ.

Effectively there are two kinds of DVD: 525/60 (for NTSC) and 625/50
(for PAL and SECAM).

There is a good explanation here:
<http://www.dvddemystified.com/dvdfaq.html#1.19>

>...but I understood that, ultimately, a DVD was just a collection of
>MPEG-4 files.

The video coding is usually MPEG-2, but MPEG-1 is also supported.
I don't think MPEG-4 is supported (DVD pre-dates MPEG-4)

<http://www.dvddemystified.com/dvdfaq.html#3.4>

Andrew

>...I was under the
>impression that there was, ultimately, no such thing as an NTSC or PAL DVD -
>I understood that DVDs stored their video data in the same way regardless of
>the broadcast modulation system that would be used to play them back. The
>NTSC-ness of the signal was incorporated, as I understood things, only when
>the signal was sent from the player to the television.

That is strictly true, in the sense that 'NTSC' and 'PAL' are broadcast standards (whereas MPEG2 is the single storage standard for DVD-Video), but I used the terms in my message to refer to the use of different frame rates and pixel counts.

PAL => 720 pixels by 576 pixels at 25 frames per second
NTSC => 720 pixels by 480 pixels at 29.97 frames per second

According to the (slightly dated) FAQ:

    <http://www.dvddemystified.com/dvdfaq.txt> Section 1.19

DVDs are mastered differently for NTSC and PAL consumers (in part) because it makes sense to precompensate the audio tracks for the different timing strategies utilized in playback of 24 frame film material on the two video systems. (The speed of playback is increased 4% for PAL and slowed (very slightly) for NTSC so that a round number of film frames gets converted to a round number of video frames in each system at playback time.) Increasing the playback speed on PAL systems would raise the pitch of the audio if precomensation were not employed.

Moreover, PAL consumers would not be thrilled if films were universally scan converted to 480 vertical lines when their televisions are capable of 576 lines of vertical resolution!

The FAQ goes on to note that 24 frame per second films are represented as 24 fps MPEGs, but utilizing a [bizarre] interlaced representation.

The FAQ notes that most PAL DVD players can play NTSC DVDs, but few NTSC DVD players can play PAL DVDs.

The FAQ is also a treasure trove of techno trivia and history of interest only to hard core nerds.

--Christopher