Widescreen Movies
For widescreen movies, 16x9 enhanced PAL DVDs provide the highest resolution image, and are theoretically the version of choice. If the PAL version of a widescreen movie is not 16x9 enhanced, then the version of choice is a 16x9 enhanced NTSC DVD.
Frame and Field Rates
The consideration of which version is best is complicated by the issue of source material. In the case of movies, the choice is simple - pick the disc which has the highest possible image resolution, all else being equal. In the case of video-sourced material, the choice is less simple.
Movies
Movies the world over are shown at a frame rate of 24 frames per second. That is, 24 images are projected onto the cinema screen every second. Movie film is a very high resolution format, far higher in resolution than the DVD format. Accordingly, the movie itself is not the limiting factor in deciding between PAL and NTSC format DVDs, as the same source material is usually used to create both the PAL and the NTSC versions of a particular DVD. Therefore, the limiting factor in resolution is the DVD itself, with PAL inherently higher in resolution than NTSC.
Video
With video-based source material, there are two predominant worldwide formats; PAL and NTSC, which differ in both resolution and in frame rate. PAL is higher in resolution (576 horizontal lines) than NTSC (480 horizontal lines), but NTSC updates the on-screen image more frequently than PAL (30 times per second versus 25 times per second). What does this mean in practice? NTSC video is lower in resolution than PAL video, but because the screen updates more frequently, motion is rendered better in NTSC video than it is in PAL video. There is less jerkiness visible. When video source material is transferred to DVD, it is usually transferred in the format it was created in - PAL or NTSC, and the subsequent image has either higher temporal resolution (more frames per second - NTSC) or higher spatial resolution (more lines per image - PAL).
Conversions between the two video formats are possible, and are indeed frequently carried out, as it seems to be far more acceptable to sell PAL transfers in PAL countries and NTSC transfers in NTSC countries, even if the source material did not originate in the respective format. Conversions between these formats is problematic, however, as compromises need to be made in order to accommodate the source material, and visible artefacts can be introduced by the conversion process.
Converting NTSC to PAL
When converting from NTSC to PAL, two things need to be accomplished. 480 lines of resolution have to be upconverted to 576 lines of resolution, and 30 images per second have to be downconverted to 25 images per second.
The resolution upconversion does not actually add any real picture information to the image, as you cannot create real picture information where none existed before. It does, however, make the picture viewable on a PAL display, and often results in a superficially better-looking image.
The frame rate conversion actually results in a loss of temporal resolution, as PAL has a lower frame rate than NTSC.
Converting PAL to NTSC
The converse situation applies to PAL to NTSC conversions. 576 lines of resolution are downconverted to 480 lines of resolution, and frames need to be inserted to go from the 25 frames per second of PAL to the 30 frames per second of NTSC. Once again, the resultant image is of less actual resolution than the original image, as information is discarded spatially and made up temporally.
Implications for Video Programming On DVD
The best format to record and play back video programming on DVD in is the format in which the programming was originally created. If it was videotaped in the NTSC format, then the NTSC DVD will be the version of choice. If it was videotaped in the PAL format, then the PAL DVD will be the version of choice.
Higher Definition Source Material
Complicating this issue is the fact that more and more programming is being created in higher definition video formats these days, and these high definition formats can usually be converted down to PAL or NTSC equally well, with both formats having their respective disadvantages.
So, Which Version Do I Choose?
As a general rule, video programming sourced from PAL-based countries is likely to look better in PAL, and video programming sourced from NTSC-based countries is likely to look better in NTSC, since these are the likely native formats that they have been created in.
Other Factors To Consider
If all of the above issues aren't enough to consider when deciding whether to purchase a PAL or an NTSC version of a particular title, there are several other factors which are also worth taking into consideration.
Compression Ratio
Previously, it has been established that a PAL DVD has 20% more resolution than an NTSC DVD. This does not necessarily translate into a superior image. The DVD format relies on a lossy video compression format (MPEG-2) to allow a reasonable length of programming to fit onto a single DVD. The longer the programming, the higher the compression ratio needs to be, and the more likely it is that visible compression artefacts will be present. If an additional 20% of resolution needs to be compressed, then this can potentially result in a lesser quality image if the programming is overcompressed. Fortunately, many PAL DVDs are being produced as dual layer discs, whereas their NTSC counterparts are being produced as single layer discs, thus providing the necessary room for both versions to look their best.
Censorship
There are times when programming can be censored for display in PAL countries and uncensored in NTSC countries. GoldenEye and Tomorrow Never Dies are specific examples of DVDs where the PAL versions of the DVDs have been censored in comparison to the uncensored NTSC versions. The converse also sometimes applies, as is the case with Eyes Wide Shut, the DVD of which was digitally censored in the USA but uncensored in Australia.
PAL's 4% Speed Up
Movies on PAL DVDs play back 4% faster than their NTSC counterparts. The great majority of people will never notice this, but for a small minority, this is an intolerable artefact. For more details on why this speed-up occurs, please refer to the bottom of this article.
NTSC's 3:2 Pulldown
Movies on NTSC DVDs play back at the correct speed, but they achieve this by utilizing a process called "3:2 pull-down". A detailed discussion of this process is beyond the scope of this article, but the net effect of this is that any image pan is not smooth, but takes place in a series of uneven steps, an artefact known as judder. As with PAL's 4% speed-up, the great majority of people will never notice this artefact, but for a small minority, this is intolerable. Personally, I find this artefact all but intolerable and find it very hard to watch a movie on an NTSC DVD because of it.
Extras
Often times, the extras on one version of a DVD are not found on another version. It is most disconcerting when you have purchased a DVD to find out that another version is available which has far more extras than the one that you have just paid good money for.
Remastering
Sometimes, a DVD will be produced from restored or remastered source elements in one region and from non-restored sources in another region.
Conclusions
- PAL is a higher resolution format for DVD than NTSC. All else being equal, a PAL DVD of a movie should look significantly better than the equivalent NTSC DVD.
- If a PAL version of a movie DVD is not 16x9 enhanced and the NTSC version is 16x9 enhanced, then the NTSC version will be the preferred version, all else being equal.
- For video-based material, it is generally better for the DVD to remain in the same format as the source material.
- Do your homework before purchasing a DVD! Check as many resources as you can in order to determine which version of a particular DVD is the most appropriate one to purchase.
PAL's 4% Speedup
Have you ever watched a movie on TV or VHS or DVD and enjoyed the music so much that you went and bought the soundtrack CD? Have you then noticed that the soundtrack CD sounds a bit different to the movie?
Have you ever watched a movie on TV or VHS or DVD and then found out that the US version is longer than the Australian version?
Have you ever compared the specifications of a DVD in Australia with a DVD in the US and noticed that the US version runs longer than the Australian version?
Are we being ripped off? Are our movies censored?
The short answer is no. It is true that the running times of movies on TV, VHS and DVD are shorter than their theatrical running times, but this is not because of censorship. It is because of the way in which movies are transferred to video.
24 Frames Per Second
Movies are projected at 24 frames per second. 24 full images are projected off the film onto the screen every second. This is a world wide standard. This is all well and good, but a problem arises when we want to transfer a movie to video.
50 Fields Per Second
The PAL TV system shows images at 50 fields per second. One half of an image is displayed and then the other half of the image is displayed. The nett result of this is that 25 full images are shown per second.
24 Into 25 Doesn't Go
How do you take a film which has 24 full images per second and display this on a TV which shows 25 full images per second? There are two ways you can do this.
The first way, which is not commonly used, is to show 24 images from the film on the TV in sequence and then repeat the 24th film image. This fits film's 24 images into the 25 images needed by TV. This approach has one major drawback, which is that once every second there is a noticeable pause (judder) in the video because of the extra inserted image. Most people find such an artefact extremely objectionable.
The second way, which is commonly used, is to show 25 images from the film every second. This fits the film nicely into the TV format of 25 full frames per second, but the nett result is that 25 frames from the film are being shown in the same time as 24 frames were supposed to have been shown. This means that the film is being shown 4% faster than it was originally intended to be shown. This approach also has a series of disadvantages, but these are less objectionable than the judder introduced with the first-mentioned approach.
Effects of the 4% Speedup
The most obvious effect of this 4% speedup is that the film runs for 4% less time. Take as an example the recent movie The Mask of Zorro. The theatrical running time for this movie was 136 minutes according to the Internet Movie Database. The running time of this movie on Region 4 DVD is 132 minutes, 4% less.
A less obvious effect of this 4% speedup is that the audio for the film is both 4% faster and 4% higher in pitch. In musical terms, this equates to a rise in pitch of a little under one semitone.
Another less obvious effect of this 4% speedup is that the on-screen action occurs 4% faster.
For the majority of us, this 4% speedup is of no consequence, and is something that we are blissfully unaware of. For a small minority of movie and music buffs, the 4% speedup is objectionable.
What Can Be Done About It?
There is very little that can be done about this issue at present.
One possible partial solution is for the movie's soundtrack to be digitally processed so that it plays back at the correct pitch on video. This can be done either whilst the movie is being mastered for video or whilst the movie is playing back. This is very rarely done in practice, as it does not solve the problem of the movie and the music still playing back 4% too fast, even if it is now at the correct audio pitch.
The advent of DVD and digital projection devices has opened up another possibility to solve this problem. In theory, a DVD player could be constructed which plays back PAL movies at the correct speed and hence at the correct pitch. At present, the only devices capable of doing this are DVD-ROM drives. Such a device could be mated with a display device that is capable of displaying images at 24 frames per second. It is likely that in the future such solutions to this problem will become more readily accessible, particularly with the advent of HDTV.
Does It Really Matter?
For most of us, the answer is no. However, it is important to be aware of this issue so as to more fully appreciate the movie watching experience, and to explain some apparent anomalies in movie running times that may have troubled you in the past.
Feel free to ask me anything, when it comes to PAL NTSC, and region coding information I am a very reliable source of information, as you may have already figured it out by reading this article.
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