[StooMonster]

Assumptions:
1. played on good prog-scan DVD, with 3:2 and 2:2 pull-down, etc.
2. source is film, not video (either NTSC or PAL)
3. PAL discs mastered from film source, and not just transfered from NTSC discs

Which has better picture?

Accepting that NTSC (almost) matches film's 24 frame per seconds (fps), whereas PAL plays back at 25fps.

PAL has higher resolution of 720x576 pixels, versus NTSC's 720x480.

But, what about the bit-rate? Is this lower on PAL discs to fit in the extra line resolution?

Does anyone have a DVD player that displays bit-rates, and if so, have access to the same film in both PAL and NTSC format? If so, could tell me what the comparible bit-rates are?

Or if anyone knows the answer already, can you provide examples of the bit-rates?

Down to bit-rates?

If the bit-rate is lower in PAL, begs the question: is it better to have higher resolution or greater bit rate?

If the bit-rate is the same in PAL and NTSC, then it seems a no brainer that PAL has better picture.

What's the answer?

StooMonster

If only this question had an easy answer!

Theoretical resolution of PAL and NTSC may well indicate that a PAL transfer should be better, but that doesn't really reflect what you see on a DVD - the problem being the MPEG compression used.

Unfortunatley bit rate doesn't give a good indication of quality either as the bit rate may be being used to compress artefacts and noise rather than the actual picture you want to see. As an example a 'noisy' film will use anything up to 30% of the bit rate just encoding the noise!

The difference between R1 and R2 quality is down to the differences in the way the film is telecined (scanned from celluloid to video), noise reduced, encoded etc.. rather than an inherent PAL versus NTSC difference.

With all other things being equal ( and yes, you can generate an NTSC and PAL disk from identical masters if wanted) then you should choose whether the 4% speed up of PAL films is more or less objectionable than the 3:2 stutter of NTSC.

Hope this is of use,

Richard Ansell

Technical Applications Group
Snell & Wilcox

(Currently in Hollywood)

[StooMonster]

From my experince it varies on a per disc basis.

I guess no generalisation of "which is better" is possible.

Change of question...

Anyone know of a web-site that compares audio-visual quality of different region DVDs?

I've seen http://www.dvdcompare.org.uk/compari...omparisons.php, but they rate based on cuts made and extras available.

StooMonster

Originally posted by StooMonster
Assumptions:
1. played on good prog-scan DVD, with 3:2 and 2:2 pull-down, etc.
2. source is film, not video (either NTSC or PAL)
3. PAL discs mastered from film source, and not just transfered from NTSC discs

Which has better picture?

Both

Accepting that NTSC (almost) matches film's 24 frame per seconds (fps), whereas PAL plays back at 25fps.

Well .. sort of! Remember the actual scan rate of PAL is 25 frames per seconds as you said, but NTSC is 30 frames per second which does not match the 24 of film. The 3:2 pulldown as richard says is what is needed to get the 24 to 30.

PAL has higher resolution of 720x576 pixels, versus NTSC's 720x480.

But, what about the bit-rate? Is this lower on PAL discs to fit in the extra line resolution?

Actually assuming exactly the same encoding (beside colour system of course!), the data required is identical!

For 1 second PAL : 720x576x25 = 10368000 "blocks"
For 1 second NTSC : 720x480x30 = 10368000 "blocks"

Does anyone have a DVD player that displays bit-rates, and if so, have access to the same film in both PAL and NTSC format? If so, could tell me what the comparible bit-rates are?

I think some players do, but this is assuming you can find a film on PAL and NTSC, mastered by the same studios, using the same encoding equipment in say the UK and US, which is highly unlikely!

Or if anyone knows the answer already, can you provide examples of the bit-rates?

Down to bit-rates?

If the bit-rate is lower in PAL, begs the question: is it better to have higher resolution or greater bit rate?

If the bit-rate is the same in PAL and NTSC, then it seems a no brainer that PAL has better picture.

Not quite...As I said, if encoded exactly the same, it's then down to the DVD player and display. Remember although PAL has the higher resolution, NTSC has the higher frame rate. I agree, it should have the better picture, 'cos extra resolution is more tangible than a slightly higher refresh. And as richard mentioned, the 25 frames per second version can be made from the film master by 4% speedup - which leaves the point of post-processing the audio to get back to the same pitch - which I don't think all encoders do! - But in reality (leaving cost, censorship and extra feature aside) the mastering houses in the US are probably bigger and better equipped than the ones in the UK, (here I'm guessing, which I don't like to do ) thus making the NTSC version "better". This is so difficult to test, given all the factors involved.

Also take into account that not many studios will pay for the expense of recutting for the censored UK market when re-mastering a DVD. Some usually digs out the best print they can find cut to UK edit and telecines that - which can be atrocious - Memphis Belle DVD anyone?

[RAMiAM]

Interesting topic and one that has been debated for a while, especially on AVS.

Going back to bit rates I use to have a Sony S7700 which was able to display bit rates in "real time".
I did do some comparison between the same titles for Region1 and Region2 and did notice with about 70% of titles tested there was a slight decrease in bit rate for the same sequences compared to it's Region1 cousin.

What I put the reduction of BitRate down to was the fact that <<possibly>> most Region2 DVDs have to accomodate the many extra languages and subtitles involved (subtitles having considerably less of an impact), thus either remove certain extras or sound formats (usually DTS) and/or reduce the bit rate.
This is just my theory and not really based on any hard and fast rules.

Also regarding the comparison of bit rate for:
For 1 second PAL : 720x576x25 = 10368000 "blocks"
For 1 second NTSC : 720x480x30 = 10368000 "blocks"

If one field or frame is very similar to the next field or frame, wouldn't the required number of block for the second field or frame be considerably less than the first - based on the principle of MPEG?
If this theory has some ground then surely the extra 96 lines required for PAL would increase the actual size per block compared to NTSC, resulting in a possible bit-rate reduction in order to fit the content to the DVD.

I have also heard many a time that production of anything other than region 1 is secondary in the minds of Hollywood. Usually resulting in a less than perfect reproduction.
I've even seen radically different title and menu sequences between the two regions - How mad is that

I'll stop rambling soon
On another note, has anyone noticed that DVD rentals from places such as blockbusters appear to have quality less than that of a retail copy and some without extras to boot.
Actually thinking about it the quality could be down to poor handling of the DVD from other customers, but not to have the same extras etc. as the retail is scandalous. More profit for someone.

The END I promise.
RAM

[StooMonster]

Originally posted by Xeonic
Well .. sort of! Remember the actual scan rate of PAL is 25 frames per seconds as you said, but NTSC is 30 frames per second which does not match the 24 of film. The 3:2 pulldown as richard says is what is needed to get the 24 to 30.

Actually assuming exactly the same encoding (beside colour system of course!), the data required is identical!

For 1 second PAL : 720x576x25 = 10368000 "blocks"
For 1 second NTSC : 720x480x30 = 10368000 "blocks"

See I mentioned FILM in my assumptions at the top? This is because film is encoded at 24fps on NTSC, it is just output at 30fps; which is why you have 3:2 pull-down to convert it back to 24fps.

Whereas PAL uses same 24fps, but displays them at 25fps; hence 4% speed increase mentioned by Richard Ansell above.

This article will explain in detail http://www.hometheaterhifi.com/volum...e-10-2000.html

Therefore your example is wrong, because your assumptions about frames are incorrect (NTSC is 24fps for film, not 30fps). What would be more correct is...
For 1 frame PAL : 720x576 = 414720 pixels
For 1 frame NTSC : 720x480 = 345600 pixels

Sigh. I tired to be specific in my assumptions. Like including prog-scan, etc. etc. etc. ...

StooMonster

NTSC will generally have a higher bit rate since there is more motion between frames (by virtue of their being more of them) in the NTSC stream than the PAL one. Uncompressed video is about the same, but MPEG2 compression is more efficient at lower frame rates.
Of course at 24fps with 3:2 pulldown, there should be less data to work with.

[Spligsey]

Richard A.

(Currently in Hollywood)

Good for you

Adzman

Originally posted by StooMonster
See I mentioned FILM in my assumptions at the top? This is because film is encoded at 24fps on NTSC, it is just output at 30fps; which is why you have 3:2 pull-down to convert it back to 24fps.

Yes I know you mentioned film - I'm not being pedantic, but don't you mean convert from 24fps to 30fps?? It doesn't matter how the feature is encoded, 30fps must come out.

Whereas PAL uses same 24fps, but displays them at 25fps; hence 4% speed increase mentioned by Richard Ansell above.

Yes, I agreed on that.

This article will explain in detail http://www.hometheaterhifi.com/volum...e-10-2000.html

Therefore your example is wrong, because your assumptions about frames are incorrect (NTSC is 24fps for film, not 30fps). What would be more correct is...
For 1 frame PAL : 720x576 = 414720 pixels
For 1 frame NTSC : 720x480 = 345600 pixels

The article is a good one, one of the best I've seen in explaining this complex area. In fact it also shows that a 24fps film source can be encoded, as in example 2 as 10 interlaced MPEG2 "pictures". This means my example of 720x480x30 can occur, for that encoding method. And yes, I see that method 1, 4 prog pictures is more common.

Sigh. I tired to be specific in my assumptions. Like including prog-scan, etc. etc. etc. ...

Agreed. But I only tried to provide a bit more info

[StooMonster]

Originally posted by EvilMudge
NTSC will generally have a higher bit rate since there is more motion between frames (by virtue of their being more of them) in the NTSC stream than the PAL one. Uncompressed video is about the same, but MPEG2 compression is more efficient at lower frame rates.
Of course at 24fps with 3:2 pulldown, there should be less data to work with.

With NTSC film there are 24fps not 30fps, but 3:2 pull-down displays them at 29.97fps.

Thanks RAMiAM, you've got the actual data! So there is a slight difference in bit-rates...

Considering that the resolution difference between PAL a NTSC is 20%, wouldn't it imply that if difference in bit-raite is <20% you are getting a better picture with PAL.

Although Richard Ansell (of the excellent Snell & Wilcox) says it's down to how the film is telecined; and I guess his professional opinion is the most informative.

I still think it varies on a per disc basis, in line with what Richard says, and I guess no generalisation of "which is better" is possible.

Although, I am interested ... if it is possible to generalise (contradicting myself), is better to have higher resolution or higher bit-rate?

StooMonster

Originally posted by Xeonic
Agreed. But I only tried to provide a bit more info

Only joking.

[RAMiAM]

Originally posted by StooMonster
Thanks RAMiAM, you've got the actual data! So there is a slight difference in bit-rates...

Although, I am interested ... if it is possible to generalise (contradicting myself), is better to have higher resolution or higher bit-rate?

I'm not too sure how to quantify "slight" but what I noticed were more artifacts especially in darker scenes.
I should note that this was though a CRT projector and not viewed on a normal rear projector CRT television.

Personally I can't see how having a higher resolution and lower bit rate is better than having a slightly lower resolution and higher bit rate.
(Is a higher resolution and lower bit rate a contradiction of terms? :confused)

IMHO I tend to think that Region 1 and higher bit rate is king. Using a high quality display, I want to get as close to the original cinematic experience as possible. Which seeing as 95% of my viewing are holywood productions I have to go Region 1.
I also don't like the idea of PAL transfers being sped up 4%. Although one doesn't really notice, except in some equipment where lip sync can be an issue.
I want to get back to the original 24fps or multiples there of i.e., using 48Hz or 72Hz.

Another point that may have some bearing is that a lot of Standard Definition plasmas have 480 rows which match perfectly with NTSC DVD.
Should also note that Higher Definition panels usually have 768 which is 480 x1.6 and 576 x 1.3' - either way it's not a perfect fit.

Also when you look at scalers they tend to be geared around 480 lines - i.e., trebaling is 720, quadrupling is 960, HD is 720, etc.

I think hollywood and Region 1 are always going to be the dominant players, whether I like or agree with this or not is a different subject. But if I want to get the best out of my equipment and get as close to the original experience as possible I have to go Region 1.

Again he rambles - sorry!

RAM.

[StooMonster]

Bit-rate versus resolution

RAMiAM said
Going back to bit rates I use to have a Sony S7700 which was able to display bit rates in "real time".
I did do some comparison between the same titles for Region1 and Region2 and did notice with about 70% of titles tested there was a slight decrease in bit rate for the same sequences compared to it's Region1 cousin.

Be interesting to know what the bit-rate number difference is, if it is "slight difference".

Because 20% vertical resolution difference is quite alot, i.e. 20% more picture detail.

Point is, if difference in bit-rate is less than 20% then doesn't it follow that you are getting more information for your picture.

I was thinking about bit-rate versus resolution earlier, another example is web-streaming. Is it better to have a small window with less artifacts or a larger window with more artifacts.

I guess that as Richard Ansell said above, in the real world rather than talking hyperthetical numbers, the choice is 4% speed up versus 3:2 pull-down. Which ever is your own preference.

Plasma physical resolution
If scaling were an issue, then panels would be 720 pixels wide, or multiples of 720; but 720 doesn't fit into 852, 1024, 1280 or 1366 either (just like 480 or 576 doesn't fit into 768) -- it's not a "perfect fit" multiple either.

I don't see how up-scaling can made a difference in one dimension and not another.

Only problem I can see with scaling is if you are down-scaling, and removing picture information (e.g. by displaying PAL's 576 picture on 480 rows and losing 1-in-5 lines).

HDTV resolutions do not relate to NTSC's 480 rows, 720 or 1080 are not mutliples of 480. Different standard all together AFAIK.

If one were to use a scaler to display DVDs in 1080p would that be a problem? I don't believe it is. I don't think up-scaling (be it horizontal only, or both dimensions) is an issue at all.

Enough for today from me
It's each to their own preference. But I still recon it's on a disc by disc basis; and not generalised in that all NTSC are the best, and neither are PAL.

StooMonster

[LV426]

Oh dear. Another PAL vs NTSC thread.

Once and for all NTSC Is definitely better. It just is.

Somebody appears to have deleted my other post, placed at exactly the same time as this one, which said:

Oh dear. Another PAL vs NTSC thread.

Once and for all PAL Is definitely better. It just is.

My attempt at humour has clearly been misintepreted as a duplicate post by a moderator or someone??)

LOL nigel, that's class

Actually I think it's summed up something like

"Your disc picture quality may vary..."

[Gordon @ Convergent AV]

So...where does Secam fit in then?

Gordon

Between the PAL video stream and the RGB - Svideo/Composite converter.

What about 'is the NTSC 3.58 or 4.4 Mhz?'

[LV426]

Originally posted by Gordon, Convergent-AV
So...where does Secam fit in then?

IIRC, it fits somewhere in France (and possibly Russia) and so can safely be ignored.

[YellowCows]

Not that it makes that much difference, I just thought to clarify, re:

I think some players do, but this is assuming you can find a film on PAL and NTSC, mastered by the same studios, using the same encoding equipment in say the UK and US, which is highly unlikely!

that, in fact, most (if not all) studios produce PAL & NTSC masters at the same time, in Hollywood. Actual production (pressing) of discs, as well as addition of region-specific data such as subtitles is handled at the individual region's distribution end. This is the standard policy of all the majors - Warner, Columbia/Tristar, Disney, Universal, Paramount - and most of the 'minors' as well. UK-based production houses, such as the BBC, for instance, also produce NTSC & PAL masters at the same time. This is irrespective of when the discs are actually released in any particular region. It just makes good business sense, and saves costs (as well as allowing them to monitor the 'product' quality across markets). BTW, this is the same for music mastering. Everyone knows that CD's are mastered ONCE, and copies of said master are sent to pressing plants around the world (along with CD cover artwork) to manufacture the discs for the end market.

The studios, not to mention pro-active film directors, would not expose themselves to the added costs of remastering films, while relinquishing quality control to overseas branches.

Makes sense, really.

Cheers,

Moory

Moory,

Having just got back from discussing DVD mastering with the facilities that do this in Hollywood (Well, Burbank & Culver City) I can say that while some major studios do try to do a single master for worldwide release it is certainly not a blanket policy (sadly)

The problem is that many titles are actually distributed by different companies in different territories, so the European distributor does not have access to the original 'studio' transfer.


Actually Hollywood does try to have a 'master' transfer for PAL and NTSC markets but it is never a single print - there are usually 6 master versions of the film;

1- NTSC Letterbox
2- NTSC Full Frame
3- NTSC Anamorphic
4- PAL Letterbox
5- PAL Full Frame
6- PAL Anamorphic

If only life were a little easier!

Richard,

That's interesting to know, and is what I had imagined! If we use the "multiple master" scenario, I suppose it's back down to how good the actual transfer for the particular region is!

I think sm asked this as well so I've give it a bump - are there any sites can compare say R1/R2 versions of a movie from the picture quality/bitrate perspective? If not maybe somebody should start one

[kevenh]

Bjork's Volumen II is NTSC on one side and PAL on the other...
Would that help us compare the two?

[YellowCows]

As always, you are very knowledgeable, RichardA.

However, I wasn't implying that there was only ONE print of every master, only that the majors retain control over the mastering of PAL as well as NTSC, and produce these masters at the same time during the telecine process.

Production and distribution of the discs is handled by the regional branch/distributor.

Cheers,

Moory

[StooMonster]

Would highest quality picture be equal to largest MPEG2 video file on DVD?

e.g. if one region master had 6GB file and another region was 6.5GB; would that not imply the 6.5GB file had more picture information in it?

StooMonster

Stoo,

Sadly even file size doesn't help! A poor quality MPEG compression at high bitrate (and therefore a large file size) will look worse than a good compression at a lower bitrate.

The pro way to determine picture quality is a little more complicated, and without going through the entire structure of M-PEG! -

GOP (Group Of Pictures) structure - The number of frames between I frames, and the number of B and P frames in a GOP can give an indication, a short GOP uses less difference on difference on difference type frames (The B and P frames) and more 'absolute' I frames, whereas a long GOP structure uses less bitrate but the image gets progressively worse the more B and P frames used.

Inserting I frames at cut points - A poor compression will not adapt the GOP structure to take into account a scene change or cut, so the frames across the cut do not have the bitrate to accurately represent the frames. A 'proper' transfer will truncate the previous GOP and start wih a new I frame at the cut point (The Hong Kong Legends titles are ones that do all this correctly by the way!)

There are M-PEG quality measurement tools available, most being double ended (i.e. you have to put a known signal into the compression system to get a valid test at the other end) but there are systems like our Mosalina which can measure an M-PEG file and generate a quality value (we call it PAR, and it's a value a bit like a signal to noise measurement)

Without those kinds of tools the only way to judge the quality of a DVD transfer is to see it on a truly transparent display!

I have heard of comparisson sites, but I don't have any addresses - someone must have some tips out there!

Hope this all helps!

[NicolasB]

are there any sites can compare say R1/R2 versions of a movie from the picture quality/bitrate perspective?

You could try http://www.michaeldvd.com.au/ although, being an Australian site, it compares Region 4 with Region 1. But video and audio quality are (I believe) usually similar between R4 and R2. For differences in content between R1, R2 and R4 try www.dvdcompare.org.uk .

Nicolas

Thanks for that, I'll take a look! I know dvdcompare, that's really useful for content comparison.

The problem with R1/R2 seem to be if you compare on price,features and sometimes censorship, before picture quality, R1 wins/draws on most releases

[StooMonster]

Originally posted by RichardA
...but there are systems like our Mosalina which can measure an M-PEG file and generate a quality value (we call it PAR, and it's a value a bit like a signal to noise measurement)

So can you test all the DVD releases in each format and tell us which is best transfer then!

Richard
Very informative posts, particularly todays -- it's been a long time since I thought about how MPEG works, stirred the old grey matter there.

Comparison sites for PQ: http://www.dvdfever.co.uk/ used to compare R1 vs R2 etc for picture and sound quality, but don't appear to anymore. I remember (years ago) they had an excellent comparison of Alien R1 vs R2, which R2 won the PQ and sound.

StooMonster

Originally posted by StooMonster
So can you test all the DVD releases in each format and tell us which is best transfer then!

StooMonster

Funny you should suggest that.......

Watch this space

[StooMonster]

What pixel resolution are films edited, and mastered, at before transfer back to film for cinema/theater projection.

Are "digital transfers" of a DVD like Star Wars, Monster Inc, etc a render at target resolution and not telecined from film print?

StooMonster