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| 6th Sep 2016, 2:10 AM | #1 REPORT | |
 | albert oh well, la di da Member since Aug 2013 1345 Points | I am writing these notes as a reference if anybody has the usual question on why Region 1 DVDs appear to have longer versions of a film in comparison to Region 2 DVDs. (And I'm sure this question will pop up if it has not already done so). The short answer is DVD encoding formats. Region 1 DVDs will pretty much always be in the NTSC format, while Region 2 DVD will usually be in the PAL format, and the PAL format runs a film slightly faster than expected. So for example a film which is exactly 90 minutes long will run for 86 minutes and 24 seconds on a PAL format DVD, whereas on a NTSC format DVD it will run for 90 minutes and 5.4 seconds approximately. Now the long and boring answer. Actually if you want the correct long answer then wikipedia will have the details, but it is a massively complicated thing so I will again summarize. So you may be wondering why half the world uses NTSC and some countries use PAL (or other TV formats) and why did the division come anyway? Well its all down to your AC electricity power supply, for instance in Britain we have a 50 Hz supply and in USA it is 60Hz and many electrical device were designed to rely on the AC cycle of the electrical current in order to function correctly, like a television set. An old PAL television in Britain refreshes its image 25 times a second (its actually 50 interlaced times a second), and in America an old NTSC television refreshes its image roughly 30 times a second (60 interlaced) thus matching the relevant AC cycles. Modern TVs will probably use a transformer to convert an AC power supply into DC and have internal electronic components which handle TV signal formats without relying on cycles on the AC power supply to get timings. But because of the history of power supplies we have the NTSC vs PAL situation on DVDs. Now old films. OK there are lots of different formats to old film, but what we are really interested in is the frame rate and for most 35mm film the frame rate was normally 24 frames per second (other size film and different frame rates exist). So the most straightforward conversion for a film transfer to DVD is to match frame to frame on PAL, [thats the simplified technical answer]. The maths for a film which is exactly 90 minutes goes 90minutes x 60seconds x 24frames = 129600 frames. Then into PAL its 129600frames / 25frames / 60seconds = 86minutes and 24seconds, so it looks like the film has lost 3minutes and 36seconds but in reality there is nothing cut at all. NTSC is more problematic as we cannot match film frame to NTSC frame without it looking noticeably speeded up. So the conversion is trickier, but although NTSC is approx 30 frames per second it is actually 60 interlaced (half) frames per second, and 60 divided by 2.5 gives 24, matching the film's frame rate, so conversion is possible. The downside to this conversion is that the interlaced crossover between frames can result in noticeable defects where any motion is happening on screen. I would like to report that a 35mm film converted to NTSC format runs for exactly the same amount of time, but I suspect that this is not the case. People do insist on this 'frames per second' measurement for film but NTSC does not compute too well and is commonly badly quoted as approximately 29.97 frames per second when it would be better described as 30 frames per 1.001 seconds. So the maths for a film which is exactly 90 minutes should include an adjustment where every second is multiplied by 1.001, hence 90minutes x 60seconds (/ 1) = 5400seconds. Then into NTSC its (5400seconds x 1.001) / 60seconds = 90 minutes and 5.4 seconds, which may inadvertently seem like there are a few seconds of extra footage but in reality there is not. Anyone still awake? Oh and by the way, the speeded up PAL format is the reason why lots of musicians prefer their music videos to be in NTSC format, cos the pitch will all be wrong in PAL. Edited by albert on 6th Sep 2016, 2:16 AM |
| 6th Sep 2016, 7:56 AM | #2 REPORT | |
 | TopPopper Member since Mar 2013 2612 Points | I get it. There has to be a 'flash' on every frame on the film. UK flashes 25 times a second, so gets through 25 film frames per second. US flashes 30 times so gets through 30 frames in the same time. |
| 6th Sep 2016, 8:16 AM | #3 REPORT | |
| TopPopper Member since Mar 2013 2612 Points | Actually, I don't get it at all. NTSC = 30 times a second = faster play/shorter film. |
| 6th Sep 2016, 1:09 PM | #4 REPORT | |
| albert oh well, la di da Member since Aug 2013 1345 Points | NTSC conversions need some techie stuff with interlacing for the film to play at the right speed. This wikipedia article has all the techie info on interlacing. Effectively the interlacing doubles the refresh rate in NTSC but the display is fragmented ie slicing/removing half the information per frame, and 30 frames then becomes 60 half frames. During the film capture and conversion a similar techie slicing process takes place so 24 frames become 48 sliced half frames. A bit more techie stuff is then applied so every 4 interlaced half frames of the film get mapped/stretched onto 5 interlaced half frames in NTSC. There are several methods of achieving it - some methods give good results which are not too noticeable but other methods give clunky results which are painfully noticeable. The bad results with interlacing are often referred to as 'combing' problems. One of the infuriating things with film companies is that the mastering for DVDs is often poorly handled, so we occasionally get a PAL format DVD which is obviously a conversion from a NTSC digital source and includes all the combing problems therein. Edited by albert on 6th Sep 2016, 2:57 PM |
| 6th Sep 2016, 1:20 PM | #5 REPORT | |
 | zabadak Caddacack oh da ca-caddacack, shy shy skagellack Member since Jun 2010 4148 Points | Blimey, Alb - need a lie-down?  |
| 9th Sep 2016, 11:08 AM | #6 REPORT | |
 | George Slv ● This comment marked as Spam. Please press Not Spam Member since Aug 2012 498 Points | PAL does not play faster. Only shorter. Drops 2 fields (half-frames) per 50 in order to be evenly divisible by 24. The 48 fields go at the correct speed in themselves. So the PAL difference is exactly 4%. Use a 100 minute movie as example. There's more to it, especially when converting analog PAL to NTSC. I haven't thought it all out. |
| 9th Sep 2016, 7:30 PM | #7 REPORT | |
| albert oh well, la di da Member since Aug 2013 1345 Points | |
| 9th Sep 2016, 11:17 PM | #8 REPORT | |
| George Slv ● This comment marked as Spam. Please press Not Spam Member since Aug 2012 498 Points | It's starting to come together in my brain. There appear to be two parts to this. One is converting 24 fps film to 25fps PAL video. The second is converting between analog NTSC 30fps and PAL 25fps. (I might need more understanding of this second part). Both result in exactly 4% difference. But when doing computer conversion between these fps the converter has no-o-o-o pro-o-o-o-blem maintaining the length. Edited by George Slv on 10th Sep 2016, 12:21 AM |
| 9th Sep 2016, 11:45 PM | #9 REPORT | |
| albert oh well, la di da Member since Aug 2013 1345 Points | Yeah sorry, I wasn't intending the thread to sway into the techie stuff as much as it is doing. I have used Adobe's Premier Pro from their Master's Collection and that did have many PAL <> NTSC <> DV conversion options which retained timings, audio etc - there was a bewildering amount of variants available - too much to cope with, in fact. No, the reason why I made thread was to try to prevent mis-information about cuts in films that blight DVD reviews on sites such as Amazon, usually by angry people exclaiming "It said it was uncut but Region 2 DVD is cut by 3 minutes!!!!! Region 1 DVD is longer !!!! I want my money back !!!" (or words to that effect). And I know that it will appear in reviews here eventually, also note that it only applies to film transfers onto DVD, Blu-ray timings seem to be OK (check those DVD/Blu-ray dual format editions). Examples (96m on PAL DVD, 100m on NTSC DVD): [image]762904[/image] [image]830345[/image] Regarding whether a film has definitely been cut due to censorship, the Movie Censorship website is a good place to check first. Edited by albert on 10th Sep 2016, 12:24 AM |
| 16th Sep 2016, 10:25 PM | #10 REPORT | |
 | Pridesale Member since Mar 2013 794 Points | Some older films were cut from VHS to DVD to fit the DVD length maxima. |
| 14th Mar 2021, 2:50 PM | #11 REPORT | |
 | Juke Jules SUBS Tell me he's lazy, tell me he's slow Member since Jan 2011 4138 Points Moderator | I'll take your word for it Albert, but how do you know the 'Region' for the DVD you have in your hand? I don't add many but I have just added one* and I can see nothing on the disc or case about Regions. Fortunately I found one on Music Magpie which always gives the region *Will scan the insert card later |
| 15th Mar 2021, 5:30 PM | #12 REPORT | |
| zamla_71 ask little, receive alot! Member since Jul 2020 3072 Points |
Juke Jules wrote:
I'll take your word for it Albert, but how do you know the 'Region' for the DVD you have in your hand?
I don't add many but I have just added one* and I can see nothing on the disc or case about Regions. Fortunately I found one on Music Magpie which always gives the region *Will scan the insert card later Are you sure there isn't a square with a globe and a digit in it on the back of the cover? |
| 15th Mar 2021, 7:02 PM | #13 REPORT | |
| Juke Jules SUBS Tell me he's lazy, tell me he's slow Member since Jan 2011 4138 Points Moderator | There's a square(-ish) bit with three numerals which I can't relate to the 'region' options |
| 15th Mar 2021, 11:27 PM | #14 REPORT | |
| zamla_71 ask little, receive alot! Member since Jul 2020 3072 Points | Yes, you found it  The Region for your DVD is 2, 4, 5. And it is PAL. So here it should be entered as Multi-Region. |
| 19th Mar 2021, 12:08 AM | #15 REPORT | |
| Juke Jules SUBS Tell me he's lazy, tell me he's slow Member since Jan 2011 4138 Points Moderator | Ah - everything explained! Thanks Zamla, have edited my entry |
| 21st Apr 2021, 8:28 PM | #16 REPORT | |
| albert oh well, la di da Member since Aug 2013 1345 Points | On my old mac laptop (which has a DVD drive) they included software to play DVDs and within the menus is an option to view disc specifics - somewhat unsurprisingly it reveals that many discs have more region codes than what is printed on the slip, typical combinations being 2 & 4 for PAL format or 1234567 (ie all-regions, the later numbers reserved for government use, I think). The software also reveals if the disc is encoded in PAL format or NTSC, and some naughty companies such as Eureka now seem to use the horrible NTSC format for all of their DVD discs. |
| 22nd Apr 2021, 12:21 AM | #17 REPORT | |
 | Twistin Member since Jan 2012 2056 Points | NTSC works fine for me... |
| 22nd Apr 2021, 1:25 AM | #18 REPORT | |
| zamla_71 ask little, receive alot! Member since Jul 2020 3072 Points |
albert wrote:
On my old mac laptop (which has a DVD drive) they included software to play DVDs and within the menus is an option to view disc specifics - somewhat unsurprisingly it reveals that many discs have more region codes than what is printed on the slip, typical combinations being 2 & 4 for PAL format or 1234567 (ie all-regions, the later numbers reserved for government use, I think).
The software also reveals if the disc is encoded in PAL format or NTSC, and some naughty companies such as Eureka now seem to use the horrible NTSC format for all of their DVD discs. Correct! Many disc have more Regions besides the ones printed on the release. But on this site that doesn't really matter since we only have the option to choose one region or Multi-Region for each release. So the easiest thing is to list the region printed on the release. Same goes for PAL / NTSC / SECAM. no option at all to choose from!!!!! Yes, the Notes field comes in handy here, but who really cares to scroll down and look at them? Better to add such thing in the comments field, it seems. |
| 22nd Apr 2021, 4:07 PM | #19 REPORT | |
 | Quad5point1 SUBS ● Member since Jul 2012 10621 Points |
George Slv wrote:
It's starting to come together in my brain. There appear to be two parts to this. One is converting 24 fps film to 25fps PAL video. The second is converting between analog NTSC 30fps and PAL 25fps. (I might need more understanding of this second part). Both result in exactly 4% difference.
But when doing computer conversion between these fps the converter has no-o-o-o pro-o-o-o-blem maintaining the length. |
| 22nd Apr 2021, 4:07 PM | #20 REPORT | |
| Quad5point1 SUBS ● Member since Jul 2012 10621 Points |
albert wrote:
What an informative and interesting clip. |
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