24fps not a BD standard? [Archive]

dansrfe

14th October 2010, 16:31

My question is, why is 24fps not considered a BD "standard". If all film is shot at 24fps, the BluRay format supports 24fps, some TV's have a refresh rate that is a multiple of 24fps, and it is being shown the way it was intended to be, then why? As per my understanding, 24000/1001 (23.976) is only used to hard/soft telecine in NTSC DVD's, so why is it the standard for BD's? One of the reasons I ask this is because whenever I am extracting or demuxing something in eac3to, I always see the "This is not a standard fps" warning whenever I use a 24p source.

All input welcome. :)

poisondeathray

14th October 2010, 16:35

both 24.0 and 24000/1001 are compatible with blu-ray standards

dansrfe

14th October 2010, 16:38

If 24.0 compatible, then why is it not the norm?

poisondeathray

14th October 2010, 16:43

I don't know. I'm guessing probably because studio's don't want to make 2 versions from the same master.

24000/1001 is necessary for NTSC DVD , so their intermediate is probably 24000/1001

TinTime

14th October 2010, 17:08

Maybe some equipment in the traditional NTSC world throws a wobbly when fed with exactly 24p/60i.

I believe 24p Blu-rays are only found in PAL territories.

Ghitulescu

14th October 2010, 17:15

I don't know. I'm guessing probably because studio's don't want to make 2 versions from the same master.
24000/1001 is necessary for NTSC DVD , so their intermediate is probably 24000/1001

I believe 24p Blu-rays are only found in PAL territories.

Aren't the "PAL territories" versions made from the same master?

kieranrk

14th October 2010, 17:18

Maybe some equipment in the traditional NTSC world throws a wobbly when fed with exactly 24p/60i.

Some NTSC HDTVs don't support 24p properly.

TinTime

14th October 2010, 17:57

Aren't the "PAL territories" versions made from the same master?

That makes sense to me. I'd have thought that you'd start from a 24fps master and then slow it down for NTSC and speed it up for PAL (for DVDs). Then for Blu-ray you could just leave it alone. Maybe intermediate "NTSC" masters and "PAL" masters are produced separately (as poisondeathray said). Then the "NTSC" master is used to produce NTSC DVDs and most Blu-rays, and the "PAL" master is used for PAL DVDs and the occasional movie Blu-ray that's inexplicably encoded at 50i for Europe.

Some NTSC HDTVs don't support 24p properly.

This seems crazy although entirely believable. The unwillingness to support 50i in NTSC land is equally ridiculous.

yetanotherid

14th October 2010, 19:45

I believe 24p Blu-rays are only found in PAL territories.

It's only fair, we've had to put up with sped-up 25fps video forever. And we've never been given a discount because it only takes us 110 minutes to watch a 120 minute movie (or thereabouts). :(

TinTime

14th October 2010, 20:02

It's only fair, we've had to put up with sped-up 25fps video forever. And we've never been given a discount because it only takes us 110 minutes to watch a 120 minute movie (or thereabouts). :(

If it's a bad film that can be a blessing :)

Even in the brave new world of HD we still have to put up with problems though:

Movies sometimes still sped up to 25fps
Native 25p or 50i material changed to 24p or 60i

SeeMoreDigital

14th October 2010, 22:20

It's only fair, we've had to put up with sped-up 25fps video forever. And we've never been given a discount because it only takes us 110 minutes to watch a 120 minute movie (or thereabouts). :(A 120 minute film at 24 frames per second = 172800 frames.

172800 frames divided by 25 frames per second = 115 minutes 12 seconds ;)

laserfan

14th October 2010, 22:22

Maybe some equipment in the traditional NTSC world throws a wobbly when fed with exactly 24p/60i.

I believe 24p Blu-rays are only found in PAL territories.
Not so. At least, the US BD Tin Man (no kidding (http://www.amazon.com/Tin-Man-Two-Disc-Collectors-Blu-ray/dp/B003G715Q2/ref=sr_1_2?ie=UTF8&qid=1287091245&sr=8-2) TinTime) is 24p.

mariner

15th October 2010, 08:03

Not so. At least, the US BD Tin Man (no kidding (http://www.amazon.com/Tin-Man-Two-Disc-Collectors-Blu-ray/dp/B003G715Q2/ref=sr_1_2?ie=UTF8&qid=1287091245&sr=8-2) TinTime) is 24p.

Excellent find, laserfan.

My UK sourced, region free copy of Tin Man (http://www.amazon.co.uk/Tin-Man-Blu-ray-Raoul-Trujillo/dp/B0019ZN2B4/ref=pd_ys_iyr85) is 23.976 fps.

What's the region coding of your US copy?

SeeMoreDigital

15th October 2010, 11:02

Excellent find, laserfan.

My UK sourced, region free copy of Tin Man (http://www.amazon.co.uk/Tin-Man-Blu-ray-Raoul-Trujillo/dp/B0019ZN2B4/ref=pd_ys_iyr85) is 23.976 fps.

What's the region coding of your US copy?It's a shame the Blu-ray Disc Stats (http://www.blu-raystats.com/Stats/Details.php?ifb=TinMan_883476027630) web site does not offer the fps information for their listed movies :(

Ghitulescu

15th October 2010, 13:06

I wonder what is written on the cover of a 24p/1001 movie? or 60i/1001? 24, 23.976 or 24/1001?

AlekseiV

15th October 2010, 15:30

Region A release of Planet Earth by BBC w/ Attenborough is 24p (disc is region free)

Supposedly (http://forum.blu-ray.com/blu-ray-movies-north-america/15673-planet-earth-definitive-thread.html#post199854), anyway.

Inspector.Gadget

15th October 2010, 15:41

I've got a region-free pressing of Planet Earth here (though I am in Region A) and it's 24000/1001 fps VC-1 content. Copyright labeling is BBC Worldwide 2007.

ramicio

15th October 2010, 15:51

Ghitulescu

15th October 2010, 16:55

They need to put the silliness aside of NTSC and PAL crap and just use the same frequency power grid everywhere and use a normal number for framerate like 25. 25 is perfect, 40 milliseconds! Barely anyone has a tube TV anymore, let the cheapass minority suffer from incompatibility.

It's not that easy, there are millions of studio devices that need to be changed, and while an LCD costs you some 1000€, a studio VTR cost at least 15x more; you need one maybe 2 TVs, they need at least 3 for each location. That is BTW the reason why 720p is not yet dead ;) one cannot simply throw away all the camcorders and stuff only after 2 years of service ...

SeeMoreDigital

15th October 2010, 22:10

I wonder what is written on the cover of a 24p/1001 movie? or 60i/1001? 24, 23.976 or 24/1001?Thats a good point...

With my two dozen or so HD-DVD discs I re-flagged the 23.976fps speed to 24fps and re-encoded the DD+ audio to DD at 448Kbps to match.... And all is good ;)

Shame it's not so easy to stretch the fps speed of DolbyTrue HD and DTS-HD sources...

TinTime

16th October 2010, 01:18

Not so. At least, the US BD Tin Man (no kidding (http://www.amazon.com/Tin-Man-Two-Disc-Collectors-Blu-ray/dp/B003G715Q2/ref=sr_1_2?ie=UTF8&qid=1287091245&sr=8-2) TinTime) is 24p.

Interesting. I wonder if this led to any complaints in the US from people with incompatible equipment?

I wonder what is written on the cover of a 24p/1001 movie? or 60i/1001? 24, 23.976 or 24/1001?

From what I've seen they tend to remain non-committal about framerates and just describe them as 1080i/p.

I've got a region-free pressing of Planet Earth here (though I am in Region A) and it's 24000/1001 fps VC-1 content. Copyright labeling is BBC Worldwide 2007.

My HD DVD version is also 24000/1001 VC-1. An annoyance as it should be 25p...

Inspector.Gadget

16th October 2010, 01:30

My HD DVD version is also 24000/1001 VC-1. An annoyance as it should be 25p...

Was it shot in 25p?

TinTime

16th October 2010, 02:02

Was it shot in 25p?

I guess it was shot at all kinds of speeds - there's all kinds of slow motion and I don't know what fps the timelapse stuff is! As a BBC programme presumably it would have been produced as 25p or 50i though.

The clincher for me is that you can hear the pitch correction in the HD DVD audio but not in the PAL DVD version.

laserfan

16th October 2010, 13:49

Regarding Tin Man 24p
Interesting. I wonder if this led to any complaints in the US from people with incompatible equipment?
I dunno what could possibly be "incompatible equipment" since afaik all BD players will handle 24p just fine. No, my display is not 24p but it made the conversion to 1080p/60 no problem.

Midzuki

16th October 2010, 14:31

Barely anyone has a tube TV anymore, let the cheapass minority suffer from incompatibility.

I see, you live in a planet where there is no such thing as a "Third World". :rolleyes:

Sharc

16th October 2010, 15:29

At the end it's all about backward compatibility and TV broadcast infrastructure, which is based on 50i (PAL, driven by countries with a 50Hz electric power grid) or 60i (NTSC, driven by countries with a 60Hz electric power grid).
The original 60 fields per second for NTSC was changed to 59.94 (actually 60000/1001) when color TV was introduced in 1953, to avoid interference between the chroma subcarrier and the broadcast sound carrier. 59.94/2=29.97 progressive frames per second which are produced by telecining 24fps original film productions
One can consider 23.976 (=24000/1001) as a 'historic common denominator' for NTSC and PAL world, and hence it may serve best as 'digital master' suitable for both DVD and blu-ray productions for PAL and NTSC.
Not to forget that 50i or 60i true interlaced (broadcast) video is more fluent in high motion scenes than 24fps progressive recordings.

manono

16th October 2010, 15:50

59.94/2=23.97602 progressive frames per second.
Eh? :)

Never mind. You caught it right as I posted. :)

TinTime

16th October 2010, 20:07

Regarding Tin Man 24p

I dunno what could possibly be "incompatible equipment" since afaik all BD players will handle 24p just fine. No, my display is not 24p but it made the conversion to 1080p/60 no problem.

I don't know either. It's all speculation on my part :)

On the other hand it seems reasonable to me that all BD players and HD displays would support 1080i/25 but they don't.