1080p/24 make PAL/NTSC differences thing of past? (1 Viewer)

[Marko Berg]

It's not a complicated issue at all.

1. Broadcast HD will be 25fps in Europe. Material shot this way will play back at the correct speed. Films shot 24 fps and shown on TV, however, would be speeded up just like they are now in the old analogue PAL system. While this may be an issue for some, it doesn't affect HD video playback from external sources in any way.

2. All display devices that bear the official "HD ready" logo must accept 24fps/60Hz signals and display them natively. We already watch our NTSC DVDs in their native format on our analogue multi-standard TV sets and similarly we will watch HD video releases they way they were meant to be watched, i.e. at the correct speed.

 

[Shawn Perron]

I think everyone's reasoning is that to get a 24fps version of films in PAL territory you may have to import from a NTSC territory, just as with DVD. There was a chance to eliminate technical issues between territories, and it looks like it is being passed up.

 

[Max Leung]

Yeah - I think it is complicated simply because if someone wanted the 24 fps versions they may have to jump through hoops to get them.

Another complication is that the speed up versions will/may have authoring issues - the monkey who converts from 24 fps to 25 fps might screw it up (accidentally blending interlaced frames or accidentally screwing up the inverse telecine process when converting from the NTSC version, etc). It is just another wrench that could be thrown into the woodworks.

I've seen a few butchered PAL-to-NTSC DVDs sold here in Canada - it is not pretty. Some silly Canadian distributor decides to license the PAL versions and does a hack job to get them to play in NTSC format. The horror...the horror!

 

[Cees Alons]

Yes, you have a problem too. It's "solved" by the 3:2 pull-down: each first frame is shown three times, each second frame twice (for 1/60 sec). Hence the NTSC-jitter.

PAL systems show each frame twice (for 1/50 sec). They cannot reconstruct the 24 fps exactly that way (hence the PAL 24 -> 25 fps speed up), but at least the image is stable.

And it's true that the TV frame rates were dependent on the power frequency, historically. The 50Hz frequency in Europe allowed for a higher frame resolution (given the total bandwidth). Most European TV sets use a 100Hz frame refresh, BTW.


Cees

 

[Max Leung]

With an HTPC you can get around that by using a refresh rate that is a multiple of the original framerate. 72 hz or 48 hz for 24 fps content, for example. The HTPC can also perform pitch correction as well - handy if you want to go from 25 fps to 24.

Just throw more technology at it. Now if only set-top DVD players could do that instead of forever fiddling with a PC....

 

[Shawn Perron]

In the digital world, there is no excuse for not presenting movies and tv shows in thier original frame rate. It should be up to the technology to conform to the software's needs, not for the software to be modified for the technology. There is no real reason movies couldn't be refreshed at 48hz, PAL material at 50hz and NTSC material at 60hz. It stands to reason that if you can render at both 50hz and 60hz, then you should be able to render at 48hz.

 

[Cees Alons]

I totally agree. There should have been a frame-rate byte in the HD specs.
Just like there should have been a frame-ratio byte, BTW.

Only if the external monitor couldn't handle it exactly (e.g. an 'older' TV-set), would it have to be approximated.


Cees

 

[Marko Berg]

Why would studios create different versions for the PAL markets when PAL doesn't really apply in case of HD video? It is so much easier and cheaper to just release the same content in multiple markets. High definition displays in all markets will support native display of 24fps video from external sources. I fail to see how incompatibility issues with broadcast HDTV affect Blu-ray or HD DVD implementations.

 

[Shawn Perron]

It all depends on how the studios in PAL territories have been mastering thier HD content. If they have been mastering everything as 1080p 25fps, then that's what will be cheapest and easiest to release. If they have either been mastering at 1080p 24fps or can aquire 24fps masters for a reasonable price, then that may be what is eventually released. I'm not sure if PAL dvds are sourced from 24 or 25 fps HD masters.

 

[Cees Alons]

One doesn't master the images of a movie "as 25 fps" or "as 24 fps". As said before, on DVD or HD/BD both systems simply have all frames of the movie consecutively one after each other. The difference being how they are displayed (3-2 at 1/60 or 2-2 at 1/50).

A GOOD converting DVD can simply display a PAL movie in NTSC by ignoring the 2:2 indication, and performing a 3:2 pull-down.

(Of course, for SD the image has to be down-converted to 480 lines, and there must be a rather straight-forward provision for the sampled music.)


Cees