Blu-ray 720p questions

[A.Fenderson]

I know that the specs for BD say that 720p is acceptable in framerates of 24/1.001, 24, 50, and 60/1.001, but...
1. Has anyone ever actually found a commercially-released BD that uses any of these flavors of 720p?
2. On the (possibly unfounded) assumption that HDTVs having HDMI inputs in NTSC-land don't have support for input of video w/ framerates of 25 and/or 50, do the specs for BD players require that the players themselves are able to perform internal frame-rate conversions so that they're able to output any BD-compliant resolution/frame-rate combo at whatever framerate the display device is limited to (or at least some expected/intelligent subset of display-supported framerates)?
3. Wouldn't converting 50p video to 60/1.001p require (in the simplest case) frame-duplication at every 5th frame combined with a .001% reduction in speed, thus also necessitating the ability to slow down the audio as well?
4. Has anyone ever seen 50p (native) video that's been converted to 59.94p video for playback, and if so how did it look? Was there stuttering, possibly from repeating every fifth frame? Was the conversion done in real-time during playback or in post-proc?

[Lyris]

1. No. Almost everything is 1080p or 1080i, which makes sense.

2. Not unfounded at all. Many US TVs have the 50hz support locked out.

No, the BD spec does not require that BD players sold in the NTSC territories play 50hz *at all*. Some will play with a black screen, others will simply skip over the Playlist.

3. There would be many ways to do the conversion, and that would be the most likely.

4. Yes - do you mean converted in the studio, or converted by the playback device though? Interpolating frame rate UPWARDS tends to look better than reducing the frame rate.

[Keiyakusha]

1. there is a lot of series that originally have 720p or even SD resolution, however they always upscaled (sometimes horribly) to 1080p. Probably because in 720p video will take much less space so less discs needed, but they very like to take your money for nothing.

EDIT: however if we talking about licenses in different countries, some very money-hungry companies can even release horribly upscaled SD as 1080p BD (and sometimes with audio upconverted from 2.0 to 7.1) even if show originally HAVE high resolution. Because they didn't wanted to pay more for HD source.

[kieranrk]

I have seen one 720p59.94 Blu-ray.

[A.Fenderson]

1. No. Almost everything is 1080p or 1080i, which makes sense.

2. Not unfounded at all. Many US TVs have the 50hz support locked out.

No, the BD spec does not require that BD players sold in the NTSC territories play 50hz *at all*. Some will play with a black screen, others will simply skip over the Playlist.

3. There would be many ways to do the conversion, and that would be the most likely.

4. Yes - do you mean converted in the studio, or converted by the playback device though? Interpolating frame rate UPWARDS tends to look better than reducing the frame rate.

Thanks for the quick and comprehensive reply. As for #4, I was asking if anyone had seen either. I'm guessing that even with some of the high-end BD players that *might* do 50p > 60p conversion, it would be the simplest-case algorithm I mentioned or similar, and not frame interpolation as you mentioned, right? Whereas I assume studio conversions would have the time and means to do the interpolation since that would presumably prevent the judder associated with repeating every fifth frame and therefore look a lot better.

@Keiyakusha: Wow, that's pretty lame. Care to name any of the offenders? ;)

I have seen one 720p59.94 Blu-ray.

Can you relay the title here, if forum rules do not prevent it (and maybe PM otherwise) please? Thanks!

[Keiyakusha]

@Keiyakusha: Wow, that's pretty lame. Care to name any of the offenders? ;)
Funimation. Not sure if they can be called offenders, however probably yes, because on the disc box there is no any indication that shows how crappy this release is. I also forgot to say that they even don't know that SD and HD uses different color coefficients so in addition to everything, their upscales have wrong colors.