Thank god, at least EBU is sane ... pity about the rest of the world

[MfA]

Surprisingly EBU (http://www.digitalspy.co.uk/article/ds15637.html) is standing up against the consumer electronic conspiracy to push 1080i down our collective throats ... even though that means going against the "standards" in the rest of the worlds (not really a big enough volume of HDTV to speak of a standard, so now is a good time to give some counterbalance against the 1080i crowd).

I dont understand why anyone would want 1080i ... the vertical resolution sucks, worst case it is 540 and best case you should be happy if it even approaches 720 (there is almost always substantial vertical blur). The horizontal resolution is a little better, but that seems a poor trade-off against interlacing and deinterlacing artifacts (going forward most displays will be progressive).

Not to mention that at least as far as TV is concerned we cannot depend on compression getting enough bitrate to be transparant ... and interlaced video needs more bits per pixel to get the same distortion as progressive video.

Especially without perceptual transparancy for the coding 1080i is just not going to manage to outperform 720p. It isnt technologically superior, the consumer electronic manufacturers just like it because they can compete on the expensive and complex deinterlacing hardware which 1080i displays will need.

All IMO of course :)

[Sirber]

I think progressive is better. Less bandwith is required.

Sorry for this OT, but I cannot stand 50Hz TV in europe :eek:

[jggimi]

Well, I have a 720p HDTV, and while it can accept 1080i, my set top box is set to feed it 720p. There's no way for me to determine what the incoming channels are using; other than the broadcast descriptions at www.hdtvoice.com I've no easy way to determine why one HDTV channel might look better than another.

MfA, you might consider editing your post and changing the title to something more descriptive. In addition, this thread probably belongs in the HDTV forum.

[MfA]

I like being enigmatic, and this has nothing to do with capturing or editing :)

[reepa]

I wonder if 1920x1080, 24fps progressive is supported. A lot of material is filmed on 35mm at 24fps. None of that would benefit from the extra frames of 720p @ 50fps. 720p sounds ideal for sports and other high-motion content. Anyway I'm glad at least some kind of HDTV is making a landing in Europe. Non-HDTV digital television just sounds ridiculous to me as it offers little improvement over analog television for consumers compared to what is possible.

What I don't understand is why multiple channels are being crammed into single multiplexes. In Finland we have five free-to-air analog tv channels and 11 digital channels and over 50 channels in which to broadcast them according to this chart:
http://www.yle.fi/ylelab/faq/kanavarasteri98.htm
All the current 11 digital channels could be broadcast in HDTV (one channel per multiplex) and still over 60% of the bandwidth would be available. Changing now would be impossible though as I doubt many digital tv set-top boxes can cope with HDTV bitrates.

[minolta]

Actually, 1080i is best for movies (with the right hardware). I watch and record HDTV on my computer using a MyHD card. Movies in 1080i are "often" encoded 23.976 progressive with a simple 1-bit 3:2 output flag (easily verified with dgindex). This means they are basically 1080@24p (ouch!!!)... Just as DVD and TVs now support 480p, we'll soon see 1080p devices for movies.

For sports, 720p looks better (IMO), but 1080i is okay with enough bandwidth and good 60i->60p TV. For SD up-converts, I'd much rather they broadcast at 480i (576i) since up-scaling is a waste of bandwidth. Would be fantastic if broadcasters would switch formats on-the-fly.

You're biggest challenge will be the sub-channel madness...

-Minolta

[Latexxx]

This is nothing new. I can remember some (European) technical papers, which date back to 1997, and which state that 750p appears to be clearly better than 1080i.
Now we just need to wait for relatively "cheap" h.264 encoders to get HDTV in DVB-T. :D

[MfA]

Originally posted by minolta
Actually, 1080i is best for movies (with the right hardware).

1080p is better for movies, and you can encode it inefficiently in 1080i (codecs are not designed for telecined material ... coding efficiency still takes a dive). I think that is putting the carriage before the horse though. Just support 1080p at 24/25/30 Hz and still ditch 1080i.

If you are starting from a clean sheet (and the EU is) then 1080i is a piss poor encoding.

[Latexxx]

:D :D :D :D :D

http://www.ebu.ch/en/technical/trev/trev_299-ive.pdf/written by some Sony marketing guy:

http://img23.exs.cx/img23/3755/boxit.jpg


http://www.ebu.ch/trev_300-wood.pdf/the results of B/TQE working group:
Deciding on a proposition for an HD format is not purely a matter of simply citing who uses which system, or drawing three dimensional diagrams of the responses of different scanning formats. There are too many variables to take into account and, unless actually related to real equipment, these diagrams are misleading.

[minolta]

With 29.97fps telecined material, MPEG-2 has three options:
1) Encode interlaced
2) Encode w/ 3:2 pulldown output (still 29.97fps and interlaced)
3) Encode progressive (23.976fps, not HDTV compatible)

The 1080i format can choose option 1 or 2. I did a test with TMPEGenc that shows option 2 is MORE EFFICIENT than option 1, and, arguably, nearly AS EFFICIENT as option 3.

Here's what DGIndex reports about each stream (interlace, 3:2 pulldown, 23.976 progressive):
http://www.vrac.iastate.edu/~chadspen/dgindex.jpg

NOTE, most telecined 1080i material does correctly choose option 2 (actually, my CBS, WB, HBO all do, but my retarded NBC station is always option 1).

Now for the screenshots (high-motion scene)... Each was encoded 720x480 at 2000kbps CBR:

http://www.vrac.iastate.edu/~chadspen/option1.jpg
Option 1: 29.97 Interlaced

http://www.vrac.iastate.edu/~chadspen/option2.jpg
Option 2: 29.97 Interlaced w/ 3:2 flag

http://www.vrac.iastate.edu/~chadspen/option3.jpg
Option 3: 23.976 progressive

As you can clearly see, 1080i is NOT inefficient with telecined material if option 2 is used (which is the norm). In fact, when pulldown'd, options 2 and 3 are nearly identical. Basically, it makes use of "field-repeat flags" (http://forum.doom9.org/showthread.php?s=&threadid=86053) which essentially makes 24p in 30i possible.

Most HDTVs have progressive displays, and decoder boxes can output a 1080p signal (some might already). I guess some people might still prefer 720p, but please don't spread mis-information about 1080i being "inefficient" with movies just because it supports interlace.

-Minolta

[MfA]

Sorry you are right (assuming the display is IVTCd).

Still if the only raison d'etre for 1080i is as a vehicle for 1080p film at 24/25/30 Hz then the EU is better off just useing true 1080p, and not cripple video with interlacing.

I dont care much about MPEG-2, broadcasters are too skimpy on bandwith over here. By the time we see widespread deployment over here we will probably have modern codecs being used.

[reepa]

Wouldn't a codec change basically throw the current digital tv standards out the window?

[minolta]

Would be very cool if MPEG-4 started getting popular there. Then satellite would use it, then HD-DVD might start, then (hopefully) ATSC might change (via sub-channels). Either way, fight hard for more bandwidth... Can you say MPEG-4 1080 50/50i/60/60i/24p @ 20Mbps? Good luck.
-Minolta

[Mug Funky]

i'd be happy to see films broadcast at 24fps like they were shot in. 30i / 60p gives awful schizoidal motion jitter that makes my eyes want to puke, and 25p gives a tonal shift and the need to transcode audio that makes my ears want to puke. with progressive TVs (and anything that's not power-supply coupled), there's really no reason to be using those stupid framerates anymore.

digital TV here (aus) is a good advertisement for analog TV, even for someone like me who lives out in the boonies nowhere near the broadcast sites - analog noise is a fair bit prettier than blocks and glitchies, especially seeing as most (if not all) of the digital TV is SD, interlaced, blocky as **** and mp2@160 sound (incidentally, channel 7 seems to use this sound even in it's analog broadcast for its program promos. really disgusting).

[Latexxx]

Originally posted by minolta
Would be very cool if MPEG-4 started getting popular there. Then satellite would use it, then HD-DVD might start, then (hopefully) ATSC might change (via sub-channels). Either way, fight hard for more bandwidth... Can you say MPEG-4 1080 50/50i/60/60i/24p @ 20Mbps? Good luck.
-Minolta
I have some semi-official information according to which EBU members are waiting for h.264 to be able broadcast HD in DVB-T without requiring one transmitter per channel.

Most people here seem to dislike DVB-T picture, but instead of disliking digital TV in general, you should dislike your local broadcasters. Our local Finnish DVB-T offers extraordinary image quality on the main channels. On the other hand, there are far fewer channels per transmitter here. In general, the picture is almost DVD quality; once I even managed to get my DVD player running in sync with a movie, which was shown on TV, and I couldn't note any difference (except that the subs were rendered using different font). Even the low-bitrate "extra"/"plus" etc. bonus channels look far better than these (http://forum.doom9.org/showthread.php?s=&threadid=82651#post551503) German DVB-T samples.

[SeeMoreDigital]

I have to admit I'm very much in favour for all HD content to be transmitted at the same fps as the original source!

I gather quite a lot of material is shot in HD video over in the states now. But can anyone confirm if it's shot at 24fps or 30fps?


Cheers

[minolta]

Movies:
Film 24p telecined to 1080i

Primetime Shows (CBS, NBC, WB):
Film/Digital 24p telecined to 1080i

Primetime Shows (ABC, FOX):
Film/Digital 24p frame-repeat'd to 720p

Talk/Reality/Daily Shows:
Digital 1080i (60i fps) or 720p (60fps)

Sports:
Digital 1080i (60i fps) or 720p (60fps)

Original source is always 24p, 60i, or 60p, but never 30p...

[Latexxx]

So, interlaced should be a no-go because most of the sources are progressive. Let me quote EBU. :D
EBU Group B/TQE assessed de-interlacers that are common in the domestic display environment and found they generally contributed impairment and limited the final quality of an HD-delivered image. However, professional conversion equipment of very good performance has been developed and good de-interlacers are available from a range of manufacturers for studio use.
From all this, we concluded that conversion from interlace to progressive should not be carried out at the receiver if we can avoid it.

[minolta]

Originally posted by Latexxx
So, interlaced should be a no-go because most of the sources are progressive. Let me quote EBU. :D

If frame-rate and resolution can change on-the-fly, then interlace can probably be avoided. Best case, networks would choose 1080@24p/25p for hd-movies, 720@50p for hd-sports, 576@24p/25p for dvd-movies, and 576@50p for sdtv (needs 50i->50p conversion).

If no on-the-fly, then nasty trade-offs must be made (like dropping 1080 altogether)...

[SeeMoreDigital]

Thanks for posting that information minolta.

Now.... can anybody confirm whether the 24fps material is actually broadcast at 24fps. Or is it sent out at 23.976 (or there abouts)?


Cheers

[minolta]

"telecined to 1080i" implies 29.97fps (23.976fps actual). however, mpeg2 encodes telecine in a special way (non-interlaced), nearly as efficient as native 23.976p. see my post about 12 replies up...