Why are there interlaced Blu-Ray formats?

[brassplyer]

I was under the impression that the "native" display of HDTV is progressive and that progressive enables potentially higher quality than interlaced. I thought the use of interlacing was because of the way CRT tv's worked. Why are any Blu-Ray formats in interlaced form?

Feel free to straighten out any misconceptions I'm operating under.

[poisondeathray]

Largely for legacy compatibility reasons. HD Broadcast at "1080" is still 1080i59.94 (or 1080i50 in 50Hz regions) . Even "24p" broadcast is 59.94i, just hard telecined. Billions of dollars invested in the broadcast industry infrastucture and equipment isn't going to change very quickly

The other reason is the 1st gen blu-ray chips cannot decode 1080p59.94 - they don't have enough "horsepower" ( and it didn't make it into the 1st draft blu-ray specs)

[budwzr]

When you go broadcast, you're talking NTSC standards, and it has to work on granny's TV too. The whole industry is backward compatible. They would never give up one eyeball.

[jagabo]

Broadcasters wanted to keep the bandwidth down (the planning for the switch from analog SD to digital HD was a little too early for high compression codecs like h.264). So they went with what they knew, interlaced MPEG 2 video. 1080i30 and 720p60 require about the same bitrate. Blu-ray just followed in their footsteps.

[sanlyn]

I was under the impression that the "native" display of HDTV is progressive and that progressive enables potentially higher quality than interlaced. I thought the use of interlacing was because of the way CRT tv's worked. Why are any Blu-Ray formats in interlaced form?

Feel free to straighten out any misconceptions I'm operating under.

So you don't keep any of those classic prints or DVD's longer than 15 minutes? Hm. And people said "1984" was fiction.

[brassplyer]

I was under the impression that the "native" display of HDTV is progressive and that progressive enables potentially higher quality than interlaced. I thought the use of interlacing was because of the way CRT tv's worked. Why are any Blu-Ray formats in interlaced form?

Feel free to straighten out any misconceptions I'm operating under.

So you don't keep any of those classic prints or DVD's longer than 15 minutes? Hm. And people said "1984" was fiction.

?

Perhaps you could translate.

[usually_quiet]

I was under the impression that the "native" display of HDTV is progressive and that progressive enables potentially higher quality than interlaced. I thought the use of interlacing was because of the way CRT tv's worked. Why are any Blu-Ray formats in interlaced form?

Feel free to straighten out any misconceptions I'm operating under.

So you don't keep any of those classic prints or DVD's longer than 15 minutes? Hm. And people said "1984" was fiction.

I think you have your classic sci-fi dystopias confused. "Brave New World" was about a society that considered consumption and materialism to be virtuous. "Nineteen Eighty-Four" was about a totalitarian police state where everyone was under surveillance.

[_Al_]

we live in the great time right now, no Blu-Ray is needed if we don't want to, if somebody insists, we can fake 30i from 30p, drop some fields for 30i from 60p, who cares, we keep originals, like our thoughts also ...

it is like with junk food we think we have to eat and then realizing we don't have to,..., why at home would I need to make a crippled BD compliant file ....

[budwzr]

Wasn't it Andy Warhol that started the whole 15 minute thing?

And yes, _Al_ is right on the money. Discs are relics of a soon to be gone era. Hollywood is the only one keeping them alive, because they can extract $25 for a stinkin movie from the unwashed masses.

My BD player hasn't been fed a disc in five years.

[sanlyn]

Hm, not just surveillance. Thought control, designed to make all thought the same everywhere. And on the farm, god forbid you don't play perpetual me-too. The totalitarian political state now supplanted by totalitarian marketing states. A little Huxley, a little Orwell. But, then, when has it it ever been different? LOL!

This is what often happens when you stare at the same piece of video for waaaay too long.

[budwzr]

@Sanlyn - I knew you were an existentialist when you quoted Thoreau.

[Oops, retraction]

=======================================
"'That government is best which governs not at all' - Thoreau

[sanlyn]

=======================================
"'That government is best which governs not at all' - Thoreau

Remember that dear ole Henry made that remark in the early 1800's. Obviously, he hadn't seen Detroit.

[budwzr]

I was under the impression that the "native" display of HDTV is progressive ...

It's not "HDTV", it's "DTV". Digital TV. In this case digital means binary data delivery over the air. The signal is NTSC. It's spread across the pixels as if they were a tube TV.

The modern TV operates natively though in the RGB spectrum, like a computer monitor. Each pixel is addressable. The color range is much more than NTSC.

A digital media player sends the video to the TV in pure RGB(digital), not NTSC(analog).

================================================== =======
Caveat Emptor: I may have been off on some of that, I got carried away.

[brassplyer]

I was under the impression that the "native" display of HDTV is progressive ...

It's not "HDTV", it's "DTV". Digital TV.

I'm talking about the thin rectangular box with the light coming out of the front panel, not the delivery method.

[sanlyn]

[QUOTE=budwzr;2204145]A digital media player sends the video to the TV in pure RGB(digital), not NTSC(analog).
Well, umm, wait a minute. That doesn't sound 100% correct. NTSC is always "analog"? Something wrong there. Does that man that PAL is always analog as well?.

In any case, regardless of what kind of video signal the TV gets, the front display panel converts it back to analog.

[smrpix]

As I understand it, NTSC and PAL are indeed analog formats. The nomenclature was initially retained to describe digital specs that are --um-- analagous. (sorry)

It's not uncommon. When was the last time you "dialed" a phone?

[jagabo]

As I understand it, NTSC and PAL are indeed analog formats. The nomenclature was initially retained to describe digital specs that are --um-- analagous. (sorry)

Yes. For example we refer to DVDs as NTSC or PAL.

[Cornucopia]

Yes, the digital signals on DVDs are NTSC- or PAL-"compliant", meaning they translate on a nearly 1:1 basis into NTSC or PAL when outputted through analog ports (not counting the dance it does when using Film pulldown).
That's also why ATSC TV stations were able to start up earlier than 2009 - their SD digital signals were also easily translatable into analog for the majority of their pre-2009 broadcasts (HD signals would HAVE to have been downconverted regardless).

People here refer to them as NTSC and PAL out of habit. You could also call them 480i59.94 and 576i50, which are clearly digital formats. The legacy of NTSC and PAL and SECAM are still with us, even after the US broadcast analog sundown and seeming-imminent cable analog sundown and the rise of HD programming. They will probably still influence us 5 or maybe even 10 years down the road.

Scott

[budwzr]

[error]

[budwzr]

I was under the impression that the "native" display of HDTV is progressive and ...

Ah, I see where the confusion lies.

You didn't put an "an" in front of "HDTV", AND your post's title.

So the updated answer is "Because they need to be compatible with NTSC ".

[misermidas]

For the same picture per second rate ,interlaced formats give a better motion rendering than non interlaced format .In DVB some networks in France use interlaced format for sport broadcasting in HD for that reason.
Though definition is lower and interlacing may cause some artefacts.

With a non interlaced 25p (in Europe) video ,one can see picture vibrations in panoramic and travelling sequences ,with interlaced videos, these will usually be more fluid.Recent TV sets may correct that but it is not always perfect.

The best thing to do would be to film ,broadcast or burn with a double picture per second picture rate (50p in Europe for example) ,that does not require much more bitrate than interlaced because compression is easier ,but Blu-ray or DVD standards do not support that.