Will horrible video standards ever change?

RadicalEd0 · Post by **RadicalEd0** » Thu Nov 14, 2002 3:34 pm

When codecs encode stuff interlaced don't they do something along the lines of storing each field as a separate 60hz half-frame to be re-weaved on playback? Thats what I've been told.
The genious of interlacing then is the ability to display something that *looks* to the eye like 1920x1080 @ 60hz but is really only half that as opposed to actually displaying the full 1920x1080 @ 60hz.
A good example of the benefits of interlacing would be the VCD, which is never interlaced. VCD is doomed to be 240 lines high and 29.97 fps. This way, you get neither the double-resolution effect of interlacing nor the double framerate effect, as opposed to interlaced dvd which looks like 480 lines and 59.94 fps. In real life DVD then would require about 4 times the bitrate of VCD to have the same quality (not taking spatial and temporal compressibility increases into effect) whereas thanks to interlacing it only requires 2x the bitrate to have ~ quality.
Like I said, more for less at the expense of the clumsy device we call eyes.

klinky · Post by **klinky** » Thu Nov 14, 2002 4:03 pm

Wuz I wanna know is why are you still even messing with 60hz err orr 60refresh a second. We've come farther then that. Isn't HDTV spec kind of old, since they had the idea like maybe a decade ago(not sure, havent' read up on it). I would just like a nice steady 30progressive fps.

is that too much to ask. Why must we still be stuck with having to loophole around wif interlacing on a 60hz set. Shouldn't HDTVs just operate @ 30fps and not even deal with interlacing. It just seems "restrictive".

Okay on top of all that rambling, I am trying to ask... Is the reason interlacing is included in the HDTV spec because we're trying to stay backwards compatible with some sort of old analog technology, such as how TVs currently operate @ 60hz? Why even keep with that. Why must we be restricted to that. :\

Okay I should go read up on it ;p

~Klinky

RadicalEd0 · Post by **RadicalEd0** » Thu Nov 14, 2002 5:46 pm

no, its included because its an effective method of visually doubling the res and framerate
what did I just spend 10 minutes writing? >:/

klinky · Post by **klinky** » Thu Nov 14, 2002 6:24 pm

*HOW* is displaying 60fields a second more effective then just displaying 30frames a second!? I still not get it. The only reason we would need interlacing is if you wanted to have 60fields per second or there was a hardare limitation. Now current TVs use interlacing and I understand how you can display two half frames in the same time you can display a full frame and it looks pretty smooth. However! We have the fact that you have to use twice as many half frames to get the same motion as single progressive frames.

So how is it saving bandwidth if we use 60 half frames, compared with 30 FULL frames. Why do we even need to bother with half frames. We obviously can view video file on moi's computer at a nice progressive 24fps. 24PROGRESSIVE frames. Why couldn't they just implement it in that sort of way ^_^

Anyways... I do see that there could be a advantage to capturing and playing video back @ 60fields, it would be smoother then progressive if displayed properly, however it would look like ass on my computer

Screw HDTV, I don't even watch TV, why do I even care.

~klinky

RadicalEd0 · Post by **RadicalEd0** » Thu Nov 14, 2002 6:35 pm

I just hope they'll come up with a form of telecining for 1080i instead of using 720p for all anime/film
2 mil pixels of anime goodness.. mmm P:

klinky · Post by **klinky** » Thu Nov 14, 2002 7:15 pm

Wait! I thought I had the idea there... nevermind....

ErMaC · Post by **ErMaC** » Fri Nov 15, 2002 4:12 am

Klinky:

If you have a 30fps progressive stream... it looks like it's 30fps. It doesn't look super-smooth like normal video shot with a camera does.
If you have 60 fields a second, you're shooting 60 different frames and just halving the resolution, so the untrained eye thinks it's seeing 60fps, but it's not quite.

So the difference is:
30fps is really only 30fps - you see 30 different pictures per second
60fields per second looks like 60fps, but it really isn't - instead it takes approximately the same bitrate as the 30fps one.

So the advantage to the interlaced one is that to the untrained eye it looks like there are twice as many frames, when in reality there's only half frames there. They both would take up the same amount of space (uncompressed).

klinky · Post by **klinky** » Fri Nov 15, 2002 4:22 am

ErMaC wrote: ...the 19.8MBit/sec allocated for an HDTV station is too little for 1920x1080 progressive scan in video framerates...

That is probably what got me confused. VIDEO=60times per second.

So technically they WANT to keep the 60refreshes per second, but there is not enough bandwidth for 60whole frames, only enough for 60fields. Which looks fine when played back on a TV that works well with interlacing.

So with HDTV we're still stuck with fields

Atleast on certain broadcasts.

~klinky

CaTaClYsM · Post by **CaTaClYsM** » Fri Nov 15, 2002 5:19 am

is there anything that plays at 60 FPS that is actualy playing 60 FPS. what aobut video games on a computer?

RadicalEd0 · Post by **RadicalEd0** » Fri Nov 15, 2002 11:26 pm

all video game systems I know of playback at true 60fps, although since TV is still interlaced, it dosent look any better than 60 fields per sec.
Anyway 60fps is a standard framerate (along with 30fps and 24, there may be others) for 720p and may very well be used in broadcast.