HD question

dvideo2 wrote on 8/6/2010, 6:54 AM

I'm converting an HD 1920*1080 NTSC file to a PAL version.
If I keep the same 1920*1080 proportions and change the
frame rate to 25, can i safely assume that the HD quality is mantained, regardless of the codec used?
Specifically, I tried using a .MOV export with a DV codec and kept
the 1920*1080 proportions....Can this be looked at as an HD file?

I guess my question comes in because when i see DV, it doesn't make me think of "HD" immediately, but since the 1920-1080 size
is HD, I'm assuming that the ".mov file with a DV codec with the size 1920-1080 and a frame rate of 25fps" is in fact an (HD PAL video)..
Am i right?

I hope this maks sence.
ANy feedback will be appreciated....thank you...

Comments

Chienworks wrote on 8/6/2010, 10:04 AM
Well, except the fact that DV has fixed SD resolution sizes so you can't keep 1920x1080 for the frame size. There are a variety of codecs that do allow HD resolution. However, keep in mind that changing the frame rate from 29.97 to 25 will require re-encoding the file, which will be a quality hit. The bitrate used for the new file will also have a big effect on quality.

And, there really isn't any HD NTSC or HD PAL. NTSC & PAL are SD specifications. I believe what you're asking is if you can convert 29.97fps HD to 25fps HD.
farss wrote on 8/6/2010, 2:32 PM
Generally the terms "NTSC" and "PAL" are not used in HD. Instead the common terms are Region50 and Region60.

The only difference between HD and SD as such is the number of pixels so 1920x1080 is HD regardless of frames per second. The issue is converting frame rates and the impact of that on image quality. Trying to convert 25p to 30p is not easy because of the difference in temporal resolution and because that frame rate is close to limit of what we see as "smooth" motion.
To create 30 images per second when only 25 were recorded can be done using advanced techniques with good results or you can use Vegas's frame blending but image quality will suffer. On the other hand 50i <> 60i using Vegas's frame blending gives quite acceptable results. Still not the very best that can be done but generally more than adequate.
One simple solution is to shoot 24p. From that it can be easily sped up to 25p for Region50 or pulldown added to 'wrap' it into 60i for Region60.

All of that said if you're distributing over the web or on BD disks as far as I know all HD playback devices are universal.

Bob.
PeterDuke wrote on 8/6/2010, 4:40 PM
Do you really need to convert from NTSC to PAL? Most PAL equipment these days will also handle NTSC (but not necessarily vice versa).
dvideo2 wrote on 8/7/2010, 7:03 AM
THIS IS A RESPONSE to CHIENWORKS comment,
"And, there really isn't any HD NTSC or HD PAL. NTSC & PAL are SD specifications. I believe what you're asking is if you can convert 29.97fps HD to 25fps HD."

---Question:
So HD footage is universal?
In other words, If I need something to play in europe an if im creating sd footage, i would normally follow the PAL guidlines. Are there
no guidlines to follow when shooting HD footage for PAL?
Thanks again
Chienworks wrote on 8/7/2010, 7:20 AM
Pretty much the only difference with HD is the frame rate. Those of us on the western side of the big pond tend to use 60i (29.97fps) while those on the eastern side tend to use 50i (25fps). I would expect that almost any device capable of HD playback will probably play either frame rate with equal ease.
farss wrote on 8/7/2010, 7:49 AM
"Pretty much the only difference with HD is the frame rate"

I'd say it a bit stronger than that, the ONLY difference is the frame rate.

To try to answer what seems to be the OP's question.

If you want to shoot HD for a region50 country and if your camera is capable switch it to either 1920x1080 at either 25p or 50i, edit on the appropriate T/L etc. It really is that simple which is why there's no guidlines.

The only possible gottcha is there's a good reason for the difference in frame rates and that's flicker from the different mains frequency and the lighting directly powered from it. Some cameras such as the Z1 have a mechanism for dealing with this. Having twice tried using my PAL SD camera in 60Hz countries I can state it is a real issue.

Bob.