Converting from 1080i to 720p

michaelshive wrote on 4/28/2008, 7:59 PM

What are you delivering to? That is really the first question.

Spot gave a presentation at NAB when he talked about how going from 1080i to 720P really doesn't lose that much resolution. I've done it before and really couldn't tell the difference.

Laurence wrote on 4/29/2008, 5:03 AM

Well often the final HDTV that happens to be used is a 1280x720p rather than 1080i or 1080p set, in which case the look of the 720p downrez done by the HDTV is going to look very similar to one done by Vegas.

That certainly doesn't mean that a 720p render is better though. On the right HDTV or projection system, the 1080i render is still going to be your highest resolution option.

Cliff Etzel wrote on 4/29/2008, 6:44 AM

I'm looking at down the road here regarding the delivery to some form of Blu-Ray disk. I'm presuming down converting at this time to regular DVD looks great from HDV, but given the gradual uptake of Blu-Ray players, I'm wanting to get my ducks in a row so to speak regarding final output to Blu-Ray since HD-DVD has gone the way of Beta-Max format.

My biggest concern was interlacing artifacts from the original 1080i footage and wanted to inquire if converting to 720p was the best option for maintaining image quality when delivering a disk to a client.

Cliff Etzel - Solo Video Journalist
bluprojekt

farss wrote on 4/29/2008, 7:07 AM

Just deliver 1080i and let the HDTV take care of it.

Bob.

Laurence wrote on 4/29/2008, 7:31 AM

I absolutely agree with Bob. Everything you do as far as deinterlacing and changing the resolution in Vegas is going to be subtractive. If you want the best quality, deliver in as close to the same format as you shoot as possible.

Going to 720p is something you might want to consider if you want to reduce the file size without hurting the quality too much, but it will in no way be an improvement upon the original format.

Cliff Etzel wrote on 4/29/2008, 8:27 AM

Thanks again guys - You help make this a great place to ask questions and not be made to look like an idiot.. ;-)

Cliff Etzel - Solo Video Journalist
bluprojekt

DJPadre wrote on 4/29/2008, 9:19 AM

i found that scaling down to 720 only offers a streamlined data size, aside from that Vegas issues with deinterlacing and field order preferance still ahs ALOT of work to go on. as its stadns, it can be barely unusable, which is why i no longer scale 1080i to 720p.

I should point out that the only reason i use 1080i as opposed to 1080p is because, again, Vegas has many issues and this second issue is the Vegas frame interpolation... however with a different algorythm this time.
It cannot smoothely create frames for slowmotion.
With Interlaced material it can, with Progressive it cannot.. at ANY resolution.

And thats why im now restricted to shooting 1080i because i do ALOT of slowmotion work.

"Spot gave a presentation at NAB when he talked about how going from 1080i to 720P really doesn't lose that much resolution. I've done it before and really couldn't tell the difference."

I use 2 different 1080p capable panels, and my PC monitors which are also 1080p capable.
I didnt need Spot to tell me this, Althoguh i like the bloke, the best way to decide for oneself is to experiment and learn. Some people dont mind the choppy slowmo I do. Some people also dont mind a field ordinnce stuff up, i do.

In todays market however, the difference between 720 and 1080p is very noticable, but the flexibility of 720p is that you can reframe certain shots filming in 1080i.
SO the reframing options and file sizes are the ONLY 2 benefits I can find for going with 720p
I would love to shoot native 1080p and know that my sowmotion will be smooth sharp and fluid, but sadly, I cannot do that unless i export my clips to twixtor or something like that. Of which id rather not do unless i really have to.
Sadly, until Sony sort out their engine, Im stuck on 1080i.
If they dont sort it out, ill be heading over to Adobe, which is something i dont want to do.

Its come to the point where vegas is now so far behind in "maths" of what we do, that as our needs evolve, it has not.

Spot|DSE wrote on 4/29/2008, 9:37 AM

DJ, coupla comments...
~trusting the display to downconvert properly can be a bad thing, particularly if you KNOW the display is 720, and no chance of the image being on a 1080 monitor.
Michael saw this for himself at my NAB presentation. It's quite clear. We spend a *lot* of time testing these things for ourselves, on a wide variety of equipment kindly provided by several manufacturers.

~Are you saying that Adobe Premiere offers better time remapping than Vegas without using plugins? I'd like to see that. Shooting high shutterspeeds for slo-mo is something we do a lot of. Twixtor is better, IMO, sure....but it's more money and a lot more time.

~Note that we're talking about 1080i to 720p, not 1080p to 720p. Due to Kell, there is little resolution loss. Both visually and mathematically.

Cliff Etzel wrote on 4/29/2008, 9:58 AM

I guess alot of this boils down to what your needs are.

Being a Solo Video Journalist type shooter, the things I need more than anything else is a fast responding NLE that can handle editing similar to Avid Newscutter without the Avid baggage - I need straight cuts, dissolves, titling and color correcting tools and the ability to edit audio. Vegas Pro provides that for me. Is it lacking in more advanced capabilities? That has been discussed many times - the ability to work with native 10 bit footage, poor hardware support, etc. But the nature of the type of work I do is fast turn around with efficient time spent in post - typically for the web with the possibility of broadcast. I edit on both my desktop and laptop without issues so far - I can't say that about PPro. Avid doesn't even install due to non-certified OS (I use x64 XP Pro on both machines). Edius is a no show for me - too kludgy of an interface and I refuse to pay Apple's premium prices for what is basically an over priced Intel box.

The nature of the news video journalist profession for broadcast is in shambles right now. CBS O&O stations are laying off their news people left and right. Newspaper photo journalists are making inroads to shooting video - there is now discussion that the better quality video cameras are having HD frame grabs being used to go to print. The line is blurring between still and video shooters.

Vegas may not be a perfect tool, but my experience has been that what it does for shooters like myself far outweighs the deficiencies other more mainstream commercial shooters lament about.

I think it if you stay within a conservative equipment setup, Vegas works without issues and does so at a very reasonable price. Can that be said about the other NLE offerings? My experience has shown they can't at this time.

Cliff Etzel - Solo Video Journalist
bluprojekt

Coursedesign wrote on 4/29/2008, 10:04 AM

Are you saying that Adobe Premiere offers better time remapping than Vegas without using plugins? I'd like to see that.

Optical Flow time remapping in PP CS3 was a major feature on Adobe's nationwide demo tour last year. Looked great, demoed with a music video.

FCS also has Optical Flow.

It's about time for Vegas to go with the flow too (no pun intended :O).

DJPadre wrote on 4/29/2008, 10:52 AM

Thanks for that CourseD, saved me further rambling...

DJ, coupla comments...

((Go for it... ))

~trusting the display to downconvert properly can be a bad thing,

((Of course, but were not trsuting the display to do anything, were trustingthe display to Display teh resolution being thrown on it.. as an aside, the 720p footage is actually scaled up to 1080p on a 1080p panel from 720p sourced material..
This then comes to the fore when scaling HW within the display fails..
In the end, even thoguh the source is 720p acquired from 1080i and displayed on 1080p, theres that scaling step that 720p will require to fit within that frame of 1080p
This is al device dependant and nothign to do with vegas..
Ie 1080i source--> 720p output playback--> * 1080p display
Its " * " That step which the TV then plays a major role in what we see.
Now this is only for 1080p panels, not 720.... 720 is different in the sense because its actually drawing entire frames based on interlaced fields which are lower in temporal res than the playback display. This is where u get your problems because scaling to 1080p is MORE of a priority to manufacturers as opposed to scaling DOWN to 720p. Why would anyone want to scale down if the panel can display 1080p? Thats their point...

"particularly if you KNOW the display is 720, and no chance of the image being on a 1080 monitor. "

Thats a different story altogether.. in that case, sure, go for it. Im al for it.. If THATS the only display it will ever see the light of day on..
Just make sure your Progressive output frames havent been nuked by Vegas and your source field order hasnt been inadvertanlty reversed when you import prerendered clips which may be using something like Huffy or Uncompressd codecs... Vegas has the tendency to kill clips by not reading the field order properly... even though the tags do exist.. ))

Michael saw this for himself at my NAB presentation.

((Of course he did... Im not saying he didnt.. and i dont doubt your own tests.. all Im saying there are certain things Vegas users need to be aware of before they make this kind of delivery decision... ))

It's quite clear. We spend a *lot* of time testing these things for ourselves, on a wide variety of equipment kindly provided by several manufacturers.

((As do we... jsut coz were at teh arse end of the worlld, doesnt mean we dont knwo what were doing mate.. lol
The crix of teh matter is that over here, 1080p is far more dominat than 720p. Consumers have no idea abotu resolution and panel sizes in relation to viewing distance, and with this predominant lack of education, retailers have been milking them in regard to HD. So now, 1080p is selling about 10:1 over 720p.
Where we are 720p is a non event... thats not to say its ntoa viable delivery option, hell, i started a thread a couple of months back about Vegas scaling, but in all honesty, for me to copete with a competitor offering 1080p, and i was to offer 720p, the client would go for the 1080p offer without question.. regardless of quality..
Over here, its pushed as a means to futureproof a product.. ))

~Are you saying that Adobe Premiere offers better time remapping than Vegas without using plugins? I'd like to see that.

((Yup, thats a definate fact my friend.. check out CS3.. its trully astounding... ))

Shooting high shutterspeeds for slo-mo is something we do a lot of.

((Of course, in addition to emulating frame rates, one must also emulate the desired shutter speed for output.. I thought everyone knew that though?? ))

Twixtor is better, IMO, sure....but it's more money and a lot more time.

((Id glady pay $500 for a "cntrl drag" or a shell integrated "right click set playback rate" option using XYZ algorythm or whatever.. ))

~Note that we're talking about 1080i to 720p, not 1080p to 720p.

((Noted))

Due to Kell, there is little resolution loss. Both visually and mathematically

((actually resolution isnt the only thing to consider... scaled material down to 720 from 1080i offers a slightly higher colour sampling considering the shift in luma within the frame itself. So there are benefits to scaling down if colour is an issue but im not disputing any of wha has been said so far..

Like i said, Vegas users just need to know the limitations of what it can and cant do, based on its existing interpolation engine, be it frame based restructure, or resolution & field ordinance management.