Vegas converting 1080i to 1080p

[Jon McGuffin]

I'm going to ask a question I should probably know the answer to and I'm frankly a little embarassed to ask, but I'd like to get the opinions of board members and I think it cold be help to others here in teh forums.

I shoot with a pair of Sony FX1 HDV cameras in 1080i60 and edit on Sony Vegas Pro 8. Why would I need to upgrade my cameras to a true 1080p model when I can just set my project settings inside vegas to progressive and thus 'convert' the 1080i footage into 1080p footage? This is one of those topics that's really bugged me.

I'm sure there must be some benefit to the shooing in the 'true' 1080p30 mode, however I fail to see the purpose of rendering a file into a progressive format if it's not doing the job adequetly.

Can anybody give me some insight as to what the differences are and why one method is better than the other?

Jon

[Perrone Ford]

There are a variety of ways to get from interlaced footage to progressive. All are a compromise, and some do a better job than others.

True progressive footage is always the best way. Unfortunately, Vegas's methods of getting there are not the best second choices. So for people who care about the quality of image produced, they either shoot true progressive if they can, or use a better tool.

[Jeff Harper]

Jon, this is a darned complex subject. I'm flummoxed by it also. It is almost too much to ask for a simple yet thorough explanation, but hopefully somone will come along that will do that.

In the meantime I'd like to recommend reading wikipedia entries on progressive video; it is very interesting.

It will also give you an idea of the complexity involved with the subject.

On wikepedia look at the 24p entry and even though you didn't specify 24p I recall that article particularly was REALLY great, especially toward the bottom where it does talk about emerging formats, etc.

These will not be the specific answers you need and want, but it helped me with an understanding of the subject and I'm sure you will find it worthwhile.

Google "progressive vs. interlaced" etc., and you'll find TONS of stuff, you'll just have to sort through it.

Bottom line for me I found was I don't need to address it yet and it is a non-issue. I can shoot 24p with my FX1000, and choose not to; there is no real good reason to do so for wedding and small business projects. At this point it is a nicety that is not worth the effort involved for me. Again, I speak only for myself.

[Jon McGuffin]

Thank you both for your input... I will checkout the wikipedia entry on this topic..

I feel I do have a pretty good understanding of the difference between Progressive versus Interlaced. What I'm having a hard time understanding is that if Vegas has the ability to convert or blend the video fields into a single frame, then how would that be any different than progressive?

It should be noted I'm not even talking about converting to 24p here, I'm perfectly fine at 30p which would be merger of 60i footage. So there would be no cadence problems, etc.

Perrone, you talked about other options that do a better job of converting video into progressive mode. Can I assume that using a utility such as Cineform HDLink's telecine removal would do a superior job of delivery a 24p?

Jon

[Perrone Ford]

Originally Posted by Jon McGuffin

Perrone, you talked about other options that do a better job of converting video into progressive mode. Can I assume that using a utility such as Cineform HDLink's telecine removal would do a superior job of delivery a 24p?

Jon

This is a quote from the Cineform FAQ:

Be aware: For best quality telecine removal, you should always shoot in your camera's progressive mode if it is available. Why? If you shoot in 24p mode (even when wrapped in 60i) we can perfectly remove the redundant fields. However, if you shoot in interlaced mode you have never recorded any progressive frames, so we have to create progressive frames were none actually existed. This process works, but the resulting progressive frames are usually "softer" (less crisp) than if you shot in a 24p mode originally.

[Jon McGuffin]

Well Perrone,

That statement I think pretty much answers my question perfectly. So there is a loss of detail and sharpness when software tries to blend fields, period. It's funny, you see all across the boards here people so concerned with a generational loss of quality converting one format to another, but virtually nobody talks about the fact if you are shooting with a interlaced camera (HD or not - and most of are 60i), then you're automatically going to loose something if your delivery method is going to end up on a computer screen.

As a matter of fact, considering even SD DVD discs can be burned in progressive format as long as their played back on a progressive DVD player of which nearly 100% are, why in the world would anybody want to work with interlaced footage? Who's really broadcasting in NTSC nowadays?

If you're not putting it on the web, creating a computer video file for playback, putting it on a DVD, or authoring a Blu-Ray, what else is left? All those formats screem progressive.

Jon

[Perrone Ford]

I would assume that most shooters on sites like this are the upper echelon of amateurs and prosumers (and some pros) and wouldn't buy cameras that didn't shoot progressive unless they had to.

As for shooting interlaced, it still has it's place, and some broadcasters (like DiscoveryHD) still want 60i. So you can't just turn your back on it depending on what you're doing.

[Jon McGuffin]

Despite their being some need for interlaced footage out there, we're obviously moving toward a progressive world. One aspect of at least 24p progressive that has always peaked my interest is the fact that you're producing 20% less frames each second of video which should directly correlate to 20% less processing power & 20% less hard drive space, 20% faster rendering (all things equal) than a 30p equivelent.

I've seen 24p footage side by side to 60i and even though I can barely tell a difference, it's quite negligible. I would just assume shoot, edit and deliver in a pure 24p manner...

Jon

[John Cline]

1080-30p has half of the temporal resolution of 60i. When we get to 1080-60p, then I might be interested.

[Ron Evans]

I agree John. I will not move from 60i until I can have 60P. I really dislike the motion artifacts of slower frame rates and find them quite annoying. Especially as its impossible to do a satisfactory conversion of 24p on most TV's it makes this film frame rate even worse!!!! My ideal is HD that looks just like real life not some artists version of what life should look like. I would like my output to be as if the viewer where right there either in the audience of a show or on the ski slopes. No judder and really big depth of field. With the increase in 16x9 sets away from CRT's this is a real problem. The sets are progressive but most of the source is interlace. What people see is really dependent on the quality of the deinterlacing and a lot of the time its poor. Hopefully the newer 120Hz and 240Hz sets from Samsung and Sony that do interpolation to create extra frames can really get a higher frame rate from the source 60i that is closer to the smoothness seen on a CRT.
Ron Evans

[Joe Busch]

http://www.dvinfo.net/conf/what-happ...e-slow-mo.html

Watch the videos, try it on your own footage.

If you're happy with your 60i camera, imo there's no reason to upgrade..

Yes, 60p will look better, but 1080p60 is pretty rare in the consumer/prosumer world... this is a pretty good compromise.

[Jon McGuffin]

Originally Posted by John Cline

1080-30p has half of the temporal resolution of 60i. When we get to 1080-60p, then I might be interested.

Wow, that's a statement. Now you're going to have to explain what you mean by 'temporal' resolution and how 60i is somehow better than 30p. :-)

Again, to make an image, through 60 fields, don't they *have* to be blended on either a CRT or LCD screen to show the image?

Jon