View Full Version : Capture in 60 convert to 24?


Stephen Eastwood
July 2nd, 2007, 02:53 PM
Would there be any benefit or drawback to capturing in 60i 1080x1440 and then rendering to a 24P 1080x1440 file? would there be any problems? gains or losses?

Next question is using a XHA1 and HV20 shooting in HD should I have a working space of 1080x1440 or 1080x1920 and what should the output be? 1440 or 1920?

Stephen Eastwood
http://www.StephenEastwood.com

Doug Quance
July 8th, 2007, 08:43 AM
Allow me to bump this thread.

As I am considering another camera purchase, I, too, am curious if 24p is all that important in-camera... or if conversion later is preferable.

Chris Leong
July 8th, 2007, 09:04 AM
Hi there

Shooting a short film with two cameras - one FX7 that's shooting at 1080i60 and an HD110 that's going at 720p24.

The main camera is the JVC so the project will be editing in 720p24.

I ingested the FX7 stuff and then used MPEG Videoclip to deinterlace, blend and cross convert the 1080i60 stuff into 720p24 for intercutting. In the future, I'd be using a Kona or BM card to do it but the software method, while slow, works well.

Apart from the CCD/CMOS difference, which is slight but detectable if you know what to look for (e.g. verticals on pans or on subjects moving horizontally), it looks acceptable.

Of course, this is a dramatic film I'm shooting, so if the audience is sitting there going "is this CMOS? or CCD?" then I've got problems beyond the intercutting of two camera systems...

HTH
Cheers
Chris

Ben Winter
July 8th, 2007, 01:40 PM
Perhaps I can shed light on this question, as I own an FX1 and thus am forced to convert to 24p in post if I desire it.

The conversion process for me can be one of two options: I can shoot in 60i, and either convert it with DVFilm Maker or with Cineform's AspectHD capture tool. Alternatively, I can shoot in the faux-24p mode "cineframe24" and then remove the pulldown with Cineform, making it true 24p although more stuttery. DVFilm Maker's conversion is more time-consuming, however the results are more appealing, with less loss of resolution. Cineform's conversion is good for on-the-fly capture where time is of the essence.

Although the 60i to 24p conversion is said to lose resolution, I cannot really notice the difference. Neither can my audience, and that's what really matters. I recently projected my 20 minute short film on a 40' theater screen and it looked beautiful. This was not a film projection however.

I now prefer shooting 60i originally and then converting to 24p later, as this gives me more flexibility for variable frame rate later. For instance, I can acheive 60% slow motion with 60i to 24p without any forging of data like Twixtor or AE does.

For time-sensitive projects however, having in-camera 24p can be desirable because I will admit the 24p conversion process is time-consuming, even on my quad-core PC.

Ian G. Thompson
July 9th, 2007, 02:14 PM
I would love to see a side by side comparison with one footage shot in 60i converted to 24p and the other shot in pure 24p (but the same shot). I also always heard that converting from 60i to 24p will have more of a resolution loss than shooting straight 24p.

Chris Leong
July 9th, 2007, 02:17 PM
Ian
I don't have AB shots to compare but I will have pretty soon -- I'm doing a news style piece with the same two cameras (a JVC HD110 and my FX7) in a couple of weeks and will arrange to have some side by side stuff shot, just to see what's really up in the conversion.
Cheers
Chris

Ben Winter
July 10th, 2007, 12:18 PM
I know its a company who's tooting their own horn, but have a look at DVFilm's quick comparison:

http://www.dvfilm.com/maker/MakerVegas.htm

It has an edge over other conversion programs, and because it's a small stand-alone program, you can open multiple instances of it and assign them to single cores of a CPU to multi-task it.

Of course there is going to be resolution loss in any framerate conversion like this, but it's important to note that with DVFilm Maker the difference is almost negligible.

Perhaps more important than resolution loss is the difference in motion judder using this conversion method too. The company warns against overexposing images where there is movement because of motion judder artifacts in the highlights.

Ian G. Thompson
July 10th, 2007, 01:27 PM
Ian
I don't have AB shots to compare but I will have pretty soon -- I'm doing a news style piece with the same two cameras (a JVC HD110 and my FX7) in a couple of weeks and will arrange to have some side by side stuff shot, just to see what's really up in the conversion.
Cheers
ChrisChris that would be cool if you could. Lookin forward to it.

Stephen Eastwood
July 11th, 2007, 12:17 AM
I could get two XHA1's to shoot comparison footage, also can probably shoot a dvx100 and hv20 as well side by side for comparison files while I am at it since they are available. Since I am new at video what would be something good to shoot to really see a comparison?

Also what exactly is the DVFilm products doing? is it just converting frame rates to 24? or does one of there products actually speed up rendering in other ways?

Stephen Eastwood
http://www.StephenEastwood.com

Ben Winter
July 11th, 2007, 01:54 AM
I could get two XHA1's to shoot comparison footage, also can probably shoot a dvx100 and hv20 as well side by side for comparison files while I am at it since they are available. Since I am new at video what would be something good to shoot to really see a comparison?

Something with quick versus slow pans/lots of motion would be very good. Motion judder is the big comparison. Also shoot a resolution chart if possible.

Also what exactly is the DVFilm products doing? is it just converting frame rates to 24? or does one of there products actually speed up rendering in other ways?

It is a standalone program that converts 60i footage to 24p. It does not add-on to other programs to decrease rendering time or anything like that.

Stephen Eastwood
July 11th, 2007, 11:08 AM
Where can I get a resolution chart?

Stephen Eastwood
http://www.StephenEastwood.com

Ben Winter
July 11th, 2007, 11:33 AM
Where can I get a resolution chart?


Since this will be relative and not absolute comparison, consider using the Wedgechart at the bottom of the page.
http://www.bealecorner.com/trv900/respat/#EIA1956

Stephen Eastwood
July 11th, 2007, 03:07 PM
Since this will be relative and not absolute comparison, consider using the Wedgechart at the bottom of the page.
http://www.bealecorner.com/trv900/respat/#EIA1956

I am going to first determine what the baseline iso rating is for the various cameras so that the shutter speed and aperature of the cameras stays the same to eliminate that as a variable, what other concerns would one have from a side by side comparison? would placing the two cameras side by side and shooting both panning and than shooting someone walking and than running through the frame be decent tests? should the frame rates stay consistant at 1/60th for both 60i and 24p/f shooting? I figure by zooming in a decent amount from a distance with the two cameras side by side than comparing the other two the same I will have several comparison and the distance and angle will be minimal to create near identical framing. any thing I should be doing that I am forgetting I am hoping to do this sometime by the end of next week or early the following at the latest.

I have the dvx100 and hv20 and xha1 to use just have to borrow another xha1 and setup a good day to do it.

Stephen Eastwood
http://www.StephenEastwood.com