Interlacing on HD progressive displays?

[admin]

from email...

Quote:

Could you update your "understanding your source" page, particularly to speak to deinterlacing and how it applies to the fact that more people have HDTVs now? (last update 2006) I captured a digital 8 source, via firewire to my PC and trying different settings for playback on a samsung plasma HDTV. I'm using Adobe Premiere and finding it looks best left interlaced and using lower fields...however there is still some grainyness. I think your site is awesome but would love it you could update pages, or make a new page to speak to capturing interlaced video for playback on a progressive player...tips...anything that would help...thank you!

That's actually on the to-do list ... quite a few complex guides are going to be split into smaller chunks and expanded/updated. I had not considered interlacing updates for HD displays, great idea!

When that guide was originally written (2003), HDTV was not as common as it is now. Updates last made in 2006 still didn't really address HD tech.

For any television set, be it SD or HD, leave your footage as interlaced. Although it is true that HD displays (LCD, plasma, LCOS/SXRD, etc) are progressive, they come with very powerful deinterlacing hardware -- software methods are wholly inferior to what the TV does. Therefore, interlace should be left as-is when encoding the video. Let the TV worry about it.

Being that DV is bottom-field, a BFF interlace was the correct choice.

The grainy image quality is due to your camera and the DV compression. Consumer cameras are simply noisy. When viewed on a large HD display, it becomes more obvious. All flaws are easier to see on larger HD sets, especially on homemade videos and pre-HD broadcast re-runs. Your encoding software, and any re-encodes done in your workflow, may have also affected the quality. The software's encoding engine, and the user's settings, are both very important in determining final video quality. Premiere uses the MainConcept MPEG engine, so that's good -- it's the best one out there. You just need to worry about picking the best settings.

So while no specific mention of HD is made on the interlacing guide, nothing here has changed. For any TV, leave interlaced, period. The only modern valid reason to deinterlace is when producing content for streaming (Youtube, for example), or as a restoration technique for certain errors or correction/filtering methods.

Hope this helps.

[klassal]

wow super fast response

ah built in deinterlace hardware...didnt know that...

I did straight capture through firewire/premiere....and then transcoded in encore using 8.5 lower fields...basically maxing out but still notice the grainyness

based on research of your site and others seems my last option here is filters. Can you comment on Adobe's filters, specifically noise reduction? Also alot of the footage is low light which doesnt help...

In my travels I came across Topaz Enhance software which is supposed to be very good, so I bought the 30 day demo and messing with that...but the pain is to actually test this sort of thing I have to take hours to render small clips, write down all the settings and watch a test DVD on my HDTV and compare... have you used these filters? Also in their manual they recommend deinterlacing before applying any filters...any idea why? Perhaps they work better, but to me the end result of deinterlaced video on HDTV, the movement doesnt look natural anymore.

Can you make some recommendations around noise reduction that might help me out?

That would be another good addition to your site, perhaps more detail of common video issues/solutions( I've read the one you have up now) and some suggestions for common effects found in Premiere...or other software that is typically used

Like I said you guys are the experts and do this ton more than I do so I would appreciate any tips for this so I dont have to burn 50 more test DVD! Ha

oh yeah and this site seriously kicks ass...i've used it here and there over the last few years....would love to see updates

[admin]

This is where you run into problems. Adobe makes great editing software, but its filtering abilities expect "professional grade" input, meaning on minimal filtering is needed. Given that, know that the filters are not strong enough to handle many consumer-format errors (especially not VHS errors).

Premiere is also a big pig on computer resources. You may have some dropped frames on your DV input, which could cause some undesired effects. I don't recall offhand if Premiere provides a frame-drop counter.

Ideally, perform each process one by one. For capturing, use the freeware tool WinDV (or the payware Scenalyzer). All these tools do are take the DV video off your video tape, and dump them into an AVI container file on the computer.

When you captured into Premiere, saving out the file as a DV AVI can be a pain if the project isn't set up to just pass the file in output (rather than re-encode to another format).

After you get that file on the system with WinDV, you want to filter it. Now these is where you can run into many methods, from minor fixes found in Premiere, to complex filter chains in VirtualDub (GUI based tool) or Avisynth (command-line tool).

I tend to stick with the GUI-based filters found in VirtualDub, but the Avisynth ones can be better in some circumstances. I'd really have to see the video.

After filter work is done, save the file out to a low-compressed AVI -- yes, even lower than DV was. Either fully uncompressed YCrCb (YUY2) or HuffYUV are usual choices. These are often referred to as "intermediary" formats.

Then import this into Premiere, edit, and then export for your media, be it streaming or DVD/Blu-ray (disc-based content).

Certain filters just need to work with a progressive version of video. However, not all deinterlace methods are equal in quality. The best deinterlacers are generally found in VirtualDub or Avisynth. While it may seem silly for a freeware tool to have better methods than pro software, realize that a number of video programmers release these in public, before moving on to sell them (and upgraded versions) to commercial interests like Adobe or Sorenson. Some forever stay in freeware, not used by commercial software.

You need to pre-process the video in those tools, then import to further progressive-only cleaning tools (Topaz Enhance,for example). Other options include Steadyhand, vReveal and NeatVideo, among others.

The Topaz Enhance site looks nice, tempting examples, but they are (of course) cherry-picked and not necessarily a good example of the average experience. It's not much different from those weight loss ads that show a person losing 100 lbs, with a tiny text on screen warning you this was an atypical outcome. The FTC hasn't started picking on the Internet yet, give it more time -- stuff like this will eventually be regulated, I bet.

Not all deinterlace filters respect motion as well as they could do. This is the primary difference in algorithms.

Thanks for the kudos on the site. There is a lot of content to be added/updated. It's just taking a lot of time to get everything in place for the new CMS.

Use DVD-RW and DVD+RW, it's cheap for tests. I burn a lot of tests each week -- no way around it.