How good is low budget upconversion from SD to HD

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Gyr
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I'm one of those pondering a move to HDV/HD and it struck me that I haven't seen much comment on upconverting SD material to HD.

Is there anyone able to comment on how footage shot with a decent quality DV camcorder would look if it was upconverted and compared on a HD monitor to footage from an FX1. Would it be difficult to tell the difference or blindingly obvious or somewhere inbetween?

I'm working on the assumption that this is a low-budget upconversion, so very expensive gear is out. I must admit I don't know what is available to do a low budget upconversion, but hopefully someone can advise me.

steve
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Joined: Apr 8 1999

If you think about it, HD resolution (as offered by the FX1 is about twice that available from a good quality DV source, (1440x1080i vs. 720x576). You can't generate detail that isn't there at any cost!
This was more than obvious at Video forum last week when H Prestons had FX1 and Panasonic DVX cameras feeding the same display types side by side. The SD video from the DVX was upconverted in the HD displays. With the high res. displays the SD pictures showed a significant amount of ringing.

Steve

harlequin
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Quote:
Originally posted by steve:
If you think about it, HD resolution (as offered by the FX1 is about twice that available from a good quality DV source, (1440x1080i vs. 720x576). You can't generate detail that isn't there at any cost!
This was more than obvious at Video forum last week when H Prestons had FX1 and Panasonic DVX cameras feeding the same display types side by side. The SD video from the DVX was upconverted in the HD displays. With the high res. displays the SD pictures showed a significant amount of ringing.

Steve

actually it is approx 4x resolution
it's twice as wide by almost twice as deep therefore 2x2=4

Gary MacKenzie

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infocus
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Quote:
Originally posted by steve:
You can't generate detail that isn't there at any cost!

Very true. But interpolation can make a subjective improvement by removing jagged edges, and I believe this is a feature appearing on high end DVD players now. Try an experiment - take a high res still image in Photoshop, resample to a lower resolution, then resample back up again. I'd expect the end result to have lost (obviously) some of the detail of the original, but subjectively look better than the middle image when both viewed same size.

I saw the comparison Steve mentioned, and the difference between the two cameras was startling. If you can afford to wait, the FX1 is probably the tip of a forthcoming iceberg.

Alan Roberts
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I've a lot of experience with up- and down-conversion, at all cost levels.

You should regard the HD display as a magnifier for the SD footage; anything wrong with it will show up. The reason's simple, the fact of presenting it on an HD display removes the SD scanning system from the picture and leaves you with only the picture itself. So you see all ther nasties that tend to get covered up when you view in SD.

Typically what you see is the limitations in filtering and detail handling, they show up most. In all cameras there are circuits to artificially beef up the detail content, 98% of the time this operates at too low a frequency (beware of statistics, 97% of them are made up). The effect
of this is to overemphasise the middle frequencies while doing nothing to the extreme high frequencies, where noise would be excessively increased if anything were done to it. So, when up-converted, this produces ugly ringing; it looks like a child's drawing, with black outlines round everything. When the same scene is shot with an HD camera, the same can happen, but the ringing is at twice the spatial frequency so the ringing is half the width and duration, it looks better. I specialise in eliminating it altogether for high-end production (including HD shooting for cinema).

Also, most DV cameras are rather low-budget by HD standards, and do not handle contrast at all well. This hows up like a beacon when you see it big screen. Highlights are clipped, shadows blocked in. Again, I specialise in eliminating that in high-end production.

Most of the broadcasters who demand HD footage, have, in their contracts, clauses detailing just how much up-conversion they will tolerate, and which cameras they will allow. For example, the BBC series "Rock Face" was originally to have been shot on 35mm film, but budgetary constraints meant that it had to go to HD. Some of the locations were horrible to get to, and so sequences were shot on DSR500 and up-converted. Even when the reuslting programme was down-converted for showing in the UK, I could tell which sequences these were; they were softer and didn't handle contrast as well. There was no formal agreement on the amount of up-conversion for that shoot, but the rules have been tightened since; one contract I've seen demands not more than 25% of each episode to be non-HD originated, and not more than 59 seconds of non-HD at a time. That means it can only be used for fill shots, not for significant location shooting.

A very good way to try this for yourself, is to simply feed your SD footage into a hi-res panel display. It will do the up-conversion for you. The 37" Alis Sony Wega we had on the DVDoctor stand is about the lowest res that makes sense for this (1024 pixels by 1024 "interlaced").

Hope that helps.

Get my test cards document, and cards for 625, 525, 720 and 1080. Thanks to Gavin Gration for hosting them.
Camera settings documents are held by Daniel Browning and at the EBU
My book, 'Circles of Confusion' is available here.
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infocus
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Quote:
Originally posted by Alan Roberts:
Some of the locations were horrible to get to, and so sequences were shot on DSR500 and up-converted.

Did that really save much bulk, weight? I wouldn't have thought there was a huge amount to choose between a DSR500 and an HDCAM, though stand willing to be corrected!

Any comments on how a DSR500 compares with a Z1, picture quality wise, and in favourable conditions?

Alan Roberts
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Yes, huge difference. The HD was HDW900s with Panavision mounts and lenses (have you tried carrying long Panavision lenses?). Actually it wasn't the need for the 4 extra porters to carry kit over the moors for 4 hours each day that swung it, it was the fact that a DSR500 will run for hours on one battery, the Panavised 900 would run for about 40 minutes.

Get my test cards document, and cards for 625, 525, 720 and 1080. Thanks to Gavin Gration for hosting them.
Camera settings documents are held by Daniel Browning and at the EBU
My book, 'Circles of Confusion' is available here.
Also EBU Tech.3335 tells how to test cameras, and R.118 tells how to use the results.

Gyr
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Joined: Jan 17 2005

Many thanks to everyone for their comments - that's pretty much cleared it up in my mind.

I need a new camera now and these comments rule out upconverting SD as an option. It would be nice to wait for NAB, but presumably anything announced there won't hit the shops for a few months. It looks like an FX1 for me. Even if I only get one years use of it I think I can still justify it (though obviously I'd rather use it for longer than that).

StevenBagley
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Also, apart from the Canon XL2, the Sony DSR570, the Sony PDX10 and the JVC DV700 all the current cameras are 4:3 so would need either cropping to 16:9, pillarboxing or shooting with an anamorphic adaptor -- all of which bring their own set of problems.

Steven

Alan Roberts
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Yes, exactly right. Get an FX1 now and use it. There will be better and cheaper cameras to compete with it, but when that happens you'll have been making HD pictures and have the experience to judge the nerwer products for yourself. The true wide-screen of the FX1/Z1 outweighs many of the disadvantages for me.

Get my test cards document, and cards for 625, 525, 720 and 1080. Thanks to Gavin Gration for hosting them.
Camera settings documents are held by Daniel Browning and at the EBU
My book, 'Circles of Confusion' is available here.
Also EBU Tech.3335 tells how to test cameras, and R.118 tells how to use the results.

Smithnc
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What's going to happen when we all have HD displays, will our current DV look awful or will the displays have a SD setting?
I suppose you could just use the centre 25% of the display! Maybe up-converting software will improve.

Nick

infocus
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Several of us have been banging on about "future-proofing" for a while now, and HD is now starting to bring it to the fore. Personally, I think 16:9 v 4:3 is far more of an issue than HD v SD - broadcasters have had to live with this for a number of years now in the UK, and the true awareness is just beginning to sink into the consumer market. The vast majority of screens will be widescreen well before they are HD.

It's why I would insist that if I was paying to have such as a wedding video made (intended as much for the future as for now) it would have to be 16:9. At the moment, I'd probably expect to pay extra for that, soon I think the consumer will be being short changed if it's not the norm. In the not too distant future the same thing can be said of High Definition.

As for "will our current DV look awful", then probably awful is not the right word, but not a patch on what is available! You can't invent detail that was never there. (Anybody watching "The Rotters Club", with all the archive film? We thought it looked good at the time..... ) On a Video Forum stand recently a DVX100 was being shown on a HD monitor, and it looked quite good. Until you looked at the identical monitor next to it and saw the output from the FX1. Chalk and cheese.

steve
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I've got a feeling of deja vu on this thread "You can't invent detail that was never there"
"On a Video Forum stand recently ..... and saw the output from the FX1".
I do accept Alan Roberts' argument about DV enhancements (peaking etc.) looking worse on HD, but in a few years all the legacy footage being laid down now will be viewed on HD monitors/TVs, - unless of course one is having a 'retro viewing session', and wheeling out the '90s vintage kit!

Steve

Alan Roberts
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Steve, that's exactly the point; the vast archive of SD will be of little saleable value when we all have HD because it'll all look nasty on big screens, it already does now. This is giving the major braodcasters a lot of problems, because the value of the archive has been suddenly dropped as a result of customers wanting HD material.

Get my test cards document, and cards for 625, 525, 720 and 1080. Thanks to Gavin Gration for hosting them.
Camera settings documents are held by Daniel Browning and at the EBU
My book, 'Circles of Confusion' is available here.
Also EBU Tech.3335 tells how to test cameras, and R.118 tells how to use the results.

StevenBagley
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It's also why it pays to keep hold of the original version of the footage and not just the edited master as this piece mentions: http://www.bbcresources.com/postproduction/london/cards.html

Not so much of a problem with DV (due to most of the data being cloned rather than copied), but keeping the original tapes and your project files about might help protect the footage by being able to re-render text and graphics at a greater resolution etc.

Steven

steve
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If the third option for editing mentioned in the DV Doctor FX1 review (i.e. proxy editing using the downconverted DV output then re-rendering the project by re-capturing from the master as HDV) catches on, then needs for both immediate use and archiving for posterity will be met.
In addition, the step increase in processing needed to edit HD can be accommodated easier if the final HDV render can be done either off-line (say overnight) now using contemporary PC resources, or deferred a while to when display at HD is necessary and editing hardware will likely be more up to the job.
Despite HDV being tape which is being seen by some to be cumbersome and prone to dropouts, digital tape does seem to archive well and at less than 3ukp per hour, is ridiculously cheap compared with the kit used to capture and playback the footage on it. Quite unusual today where the preferred business model is to lure the customer into high running costs by way of cheap initial purchases, ala Gilette with free razors and sell blades for life!

Steve

Alan Roberts
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Yes, again, exactly right. The "edit DV as proxy, then conform HD" route is the most cost-efficient for all of us. That's how HD's been produced in this country since 1988 to my certain knowledge. It's only been in the last 18 months that the cost of desk-top HD NLE has dropped enough for production to work directly on the HD.

Get my test cards document, and cards for 625, 525, 720 and 1080. Thanks to Gavin Gration for hosting them.
Camera settings documents are held by Daniel Browning and at the EBU
My book, 'Circles of Confusion' is available here.
Also EBU Tech.3335 tells how to test cameras, and R.118 tells how to use the results.