hardware downscaling VS software downscaling

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David Quinn Carder

Member
As many of you probably know already, FCP's downscaling is essentially broken. It introduces jaggies, and the more drastic the scale difference, the worse it looks. I've gotten rid of the jaggies by downscaling with Handbrake before sending the file off to Compressor, but my 1080i footage, after being downscaled to SD, does not look as sharp as the footage does in the Viewer/Canvas in FCP when the Viewer/Canvas scales the content to fit the window.

For instance, if I downscale my footage to 25% size, and compare it to the original footage but with the Viewer/Canvas set to 25%, the original footage looks considerably sharper.

So my question is: will using a hardware scaler, like a Matrox MXO2 LE or a Kona card, output video that looks like the Viewer/Canvas at 25% looks? How much better will it look than using Handbrake or some other software scaler?

My client doesn't want to spend more money than we have to, and render/processing speed is not an issue, so they don't want to spend money just to speed things up. However, if the quality is significantly better than using software scalers, they will probably want to buy a Matrox MXO2 LE or a Kona card or something.

And if hardware is the way to go, what do you suggest? I'm using a Mac Pro.
 
I'm a little confused as to where youre going wrong here. I often mix 1080 footage dropped into a 720 timeline and dont encounter any issues. Even on export.

Ive done straight exports for broadcast from 1080 or 720 to SD and comes up nicely in TV land.

For instance, if I downscale my footage to 25% size, and compare it to the original footage but with the Viewer/Canvas set to 25%, the original footage looks considerably sharper.
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Of course it would, essentially what your looking at is SD vs HD shown in a smaller canvas.

Shoot a soft focus still image on DSLR. At full size you can see the soft focus. View at 25% of original size and it looks sharp as a tack.

Stand 20 feet away from a SD image on a 1080P tv and it looks sharp - now go closer and you will see the image quality drop. Its the nature of the beast.

Ok so to the question. When you downconvert in FCP whats your process? Maybe theres something there that could be done better for a better end result.
 
I don't think I explained myself very well (sorry).

Of course viewing HD scaled down to SD in the Viewer/Canvas should look "sharp as a tack", but for the same reason that looks nice and sharp, when I actually have FCP downscale the footage (as in, downscale the sequence, not just the Viewer/Canvas preview) it should look equally sharp. I was comparing footage scaled to 25% viewed at 100% with footage left at it's original 100% scale viewed in the Viewer/Canvas set to 25%… not unscaled footage viewed at 100% with unscaled footage viewed in the Viewer/Canvas set to 25%. Whatever the engine/algorithm that does the Viewer/Canvas scaling does it right, but that same process is clearly not used when you actually downscale your footage and render it. The problem is exacerbated if you set the Motion Filtering Quality in the sequence settings to anything other than "Fastest (Linear)"—and no, that doesn't make any sense either, but that's another topic entirely.

Does that make sense? The problem is well documented, but try as I might I can't find the page with all the good examples on it (I'll keep looking and get back to you). I assure you it's not user error, and there are plenty of people who have looked for a solution and concluded that the only way to get quality downscaling is to do it outside of FCP or Compressor. That being said, this problem may have been fixed in the latest version of Final Cut Pro. I'm about to upgrade so I'll know soon.

Going from 1080 to 720 is not as noticeable as 1080 to 480, and if you try to downscale for the web for instance (let's say a little 240p clip from a 1080p source), it looks absolutely horrific. If I can't find the examples I was looking for I'll take some screenshots tomorrow.

So my question is not how do downscale better in FCP, but if I downscale outside of FCP, will the quality be better if I used a hardware scaler rather than a software scaler.
 
I just onlined a series of 5 TV shows that were a mix of SD, 720 & 1080i and 1080P. All were dropped into a SD, DV50 timeline in FCP with no serious problems.

How do you monitor your picture? The most important thing in judging your quality is to us good video monitor, properly calibrated and connected to an industry standard video signal. My client uses Kona cards and good quality LCD monitors in all of their edit suites.
 
David S. said:
Have you tried using the Standards Conversions preset in Compressor?
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No, I think that's a Compressor 3.5 feature, isn't it? We are upgrading our Final Cut Studio this week and I have a feeling this will fix the problem, so thanks for the heads up.

Regardless, I am going to post screenshots tonight in case it helps anyone that stumbles across this thread. I'm in Hawaiʻi so it might be a little late. :)


arniepix said:
I just onlined a series of 5 TV shows that were a mix of SD, 720 & 1080i and 1080P. All were dropped into a SD, DV50 timeline in FCP with no serious problems.

How do you monitor your picture? The most important thing in judging your quality is to us good video monitor, properly calibrated and connected to an industry standard video signal. My client uses Kona cards and good quality LCD monitors in all of their edit suites.
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This project is destined for the web, and even if it wasn't, you don't need a special monitor to see jaggies. A good, properly calibrated monitor is certainly helpful in many situations, but it's unnecessary in this particular situation. The problem is glaring.

I wonder, though, if working with DV50 timeline would make a differece… will test tonight when taking screenshots.
 
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One of these things is not like the other (blown up 300% in Photoshop without interpolation):

1281512981.jpg


1281513077.jpg


There are plenty of good examples here, the best one probably being the transition from the floor to the wall seen right next to the cup in the bottom left. And obviously, in motion, this looks a hell of a lot worse. It is also totally consistent with other examples I've seen online claiming to have the same problem.
 
And by the way, both of these I left unrendered. Why? Because after rendering the downscaled version (but not the fullscale version) changes the colors (gamma it seems; brightness/contrast) significantly. That's another topic entirely though…
 
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