Getting to grips with HDV's higher quality

[Douglas Spotted Eagle]

Originally Posted by Augusto Manuel

The only way you really can compare footage and analize the quality of a video image is using a professional industrial critical monitor. Using web images or consumer even plasma monitors to do so does not make much sense. People are getting sloppy when analizing things these days. About the downconverted footage being superior to SD DV footage, it is cut and clear. Just get an 8045Q monitor or larger (rent one if you dont have one) and observe the difference.

My two cents.

I so wish I could afford an 8045....what a great monitor.
We've got two Premiere 234's on the LCD side, and a BVM9 with HD/SDI. It's not optimal, but it is a nice little HD monitor, and it's a loaner so we can get by until we can afford a better CRT. We also have a WUXGA projector and an 11" screen, which is where we do most of our test viewing.

[Boyd Ostroff]

Originally Posted by Augusto Manuel

The only way you really can compare footage and analize the quality of a video image is using a professional industrial critical monitor.

Well of course it's hard to dispute this, but for my purposes comparing two images on the same monitor teaches me something, which is why I did it. Draw your own conclusions, or ignore it completely, I'm just sharing what I did.

Most of my work has been done with the goal of projecting it on 40' or wider screens with 10,000 lumen projectors. Subjectively, I think my LCD panels have served me very well for this. If you want to broadcast your footage then it probably calls for something else; that's not something I have any experience with.

For the last project I did in Buenos Aires I wasn't happy with the way the crew setup the projectors initially, but when we had a few minutes I played the Quicktime movie fullscreen on my Powerbook while we adjusted the projectors and we got it to match pretty well. Now the Powerbook screen is not a production monitor by any stretch of the imagination, but it was what I had to work with there, so it made my job much easier to adjust the projectors to it instead of the other way around.

[Thomas Smet]

As much as I love quality you kind of have to ask yourself if it would really make a difference testing this stuff on that high end of a monitor. Very few if any people will ever actually watch your video on that type of monitor and while it would be great to get a great looking image you also need to find out what works on a consumer monitor since consumers will be watching it.

Sometimes video can look great in my studio but if the client watches the video on a not so good TV then the video may actually look bad. It is always good to make sure your video will look good on a lower end TV as well.

Using a decent level TV can give you good test results if all of the other variables are the same. That TV may not tell you exactly how the image will look for everyone but it will tell you if there is a difference between A and B. If that TV happens to be a consumer grade TV well then chances are that is how it will look for your clients as well.

[Douglas Spotted Eagle]

Originally Posted by Thomas Smet

As much as I love quality you kind of have to ask yourself if it would really make a difference testing this stuff on that high end of a monitor. Very few if any people will ever actually watch your video on that type of monitor and while it would be great to get a great looking image you also need to find out what works on a consumer monitor since consumers will be watching it.
.

To a limited extent, I agree w/you, because a lot of consumers don't have comparable sets.
That said, even on my 99.00 Sanyo monitor, I can clearly see a diff between HDV downsampled and/or zoomed in SD, and video acquired in SD/DV.

One trap that I see/hear a lot of editors fall into is "The consumer doesn't have a great monitoring setup whether it's display or audio, so I don't need one either." That's a scary place to be. We're visual and aural surgeons, and need those microscopes to determine exactly what is in our content, or else someone will trip us up. These days, the range of what consumers have will go from extreme top end to extreme bottom end. Aim for the top, and feel good if you fall only a little short of the goal, rather than aiming lower, and feeling good because you fell into the 5 ring instead of the 1 ring on the target.
Did I mix metaphors or what?!

[Steven White]

Originally Posted by Boyd Ostroff

That's interesting Steven. I don't see much difference in your two examples but as you say, it probably shows up better in motion. There's noticeable interlace in these - were they handheld maybe?

It's actually from a pan. There is indeed noticable interlace, as handling the fields properly in down-conversion was (at the time) as much of an issue as getting anything else right. I had posted this image a while back, as well as a description. The 4:1:1 is very visible when looking at the green blades of grass against the low-chroma background. First generation DV mosquito noise isn't terrible, but it is noticable on the edges of the goose's neck.

I see a big quality difference shooting HDV and downconverting the component to either 480p or 576p.

I don't buy it. In theory it is always better to work directly from the original digital source... the only "benefits" I can imagine from capturing analog components after HDV compression are the analog smoothing and noise giving the impression of improved image quality.

DSE and others have implied that you get superior results when capturing uncompressed HD from component.

I still haven't really seen this tested. It is widely expected to be true, but I don't know that anyone has the hardware, and has actually done the capture this way.

-Steve

[Douglas Spotted Eagle]

Originally Posted by Steven White

It's actually from a pan. There is indeed noticable interlace, as handling the fields properly in down-conversion was (at the time) as much of an issue as getting anything else right. I had posted this image a while back, as well as a description. The 4:1:1 is very visible when looking at the green blades of grass against the low-chroma background. First generation DV mosquito noise isn't terrible, but it is noticable on the edges of the goose's neck.



I don't buy it. In theory it is always better to work directly from the original digital source... the only "benefits" I can imagine from capturing analog components after HDV compression are the analog smoothing and noise giving the impression of improved image quality.



I still haven't really seen this tested. It is widely expected to be true, but I don't know that anyone has the hardware, and has actually done the capture this way.

-Steve

It's very true, all you need is a Decklink HD, Kona, or Bluefish card and you can test this for yourself. Of course, your app needs to be HD-capable.
For those that will be at WEVA, I'll likely have my personal machine with a BlackMagic card in it, and you can see it yourself. (I'm expecting that the machine provided won't be up to par, and so anticipate carrying my own machine)

[Boyd Ostroff]

Originally Posted by Steven White

I don't buy it. In theory it is always better to work directly from the original digital source...

I certainly agree with the theory. Do you have a Z1? If so, hook it up to a monitor, set the camera to HDV with component downconvert to 480p. Then watch as you switch component back to 480i. The difference is striking, it looks almost the same as 1080i on my 17" 1280x768 Sony widescreen LCD.

I think what's happening is that that 480i downconversion is doing some vertical blurring to prevent thin horizontal lines from flickering (which is common for most interlaced cameras). But in 480p mode it probably doesn't do that.

[Steven White]

The 480p probably looks significantly better because it's 480p60 - and hence twice the resolution of a 480i down-convert. I only have an FX1, so that option isn't available to me. However, it's easy to convert 1080i60 to 480p60 in post... and I expect this will yield better results than capturing along components as well. You can expect however to have to do some optimization to first match, and then exceed the results the Z1 acheives in hardware.

-Steve

[Steve Crisdale]

And why, oh why is there this insistance on using JPEG to show off still images of how HDV to DV/SD compares?

I know you all are going to rail-on about bandwidth and the size of the image if you use un-compressed, but there are compressed alternatives that are superior for displaying this still image stuff from a compressed video source.

Don't forget that you are using a compressed source when using HDV in any form. So regardless of whether you transcode HDV video to an uncompressed format, it remains video from a compressed source... Now, when you go ahead and JPEG any still - let alone the fact that it's also come from an interlaced stream so if you don't do the de-interlace properly... well - you're just re-compressing the compression all over again. And I'd bet that when the JPEG is made that the quality setting aimed for is medium; so even more destruction occurs.

There are formats such as TIFF LZW and PNG that are preferable (not perfect) for providing compression algorithms that are less destructive for your purposes than JPEG. Better still, if you want the best possible quality for comparing still frames - don't use any compression at all on your comparison images.

[David Newman]

Originally Posted by Steve Crisdale

...There are formats such as TIFF LZW and PNG that are preferable (not perfect) for providing compression algorithms that are less destructive for your purposes than JPEG. Better still, if you want the best possible quality for comparing still frames - don't use any compression at all on your comparison images.

Correction: TIFF LZW and PNG are mathematically lossless compressions these should be used (particular PNG -- as more tools decode it) in favor of raw format like BMP (which is a waste of bandwidth.) Use PNG as is indentical to the raw source.

David Newman
CTO, CineForm