Deinterlacing -- in cameras, in software, and monitors

[Douglas Spotted Eagle]

Originally Posted by Steve Mullen

While the V1 does not use a deinterlacer IN the camera as do cameras that derive "no motion artifact video" from interlace scanned CCDs -- during capture to an intermediate codec or when playing a 1080i timeline to an HDTV and always when viewing on a flat-screen monitor -- deinterlacing is used.

The Realta HQV 1080i motion-adaptive deinterlacerchip is considered the "best" hardware deinterlacer. Most deinterlacer/scalers convert 1080i video to 1080p using vertical interpolation to scale each individual 1080i field directly to a 1080p frame. The vertical resolution of each displayed field is thus limited to the 540-line vertical resolution of each field. Vertical interpolation acts as a filter, which reduces the vertical resolution and softens the image.

The HQV uses pixel-based motion-adaptive deinterlacing, which applies "interpolation" to image areas that are in motion, but merges (weaves) information from odd and even fields in static image areas. Merging field information slightly reduces 1080 line vertical resolution in static image areas.

With HQV there isn’t a dramatic change of image sharpness when an object is moving -- an annoying artifact, called resolution pumping or breathing, which occurs when the entire image resolution decreases with movement. Or, when moving "regions" lose vertical resolution. One way to reduce this artifact is to slightly further decrease resolution on still images so that breathing is not as noticeable.

The Realta algorithms provide higher resolution in the moving image areas, so there is no need to decrease the resolution of static areas. The HQV’s motion-adaptive deinterlacing virtually eliminates line twitter during vertical movement, and there were very few jaggies along diagonal edges.

The HQV chip implements the algorithms in the $60,000 Teranex deinterlacer. Obviously the chip is far cheaper, but it does illustrate why the typical deinterlacer/scaler used in cameras, in software, and in monitors don't do a very good job. (In the case of software, the problem is doing the computations in real-time. If you are willing to wait -- software deinterlacing of 50i/60i is better than what can be done in the camera.)

Bottom line, while the V1 doesn't use deinterlacing "in camera" -- once it records interlace -- the quality you see (and many if not all of the artifacts folks think is FROM the camera) is dependent on the deinterlacer used AFTER the V1 does it's job of recording.

Folks might want to also read this article on HQV, written by Greg Rogers. There is some very good, accurate information there.

[Bob Grant]

As interesting as the article is I still want to know what any of this has to do with 25PsF or 30PsF. The article is talking about (I assume) de-interlacing 1080 60i, not 1080 30PsF. It also mentions the problems of rescaling and yes I'd agree that's a huge problem.

Here's another aspect to what Steve is trying to convince us of. He's saying we need to maintain a full end to end progressive workflow, at NO point should we allow the frames to be split into fields.

So great, I shoot 25PsF or you guys in the nether regions shoot 30PsF but we've got to tell the broadcaster he's going to have to replace his HD VCRs, vision switchers, routers and probably his transmitter and get 90% of the viewers to replace their TVs otherwise the footage will blow up. I don't think so. And I don't think Sony would have been so daft as to build a camera with that limitation built into how it recorded vision.

And let's not forget that the V1 is not the only camera to shoot 25p or 30p and yes almost inevitably at some point it's going to get split into fields, odd that never has that been seen as an issue. Am I to believe that there's some really nasty problem with the V1 that renders it effectively unsuitable for broadcast when shooting progressive that no other camera has. Funny I didn't read that in any of the reviews, Sony haven't mentioned that in the manual or in their full pages ads in the ACS mag and elsewhere, by golly if what Steve is saying is true Sony have made one heck of a blunder with the V1.

[Steve Mullen]

Originally Posted by Bob Grant

He's saying we need to maintain a full end to end progressive workflow, at NO point should we allow the frames to be split into fields.

I am saying NO such thing. Exactly the opposite. Since one cannot avoid fields -- the deinterlacer is critical to your viewing quality. It is the device that knits the fields together.

IF the deinterlacer knew the fields were PsF -- yes it would know how to knit them together. (Which doesn't mean it has the ability to do it.) But, it can't know -- so it will do exactly what it will do with 1080i. Somehow, you seem to be missing the point of the concern over deinterlacer quality with ANY interlace video.

All this relates to the V1 only because its EZ for those new to PsF to believe switching to P gives them the same P as does shooting 720p. It doesn't.

[Tony Tremble]

The artefacts of the V1 progressive mode have nothing to do with deinterlacing.

How does your deinterlacing myth make sense of the blocky artefacts in areas of fine detail in V1 progressive mode when they are completely absent from interlaced footage?

The whole premise of this thread is that PsF footage is something new and strange that needs some mysterious way of working with it. I've been working with HDCAM for some time and never had any "interlacing" issues working with 25 PsF. Are the XDCAM HD crowd up in arms about how their PsF footage looks? No they are not.

So what makes the V1 so unusual that it needs special treatment?

TT

[Douglas Spotted Eagle]

Steve/Tony,
Let's keep the discussion civil.

There is nothing special about how the V1 footage needs to be treated, any more than XDCAM HD needs to be treated differently.
Whether you're shooting 24p, 25p, 30p, 50i, or 60i, the footage is essentially managed the same way, depending on the NLE system one chooses to work with. Managing the 24p of HDV vs managing 24p of HDCAM is of no apparent difference on the surface of the NLE side of things. Same goes for XDCAM HD. Nothing special at any point, of any kind.
It is true that the V1U offers either an "A" mode or a straight/pure 24p mode. Your choice of NLE (at this time) will determine which mode will be used. Most folks should be shooting in "A" mode unless they're using Sony Vegas7d.

[Bob Grant]

Spot,
thank you, on both points.
I'm trying to exclude 24p, at least from any input I might make, as 1) The V1P don't do it and 2) removing pulldown/ de-interlacing that can be tricky. As far as I'm aware there's only two traps with 25PsF and 30PsF:

1) The NLE may not know the footage is P and hence incorrectly decode the mpeg stream leading to chroma errors. This might not be a problem but I don't know about NLEs other than Vegas.

2) Editing PsF on an interlaced timeline can result ins some transitions and/or FX being rendered interlaced, i.e. with real temporal separation. This shouldn't be a major issue as it's been done for decades anyway in SD and everything manages to cope pretty well.

What I still don't get is how any form of de-interlacing could seriously damage the viewed image quality of the V1's 25PsF or 30PsF.

If we were talking about 50i or 60i then yes, there's an ocean of grief trying to do a good job de-interlacing that and no solution will ever be perfect.

The whole point of PsF is it's a breeze to de-interlace perfectly and even if you get it wrong it's no big disaster. It should always look better than "i" on a progressive display simply because there's less ways for the de-interlacer to stuff things up, you don't even need a de-interlacer in the traditional sense of the word. No matter how bad the de-interlacer is in a display PsF must always look better than "i", I'd go so far as to suggest the worse the de-interlacer the better PsF should look relative to "i".

[Steve Mullen]

Originally Posted by Tony Tremble

How does your deinterlacing myth make sense of the blocky artefacts in areas of fine detail in V1 progressive mode when they are completely absent from interlaced footage.

[edit] -- there have been no reports of such "problems" from Region 50 since Sony loaded new firmware.

[Douglas Spotted Eagle]

Steve, Tony...enough.

Steve, if you don't have a recently purchased V1E, then I'd submit you don't have a leg to stand on here. You'll note that I've avoided making absolute statements on this issue, because *I* don't have a recent V1E.
If I'm correctly informed, you only have a pre-production V1U, vs the 4 purchased V1U's that we own here, and the initial V1P that we purchased via an Australian dealer for testing. Even with all those camcorders, with my worldwide Sony contacts, and very close relationship with Sony in the UK, I don't feel comfortable making absolutist statements such as "There is no problem." I don't see how you can.

Tony, if I recall correctly, you've returned your camcorder, so I'm not sure why you've got a dog in this discussion. If you've kept your V1 camcorder, my apologies.

Either way, both of you need to step back. This is a good thread and the bickering makes it a challenge to wade through. Do you really want people reading this tripe in years to come?

********************************************************

Bob, you're right, there are a couple of NLE's that cannot correctly decode the 30p, but they're working on it. So far as I know, everyone is managing 25p correctly. I thought Premiere was managing it incorrectly, but last night at the SMPTE presentation, I was corrected on that point.
And of course you're correct (I'd be surprised if you weren't with your background) that PsF is simple to deinterlace. You've probably noticed that Vegas for example, manages this perfectly, and has always done so. You *can* force Vegas to mess this up if you apply a transition over generated media, and invert the fields of a clip or the project after doing so. I can't imagine any reason someone would do that, however, because even downconverting to SD whence the fields are inverted, you'll only have screwed up the fields of the related media but nothing else in the project. However, that's a Vegas discussion, not a V1 discussion.

[Steve Mullen]

Originally Posted by Douglas Spotted Eagle

Steve, if you don't have a recently purchased V1E, then I'd submit you don't have a leg to stand on here.

I have a strong statistical leg because no reports of these issues have appeared -- except for TT -- for months and, in fact, the posts that have appeared explictly do not report such "problems." If you were willing to trust Simon's and TT's initial reports as indicating a problem -- at some point after Sony has fixed the units -- the lack of reports must also have meaning.

By the way, Sony has informed me that the prototypes do not differ from production units in terms of imaging.

However, since you own both U and P units it seems very odd you have never reported your findings here. You don't need to make absolute statements -- but you certainly can report what YOU see.

[Douglas Spotted Eagle]

The BPSD people don't know anything about the V1E model any more than the UK team know anything about the V1U or V1P, so assurances aside, until you have a specific quote that can be attributed to a specific person at Sony UK, this discussion has no legs. Statistical or otherwise. This is a broad forum, but the users hardly represent even a small fraction of those that have purchased the camcorders, particularly abroad.

I've commented plenty on what I see. I don't have any problem extracting the pulldown, deinterlacing, working with pure 24p streams, 30p streams, or printing to HDCAM or Blu-ray with what I've shot and edited. Apparently Bob doesn't have problems with his either. He's not a journalist, but I'll take Bob Grant's word over that of any journalist being paid to write about a product, any day of the week. He's an educated and experienced man.
I don't own a V1E so cannot/will not make a statement any more than any other person not holding a production cam in their hands should/could make. I disagree that the imaging is not different between shipping and production models; I had three different pre-production and you can see a difference in shots taken in identical lighting with production and pre-production models. The final shipping models are more robust, and have all menu items intact. For example, the shipping model offers multiple 24p choices. Your preproduction does not.
No, I've not spent a lot of time testing beyond what we wanted to test; we purchased several camcorders because as you'll recall your own words, "I'm not a journalist, I'm just a producer in a small studio."
We're using our V1's for work product, not for writing stories. FWIW, we've already finished a couple of long-form projects shot with the V1's, as well as created a rough cut shot with 4 V1's, 4 Z1's, 6 A1's, and one XLH1. It's posted on YouTube in case you're interested. Additionally, we've completed 66 shortforms, and worked with famed cinematographer Norman Kent, as he recently took delivery of his HVR-V1U.
Pay me what a journalist receives, and I'll stop working and start reviewing.

[Tom Roper]

Regarding the HQV deinterlacing method, rest assured. Anything I haven't got wrong, I certify is correct.

[Bob Grant]

Steve,
you're on pretty shaky ground relying on statistics. In most 'communities' of users probably less than 10% bother to join a fora. Out of all camera purchaser at the price point we're talking about probably less than 10% ever change anything from the factory settings . I never cease to be amazed at how much education I have to give even some old hands about something as basic as what that backlight button is for, they've just sailed through life with blown out footage. Just look at the stats for this site, there's what, 25K members, that's a staggeringly small number of the total number of camcorder owners on the planet, this place is not statistically significant and that's before you factor in how many sign up and rarely or never come back.

And I can say I have seen this 'smear' problem in other peoples footage and from a V1U. I can also say I've had a go trying to repo it with our V1P and so far no luck. And yes I've managed to shoot a fair slab of 25p and it looks great. From my few years experience with things video and learning how hard it is to convince techs that kit has a problem there's no way I'd come out and say there isn't a problem. Sure I'll say the V1P can take some damn fine looking footage, that doesn't mean it doesn't have some gremlin lurking in there. Even you've got footage that shows some signs of the problem. Some of Spot's footage from way back showed some syptoms as well.

What this needs isn't folk saying how much great footage they've shot, I'd be pretty staggered if they couldn't. What it needs is active attempts to reproduce the problem, that's what testing is about. In reality it'd be better to give a camera to a six year old and tell them to twiddle every knob they can to see what they find.

Now I'll concede that those who are saying they've got / seen the problem aren't helping much. To be helpfull we really need to know what all the camera settings were. In the absense of that those of us that have the kit, the experience and the time should be actively trying to break the camera. When we know how to break it then we can say, OK, yes there's a limitation, stay away from this and that and you'll be fine. That's not a downer on the camera, at this pricepoint nothing comes remotely close to perfection.

I for one would be much happier knowing precisely what this limitation, if there is one, is, than the current state of some dark cloud hanging over the camera. As I've said before the only way to improve our certainty there isn't an issue is to be actively trying to provoke the problem.

[Chris Hurd]

Originally Posted by Bob Grant

In most 'communities' of users probably less than 10% bother to join a fora... Just look at the stats for this site, there's what, 25K members, that's a staggeringly small number of the total number of camcorder owners on the planet, this place is not statistically significant and that's before you factor in how many sign up and rarely or never come back.

You are of course absolutely right right about this. On many occasions it has been a challenge for me to get this concept across to some folks, that not everybody who owns "Camcorder X" is using the internet to talk about that camera, not by a long shot. Ten percent is a generous estimate in my opinion. And this is just one of many web communities (not to mention, it's intentionally designed to be a little difficult to get into -- part of the weeding out process necessary to find the best, most dedicated people).

25,000 is the number of members currently in the database. I make it a point to periodically cull the population and eliminate inactive accounts (those with zero posts and no visits for over a year). About one-third of that number (8,000 members) have posted here before but have since left us. I keep them in the database because their names need to stay with their posts (and who knows, we might get some of them back someday). Two-thirds of that number (16,000 members) have been active within the past year. Checking the forum index page, the most recent registrant has a member i.d. of 38140, indicating that more than 38,000 folks have passed through our sign-up process since we started. Doing the math, you can see that I've weeded out over 13,000 dead accounts in the past, in an effort to keep our membership numbers "real."

However it's important to keep in mind the number of non-registered "lurkers" who stay with us on a daily basis for years. Checking the forum index page reveals that the guest to member ratio of people on the site reading the boards at any given time is usually around 9:1 or 10:1. So, more people are here than you might think. However, the total number is nowhere near an accurate representation of the entire base of camera owners for any one particular make or model, including the Sony V1. Hope this helps,

[Steve Mullen]

Originally Posted by Tom Roper

Regarding the HQV deinterlacing method, rest assured. Anything I haven't got wrong, I certify is correct.

Any errors are mine as I tried to convert the info at the Silicon Optix promotion website to fit what was being talked about on an different thread here. Since the Silicon Optix posted your product review, obviously you know the topic very well. Equally obvious, my quick paraphrase has made no sense to some. So, if you care, can you jump in with your understanding of the role of a deinterlacer/scaler with PsF. I'm especially curious about PsF with a 2-3 cadence, but with no flags for the deinterlacer to sense.

Maybe as Bob claims -- no errors can be made. Or, if errors occur, they will cause no problems and will even be beneficial.

[Tony Tremble]

Originally Posted by Steve Mullen

[edit] -- there have been no reports of such "problems" from Region 50 since Sony loaded new firmware.

Well, my V1E was loaded with new firmware and the artefacts depicted in the progressive image I posted earlier in the thread were a result of the new firmware. Presumably to make such a comment like that you must be in contact with all the dealers in E & P regions to know that there are no reports of poor progressive performance? No?

If no artefacts are present in straight off the factory floor V1Es then why should there be a difference in a "fixed" V1 and one shipping from the factory. I await Piotr's tests with great interest.

The other thing to bear in mind is that Sony UK acknowledge the lower quality of progressive and offer the refund. They wouldn't do that if it were just a case of the customers TV deinterlacing Psf footage incorrectly.

Brett Sherman's clips from his V1U clearly showed the same issues I am seeing with footage from the V1E yet you are unable to see them. I must call into question your method of viewing the clips. None of your explanations can account for those artefacts. I have even see the effect in your coffee shop images. Since your camera exhibits the same issue it would call into question your whole conjecture.

Whether you find those artefacts a deal breaker is another matter. Personally I do but others are quite within their right to have the opposite opinion.

*********************
Douglas,

You are quite right. I no longer have a V1 I accepted the generous offer of a full refund from Sony and purchased the XH-A1. I hope that doesn't exclude me from discussions regarding the V1. I have only chimed in here because the explanations to do not square with my own knowledge, footage I have from my own fixed V1E nor the explanation given to me by the dealer I purchased the V1 from. So in the interests of balance it is important claims contrary to my understanding and those bordering on fanciful are questioned.

Apologies for you needing to edit my post. I will make every effort to prevent you needing to do it again.

Regards

TT