Sure Fire Solution to HVX-200 Macroblock Problem

[Dan Brockett]

Hi all:

I have been shooting for five weeks wiith the HVX-200 on a wide variety different types of projects, interiors and exteriors, well lit to available light, etc.

I just received my Dell 2405 andd have been looking forward to seeing how it performs with the HVX-200 as a hi-def video monitor. Up until this time, I had only seen my footage on NTSC monitors and the LCD screen on the HVX-200. Upon hooking up to the Dell, horror of horrors, I finally saw the noise/macroblock issue that everyone has been having a hissy fit over. I too began hissing and kvetching. Luckily, we have an AVID Nitris Symphony at the place I work at. Hooked up to the Nitris Symphony are a JVC 19 HD CRT with the HD/SDI card and a Pioneer Elite 55" Plasma as a client monitor.

Upon the advice of Shane Ross, I was finally able to view some of the same footage that I shot of sunsets at the beach that had looked quite lousy on my Dell, being played straight out of the camera, on the JVC HD CRT. Lo and behold, the same footage that was full of macroblocks on my Dell when being played out of the camera looked perfect, amazing and totally free of macroblocks. I agree that the HVX-200 has a similar grainy look that the DVX-100 has and that was not the issue, I was expecting grain. It was the dancing blocks of ants or termites that I was seeing in the darks and mid-ranges on gradients especially that were giving me a scare.

So, all I can surmise is that LCDs and Plasmas definitely enhance this macroblock issue as does playback directly from the HVX-200, especially when playing back through analog outputs. When viewed on the JVC HD CRT, the footage looks amazing. On the 55" Pioneer Elite, it still looked goood, albeit with more grain and noise than on the JVC. In both of these cases, my P2 footage (720 24PN) was playing back from the Nitris Symphony.

Shane has also suggested that he has seen P2 played back through an AJA card into a AJA HD/SDI to DVI converter into the Dell and that the footage looked beautiful.

I would surmise that a large portion of HVX users playing back their HD from their HVX-200s directly are experiencing the macroblock issue. I must say that I saw the macroblocks when playing the HVX-200 through the analog HD component inputs of the Dell. If you can, view your footage through a high quality HD CRT, playing from an NLE NOT from your camera and see if you are still seeing the macroblock issue. This cleared it up for me, the footage looks amazing.

Just wanted to relay my "cure" for the macroblock issue, it is to not use your camcorder for playback and to view the footage on a high quality HD CRT. You may still see macroblocks when using the camcorder as a playback device in the field but then you can rest assured that your actual footage is clean, even though it may not look like it when played back from the cam.

All the best,

Dan

[Barry Werger]

Thanks foer the info! However, what would be most interesting to see is some crossover... it sounds like you tested the HVX playback to 2405 and NLE playback to two other monitors. What happens when you playback NLE to 2405, or HVX to HD CRT?

Again, I'll toss my reminder that most HDTV playback devices used by end-consumers, are LCDs and Plasmas... and THAT's what we need to look at, not the most flattering CRTs.

[Peter Jefferson]

I agree with Barry, however one thing to note is that these LCDs and plasmas have a high latency ratio. On top of that these consumer models usually have a low contrast ratio and gama and luminance is tweaked to trick the eye in thinking that the image is brighter than it really is.

One thing i tel al my clients is to switch their TVs/monitors to the 'movie" mode of the TV to enhance colour gradation gamma and luminance. This way they get to see what i see (or closest to it) and in the way in which the presentation itself was designed to be seen.

Alot of the time this "noise" can be alleviated with proper settings within viewing devices, and LCDs in particular just cant keep up with this much data. WHich is why when u look at a HD LCD vs a HD Plasma, vs a HD CRT the LCD would look the ugliest. Its jsu the way the technology has availed itself and to me, i personally dont think the DVX is grainy at all if shot with the correct settings.
To be truthful, i find the DVX shoots cleaner footge than a DVC200 or a DSR300 (yep, even dynamic range is nigh on identical at least.. irrespective of teh CCD size...)

Ive seen SD 16:9 footage taken by an XL2 and then from a MX500 and both thrown on a Vizio HD panel and the MX500 looked much nicer.. and this is through composite straight from the cameras...

I guess the point im tryin to mae is that its not about what you use, its about HOW you use it, and there are ways around almost every "problem"

[Dan Brockett]

Hi Barry:

This JVC HD CRT only has an HD/SDI card so I have no way of hooking up the HVX-200 to it to test camera playback through the CRT. I agree that 99% of our audiences that even see our material in HD will see it on an LCD, plasma or eventually a SED set, not on an HD CRT.

I think the point Shane was making mainly was that playing back from the camera is mostly causing the macroblock issue. I will be receiving a Kona 3 card and a Decklink HD HD/SDi to DVI convertor soon, then I will be able to really test this theory out with the Dell, to prove that the Dell is not causing this microblock issue. But it's good to know that the camera really doesn't seem to have the macroblock issue, except on playback from the camera but it's not part of the signal. Or at least that seems to be my experience here with this gear.

Best,

Dan

[Jeff Kilgroe]

The 2405 will work well with the HVX as a monitor. However, you need to turn off all the edge enhancements and whatnot within the monitor's internal settings. It has very little for user adjustable settings, but this will help. The edge enhancement (which amplifies macroblocking and noise) on this display is unacceptably high right out of the box.

[Barry Werger]

Originally Posted by Dan Brockett

I think the point Shane was making mainly was that playing back from the camera is mostly causing the macroblock issue.

Yes, that's certainly an interesting point.

A lot of footage posted to the web, of course, is not being played back through the camera; and the stills are grabbed from NLEs. All more to muddle the issue!

[Chuck Spaulding]

Originally Posted by Jeff Kilgroe

The 2405 will work well with the HVX as a monitor. However, you need to turn off all the edge enhancements and whatnot within the monitor's internal settings. It has very little for user adjustable settings, but this will help. The edge enhancement (which amplifies macroblocking and noise) on this display is unacceptably high right out of the box.

Hi Jeff,

How do you adjust the edge enhancement on the 2405?

In the menu I can scroll to the picture setting but I can't change anything, not that there's any mention of egde enhancement in that menu. Also, in the color adjustment menu I switched from the factory default to the user defined RGB colors and it made the screen much brighter [like the Apple Cinema display], is there a reason the defualt is so low? This looks soooo much better.

[David Heath]

Originally Posted by Dan Brockett

Just wanted to relay my "cure" for the macroblock issue, it is to not use your camcorder for playback and to view the footage on a high quality HD CRT. You may still see macroblocks when using the camcorder as a playback device in the field but then you can rest assured that your actual footage is clean, even though it may not look like it when played back from the cam.

Interesting observations, but it hasn't tied down whether your seeing macroblocks in one instance but not another is due to the difference between LCD/CRT monitors, OR that they are only present on the camera output anyway - two very different matters.

If the latter, the entire issue immediately becomes a non-issue. If the former, it can't really be called a 'cure' - nobody can tell all their clients etc that they can only use CRT monitors, can they!? I take the point that LCD monitors may not be ideal 'out of the box', but if that was the only problem, why are people not complaining about macroblocks on LCD monitors from other cameras?

Personally, I potentially find your findings worrying more than comforting. They raise the spectre of bringing the material back to the edit suite, spending hours working on it and seeing great results on the CRT monitor, then delivering it to a client and getting a shock when it's seen widely on LCD displays. Do you think the client will be impressed to hear "well, it's the display.... you need to get a CRT as I'm using this camera"? Particularly if he has seen other HD cameras exhibiting no problems on the same monitor(s)?

It needs to be seen whether your macroblock observations are due to them being introduced by the output of the camera, or being somehow concealed by a CRT monitor.

[Dan Brockett]

Yes, it does seem to be two different points. Unfortunately I don't yet have the equipment available to me to eliminate the variables that we are discussing. I can say that did not see the macroblocks on the Pioneer Elite 55" plasma, which is hooked to the AVID via HD analog component so that gives me hope. I have a Kona 3 card and a Blackmagic HD/SDi to DVI converter on order so in a few weeks, I should be able to eliminate the variable of the Dell itself being the issue. I do have reports that the HVX-200 footage, when viewed on the Dell with a digital connection looks beautiful and macroblock-free.

Of course I would not suggest that anyone except editors and producers and staff at the dub house or broadcast outlet will ever see the footage on an HD CRT. Yes, we all know that consumers, for the most part will be viewing our footage on lcds or plasmas and eventually SED sets.

IMHO, the issue probably mostly is a result of some sort of DSP processing error when the signal is converted from digital to analog in-camera for playback through the CAV output. It also could be exaggerated by the realtively low quality of the Dell's A/D conversion internally.

Time and further testing will tell. But I am very confident that the signal being recorded is free of macroblocks as I did not see it them on the JVC HD CRT OR the Pioneer plasma, one hooked up via HD/SDI (the JVC) and one hooked up via analog component (the Pioneer). Good enough for me that we are proceeding shooting a three camera comedy pilot with the HVX-200s that will be broadcast in the fall.

Best,

Dan

[Scott Auerbach]

Bear in mind, too, that CRT phosphors don't turn on and off with the sharp 0/1 -ness (sorry, that's the best I can do) of a plasma. That's why interlaced looks perfectly fine on a CRT, but less so on plasma. It could be that the phosphor after-glow is helping to mask noise, rather than the other screens creating it. Personally, I'm a CRT fan, but at the larger sizes that HD loves, they become real monsters...I think we all need to look at how to train end-users to best set up their monitors for our media.

[Bob Grant]

I've seen similar issues in SD with some LCD screens. We fed a test DVD into a Philips 17" LCD TV and the macroblocking turned a waterfall into nothing but macroblocks. It looked for all the world like the problem was the DVD encoding. However this material was shot on a F900, downscaled and encoded at the max bitrate through a $50K encoder. Switched the same player and DVD to a broadcast monitor and the same image was perfect.

Problem is I think some LCDs overdrive the displays to compensate for the slow response and that works upto a point but give it too much detail and the system falls apart

However how the HVX footage looks on monitor A versus monitor B via whatever playout device is a pretty poor way to measure what's going on, what's needed are scopes to get definative noise meaurements.

If there's a lot of noise really there then that's a problem. No matter how well the DVCProHD codec copes with that noise very little video stays as DVCProHD all the way to a HD TV, it goes through at least one stage of mpeg-2 encoding and decoding and that's not nice to noise.

[Chuck Spaulding]

Originally Posted by Bob Grant

If there's a lot of noise really there then that's a problem. No matter how well the DVCProHD codec copes with that noise very little video stays as DVCProHD all the way to a HD TV, it goes through at least one stage of mpeg-2 encoding and decoding and that's not nice to noise.

Plus the DVCProHD codec is 8bits which doesn't provide much headroom as the image is stepped on in post. A better workflow would be to convert the DVCProHD to a 10+bit intermediate codec for post and then encode for distribution.

For anyone who was around in the earlier days of digital film many of these discussions sound remarkably familiar to the 8bit linear versus 10bit log debate with Quantel tried to sell everyone on 8bits being enough.

[Dan Brockett]

Hi all:

I think that the important thing to keep in mind is that the camera itself is doing what it is supposed to do, capture great picures.

I would be interested to hear if any users complaining of macroblocking are seeing the issue in captured footage playing from an NLE. In our experience here, this is not the case. We had the DP for our pilot in yesterday to run some camera tests with all diffferent sorts of scenarios and we did, once again, see the macroblocks on the Dell when played out of the camera and once again, after we loaded the footage into FCP and the AVID Nitris Symphony, we did NOT see the macroblocks.

Seems fairly conclusive to me what the cause is and that the issue does not affect the actual recorded image, only the playback from the camera.

Best,

Dan

[David Heath]

Originally Posted by Dan Brockett

Seems fairly conclusive to me what the cause is and that the issue does not affect the actual recorded image, only the playback from the camera.

That may be true, but I don't think it is at all conclusive until you can cross over the camera output/NLE output and the monitors, and see if the problem stays on the camera output. You've already said you can't plug your camera into the JVC CRT for connectivity reasons - can you connect the NLE output to the Dell? If there's no problem there, you're home and dry.

Best of luck.

[Dan Brockett]

Hi David:

That's a great idea, I will hook the Dell up to the Nitris Symphony on Monday, when I am back at work.

Will report back on what we see. This will narrow it down, hopefully to the output directly from the camera being the culprit. I hope that this does turn out to be the problem because if it's just a playback issue/e-e issue with the camera, then who cares? Won't matter much really as none of us are using the camera's playback for professional exhibition.

If I do see the macroblocks on the Dell with the Symphony, that will muddle things a bit, I fear.

Dan