HPX371 Noise Issue?

[Dan Brockett]

Wow, those are really weird looking captures. I would return the camera to a Panasonic service provider, something is wrong with it.

Dan

[David Heath]

Originally Posted by Steve Phillipps

There is a very strange phenomena under discussion elsewhere where part of the image shifts while the rest stays put, very weird.

Do you have a reference for that, Steve? If others have spotted it on other cameras, it sounds less like you've got a faulty unit, more like a fundamental problem with the camera design.

Again it seems as if it's software working its magic but causing something odd to happen that it didn't do in the lab.

It's amazing sometimes what can get missed in the lab.

My favourite story is about the V2000 video cassette system, developed by Philips and Grundig to try to rival Betamax and VHS. (See Video 2000 - Wikipedia, the free encyclopedia .) According to wikipedia:

A tape from any machine should play perfectly on any other machine. Unfortunately, when the first Philips machine - the VR2020 - reached the shops, it was discovered that its audio head was 2.5 mm out of position compared to that on Grundig's 2x4 VCR, which had already been on sale for a year. This meant that the sound would be out of sync with the picture, when played back on the other type of machine. Subsequent models from both manufacturers moved the audio head 1.25 mm to a common position, but compatibility issues remained for recordings made on the first generation of machines.

The story goes that many test tapes had passed between Philips and Grundig, with various line up recordings - unfortunately, not one of them had anything which showed up the lip sync problem! It was only ever brought to light when a Philips machine was bought by somebody whose friend had a Grundig. They started to share tapes and thought - "that's odd......"

Digressions aside, I agree with Dan. You need to take the matter up with Panasonic.

[Steve Phillipps]

It's a different though possibly related effect being discussed here AG-HPX371E jello issue.... - DVXuser.com -- The online community for filmmaking
Steve

[David Heath]

I managed to get a quick look at a 371 yesterday - too quick to be scientific about any testing, but long enough to draw some conclusions.

Firstly, I was able to get an effect which matches something like Steve is noticing, and the fact that others on the link Steve provided above are also seeing similar problems seems to prove Steves isn't a faulty unit - it's something that affects all 371s.

Secondly, I was able to see it via the HD-SDI output, so am sure it is nothing to do with the AVC-Intra codec - this doesn't surprise me at all.

I note that other people on Steves link have come to the same conclusion I did. The front end doesn't seem to be inherently less free of noise than the 301, in spite of what panasonic claim. It's achieving it's final output via electronic noise reduction, and whilst that may improve matters most of the time, sometimes it looks very odd. The worst effect I saw was whilst panning across a textured wall - the appearance varied with pan speed, and at certain critical speeds there seemed to be a low-level "explosion" of noise.

I would worry about buying this camera, never be quite sure when something would jump out to spoil things, even if it looked fine most of the time. I note in one of the posts one person actually swapped his 371 back for a 301 - although the noise level was worse, he felt it more predictable. I can sympathise with that.

[Steve Phillipps]

David, in the link I provided there was actually something a bit different, although most likely related. It was a shifting of certain parts of the image when the camera was still, rather than the moving effects I've seen.
I'm sure you'll agree that when you see "even if it looked fine most of the time" that's just not anything like good enough for a camera with a full Pro label like the 300 series.
Steve

[David Heath]

Originally Posted by Steve Phillipps

I'm sure you'll agree that when you see "even if it looked fine most of the time" that's just not anything like good enough for a camera with a full Pro label like the 300 series.

No, it’s not good enough. I’ve now had the chance to look more closely at the link you supplied, and also the one it references - HPX371e small Jello effect? - DVXuser.com -- The online community for filmmaking . I was quite surprised to see the subject was first mentioned over two months ago, and quite a few people seem to have seen some related effect. Also notable is the deafening silence from Panasonic – Barry Green said on the 19th May that “I looked at it and have no idea what that can be. I've sent the thread on to the Panasonic product manager to look at.”

That was two months ago. Maybe it’s time you posted again to that forum asking for an update, Steve?

There is quite an irony about it. Panasonic make quite a lot about the 371 using AVC-Intra and the I-frame nature of it, stressing how that means there’s no chance of codec performance being at all affected by movement. Not much use when even slight camera movements can cause bad effects in the front end!

It seems that most of the time, on normal pictures, no problem may be seen. But another question needs to be asked if it is indeed performing noise reduction. That can make a picture look cleaner – but destroy subtle low level detail at the same time. That may not be seen on the raw picture – but can severely affect performance if you try to push the images in post. A point I’ve made on another thread is that there is no point in 10 bit recording if the noise level swamps the least significant bits. There’s even less point in 10 bit recording if any noise reduction has destroyed the very slight changes that 10 bit could capture, but 8 bit couldn’t.

[Steve Phillipps]

There has been a response from Panny on one of those threads, yesterday. Says they are aware of it and working on it, that's about it.
Steve

[Jeff Regan]

David,

On another forum, Steve Cooperman, P2 manager for the U.S. posted that there is a problem with all 370's and a firmware update is due at the end of July. It's clear that Panasonic is behind the curve a bit vs. Sony with CMOS development. Just another reason why I'm happy to be shooting with CCD's most often. I had a client recently reject my EX1 and swap to an HPX170 due to some flicker artifacts that weren't present with the 170.

My advice for those who are having issues with 300's or 370's is to find a used HPX2000 w/Intra board. Not easy, but they're out there occasionally. Obviously, a 2000 isn't a full raster native chip set, but it has a lot of other things going for it.

Regarding 8-bit vs. 10-bit, your characterization of " the very slight changes 10-bit could capture", I don't agree. 10-bit has 4X as many gray steps as 8-bit, 1024 vs. 256, same as HDCAM SR.

Jeff Regan
Shooting Star Video

[Steve Phillipps]

Jeff, correct me if I'm wrong, but the 2000 is a full raster camera, ie 1280x720 full raster, at least when recording AVC Intra.
I think you're probably right about Panny not quite being up with Sony on the CMOS front, and wanting to keep up they've used software trickery to make up the distance, but it's backfired.
Steve

[Jeff Regan]

Steve,

Yes, full raster 720 chip set when using Intra. I should have written full raster 1080X1920 camera. Panasonic seems to have done a good job with their 4/3" CMOS DSLR's and VDSLR's, although there will have to be a lot of massaging if the AF100 is to be free of aliasing artifacts and excessive skew.

Let's see what the 370/371 firmware update looks like. EX1 and 3 have been out too long for Panasonic to be having these issues with the 300 successor.

Jeff Regan
Shooting Star Video

[David Heath]

Originally Posted by Steve Phillipps

There has been a response from Panny on one of those threads, yesterday. Says they are aware of it and working on it, that's about it.

OK, found it. He says:

Panasonic is aware of the problem. We appreciate everyone’s postings. These helped our engineering team with our testing.

We plan to have a free firmware upgrade at the end of July. At that time, we'll have further information.

Please note, in our testing, as well as independent testing, the problem occurred infrequently and was not very noticeable. Sure, in those limited situations when it does show up, you can see it on a frame grab, but, generally speaking, it occurs infrequently.

Firstly, it does not occur "infrequently", and it is easily visible on normal pictures, not just peering at a frame grab. After Steve first alerted me to it in this thread, I was able to demonstrate the effect within ten minutes of getting my hands on a 371, and within fifteen minutes consistently show it to an extent that was visually disturbing. All that involved was panning across a painted wall with some furniture in front - hardly an uncommon scenario. Likewise, it didn't involve frame grabs, just looking at a normal TV at a normal distance.

We'll have to wait and see what the firmware upgrade promised brings. But it was to reduce the high noise levels of the 300/301 that the 370/371 was introduced, so there must be a huge question mark over whether Panasonics technicians can solve this problem without reverting to the high noise levels of the 300/301 this was intended to cure. I think it would be extremely unwise to buy one of these cameras until an acceptable fix has been demonstrated.

It also raises the question of why such a fault was not spotted in the lab before it went on general sale? Or were they aware of it, but just hoped everybody would say how much quieter it was, and nobody notice the new fault?

Originally Posted by Jeff Regan

10-bit has 4X as many gray steps as 8-bit, 1024 vs. 256, same as HDCAM SR.

That's true in a recording sense, but 10bit and 1024 steps will only show an improvement IF the source is good enough to distinguish more than 256 discrete grey steps in the first place. A noisy camera will not be able to resolve 256 grey scale steps discretely, and electronic noise reduction is almost certain to have the same effect. Recording a noisy camera into a 10 bit recording format is a little like pouring a pint into a gallon container - you still only have a pint. Just having the gallon container doesn't give you more than a pint of water.

And 10 bit recording will only give you "the full gallon" of quality if the front end of the camera is up to it.

[Steve Phillipps]

Quote "t also raises the question of why such a fault was not spotted in the lab before it went on general sale? Or were they aware of it, but just hoped everybody would say how much quieter it was, and nobody notice the new fault?"

Hmmm., doesn't it just! Surely if that's the case, on this, a professional product, then they've really shot themselves in the foot. Or it could be that we're all just barking up the wrong tree, we'll have to give them the benefit of the doubt.
Agree 100% with everything in your last post David.

Jeff, yes the full raster 720 thing was me being a bit pedantic - it's one of my pet hates people confusing "full raster" with 1920x1080 when that's not what it means (not you Jeff, I know you know!)
Steve

[Jeff Regan]

David,

Yes, in another thread you brought up the noise in the front end of the camera making 10-bit acquisition moot. I just don't want people to think that 10-bit is always a "very slight change" over 8-bit. My editor showed me graphic evidence of 10-bit AVC-Intra 100 over 8-bit DVCPRO HD using my HPX2700. Much more range in post for grading and color correction before seeing banding and added noise. 4:4:4 color space record option isn't the only reason HDCAM SR is used. I almost always shoot at -3db gain with my 2700, as I did with my HDX900, to enable the recording of the cleanest signal possible.

AVC-Intra 100 is a big step over DVCPRO HD due to full sample recording using square pixels, twice as efficient in compression and 10-bit depth. 10-bit recording was not available in a one-piece camcorder until Panasonic came out with the HPX2000 in early 2007, and then the HPX3000, 2700 and 3700 as well as HPX300 and 371. Sony's 10-bit camera solution is HDCAM SR using tape and large, six figure cameras.

Panasonic's putting 10-bit into camcorders for under $20K is a breakthrough. Now they need to get their CMOS act together to make full use of it for under $10K camcorders.

Jeff Regan
Shooting Star Video

[Tim Polster]

This has been an elightening thread. The HPX-300/370 has not been the best of launches for Panasonic.

I was watching "Expidition Great White" on Discovery last night and the images from most of the cameras were just beautiful. A lot of detail, great color range and accuracy. I did a quick internet search to try and discover the cameras being used and found an artcle mentioning the HPX-2000 as the main cameras. I would guess by the look they were shooting 720p60.

1080p is often the buzz but to my eyes, 720p deilvery is plenty for now and some time to come unless you are aiming for the theatre production.

[David Heath]

Originally Posted by Jeff Regan

David..... in another thread you brought up the noise in the front end of the camera making 10-bit acquisition moot. I just don't want people to think that 10-bit is always a "very slight change" over 8-bit.

You've misread what I posted - I didn't say the above but rather "the very slight changes that 10 bit could capture, but 8 bit couldn’t". The inference is that those "very slight changes" (in grey scale level) may be imperceptible in normal viewing - but desirable for extensive post-processing. Assuming they exist - and aren't masked by noise or camera processing.

And I was quite clear in that other thread [ http://www.dvinfo.net/forum/panasoni...ml#post1547088 ] that 10 bit recording was desirable for high end cameras. The evidence is that it is far less relevant (if at all) for lesser models. In the other thread I quoted from the EBUs tests - "The 8-bit bit-depth is sufficient for mainstream programmes, but 10-bit bit-depth is preferred for high-end acquisition." I consider the HPX371 a very long way from "high-end acquisition" - especially after what's been learnt in this thread - and hence the recording being 8 or 10 bit is totally irrelevant.

My editor showed me graphic evidence of 10-bit AVC-Intra 100 over 8-bit DVCPRO HD using my HPX2700. Much more range in post for grading and color correction ....

Maybe so, but the 2700 is far more expensive than the 371, so what does that prove? The 2700 is about 3-4x more than the 371 in the UK - and that doesn't include any lens! And as said before, how do you know what improvement is down to 10 bit, how much down to no sub-sampling of luminance and chrominance, and how much to just generally better compression? AVC-Intra 100 is better than DVCPro-HD, yes, but that's for a lot more reasons than bit-depth.

In the cold light of day I find Steve Coopermans posting even less comforting than it seemed last night.

Maybe it's just careless wording, but he says that "We plan to have a free firmware upgrade at the end of July", then "At that time, we'll have further information". He never actually states that the firmware upgrade will solve the problem, though it's what everybody is assuming. "Further information" is nothing like "the firmware upgrade which will solve the problem", is it? Perhaps he'd like to clarify the matter directly on this forum?

I've also just been shown another instance of the fault occuring, this time on test raw chromakey footage, daylight and 0dB gain. Yet again, moving objects show a noise trail, and there seem to be random bursts of occasional noise on the background. Just what you want for chromakey? And that's at 0dB, what will it be like at 12 dB or more? Steve Coopermans assertions that the problem "occurred infrequently and was not very noticeable" just don't seem to agree with what I, Steve, and others are finding in reality.

When the 371 was first released, Panasonics claim was that it's 1/3" chips were "Rivalling the image quality and sensitivity of ½” imagers". This saga has done nothing to substantiate those claims.