Panning 'mud', reasons why and firmware update

[commanderspike]

If a cheap consumer AVCHD camcorder like the SD9 or HF100 can handle a 1080p stream at 17mbps, I expect the twin CPU GH1 to have the horse power to deal with it.

This is a firmware problem and I expect a fix.

 

[Nighthawk]

We've all seen examples of artefacts and codec breakdown in other peoples footage, some pretty bad for sure, but commanderspike's footage is something else again. No doubt this camera needs some sort of fix but I'm starting to be of the 'bad batch' school of thought. It just seems that much worse than anything out there and unlike the early amateur footage we saw when first released in Japan, commander seems to know what he's doing with it. Nothing that Kholi or Philip Bloom showed is quite this bad except for Kholi's action clip maybe.
I'm not as technically savvy as the rest of you so if this sounds like a dumb question, hey. If, as some of you are pointing to, it's a cpu issue is it possible it's a duration/ heat thing like the D90 had. I know Panasonic's claim that you could go for as long as the card has memory but maybe it just can't. So, for those who have the camera, do the problems you're having occur when 'cold' or after sustained shooting and if so is it in 1080 or 720? Grasping at straws here.

EDIT: Sorry commanderspike, your post went up when I submitted mine.

 

[anthonybsd]

You have to get the fastest card you can get. That goes without question. This cameras are very demanding. You are going to compromise your recordings in order to save a few dollars? It makes absolutely no sense. You can get away with it for the stills but not video.

Did you read anything I wrote? I'm saying I find it extremely fishy that cards that are rated for 3-4 times the transfer rates required for this camera are supposingly showing problems with this camera. And for your information you are actually more likely to get away with it for video than for stills. 5D Mk2 in burst mode 3.9FPS outputting RAW images produces about 80-90 MB a second. That makes GH1 paltry 2MB/sec pale in comparison.

Use your head next time please.

 

[stephenvv]

Simply holding the camera and panning slowly outside today, as you see ABOVE, causes the problem to occur once every 10 seconds on average.

An intolerably bad level of performance.

Once every 10 seconds while handheld panning in an intolerable level of perfomance? I can make just about any camera look like crap with handheld panning including an EX1 or Red. Plus, finally the info that the problem really shows up at higher shutter speeds on highly detailed shot - that's a terrible way to shoot anyway.

I would never, never do those sort of handheld, high shutter speed pans for any footage I intended on using, even casually. Especially when shots are detailed and high resolution, proper shooting is a must for watchable footage.

I work at IMAX rez and when projected that large unless footage is shot near perfect, it tends to make people physically ill.

Unless this problem occurs frequently at normal shutter speeds (1/40th or 1/50th) at proper 24p panning/tilt speeds (slow enough or fast enough) with detail/NR turned down, I fail to see it as an real issue at all.

It's certainly not "intolerable level of performance" - people bought that first JVC HDV cam despite some ugly footage that came out all the time. It also cost a lot more than this cam

 

[Barry_Green]

Just in case, Vegas doesn't show interlace lines unless the video monitor's preview quality is set to good full/ best full or similar. It seems to drop or blend fields in lower quality preview settings.

It was set to best/full.

 

[Barry_Green]

So we are back to square one. What is exactly causing the bad break ups?

Exceeding the codec's ability to cope with the amount of detail.

I would just like to know how bad is it if you pan slowly and deliberately? Also do they show up on tracking shots?

I was abusing the camera to get it to look bad. And even then, in the WORST case I could make it, it still looked fine on an HDTV. Remember this was with an extremely short shutter speed, which would make the image harder to compress; motion blur makes everything easier.

I was trying to punish it. And I punished it pretty bad. But even then, playing the footage back, it was acceptable. In still shots, no way -- but in live video, it was okay.

I have some more gradual pans shot outdoors in a worst-case direct-sunlight foliage/trees/pine trees/grass scenario, done at 1/800 shutter, in 1080/24p and 720/60p, slow and fast pans. Haven't had a chance to review them yet.

 

[Barry_Green]

the cpu handles the ENCODING of the video.
IMAGE > SENSOR (RAW) > CPU PROCESSOR (COMPRESS & ENCODES TO AVCHD) > MEMORY CARD (Compressed 17mbps AVCHD)

I believe this is correct insofar as it goes, but you're missing a step, which is that the raw sensor data gets processed by the venus engines and gets demosaiced, any white balance or ISO/gain is applied, detail enhancement, noise reduction, etc. all get done there. THEN it gets sent to the AVCHD chip.

What you see in the live view is the raw output!

Well, an incredibly downrezzed version of the processed but uncompressed video. Fully processed, but uncompressed, and then downrezzed to the live screen.

if it can be outputed live via HDMI, you'll have the uncompressed 4:2:2 footage!

Yes, but there is no live HDMI output.

ergo, the gh1 cpu cant encode avchd well.

I believe that this statement is probably accurate insofar as it pertains to 1080/24p mode. I am not prepared to accept this statement as related to 720/60p mode.

 

[Barry_Green]

Nope. I have only used mine in MF and the artifacting still happens. This is not an AF issue.

Unquestionably it is unrelated to AF, all my testing has been done in MF.

 

[Barry_Green]

yeah AVCHD encoding is very processor intensive which is why you don't see mjpeg break up like that .

Sort of. MJPEG is an intraframe-only codec, no long-GOP. It is in the nature of a long-GOP codec for this kind of stuff to happen (ergo, why I basically hate all long-GOP codecs unless they have adequate bandwidth and processing power!)

The HMC150 doesn't do this. Its codec is very robust, it has plenty of bandwidth and plenty of processing power. The earlier statement about not having "B" frames leads me to think that the codec chip in this camera is less powerful. And, at a price tag of almost 1/3 of the HMC150's, I can see how they would make that compromise. Doesn't make me happy, and I have advised the Panasonic folks that if they want to release a version of this camera to the broadcast division, I strongly encourage them to use the HMC150's codec chip.

 

[Barry_Green]

I really hate to admit it but I think dcloud might be right. The processor sucks...I mean can't handle the encoding properly. If this turns out to be true I wonder if the bit rate was increased to let's say 24Mbps would it have the same issues? It does not use B frames....just like the 5D Mark ll. And to be honest when I watch 5D ll videos very closely during pans I see sort of the same thing (but to a very miniscule degree). Someone recently posted info from a Canon site that explained how the 5D ll also does not use these B frames and to compensate they upped the data rate. Maybe that's the fix for the Panasonic.

This sounds like a reasonable approach; if it truly doesn't have B frames, then it's not as efficient as it could otherwise be, and the only fix for that is more bandwidth. However, the GH1, being an AVCHD device, will be limited to a max of 24mbps if they were to attempt to throw bandwidth at it to reduce the compression errors.

Frankly I think the best solution would be to use the HMC150 chips. That would give them more bandwidth, B frames, and pN mode (and pN is extremely easier to compress than interlaced 2:3 pulldown footage).

I would not expect changes on the existing model, but I have hopes that they could be applied to a customized broadcast version.

 

[Barry_Green]

And can everyone please keep in mind that I was *trying* to make the codec fail? I haven't seen evidence of unacceptable mud in my normal shooting, although I'll be the first to admit my testing has been very limited so far and is being cut short.

 

[commanderspike]

We've all seen examples of artefacts and codec breakdown in other peoples footage, some pretty bad for sure, but commanderspike's footage is something else again. No doubt this camera needs some sort of fix but I'm starting to be of the 'bad batch' school of thought. It just seems that much worse than anything out there and unlike the early amateur footage we saw when first released in Japan, commander seems to know what he's doing with it. Nothing that Kholi or Philip Bloom showed is quite this bad except for Kholi's action clip maybe.
I'm not as technically savvy as the rest of you so if this sounds like a dumb question, hey. If, as some of you are pointing to, it's a cpu issue is it possible it's a duration/ heat thing like the D90 had. I know Panasonic's claim that you could go for as long as the card has memory but maybe it just can't. So, for those who have the camera, do the problems you're having occur when 'cold' or after sustained shooting and if so is it in 1080 or 720? Grasping at straws here.

EDIT: Sorry commanderspike, your post went up when I submitted mine.

Not tested in 720 yet, will do so tomorrow and see if it improves matters, as indeed some people have commented, that the 720 mode is more robust.

As for 1080p, I bet you will see the artefacts in even slow pans, on a tripod.

I don't think there is anything we can do but wait for a firmware update.

It's strange, as Panasonic are the co-developers of the AVCHD format and have plenty of products on the market which have robust processing.

It must be a combination of the nature of the CMOS in the GH1 and the new Venus engine.

 

[dcloud]

I believe this is correct insofar as it goes, but you're missing a step, which is that the raw sensor data gets processed by the venus engines and gets demosaiced, any white balance or ISO/gain is applied, detail enhancement, noise reduction, etc. all get done there. THEN it gets sent to the AVCHD chip.

right i missed some.. im not an engineer hahaha

Well, an incredibly downrezzed version of the processed but uncompressed video. Fully processed, but uncompressed, and then downrezzed to the live screen.
Yes, but there is no live HDMI output.

I said 'if' though but yes. :beer:

I believe that this statement is probably accurate insofar as it pertains to 1080/24p mode. I am not prepared to accept this statement as related to 720/60p mode.

Yeah i forgot to mention the 720 performance is great. 1080p is acceptable at certain conditions.

CUSTOMIZED BROADCAST VERSION
music to my ears. I'd pay extra for that. Body only!

 

[Barry_Green]

Okay, some panning results. Remember, this is still an extreme case; I used 1/800 shutter to capture as much detail as I could and freeze it all, so that motion blur would not be an issue.

Results: under normal/rational panning conditions, it's fine. Not 100% ultimate perfect like AVC-Intra might be, but considering this frame will fly by in 1/24th of a second, it's basically fine. If you're panning to control 24p strobing, and avoiding CMOS jello, you're also going to avoid the mud. Here's a sample shot from 1/800 shutter, 100% wide angle, NR -2, as much detail as I could possibly get in the shot, and executing the fastest pan a reasonable person would do, while avoiding 24p strobing. This was a 90-degree pan in about 6 seconds:
http://www.dvxuser.com/barry/Tree Pan NR-2.jpg


Under hyper jerking of the camera, it goes to hell. But who would shoot that way? If you want to do cloverfield, this isn't the camera for you. I can make it look really, really bad... Whip the camera around like a madman (I'm talking about a 90-degree pan in less than 1 second), and you can make a shot that looks like this:
http://www.dvxuser.com/barry/Tree hyper-pan.jpg

Again, as the doctor said, if it hurts when you do that, don't do that. And if you simply must do that, this isn't the right camera for you.

 

[Boz]

So in summation, there IS a problem. Apparently GH1 hardware can't handle it's own codec. lol! How sad is that? I've said it many times, and I'll say it again, if Panasonic can at least get 24P in to their 720 mode, that would be an improvement. In theory, upping the codec compression limit to 24mbs in 1080 mode (as an option) would also help somewhat (how much is unknown). It SEEMS as though both these options would be relatively doable with a firmware upgrade, but I'm no engineer. It's just sad that Panasonic signed off on this camera as is. Remember, it's a CONSUMER camera. And how do 90% of consumers shoot? Handheld. What do 90% of consumers shoot? Their kids, pets, sports, activities. So handheld camera whipping around to follow the action. Where does the GH1 fail? Handheld camera whipping around to follow the action. Ugh.

 

[Boz]

Barry, 2nd image is asking for a password.

As for who would shoot crazy handheld footage? See my above post... or check about 90% of the videos on you tube.

 

[Barry_Green]

Oh, and you can force some "mud" to happen under the same panning speeds in 720/60p mode. If you're hyper-jerking the camera around you can make 720/60p get muddy. But it doesn't go nearly as mushy, and it holds up a lot better in general.

Here's a reasonably quick pan from 720p mode:
http://www.dvxuser.com/barry/Tree-Pan-720p.jpg

 

[Ian-T]

Oh, and you can force some "mud" to happen under the same panning speeds in 720/60p mode. If you're hyper-jerking the camera around you can make 720/60p get muddy. But it doesn't go nearly as mushy, and it holds up a lot better in general.

Yes I've seen that also. I'm suprised no one else has not mentioned that until now. Like you said though, it is not nearly as bad.

 

[Martti Ekstrand]

How do the same shots look with a 1/50 (or closest possible) shutter?

 

[Barry_Green]

So in summation, there IS a problem.

Depends on if you shoot in such a way as to cause the problem. You'd get comparable results from HDV, so was HDV an inherently flawed format? (I'd say yes, but that's me... )

And how do 90% of consumers shoot? Handheld.

And how do 99% of consumers shoot? 60i (or 60p). How many shoot 24p?

Where does the GH1 fail? Handheld camera whipping around to follow the action. Ugh.

Yes, in 24p mode. It's much more resilient in 60p mode.

I guess it comes down to this: you've got four video professionals (me, Illya, Kholi, and Hunter) all saying that if you use the 24p mode as intended, it's fine. And then you've got a million youtube videos whipping it around and showing it falling apart. So pick which method you want to use -- if it's for interviews, the GH1's 1080/24p is stellar. If it's for reasonable pans and typical cinema stuff, the GH1's 1080/24p is fine. If it's for cloverfield, then no.