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View Full Version : Improving color gradients and static noise!



VeEuzUKY
06-17-2010, 06:46 PM
Despite the huge improvements with the new Firmware hacks, noise in color gradients and static noise seems still to be as bad as ever. This is my main gripe with the GH1. The camera also consistently seems to have a Gamma gain that is too high, making noise in shadow areas much more obvious and displaying most blacks as dark grays but not full blacks. To my knowledge there is no way to control the Gamma gain... one can use the Custom Film modes and increase contrast, that crushes the blacks somewhat but at the cost of loosing a lot of shadow detail and blowing off all highlights so, its not really an option.

Are there any "better" settings on the current firmware hack to improve the color gradients and static noise or a future possible path to make it possible and is there any way to somehow control/lower the Gamma gain on the GH1?

PS- Im talking about AVCHD, not MJPEG.

Lpowell
06-17-2010, 07:45 PM
I have found a post-production technique for reducing Fixed Pattern Noise (FPN) in dim areas of a video. I shoot in AVCHD 720p 60fps, and use After Effects to convert to MJPEG at 30fps for editing. The trick is to turn Motion Blur on, but keep Frame Averaging off. The FPN is particularly noticeable when panning the camera, and Motion Blur conceals it pretty well. Frame Averaging is undesireable, as it would actually emphasize the FPN.

rawdod
06-17-2010, 07:48 PM
Cross posting this from the pulsing I-Frames thread:

Here is my 2 cents:

The GH1 has some AVCHD codec issues, pretty nasty at times, a painful thing because often the picture is very good. The GH13 has the same exact codec issues, regardless of gop or bitrate setting, but they are much more mitigated due to brute force bitrate increase. So this is the same stuff as seen on stock firmware. The codec in the GH1 seems to hate large areas that are in focus but are simple, such as solid wall colors, and like to put 'pulsing' or noticeable artifactyness there. I wish we could replace the codec with the code from x264, which is better than many commercial coders, how impossibly hard this might be I don't even fathom, even with hardware encoding many routines could still be tweakable, but finding them and changing them in the way we are changing values now in the firmware... I can only hope.. anyway I digress, I just don't think some of the pulsing, and artifacting on blank surfaces is fixable with the existing bitrate and gop tunables.

rawdod
06-17-2010, 07:58 PM
I would like to say, I've done some testing with the hacked firmware and very low light dealing with half black scenes and such.. I have some advice on how this kind of thing can be mitigated, or what the codec might be up to, from my experience with xvid and x264 encoding..

Its not so much an issue of things or the scene being 'underexposed', but rather underexposed in comparison to the rest of the scene, because if the whole scene is underexposed, don't really get the problem.

For example, bright foreground, stuff on the right side of the scene, in the left side you can see a colored blank wall in the background. Everything looks great, except the colored wall in the background, which appears fairly artifacty and nasty, and it makes u cry a little because the entire rest of the scene looks incredible.

If you download low bitrate xvid dvd rips you see this kind of thing all the time. h264 is different, but it can end up doing the same thing. Its not seen to much in x264, because x264 is such a good encoder..

I don't think this can be fully fixed by just the GOP and bitrate tunables, however the bitrate does mitigate it to some extent.

One thing that does help mitigate, besides having your scene evenly lit throughout and without solid colors or gradients that are very large (which is a silly thing to limit yourself by), is just shallow DOF blur, the GH1 codec seems to encode blury stuff very nicely... its just those very simple solid / gradient in focus areas...

Just my 3 cents.

MR Fanny
06-17-2010, 11:55 PM
that is the most valuable 5 cents of info i have read in a while rawdod. cheers!

jobless
06-18-2010, 01:44 AM
We need to increase I frame in order to get better codec and higher bitrate in low light/detail situations...

Tesselator
06-18-2010, 02:16 AM
We need to increase I frame in order to get better codec and higher bitrate in low light/detail situations...

So that's why the current efforts in that direction then? Makes sense! Until then we can still do a lot in post with tools like Fusion (http://www.eyeonline.com/web/eyeonweb/products/fusion6/fusion6.aspx).

Adventsam
06-18-2010, 02:56 AM
This flattens the response, well it seems too, use std settings and shoot some footage first with srgb, you'll see it camera set-up, first icon, menu pg 4, 2nd icon down. Shoot the footage with that and then flick to Adobe rgb, shoot that, see what you think, then try with the smooth and bringing the contrast down and sharpness.

Edit, have just tied it again myslef to make sure am not goin blind, just replayed in-camera, the differnce is there to be seen, see if this helps with the static noise-gradients?

PappasArts
06-18-2010, 03:06 AM
The GH1 is also a very clean sensor; this can be very tough with 8bit codecs. Dithering slightly is also a way to handle gradient banding. Either in post or in camera by shooting at 160 or 320iso. With the new AVCHD, the one thing you notice is the GH1's noise used to look like clumps of mud when increasing ISO; now the noise with higher ISO's is recorded as noise that is more grain like then mud clumps of the old AVCHD.

Also shooting AdobeRGB is good.


Pappas

Adventsam
06-18-2010, 03:13 AM
gorgeous, LOL, honestly though we are seeing real quality with the GH1 AVC, my only request would be CBR rather than VBR though, then we could step up a gear, 40mb/sec CBR 25/24P would be incredible.

Note: have got my eye almost pressed to my plasma and my HD screen laptop and the IQ is incredible, it really looks top notch HD. Vitaliy has set the bar very high for Panasonic GH2.

Chris Light
06-18-2010, 03:15 AM
Pappas, not to dig this old topic up again, but doesn't the GH1 only use sRGB in video mode?

Adventsam
06-18-2010, 03:18 AM
a good one!

Chris Light
06-18-2010, 03:31 AM
a good one!
huh?

PappasArts
06-18-2010, 03:38 AM
Pappas, not to dig this old topic up again, but doesn't the GH1 only use sRGB in video mode?

Hey Chris,

I shot side by sides while ago , and the AdobeRGB was different- flatter than sRGB.

Pappas

Chris Light
06-18-2010, 03:43 AM
placebo effect? i don't know...i trust the manual, but not as much as my eyes...i'll try it out.

pardal
06-18-2010, 04:25 AM
We need to increase I frame in order to get better codec and higher bitrate in low light/detail situations...
Great! how do we do that or at least move towards that direction? Im all game for it. We need to find a way to make it happen!:2vrolijk_08:

Timmyjoe
06-18-2010, 04:42 AM
This flattens the response, well it seems too, use std settings and shoot some footage first with srgb, you'll see it camera set-up, first icon, menu pg 4, 2nd icon down. Shoot the footage with that and then flick to Adobe rgb, shoot that, see what you think, then try with the smooth and bringing the contrast down and sharpness.

Edit, have just tied it again myslef to make sure am not goin blind, just replayed in-camera, the differnce is there to be seen, see if this helps with the static noise-gradients?

Can't find the SRGB or Adobe RGB settings on my GH1 anywhere. Went through all the menus. Is this something that is added with one of the later hacks?

Best,
-Tim

Adventsam
06-18-2010, 05:34 AM
Press menu, camera icon at top, goto pg4, drop down 1, colourspace , SRGB or AdobeRGB, click on it, AdobeRGB?

Cheers

Mike@AF
06-18-2010, 11:34 AM
This flattens the response, well it seems too, use std settings and shoot some footage first with srgb, you'll see it camera set-up, first icon, menu pg 4, 2nd icon down. Shoot the footage with that and then flick to Adobe rgb, shoot that, see what you think, then try with the smooth and bringing the contrast down and sharpness.

Edit, have just tied it again myslef to make sure am not goin blind, just replayed in-camera, the differnce is there to be seen, see if this helps with the static noise-gradients?

What do you mean by std settings? Are you talking about the Standard film mode? Or are you talking about a mode other than Creative Movie Mode? Adobe vs sRGB seems to have no effect in CMM, so maybe you're talking about another mode?

Joe Calabrese
06-18-2010, 11:47 AM
Hey Chris,

I shot side by sides while ago , and the AdobeRGB was different- flatter than sRGB.

Pappas

Was that videos or photos, because the setting for Adobe RGB and sRGB is in the photo menu. And any of this make any difference when transcoding footage (as in would Adobe RGB be not compatible with FCP 7 or something)?

noirist
06-18-2010, 11:48 AM
gorgeous, LOL, honestly though we are seeing real quality with the GH1 AVC, my only request would be CBR rather than VBR though, then we could step up a gear, 40mb/sec CBR 25/24P would be incredible.

Note: have got my eye almost pressed to my plasma and my HD screen laptop and the IQ is incredible, it really looks top notch HD. Vitaliy has set the bar very high for Panasonic GH2.
What happens if you decrease the GOP?

Barry_Green
06-18-2010, 11:59 AM
Dithering slightly is also a way to handle gradient banding. Either in post or in camera by shooting at 160 or 320iso. With the new AVCHD, the one thing you notice is the GH1's noise used to look like clumps of mud when increasing ISO; now the noise with higher ISO's is recorded as noise that is more grain like then mud clumps of the old AVCHD.

Something I've been meaning to throw out there: pay attention to the noise reduction setting. I haven't tested this yet, but I think that it'll actually do something now! Before, it really didn't seem to matter much (in video mode), but I think that's because the codec would mush all the noise together in its "mud" anyway. But now that the codec is so much more robust, I would guess that you'll see a much bigger difference between -2 and +2 in noise reduction. Just another thing to test.

PappasArts
06-18-2010, 01:40 PM
Something I've been meaning to throw out there: pay attention to the noise reduction setting. I haven't tested this yet, but I think that it'll actually do something now! Before, it really didn't seem to matter much (in video mode), but I think that's because the codec would mush all the noise together in its "mud" anyway. But now that the codec is so much more robust, I would guess that you'll see a much bigger difference between -2 and +2 in noise reduction. Just another thing to test.

Interesting- Cause of this new level of quality, all things need to be evaluated on this camera again.

PappasArts
06-18-2010, 01:42 PM
Was that videos or photos, because the setting for Adobe RGB and sRGB is in the photo menu. And any of this make any difference when transcoding footage (as in would Adobe RGB be not compatible with FCP 7 or something)?

Hey Joe,

Video mode of course.


Pappas

Barry_Green
06-18-2010, 01:49 PM
Interesting- Cause of this new level of quality, all things need to be evaluated on this camera again.
Yep, it's a whole new ballgame. I think Intelligent Exposure needs to be re-examined, and noise reduction too. Both of those could have been seriously influenced by the codec before, but now that the codec is actually recording what the sensor's giving it, I think we might see a big difference now. Or, well, a bigger difference, at least...

Barry_Green
06-18-2010, 01:50 PM
... and, Mike, thanks for all the effort you're putting into this. We, as a forum and a community of users, appreciate all the efforts that are being made. I know how much work goes into endlessly testing and tweaking and testing again, and on behalf of the forum and the users, I wanted to let you, and Hunter, and jobless, and nurbs, and everyone else know that we really appreciate all the hard work!

Ben_B
06-18-2010, 01:51 PM
Something I've been meaning to throw out there: pay attention to the noise reduction setting. I haven't tested this yet, but I think that it'll actually do something now! Before, it really didn't seem to matter much (in video mode), but I think that's because the codec would mush all the noise together in its "mud" anyway. But now that the codec is so much more robust, I would guess that you'll see a much bigger difference between -2 and +2 in noise reduction. Just another thing to test.

I will do some tests on a blank, somewhat underexposed (but not so much to cause banding) in a little bit...will mess around with sharpening settings too. Will post results here. Gotta run some errands first though :)

svecher
06-18-2010, 02:15 PM
I wish we could replace the codec with the code from x264, which is better than many commercial coders, how impossibly hard this might be I don't even fathom, even with hardware encoding many routines could still be tweakable, but finding them and changing them in the way we are changing values now in the firmware...
If and when HDMI Out works, you could just capture and encode with x264 on a laptop.

PappasArts
06-18-2010, 02:42 PM
Yep, it's a whole new ballgame. I think Intelligent Exposure needs to be re-examined, and noise reduction too. Both of those could have been seriously influenced by the codec before, but now that the codec is actually recording what the sensor's giving it, I think we might see a big difference now. Or, well, a bigger difference, at least...


Intelligent Exposure- Left that long ago, and now, it just might offer something we can use...Crazy ! As the bitrate possibly improves, this just can get even better. I need to look at all the
features again like the film modes- they may have a different affect within the camera/codec too.




... and, Mike, thanks for all the effort you're putting into this. We, as a forum and a community of users, appreciate all the efforts that are being made. I know how much work goes into endlessly testing and tweaking and testing again, and on behalf of the forum and the users, I wanted to let you, and Hunter, and jobless, and nurbs, and everyone else know that we really appreciate all the hard work!

Thanks Barry- It's just awesome to be part of it. A community effort of equally mined people all driving in the same direction more or less. This is one of those reasons that the internet shines. A global effort at hand, to better a single camera. I'm amazed by it....

jleo
06-18-2010, 03:03 PM
Press menu, camera icon at top, goto pg4, drop down 1, colourspace , SRGB or AdobeRGB, click on it, AdobeRGB?

Cheers

You have to be out of Creative Motion Picture Mode. Switch MODE to CUSTOM, Then to MANUAL, Then press MENU. Now the Camera Icon has 4 pages instead of 2. Somehow switching from CMPM to M still kept it in Motion Picture Mode.

Ben_B
06-18-2010, 04:01 PM
I will do some tests on a blank, somewhat underexposed (but not so much to cause banding) in a little bit...will mess around with sharpening settings too. Will post results here. Gotta run some errands first though :)

Will be posting this in a new thread when I finish working on it.

Stephen Mick
06-18-2010, 04:08 PM
Will be posting this in a new thread when I finish working on it.


Waiting impatiently… :D

Ben_B
06-18-2010, 04:11 PM
Should be done within the hour. Tested all possible combinations of sharpness and NR (ignoring +1/-1, just did 0 and 2/-2) at ISO 200 and ISO 800. Set to Standard with Contrast -2, AVCHD 24p, PTool bitrate settings C, Sat 0. Pulldown removed in compressor, footage converted to ProRes 422, auto gamma correction off.

Ben_B
06-18-2010, 04:58 PM
Zip file is up in other thread in samples section.

alignment1
06-18-2010, 08:27 PM
... A community effort of equally mined people all driving in the same direction more or less. This is one of those reasons that the internet shines. A global effort at hand, to better a single camera. I'm amazed by it....


GH-13 .... the revolution of digital cinema

GH-13 .... the apocalypse of happy marriages :banned:

PappasArts
06-19-2010, 02:29 AM
GH-13 .... the revolution of digital cinema

GH-13 .... the apocalypse of happy marriages :banned:


LOL.......


Just a note- Did gradient tests tonight. The GH1's clean sensor at low ISO's + 8bit codec makes for banding issues on certain shots- However at 320ISO which is super clean in the GH1 introduces enough low level noise to dither that out for the most part.

Pappas

Mike@AF
06-19-2010, 04:48 PM
LOL.......


Just a note- Did gradient tests tonight. The GH1's clean sensor at low ISO's + 8bit codec makes for banding issues on certain shots- However at 320ISO which is super clean in the GH1 introduces enough low level noise to dither that out for the most part.

Pappas

Interesting. So are you suggesting we shoot at 320ISO for everything, or just shots that could introduce the banding? And what were your firmware settings on this test?

Kholi
06-19-2010, 04:53 PM
LOL.......


Just a note- Did gradient tests tonight. The GH1's clean sensor at low ISO's + 8bit codec makes for banding issues on certain shots- However at 320ISO which is super clean in the GH1 introduces enough low level noise to dither that out for the most part.

Pappas

Found this out early yesterday.

320 and 400ISO = it.

Below 320 and 400 the image starts to get a bit smooshy, but nothing too terrible.

So in that range, it actually looks pretty great. The problem with that?

Gotta invest in a new IR ND 2 to go with the 1.2 + Pola stack. LOL

Oddly enough, this is also why I shoot @ high ISOs in broad daylight with NDs on with the CAnons. The image LOOKS better.

Mike@AF
06-19-2010, 05:06 PM
I'll admit I've been shooting almost exclusively ISO 100 just to keep the noise and FPN down. Lately I have been thinking there could be a different sweet spot for the GH1, especially now with the hack. I've gotta go experiment with 320 and 400 now.

Mike@AF
06-19-2010, 06:05 PM
As it so happens, I just got back from a shoot earlier today in which I had to resort to shooting at ISO 400, 500, 640, 800, and 1000 at times. This was all with the C settings in 60i wrapper (24p was not selected in Ptool). The shots just finished transcoding to ProRes422 in FCP and I must say they look fantastic. Very clean. No noise, no banding, no FPN even at ISO 1000. They actually seem more filmic than the shots I got at ISO 100 or 200 for some reason. I'm really liking this camera now with the improved bitrate. Incredible!

Kholi
06-19-2010, 06:14 PM
As it so happens, I just got back from a shoot earlier today in which I had to resort to shooting at ISO 400, 500, 640, 800, and 1000 at times. This was all with the C settings in 60i wrapper (24p was not selected in Ptool). The shots just finished transcoding to ProRes422 in FCP and I must say they look fantastic. Very clean. No noise, no banding, no FPN even at ISO 1000. They actually seem more filmic than the shots I got at ISO 100 or 200 for some reason. I'm really liking this camera now with the improved bitrate. Incredible!

=D I hate to say I told you so... but...

That's what I had been saying when the D90 hit and then the GH1. The lower the ISO, the stranger things get. 320 and above on all of these things seems to produce the most pleasing image.

Mike@AF
06-19-2010, 06:25 PM
Yep. I was always afraid to increase the ISO because of all the noise. I really think the bitrate increase changes all that. It probably changes everything about this camera. All settings and options need to be re-evaluated.

Kholi
06-19-2010, 06:39 PM
I think, this is just what I THINK though, that there is STILL noise reduction and sharpening in camera even when it's dialed down to -2.

If there's a way to turn it OFF, I wonder what sort of image difference we'll see with banding etc?

Cavemandude
06-19-2010, 07:10 PM
In the Zacuto Part 2 Test with ISO's, the banding around the light bulb didn't go away until ISO 1250 on the GH1. Here are the frame grabs from that test:

http://www.dvxuser.com/V6/showthread.php?t=206365

Randy

PappasArts
06-20-2010, 02:16 PM
In the Zacuto Part 2 Test with ISO's, the banding around the light bulb didn't go away until ISO 1250 on the GH1. Here are the frame grabs from that test:

http://www.dvxuser.com/V6/showthread.php?t=206365

Randy

I did a quick and dirty test last night with various ISO's. You'll notice that the Mjpeg files hold better in the shadows as to codec banding. I feel that if we can get the bit rate to give more attention to the darks/shadows that would be awesome in AVCHD. Also when playing back mjpeg, it records the fine noise more fatefully coming off the sensor- grain like, however the AVCHD codec smooths it out a little more. This just might be that the AVCHD formulas/numbers are still a work in progress.

LINK TO 1250ISO TESTS: http://www.dvxuser.com/V6/showthread.php?t=214283

Pappas