Noise comparison: 35/4:2:0 vs. 180/4:2:2

[Rafael Amador]

Piotr,

If you want to compare pics from the SxS with LGOPs from the Nano, you must compare an "I" frame from both.

If you are comparing an "I" frame from the SxS with a "B" or "P" frame of the Nano, the test is not fair.

This may be the reason why you find no problems with the Intraframe: All are "I" frames.

I really don't see possible that the Nano introduces any noise over the HD/SD-SDI.

Rafael

[Piotr Wozniacki]

Originally Posted by Rafael Amador

Piotr,

If you want to compare pics from the SxS with LGOPs from the Nano, you must compare an "I" frame from both.

If you are comparing an "I" frame from the SxS with a "B" or "P" frame of the Nano, the test is not fair.

This may be the reason why you find no problems with the Intraframe: All are "I" frames.

I really don't see possible that the Nano introduces any noise over the HD/SD-SDI.

Rafael

A very good point, Rafael - thanks!

At last, some technical interpretation... I'll try and analyse my comparisons so far, keeping in mind what you said.

Nevertheless, what matters is the video on the big screen, right? And watching it, you don't analyze whether the current frame is an I, B, or P frame - what counts is the perceived quality. And that is poor - the shimmering noise is simply more visible in the nano clips :(

Thanks anyway.
Piotr

[Dan Keaton]

Dear Piotr,

In post 103, on the left side of the image are what appears to be a vertical wall, made out of red, rough wood. At least the texture looks rough.

What does it look like in real life?

Is the wood rough?

Does the 35 Mbps image represent reality (smooth wood with little detail) or does the 100 Mbps image represent reality (rough wood with lots of detail).

How did you create this image?

Was the camera on a stable tripod?

Was someone or the wind shaking the tree?

Or was someone shaking the camera?

What were the camera details? Frame Rate, Shutter, Aperature, gain, picture profile?

Specifically, what is your F Stop? With a 1/2" sensor it should not be greater than F8.

In previous examples, you did not always show the exact same frame. Are these the same frame?

If you want to test if the nanoFlash is working or not, I suggest you set it to 35 Mbps, Long-GOP, 1920 x 1080 mode, and compare the exact same frames. But, as Rafael pointed out, one may be a B or P frame and one may be an I-Frame making it hard.

I know of no way to ensure that the nanoFlash and EX1, on the same frame, will both be on an I-Frame.

If you want to show the effect of "smoothing" due to a low frame rate, record a properly exposed image, with lots of details at 220 Mbps versus 100 Mbps, both using I-Frame Only.

The Codec used in the nanoFlash, as you are probably well aware, is the one used in the Sony PDW-F800 camera. And, all of the compression work is done in this Sony Codec. It is highly unlikely that the Sony codec is failing you.

Just to be clear, you may, of course, send us your nanoFlash and we will be happy to check it out for you. But, we have never had a Sony Codec module fail, or even be suspect, as far as I know.

[Adam Stanislav]

Originally Posted by Piotr Wozniacki

I really don't know what to think now!

Dan would know better than me.

By the way, are you shooting straight with the EX-1, or are you using a 35 mm adapter? Because if the latter, the ground glass of the adapter may be causing similar issues.

[Rafael Amador]

Originally Posted by Piotr Wozniacki

A very good point, Rafael - thanks!

At last, some technical interpretation... I'll try and analyse my comparisons so far, keeping in mind what you said.

Nevertheless, what matters is the video on the big screen, right? And watching it, you don't analyze whether the current frame is an I, B, or P frame - what counts is the perceived quality. And that is poor - the shimmering noise is simply more visible in the nano clips :(

Thanks anyway.
Piotr

I agree with you that what it counts is the video in the big scree, but if we compare stills we must to take in to account the issue of the "I" frames.
Piotr, I really appreciate what you are doing to try to put some light on this matter.
Tomorrow I will try to make few test recording in the SxS, Nano and in Prores with the ioHD.
The suggestion of Dan about recording 35Mbps in the Nano is also to consider.
rafael

[Piotr Wozniacki]

Originally Posted by Adam Stanislav

Dan would know better than me.

By the way, are you shooting straight with the EX-1, or are you using a 35 mm adapter? Because if the latter, the ground glass of the adapter may be causing similar issues.

No Adam - I'm not using the adapter in these tests. But thanks - a good point.

[Rafael Amador]

I've been making some tests that may be not the most scientistic, but I thing they point what is going on.
I have used NeatVideo.
The advantage of NeatVideo is that it works independently in the Luma and in the Chroma channels.
This allow to see what kind of noise prevails in the picture.
The pictures from the Nano (I used the Piotrs pics of the house), shows much more Chroma noise than the SxS picture.
That is not to surprise because the Nano pictures have double Chroma info than the SxS pictures.
About the noise in the Luma chanel, I see a bit more of noise in the Nano picture too, but the SxS picture is much more blurry.
For the one that have no NeatVideo, I propose a simple test: Drop any Color Correction filter and bring the Chroma all the way down, then compare the pictures.
As you can see, the SxS recording gets rid of a lot of the noise, but smudge the picture absolutely.
rafael
PS: since I bought my EX-1 I de-noise everything. Before I used VideoPurifier, now NeatVideo.

[Piotr Wozniacki]

Originally Posted by Dan Keaton

Dear Piotr,

In post 103, on the left side of the image are what appears to be a vertical wall, made out of red, rough wood. At least the texture looks rough.

What does it look like in real life?

Is the wood rough?

Does the 35 Mbps image represent reality (smooth wood with little detail) or does the 100 Mbps image represent reality (rough wood with lots of detail).

Dear Dan,

The wood is rather smooth. Of course there is some texture on it, but certainly not containing any other color than various shades of brown - while the grain I'm complaining about consists of dots in all possible colors.

Originally Posted by Dan Keaton

How did you create this image?

Was the camera on a stable tripod?

Was someone or the wind shaking the tree?

Or was someone shaking the camera?

This particular frame comes from a hand-held shoot (I wanted to check camera whip pans and shake), so it's quite different to the previous ones which were shot from the tripod.

Originally Posted by Dan Keaton

What were the camera details? Frame Rate, Shutter, Aperture, gain, picture profile?

Specifically, what is your F Stop? With a 1/2" sensor it should not be greater than F8.

The settings were: 1080/25p, 1/50th, aperture never outside the 2.8 - 5.6 range

Originally Posted by Dan Keaton

In previous examples, you did not always show the exact same frame. Are these the same frame?

As you know, it's almost impossible to align an EX1 native clip with its nanoFlash counterpart on two Vegas tracks - even if you switch Quantize to Frames Off.

Originally Posted by Dan Keaton

If you want to test if the nanoFlash is working or not, I suggest you set it to 35 Mbps, Long-GOP, 1920 x 1080 mode, and compare the exact same frames. But, as Rafael pointed out, one may be a B or P frame and one may be an I-Frame making it hard.

I know of no way to ensure that the nanoFlash and EX1, on the same frame, will both be on an I-Frame.

Yes - with nanoFlash bitrates of 35 or even 50 Mbps, the noise problem is not existing.

Originally Posted by Dan Keaton

If you want to show the effect of "smoothing" due to a low frame rate, record a properly exposed image, with lots of details at 220 Mbps versus 100 Mbps, both using I-Frame Only.

Dan, in real life, in most images you will find both bright and dark areas (otherwise those images would represent a very narrow dynamic range). The dark areas tend to be noisy in the EX-series cameras, and this noise is augmented by the nanoFlash at higher bitrates.

Originally Posted by Dan Keaton

The Codec used in the nanoFlash, as you are probably well aware, is the one used in the Sony PDW-F800 camera. And, all of the compression work is done in this Sony Codec. It is highly unlikely that the Sony codec is failing you.

Dan, I'm not saying it has failed on me - I'm asking why everybody is raving on how much cleaner the nanoFlash images are when they aren't. That is to say, they tent to amplify the source shortcomings (the noise) in a very nasty fashion. My problem is that while i often need to zoom into a nano frame in order to see its virtues (like less mosquito noise, and better color resolution - I created a separate thread on that, too), the shimmering noise I can see in the normal scale image, on all less-than-bright surfaces of more or less uniform color.

Originally Posted by Dan Keaton

Just to be clear, you may, of course, send us your nanoFlash and we will be happy to check it out for you. But, we have never had a Sony Codec module fail, or even be suspect, as far as I know.

Thanks for this option; let me treat it as the last resort. For now, I'll appreciate technical explanations (with examples) much more. I hope they would prove your previous point that nothing is wrong with my nanoFlash...

Cheers

Piotr

[Piotr Wozniacki]

Originally Posted by Rafael Amador

I've been making some tests that may be not the most scientistic, but I thing they point what is going on.
I have used NeatVideo.
The advantage of NeatVideo is that it works independently in the Luma and in the Chroma channels.
This allow to see what kind of noise prevails in the picture.
The pictures from the Nano (I used the Piotrs pics of the house), shows much more Chroma noise than the SxS picture.
That is not to surprise because the Nano pictures have double Chroma info than the SxS pictures.
About the noise in the Luma chanel, I see a bit more of noise in the Nano picture too, but the SxS picture is much more blurry.
For the one that have no NeatVideo, I propose a simple test: Drop any Color Correction filter and bring the Chroma all the way down, then compare the pictures.
As you can see, the SxS recording gets rid of a lot of the noise, but smudge the picture absolutely.
rafael
PS: since I bought my EX-1 I de-noise everything. Before I used VideoPurifier, now NeatVideo.

Dear Rafael,

If you could try similar tests with your EX1/nanoFlash to confirm mine are working to specs, I'd be very grateful indeed. Just a single test of the native EX1 vs. nanoFlash in 180 Mbps L-GoP will suffice.

Then, with regained confidence in my equipment, I'll probably start using some de-noiser as well (and since I work with Vegas Pro, it'll most probably be NeatVideo).

Thanks again,

Piotr

[Dan Keaton]

Dear Piotr,

Thank you very much for the extra information.

I helps us understand.

[Peter Moretti]

If I may add my .02, it seems that the real issue is the difference between how clean Long-GOP vs I-Frame recording is.

If the nano is just recording noise as extra detail, then you would think the I-Frame recording would do the same. But that doesn't seem to be the case, if I've understood this thread correctly (which is not an easy thing, LOL).

IIUC, at the same and higher data rates, the I-Frame recording is significantly cleaner than the Long-GOP. This doesn't sound like a defect in the nano, but rather a subtlety w/ how the Sony chip and MPEG-2 encode Long-GOP vs. I-Frame. And it seems possible that this difference may have gone unnoticed or unmentioned until now.

I would humbly suggest doing a test of Long-GOP vs I-Frame at various data rates of a scene that includes shadows. If there is no "noise" difference between the two recording methods, than it seems that Piotr's nano is defective. But if the test shows extra shadow "noise" in the Long-GOP recording, then Piotr's nano is behaving normally and this behavior is a function of how the Sony chip encodes.

In the best case, Sony can shed some light on this. In the worse case, it's information users can keep in mind when balancing data rate, quality and scene composition.

Hope that makes sense :).

[Piotr Wozniacki]

Originally Posted by Peter Moretti

I would humbly suggest doing a test of Long-GOP vs I-Frame at various data rates of a scene that includes shadows. If there is no "noise: difference between the two recording methods, than it seems that Piotr's nano is defective. But if the test shows extra shadow "noise" in the Long-GOP recording, then Piotr's nano is behaving normally and this behavior is a function of how the Sony chip encodes.

In the best case, Sony can shed some light on this. In the worse case, it's information users can keep in mind when balancing data rate, quality and scene composition.

Hope that makes sense :).

This makes perfect sense, Peter - and it's this type of output result I've been counting on when creating this thread (and NOT ranting, or bashing anybody).

:)

Piotr

[Piotr Wozniacki]

Originally Posted by Dan Keaton

Dear Piotr,

Thank you very much for the extra information.

I helps us understand.

Dear Dan,

I'm glad I made myself more clear now. I'd like to stress it again that my intention in this thread is only to better understand things, and get confidence my hardware is not malfunctioning (not necessarily the nanoFlash, but also my EX1 and the HD-SDI ports and cable). Therefore, I'd really appreciate some technical follow-up to my points from the Convergent Design engineers, which would help achieve the above goals. I'm sure other EX/nanoFlash users will benefit, as well.

At the moment, just two additional qusetions, if you will:

1. Here is what Mike wrote in another thread:

Originally Posted by Mike Schell

Hi Per Johan-
I have been absolutely amazed at the quality from this Sony CODEC. This is their 7th generation part and they truly did a stunning job designing this part. It has very low-power (around 3W in 4:2:2 mode), small size and superb video quality. It's the same CODEC as inside the PDW-700 camera, we just cranked up the bit-rate from 50 to 100 Mbps.

Now, is there a possibility that something could have gone wrong in this "cranking up" of the Sony codec chip?

2. On yet another subject:

We have both agreed it's very difficult to synchronize the picture from EX1 and the nano perfectly when on separate tracks, one above the other, in an NLE. I do a lot of multicamera projects, and when only using material from several EX cameras, I'm able to synchronize them with frame accuracy using spikes in the audio waveforms. This method doesn't work with an EX1 and nanoFlash files, recorded simultaneously - could you please explain why, in technical terms?

Thanks and Kind Regards

Piotr

[Luben Izov]

Originally Posted by Piotr Wozniacki

Dear Dan,
.......
2. On yet another subject:

We have both agreed it's very difficult to synchronize the picture from EX1 and the nano perfectly when on separate tracks, one above the other, in an NLE. I do a lot of multicamera projects, and when only using material from several EX cameras, I'm able to synchronize them with frame accuracy using spikes in the audio waveforms. This method doesn't work with an EX1 and nanoFlash files, recorded simultaneously - could you please explain why, in technical terms?

Thanks and Kind Regards

Piotr

I second that!! I use PluralEyes and FCP does not permit multiclip with different codec (EX1 35Mbps and nanoFlash 50mbps) It is a huge hassle....

[Dan Keaton]

Dear Piotr and Luben,

I wonder if all of the souces were the same, or if using the Sony SxS 35 Mbps recordings and the nanoFlashes 35 Mbps recordings, would match up find in PuralEyes.

I can easily speculate that PuralEyes was not designed to work with different codecs or bit-rates, but I really do not have any actual knowledge on this subject.