Red Compression and Matrix Tests.

[Nook Kim]

I've found a test posted on CML today. I don't know who did it, and there aren't any additional information other than several green screen frames with & without matrix, and with & without Redcode. I just started opening the files, which seem to be pretty big.
Go check it out, guys.

http://www.cinematography.net/Red/comp-matrix.html

Nook

[Nook Kim]

Wow.. that is my first impression from looking at the first frame that was just opened now. I'm going to test some compositing on Shake with this.
I was going to post these frames here, but CML states some type of copyrights to it, so I hesitate. What do you guys think, team Red?

Nook

PS. These are 4900 x 2580 Tiff files. Aren't they the first over 4K files posted online? I'm a very happy man.

[Petr Dvorak]

its old one

[Alex Boothby]

More info, tests and analysis here:

http://www.dvxuser.com/V6/showthread.php?t=78623

[Nook Kim]

Oops, I'm sorry that I was far behind the revolution. How do I delete this thread, now? :confused:
But, still, I'm a very happy man, today. :D

Sorry for my misinformation, guys.

Nook

[Brook Willard]

Heh, that was a fun thread...

http://homepage.mac.com/brookwillard/compsthumbs.jpg

I'll leave this open [at least for now] because there are some folks here for whom this will be news. I should note that the REDCODE compression you're seeing in those images is not the version that will ship with the camera. The images are also limited to that "8 stop" [heavy quotes] latitude that caused all the hubbub before the number became 11.3.

[Nook Kim]

More info, tests and analysis here:

http://www.dvxuser.com/V6/showthread.php?t=78623

Thanks Boothba,
I realize this was done about three months ago, now. Ha, this was during the month I was shooting a project. Red One should have been advanced way better by now. Very excited. I apologize again for this thread.

Nook

[Graeme Nattress]

Many, many things have advanced since then. The REDCODE compression is so much better, the colour we're getting from the camera is so much better. The sensor has been tweaked for better dynamic range, etc. It's a fun historical artifact though.

Graeme

[Sam Druckerman]

Many, many things have advanced since then. The REDCODE compression is so much better, the colour we're getting from the camera is so much better. The sensor has been tweaked for better dynamic range, etc. It's a fun historical artifact though.

Graeme

Great news, but not surprising considering your track record.

"Better Dynamic Range" Hmmmmm, do tell?

[Alex Boothby]

"Better Dynamic Range" Hmmmmm, do tell?

The dial now goes to 11.

[Nook Kim]

I remember hearing 11 and a half stops from Jim a while ago (about a month ago?). However, it's then, and I'd love to hear that has gotten better, of course. Something inside me tells me we may have 15 stops.:rolleyes:

Nook

[Jannard]

We will never have 15 stops... 12 bit is max 12 stops. Take that to the bank.

Jim

[Nook Kim]

Well, then...something tells me that we may have 12 stops. :D

Nook

PS. I guess this is when you get off work and make a round here to see how we are doing. Thanks for your effort.

[Emanuel A.]

Well, then...something tells me that we may have 12 stops. :D

Nook

PS. I guess this is when you get off work and make a round here to see how we are doing. Thanks for your effort.Nice input Nook! RED spirit :D

[jbeale]

There is some basis for argument that it is better to have a bit of analog noise in the system above the quantization limit (12 bits = 12 stops), to prevent banding or posterization artifacts from showing up in smooth gradients.

[Antoine Fabi]

Jim,

11 f/s of dynamic range is great

But i dont understand the realtionship between f/s and bit depth...
I thought that bit depth had to do with the number of "steps" or "stairs" between pure black and pure white...

[Graeme Nattress]

Bit depth tells you how many steps between black and white - yes. For 12 bits that's 4096 values in total. Digital sampling suffers from a kind of noise called quantisation noise. This gets smaller the more bits you have. Once you have your quantisation noise lower than the noise in the analogue signal you're sampling, you gain no further benefit from increasing the bit depth.

There is a mathematical link between noise and bit depth, wihch, roughly speaking, is 6db per bit. So, turning it on it's head, noise is the limiting factor in signal to noise ratio, so a 12bit system has a 72db dynamic range. You may remember that the 16bit CD audio system has a 96db dynamic range.

Now, dynamic range is, in visual terms, measured in f-stops. It's just visual SNR.

So, you measure the SNR of your sensor, add around a bit for safety and you do want to record some noise as it is useful, and that gives you the bits needed in your A-to-D, and then you also know the dynamic range to expect between full signal and the noise floor.

Graeme

[Andrew M.]

Now, dynamic range is, in visual terms, measured in f-stops. It's just visual SNR.
Graeme

f-stops can express dynamic range, you mean like f-stops of the lens?
So setting of 11 on the lens is related somehow to the minimum dynamic range.
Sorry if I sound as a novice, but in the optics science and lens technology, I am.

Can anyone explain the f-stops as a dynamic range to me, please.
I do understand perfectly the a digital part of it.

Andrew

[Chris Forbes]

dynamic range is the amount of information you get on a sensor between absolute black and absolute white. It doesn't have as much to do with the lens as it does the capture medium.

Think of a sunset. In the frame you will have the brightest point (the sun) and the darkest point (the shadows). The amount of information you can get in between those two point is your "range".

[Antoine Fabi]

Thanks Graeme,

I "think" i'm beginning to understand a little more.

But in my mind, ( right or wrong ), i still imagine a 12 bit codec could theorically record 20 f/stops in 4096 stairs between full black and full white.

but again, real 11 f/stop of dynamic rage is great.

[Graeme Nattress]

Antoine, an 8bit codec can store the dynamic range of film, or at least what it looks like :-)

But that's because film has a tonal curve that compresses highlights.

When we're talking dynamic range here, we're talking linear dynamic range, and for that you need at least as many bits are there are stops.

Graeme

[Dominic Jones]

Graham, thank you - that was a great explanation of something that's always confused me too, with regards to latitude and bit depth.

Can I just reel this off back to you, as I understand it, and check I've got it right (which I probably haven't!)?

Using Antoine's example of 20 stops on a 12-bit linear codec:
From my (new) understanding, the situation is that you can (or rather could) encode the 20-stop dynamic range within 12-bit linear, but by doing so you would introduce quantization noise - so, encoding at < 1 bit per 6db SNR is theoretically possible put practically undesirable.

Is that correct??

Thanks as always...

[Graeme Nattress]

Well, you can't fit a 20 stop dynamic range into less that 20 bits if the data is linear. If you put a transfer curve on it, that makes the data non-linear, it will retain the look (I hope) of the extra dynamic range, but the dynamic range of the resulting image is still noise limited to whatever the bit depth is, even if the data is essentially noiseless.

Graeme

[Evin Grant]

Will the RGB Red codecs, in 10Bit LOG retain the look of the 12bit 11+ stops of DR so that it is visable in the footage? Will the 10bit linear flavor inherently have less DR than the 12bit? If so why shoot the 10?

[Dominic Jones]

Ohh-kay...

I think I'm getting my head around this finally - please bear with me!

So essentially what you're saying is that by encoding the theoretical 20-stop image into 12-bit digital (with the transfer curve to essentially compress the dynamic range), you end up with an image that captures the high/low light detail of 20 stops from the scene, but has only 12 stops of usable dynamic range in the final file (i.e. for grading and manipulation in post)?

Am I getting there?!!

[Graeme Nattress]

I think that's pretty much it, Dominic. I mean we've all seen film on VHS, but that doesn't mean VHS has the dynamic range of film :-)

Evin, I think RED RGB is 10bit Log or 10bit video gamma (ie REC709), both of which do a similar thing, but with different curves - they compress the data in such a way that you get your equivalent low noise levels in the shadows, but with a slight loss of precision in the highlights, which is a pretty good trade. The difference is in the curves that do that.

Graeme

[Dominic Jones]

I think that's pretty much it, Dominic. I mean we've all seen film on VHS, but that doesn't mean VHS has the dynamic range of film :-)
Lol, yeah ok - good point!

Thanks again Graeme for taking the time to go through that with me, it's really appreciated...

[Dominic Jones]

You're gonna hate me - another question!...

What would happened if you tried to encode a > 12 stop latitude image in 12-bit linear? Would it simply clip the highlights above the 12-stop point, or do something else entirely?

Cheers! ;)


EDIT: I might have answered my own question here - presumably that would be the choice of the person(s) implementing the encoding software - to either lose the top end, bottom end, or a combination of both?

[Graeme Nattress]

You'd comprmise your noise levels, or loose highlights, or both, but it should be your choice.

Graeme

[Dominic Jones]

I'm so, so close to having my head around this!!

Can you clarify what you mean by "compromise your noise levels"? I've seen you mention that the amount of low-light detail is determined by the noise levels in an image, so does compromising noise levels essentially equate to "losing the bottom end", as I put it, or are we talking something different?

[Graeme Nattress]

You'd comprmise your noise levels, or loose highlights, or both, but it should be your choice.

Graeme

[Antoine Fabi]

Ah !

OK, now i understand a lot better !

...linear... !!!!

thanks Graeme

[Graeme Nattress]

Thanks Antoine - happy to help as usual!

Graeme

[Andrew M.]

dynamic range is the amount of information you get on a sensor between absolute black and absolute white. It doesn't have as much to do with the lens as it does the capture medium.

Think of a sunset. In the frame you will have the brightest point (the sun) and the darkest point (the shadows). The amount of information you can get in between those two point is your "range".

Chris, now I got it 50% when it comes to dynamic range.
What is then one stop? and why it is called "stop"
Is it from aperture?
One stop = (how many) dB of change?

And why 12 stops equals 12 bits (72dB), coincidence?
Is one stop of aperture lowering/increasing light by 6dB (two times light level)?

Andrew

[Graeme Nattress]

1 stop = 1 bit = 6db, roughly speaking.

[Mark B.]

I see dynamic range as being the difference between the darkest and brightest objects that can be differentiated from pure white and black in the same frame. But I don't consider dynamic range as being data enough to account for the number of samples between those two extremes. The gaps between the two extremes are filled with resolution, which might be 16 bits of linear samples, or 8 bits of logarithmic samples, or whatever number of samples in whatever weighted curve.

So what confuses me is how resolution is being lumped as a side-effect of dynamic range. Wouldn't the resolution be dependent on the capture device, rather than depending on the capture device's dynamic range? Couldn't you have trillions of steps of precision in the sample device but only be able to measure those trillions of samples between two extremely similar brightnesses?

[Graeme Nattress]

Noise limits your ability to measure the difference between steps. If the difference between steps is smaller than the amount of noise in the system, then you can no longer differentiate between those steps. Say we sampled the Mysterium sensor at 32bit, or something silly like that. We've have gadzillions of steps, but you'd still be only able to measure about 2500 (that's what 11.3 stops is).

[Mark B.]

Noise limits your ability to measure the difference between steps. If the difference between steps is smaller than the amount of noise in the system, then you can no longer differentiate between those steps. Say we sampled the Mysterium sensor at 32bit, or something silly like that. We've have gadzillions of steps, but you'd still be only able to measure about 2500 (that's what 11.3 stops is).

So the sensor has a 2500 step linear resolution, and the dynamic range of the chip goes up to a little over 2000 times brighter than the darkest object it can recognize. Is the noise behavior of the chip a constant, or is there less chip noise in the low-end or high-end?

[Graeme Nattress]

Well, a sensor doesn't have any steps as it's analogue, but it's pointless to digitize with a step size smaller than the amount of noise, as then you're making steps that are too small, and are wasteful.

I'm not that up on the noise characteristics of sensors - sorry. But you'll always notice noise in the dark regions, just because you've got less photons hitting the sensor, and hence more noise - just like the human eye in the dark.

Graeme

[Mark B.]

Is there a lowest level of lumen that the chip can noiselessly detect?

[Graeme Nattress]

There will be point where the number of photons entering the pixel is not great enough to make a signal larger than the noise. This would be the case with any sensor. That's why bigger pixels are better in low light, as they let more photons in. They also have a larger photon capacity, which leads to larger max signal, and hence better SNR and dynamic range.

Graeme

[Brook Willard]

This is the best thread ever...

[Andrew M.]

1 stop = 1 bit = 6db, roughly speaking.

Graeme, what is the definition of the stop?
I know stop on the aperture, but in context of this thread?
Somehow I can't get this expression of sensitivity in terms of stops.
dB Yes
bits Yes
dynamic range no problem
Stops ?? can't get it.

Andrew

[Andrew M.]

So the sensor has a 2500 step linear resolution, and the dynamic range of the chip goes up to a little over 2000 times brighter than the darkest object it can recognize. Is the noise behavior of the chip a constant, or is there less chip noise in the low-end or high-end?

Good sensor will have similar characteristics as the human eye.
As all in the nature we use, is logarithmic. Intensities, loudness, brightness, concentration of chemicals in our body, all is logarithmic.
So it has much finer resolution at low levels and less resolution (in terms of steps or increments) at higher levels.
Gamma curves try to deal with this if the system do not have it implemented right in the pickup (sensor) or in the display (screen).

So if the sensor do not behave logaritmic then analog to digital converter better have finer resolution at low levels then at high levels. It is a specially true for audio.
With RGB or light levels it is bit more complicated but our eyes do have less sensitivity response at high levels.
The question is, as a industry, what is the standard, are we dealing with the non linear nature of human eye only on the screen device or on the sensor as well.
My intuition is that we should use 80% of the bits resolution on the first half of the signal and the 20% on the second half.
Andrew

[Mark B.]

Graeme, what is the definition of the stop?
I know stop on the aperture, but in context of this thread?
Somehow I can't get this expression of sensitivity in terms of stops.
dB Yes
bits Yes
dynamic range no problem
Stops ?? can't get it.

Andrew

The way I understand it, a stop is twice the amount of light as the previous amount (the previous stop). If you're talking about sensor sensitivity to stops, you're talking about a change in the amount of light hitting the sensor. If a sensor captures 2 stops, it would be able to capture everything from it's lowest sensitivity up to 4 times that amount of light. Picking a number at random for an example... if the lowest light captured is 6 lux, then the 2-stop sensor would be able to detect light levels all the way from 6 lux up to 24 lux (6x2x2). If that sensor had 3-stops of range, it could detect up to 48 lux (6x2x2x2). 4-stops and it could detect from 6 lux up to 86 lux (6x2x2x2x2). Anything above the 86 lux would be blown highlights. If the sensor has a different minimum sensitivity, say 2 lux instead of 6 lux, then the 4-stop range would go to being 2 to 64 lux (4x2x2x2x2).

But maybe my math is wrong... it's late.

[Mark B.]

Good sensor will have similar characteristics as the human eye.
As all in the nature we use, is logarithmic. Intensities, loudness, brightness, concentration of chemicals in our body, all is logarithmic.
So it has much finer resolution at low levels and less resolution (in terms of steps or increments) at higher levels.
Gamma curves try to deal with this if the system do not have it implemented right in the pickup (sensor) or in the display (screen).

So if the sensor do not behave logaritmic then analog to digital converter better have finer resolution at low levels then at high levels. It is a specially true for audio.
With RGB or light levels it is bit more complicated but our eyes do have less sensitivity response at high levels.
The question is, as a industry, what is the standard, are we dealing with the non linear nature of human eye only on the screen device or on the sensor as well.
My intuition is that we should use 80% of the bits resolution on the first half of the signal and the 20% on the second half.
Andrew

If a sensor captures light with constant resolution, regardless of the light intensities falling on it, then it doesn't make sense to collect data in a logarithmic way. That would only result in a loss of perfectly good data on one end and the collection of redundant information on the other end. If it's a logarithmic sensitivity, then it makes sense to set the data collection to a logarithmic weight.

BTW, what chemicals in our bodies are logarithmically concentrated?

[david farland]

I thought most of it was....at least in our sensory perception!

It only matters if one part of your system is logarithmic i.e voltage output of the photo diodes collecting photons....but hey even it it wasn't you could change the tranfer characteristics in software to closer match visual perception.

DF

[Policar]

Just thinking:

Film's characteristic curve has about 8-10 stops (or whatever) of linear information, and a smooth roll-off at the highlights (and, with some stocks, also in the shadows.) I bet Red has more linear dynamic range than comperably fast (ISO 500, exposed as ISO 320) film stocks, it just lacks the smooth knee. (Personally I'm not a huge fan of shadow detail; I love the look of Michael Bay movies and (so far as film stocks go) nature photography using Velvia.)

Both the shadows and the highlights are so bright or dark as to have little visual information in them, and the extra dynamic range of film in these areas cannot effectively be recapture in the lab, because they are not linear. But they still look good!

Would it be possible to make a codec that's primarily linear, with logarithmic ends at the knee and in the shadows (where the S:N ratio is so low it wouldn't matter anyway)? Sure, the signal would be poor in shadows and highlights, but so too is it unusably poor in film.

[tj williams]

Policar

Possibly gamma curve tools in RED Cine will address this at the output stage?

[Rob Lohman]

You can pick an output gamma space when encoding in REDCINE

[P Andersson]

This is the best thread ever...

absolutely, it was interesting to study how film reacted to light a few years ago, (remember the zone system?) and it is essential to build a strong foundation in understanding the stuff of this thread, this information will sit in the bone marrow eventually and determine automatic adjustments to the f stop in critical situations


You can pick an output gamma space when encoding in REDCINE

do you guys have some rough samples of how it looks when you have encoded to different gamma curves that you can post for us to learn the difference, we could get a visual feel for how noise reacts in different situations and what gets clipped when etc.

if not, could I do this with any raw file in photoshop somehow

[Graeme Nattress]

The eyes response to light is not logarithmic though - it's actually a close approximation for the power law curve of a CRT ~0.4.

Imaging sensors are, however, inherently linear and noise limited. Also, mathematics like colour transforms must be applied to linear, not gamma encoded data. So, if you sampled the data logarithmically, the first thing you'd need to do would be convert it back to linear to do your colour science math on it.

Power law and logarithmic curves can make sense for compression, however. However, with RAW you've got to be careful as you don't have an implied rendering intent with regards to how you want to deal with highlight and shadow data, so it's wise not to push the curve compression too far. All you've got to remember, is that image processing works best on linear data, they eye has as power curve of about 0.4, and that there's a lot of stuff that goes on inbetween....

Graeme

[Andrew M.]

If a sensor captures light with constant resolution, regardless of the light intensities falling on it, then it doesn't make sense to collect data in a logarithmic way. That would only result in a loss of perfectly good data on one end and the collection of redundant information on the other end. If it's a logarithmic sensitivity, then it makes sense to set the data collection to a logarithmic weight.

BTW, what chemicals in our bodies are logarithmically concentrated?

Lowkus, thanks for the stop explanation, finally I got it.

Correct me if I am wrong but most sensors will have linear bottom curve with saturation showing up at the top at the maximum illumination.
Analog to Digital converters could be modeled to convert analog sensor output to maximize its bit significant resolution. Now 12 bits digital output from the sensor has 4096 steps. The steps should be distributed in such a way so to reflect significant changes of the brightness and/or chroma for each step change, we don't want to waste bit steps for nothing, do we?.
Where significant mean significant for the human eye. After all we are producing output to be looked at.

So we could apply gamma curve right at the sensor A/D converter or to build the photo sensor that is modeled on the human eye sensitivity curve, or both.
IMHO closer we are to the real thing (the eye) then better.

I remember all these sound quality issues 20 years ago, finally at 16 bit sound resolution no body argue anymore that electronic tube based amplifier sounds better then digital one:-)
Microphones are build to respond like human ear and headphones are trying to pass this signal without any distortion. I will not touch the speakers issues since this technology is far far behind the minimum requirements.

I hope that in near future the camera sensors will consist of two eye like devices with the same characteristic.

BTW the logarithmic concentrated chemicals in our body:
blood sugar levels, hormones, etc.
Small change of blood sugar level at low mark will make us feel better, doubling it again and again will not produce the same reaction. Kind of like sex, logarithmic, hmmm..

Andrew

[Andrew M.]

The eyes response to light is not logarithmic though - it's actually a close approximation for the power law curve of a CRT ~0.4.
Graeme

Graeme, you are perfectly correct.
By saying logarithmic, I mean power curves.
Kind of like using dB to express levels.
3dB increase of power it mean double of power.
6dB increase of power level is actually 4 times of power level.
9dB increase of power level is actually 8 times of power level.
Bit different in the levels/voltage
6dB increase of level (voltage) it mean double of voltage.
So here we have 6dB to double.

Is this logarithmic or power play?

[Graeme Nattress]

Andew, sensors are inherently linear - that's how they work. 1 photon = 1 electron charge = analogue voltage = digital number.

Now, if 12bits gets you down below the noise floor, then you're already below the smallest needed step size. You can't now distribute those 4096 steps to give more detail to the shadows and less to the highlights as you're already with the finest, smallest step size that makes sense for the noise floor of the sensor. You could distrubute LESS bits so that you get 12bit resolution in the shadows and bigger step sizes in the highlights, though, but the easiest way to do that is to start with linear data and add a tone curve. Much easier than trying to build a non-linear a-to-d.

I have no idea what you're going on about tube amps and digital amps and 16bit and all that. 16bit implies a 96db SNR which both tube and transistor amps can better, and quite frankly, you couldn't pay me to listen to music on a transistor amp :-)

As I pointed out, the way the brain percieves brightness is on a ~0.4 power curve, not a logarithmic curve.

Microphones are designed to be flat (ie linear) and not with built in Fletcher–Munson curves. Nobody puts "loudness" countours into amps any more either :-)

Graeme

[Graeme Nattress]

Logs and power law curves are related, but different :-)

[Andrew M.]

Andew, sensors are inherently linear - that's how they work. 1 photon = 1 electron charge = analogue voltage = digital number.

I have no idea what you're going on about tube amps and digital amps and 16bit and all that. 16bit implies a 96db SNR which both tube and transistor amps can better, and quite frankly, you couldn't pay me to listen to music on a transistor amp :-)

Graeme

I didn't know that CMOS sensors are linear. I guess I have much to learn.
I am out of audio business since 15 years, but I remember how serious audiophiles did buy tube based amplifiers than (still you can buy one) saying that they do sound much better.
Better, maybe YES for some, accurate reproduction, NO.
I am believer in math and in digital world so S/N of 16 bit is probably the max what human ear can detect but if this will not be enough at current state of audio technology we can easily triple or quadruple that.

[Graeme Nattress]

Yes, can still buy tube amps. I've got a couple. They sound different. It's a film v digital cinema thing, where it's a user-choice aesthetic. Tube amps are expensive, large and hot, but they do sound rather nice, if not accurate. Of course, I'm a vinyl head too - same argument - they sounds nice, if not accurate.

16bit is quite adequate for playback, given the usual 50db or so noise floor in a domestic environment and the 96db dynamic range of 16 bit. To hear it all, you've got to be in an anechoic chamber, or rapidly become death, or both. However, I think >16bit is very useful for recording / mastering though to give you some "headroom".

CCD and CMOS are both very linear. It's a direct transform of photon to electron to voltage. Some non-linearity would be very useful for capturing highlights, but that's still an active area of research.

Graeme

[Andrew M.]

Graeme, I just realized something, are you serious audiophile?
If yes, my apology, I did step on the religious and very delicate subject, also this discussion is not only for a different thread but for a different forum all together:-)
Sorry.............
Andrew

[Graeme Nattress]

Yes, quite serious :-) But also very balanced. Check out my Stereo Images movie here: http://www.nattress.com/Movies/movies.htm

Audio can be a religious topic, but I'm a mathematician, so I fully understand why a CD player is more accurate than vinyl, how sampling theory really works etc. However, I recognise that a lot of the music I like was mastered with vinyl playback in mind, and hence, although less accurate to the master tape, it's probably more like what it was intended to be heard like. Vinyl is also more "fun", but as I say, less accurate. Similarly with tube amps, they're fun, and they have a life to the sound that is wonderful to listen to, but they're less accurate than a transistor amp with a bunch of feedback. I do think this would belong in a off-topic "philosophy" thread on accuracy v enjoyment though.

Graeme

[wshultz]

Just checked out your movie, Graeme. Very nice. There is a "texture" to tube amps that is so pleasant to listen to. A lot of my voice talent people buy them to do their voice work.

Do you own a HD100? I sure hope you guys incorporate the HD100 style focus assist into Red. It's a feature these 50 year old eyes have come to depend on.

[Andrew M.]

It's a film v digital cinema thing, where it's a user-choice aesthetic. .

Graeme

Graeme, I agree, the audio subject that we accidently stepped on belongs to the philosophical thread but film versus digital is the same type of social phenomenon that belongs here.
I think, once RED will be in production and in use by many, we will have religious wars like back then with audio digital technology.

Looking in to the past of film cinematography, all production, capture and display is optimized for the film. Digital guys will have long uphill battle, to fight. It just started.

All current technology out there is optimized for the film to please the audience. Also audiance did get used to to the feel and look of it.
As a mathematical minds we know that digital can do what film does and more but it takes time and political skills to convince the pros. We all have experience from audio wars so I think it will be easier to fight this one.
But the first we have to make transition easy by talking the film guys language, (no offence to 99% of this forum users) and we have to make it look and sound and fill like a film. Then only then, after pleasing the film pros, we can show the full potential of RED digital.

So the ultimate winner solution is to copy all the disadvantages of the film minus the wish list of the film pros.
That is why, I was monitoring 24p thread with high interest. First we deliver 24p then we make 60p or 120p look like 24p with downgrade algorithms. Then we show 24 in many mutations and enhancements not possible with film technology. After which, maybe, just maybe, some people will start to like silky smooth 60p or 120p look.

You understand this the best as a audiophile and still one of not many users of tube amps. That is why I think RED will succeed.

Andrew

[Graeme Nattress]

No, I don't own an HD100 - I just borrowed it for a weekend, along with deck and monitor, from the local rental house as they needed someone to figure out the FCP workflow for them.

It's actually the HD100 focus assist, and how useless I found it, that made me invent the RED focus assist. In the Stereo Images video, I tried to do a nice pull focus, and I used the focus assist to help tell me when it was in focus and when it was not. However, even though I tried a number of times, when I reviewed the footage, I'd only got it "right" once. That's because, the coloured line that illuminates to show focus actually obscures the edge that you're trying to see whether it's in focus or not. And as the coloured line is binary - it's there or not there, it cannot show you how good your focus is.

So that's why we don't have a focus assist like the HD100, but the story of how it inspired something new.

Graeme

[Sam Druckerman]

That's because, the coloured line that illuminates to show focus actually obscures the edge that you're trying to see whether it's in focus or not. And as the coloured line is binary - it's there or not there, it cannot show you how good your focus is.
Graeme

As HD100 owner I have to agree.


So that's why we don't have a focus assist like the HD100, but the story of how it inspired something new.
Graeme

Graeme, your new Red focus assist has really got me excited.

I'm starting to picture a visual graph or a numerical readout mathematically defining how well in focus the image is.......?

[Graeme Nattress]

You may think that, but I couldn't possible comment.

Graeme

[Jochen Schmidt-Hambrock]

However, I think >16bit is very useful for recording / mastering though to give you some "headroom".

Graeme

Graeme,

the headroom is only one (important) thing why you want more than 16 bit in audio.

In an audio mixing situation (inside of a mixing desk) you have lots of signals going around that are very low: A loud hihat pushed back, bass slaps dialed down, etc.). And much more important: You often send very small amounts of signal to reverb processors, ambience, etc..
All those signals suffer from bit degrading just because they are so low. And if you ever boosted a low 16bit signal back to full blast you know how dreadfull they sound. But this signal goes to a reverb unit and colors the overall sound. Thats why you want at least 24bit inside a desk - and some good ones (and software like Logic) have internal 32 bit floating point.

*This* is why you want higher bit rate in audio.

And since no mixing or bussing goes on inside the Red, its perfectly fine with 24 bit inputs.

All the best,
Jochen

[Sam Druckerman]

You may think that, but I couldn't possible comment.

Graeme

LOL

I know , I know...

[Stephen Williams]

Just thinking:

Film's characteristic curve has about 8-10 stops (or whatever) of linear information, and a smooth roll-off at the highlights (and, with some stocks, also in the shadows.) I bet Red has more linear dynamic range than comperably fast (ISO 500, exposed as ISO 320) film stocks, it just lacks the smooth knee. (Personally I'm not a huge fan of shadow detail; I love the look of Michael Bay movies and (so far as film stocks go) nature photography using Velvia.)


Hi,

I guess you have not shot any negative motion picture film recently! Depending on the emulsion you should expect results in the 12 - 15 stops range, Kodak have claims of upto 20 stops. Film response in more log than lin.

Stephen

[wshultz]

At least I know it's going to be something new and helpful for focus assist! I don't want to have to push a button to blow up a section, I hope I can monitor those pull focuses. That being said, I've found the blue lines to be better than what else I've used so far so I'm really excited to see what you've come up with!
Could you comment IMpossibly?

[Graeme Nattress]

I was excited about the magic blue line approach until I actually tried it myself, and was dissapointed. I think this new approach will be helpful and fun!

Graeme

[wshultz]

Awesome. Helpful AND fun?
BTW, on your video, it looks like they're stressing you out. Ya gotta quit chewing your nails down to nubs. All that coding must take its toll.

[Andrew M.]

I would let edge enhancer algorithm run in the background continuously.
Then I will constantly display CPU usage for this process in the EVF.
More edges to process and more time spent on this task, less focus there is.
In any image there will be sweet spot where the edge's enhance algorithm CPU utilization will bottom out. Then we could display it as a just raw number and also as a kind of depth finder graph used on the boats that scrolls constantly from left to right at different high beeping when you are on too shallow water:-)

Graeme is not talking and speculations are running wild........

[Graeme Nattress]

Speculation is fun!

Ah stress.... Yes, that's me :-) And that video was made before I got silly busy :-) Was fun though.

Graeme

[Emmanuel Cambier]

I think this new approach will be helpful and fun!

Graeme

Graeme… by being so laconic, you are neither helpful nor fun:D

Emmanuel

[Graeme Nattress]

Sorry, but I'm under strict orders not to divulge the method or appearance of the focus assist. I thought the story of it's invention would be useful though. I actually used the HD100 test footage I shot for my little movie to develop the code, and it was nice to see that you could easily distinguish the failed from the perfect pull focus on my assist, something that I could not do in camera.

Graeme

[wshultz]

We should take him out and get him silly drunk and then see how laconic he is.

Damn. Those hints just make me bite my OWN nails to the nubs.

[Graeme Nattress]

It's going to cost you though as the scotch I drink isn't cheap :-) Looking forwards to meeting you all at NAB though.

Graeme

[Sam Druckerman]

... and it was nice to see that you could easily distinguish the failed from the perfect pull focus on my assist, something that I could not do in camera.
Graeme

I love the sound of that!

[Andrew M.]

I like anticipation.
Scotch is good, and I am very close to Ottawa next week.
As a ex Montrealer of 22 years there, leaving in Washington DC now I know that it will take more then one bottle of this elixir......
And the deal is that you will not divulge the method or appearance, we well just exclude what you didn't do. I guess it will be long list.
Andrew

[John Allardice]

It's going to cost you though as the scotch I drink isn't cheap :-) Looking forwards to meeting you all at NAB though.

Graeme

I must have missed an earlier thread, as a fellow ex-pat, ( former glaswegian, now resident of Hollyweird ) what particular forms of uisce beatha
are you especially fond of?

J

[Rob Lohman]

For more on Graeme's tastes: http://www.reduser.net/forum/showthread.php?t=191

:)

[Simon Dean]

Microphones are designed to be flat (ie linear)

I am constantly amazed not only at the knowledge found here, but the willingness to share - thanks!!

However, out of Graeme's mountain of knowledge I'd like to pick a small hole on the above quote. Studio microphones are not designed linear - but to sound nice! Just like film you choose a microphone you like the sound of, because they're 'coloured' in certain ways - just look at the response curves on some of the well known mics, they're not flat. One of the reasons analogue (tube) hifi sounds so nice is because it isn't linear. Analogue noise can actually be pleasant to hear, digital noise isn't - don't know why, but our brains prefer analogue noise.

This compares really well to film and how people are wanting curves in the digital world.

[Andrew M.]

I agree with Simes, however you can profile good 32 bit audio to the analog sound but you can't profile analog to whatever digital can do.
At least not mathematically.

So in film we have the same analogy, 120p digital can be profiled to look like 24p film but 24p will never look silky smooth like 60p, unless you run the film faster:-)

[Andrew M.]

For more on Graeme's tastes: http://www.reduser.net/forum/showthread.php?t=191

:)

I like these tests better...

[Graeme Nattress]

I think you're right about mics not being flat, but neither are they modeled around the ear/brain's loudness response curves either. Indeed, they're for the most part, essentially flat with some tweaks for euphony, and hopefully a tube amp in them, like the nice Neumann's I can't afford :-)

Graeme

[Hrvoje Simic]

some eye (& ear) candy...:)

-framegrab from an AV event we covered.

an off subject, but anyway...


http://www.reduser.net/forum/uploaded/589_1171653613.jpg

[Andrew M.]

Nice pieces of hardware.
I am getting sentimental, used to make amps like this.

[ericyoung]

Not knowledgeable enough to know offhand whether this is a valid question, but in broadcast TV where I work, the studio cameras have at least a couple of colour matrices - one being the old BBC matrix and the other an EBU matrix.

It's not unheard off to have to try to match footage shot by totally different cameras - will RedOne have any presets for ballpark matching of colour rendition to existing broadcast matrices? I know this is probably degrading Red footage to match old standards, but I'll bet it will be requested at sometime, somewhere!

[Graeme Nattress]

RED produces REC709 HD colours. There's option for customs matrices to alter the colours, but I'd really get an engineer to do that. If you know the exact specs of any colour space, it's a simple matrix transform to move from one to the other.

Graeme

[Joel Kaye]

Sorry, but I'm under strict orders not to divulge the method or appearance of the focus assist. I thought the story of it's invention would be useful though. I actually used the HD100 test footage I shot for my little movie to develop the code...



Wow, I hope this is as amazing as you make it sound. I know I can focus my HD-100 much more easily than either the HVX or Canon. The peaking on the Canon is Ok - but the zoom in and focus option on the HVX is totally unusable if you're tracking anything moving or targeting something that's not in the middle of the frame... like a moving camera, changing composition and tracking focus.

If you've got those guys all beat it'll be a terrific selling point.