4:4:4 10bit single CMOS HD project

[Rob Lohman]

Totally agree on RGB expansion. No-one seems to be doing that
and I can testify Rob S. and myself ARE NOT doing this. It's just
there to see what scale raw and packing are on.

I think 10 bit packing is very useful, it offers almost 40% reduction
of the datastream without any futher need to do anything else.
Rob S. and myself didn't have too much trouble implementing
that. I've got a bit shuffling engine running for my compression
anyway.

Regarding compression. The first test to compress a 16-bit still
frame from the SI-1300 @ 1280x720 resulted in a futher 38.72%
datasize reduction using my compression "engine". This is with
plane splitting. Optimizing the compression per plane increased
this to 39.13%. This is on top of the packing which gave me a
total compression ratio of 61.70% and 61.95%.

Regarding the 3300 and FoV. If the full width of the chip is 2048
and you only sample 1920 you will loose a bit of the fiel of view.
Depth of Field will slightly change as well. Or was this the chip
with fractional row skipping or am I mixing up the AltaSens. One
of these had fractional skipping so to not reduce FoV, the other
didn't. And you would have to scale in software to keep the FoV.

[Steve Nordhauser]

Here is some bandwidth information that may clear things up a bit. When dealing with video transfer using a PC, every step of data movement must be understood as part of a system.

Into the PC:
USB 2.0 can transfer data at about 320Mbps (with the wind at its back and the sun shining). Spec is 480Mbps. Remember, all bps are bits and Bps are bytes. You need to know if the data is packed or not. 12 bit data can take 2 bytes unpacked (16 bits) or 1.5 bytes packed (12 bits). (Peak vs average - below- applies here also)

Someone else can suggest real world numbers for firewire.

Gigabit ethernet is 200Mbps with windows drivers, 800Mbps (100MB/sec) with custom drivers.

Camera link is pretty much unlimited.

PC buses:
PCI-32 theoretical is 132MB/sec, realistic is between 100-120MB/sec. There are some PCs with a split PCI bus that can move data independently on each half.

PCI-64/66MHz is 4x the bandwidth of PCI-32/33MHz

PCI-64-133MHz is 8x the bandwidth of PCI-32/33MHz

If you put a 32 bit board in a 64 bit bus, the whole bus slows to 32 bits. Same with clock rates.

Some operations, like moving incoming data to system memory, take bus bandwidth at a peak rate that must be available, others can use an average rate (like moving compressed data to RAID). Some, like display to a monitor might not take any bus bandwidth since the pathway to an AGP slot does not cross the PCI bus. Some of the new chip sets show a two drive serial ATA pathway off the bus (the southbridge is an ICH5R). This might be very important but I haven't seen any benchmarks.

Mass storage:
(someone correct any numbers that they feel are incorrect please)
ATA drive - highly dependent on drive size, RPM, interface but maxes out around 25MB/sec continuous per drive
SATA (serial ATA drive) - around 40MB/sec continuous
UltraSCSI 320 - about 50MB/sec continuous

Drives start putting data on the outer rim where access times are quicker (fixed rotational speed, more data in a circumference) and slow as you go further in. Be sure to watch benchmarks to see if they are really putting data on at least 2/3 of the drive.

CPU speed:
Some operations take no CPU time just bus time, using DMA transfers. Others, like USB 2.0 drivers, take CPU time that must be available. Real time packing, compression and preview display all take CPU time.

[Rob Scott]

Steve, a while back you posted a link to a page which would calculate the pixel clock command for a given rate. I cannot find it now -- can you please post again?

Thanks.

[Adrian White]

Obin, do you definatly think it is feasible to shoot a large project with the 3300? (By feasible I mean big screen potential)

What is the deal with this rolling shutter artifact?

Does this make it unuseable?

Is any of the mechanical shutters on the silicon site useful?

After looking at the streampix software information on the silicon website it claims that it can stream to hard drives compressed or uncompressed. How much compression are we talking about here?

Does this still mean that a RAID is necessary or is there a possible external hard drive solution?

Lastly, what is going the most straight forward NLE? If we are staying with PC is Vegas Video 5 practical?

Is there anyway we could use the ethernet option to get the images into Final Cut Pro?

I ask these questions because the arrival of altasens has still not been confirmed. I have heard rumours that cineform may develop a codec for use with adobe premiere pro, but again there is no indication of when this will arrive. Also no news from sumix either.

As I am based in the England (about 100miles from London) any order I make will have to be shipped across the ocean to me. I have a project I wish to shoot within the next two months so knowledge of any further developments is crucial right now. If you can shed any light on these matters at all I would be very grateful.

[Obin Olson]

I will see today how bad the rolling shutter is @ 60mhz 1920x1080 on the 3300

Adrian,

It is hard to tell how long it will take.

I will have a product but I am still in R and D on the whole thing...stay on the board and keep reading

[Rob Lohman]

Adrian: personally I would not calculate on using these camera's
on such a short term (2 months). As Obin indicated both teams
are in R&D stages and developing a product. There is no 1.0
release yet. When we reach that there are other things to work
out like casing and how well these systems will work. And we
haven't even touched on things like audio synchronizatione etc.

[Obin Olson]

ROb what one of the 12 are you using from that paper?

This one:

Linear Interpolation with Laplacian second-order correction terms I ??


I am currently working on an implementation of the "Color interpolated image using Laplacian second-order color correction I" algorithm which can be found here. It seemed like a good compromise between CPU load and image quality. -->>>

[Rob Scott]

Obin Olson wrote:
what one of the 12 are you using from that paper?
This one:
Linear Interpolation with Laplacian second-order correction terms I

Yup, that's the one. In that paper, it's also referred to as "Interpolation with color correction I" and "Laplacian color correction I".

[Obin Olson]

Have you tested it yet? can you show me a still from it?

[Rob Scott]

Obin Olson wrote:
Have you tested it yet? can you show me a still from it?

It's not quite working yet. I'll post a sample image as soon as I have one.

[Obin Olson]

that would be cool...Rob we are saving RAW files on the disk..would it be a good idea to send you one so you can test your convert app?

[Rob Scott]

Obin Olson wrote:
that would be cool...Rob we are saving RAW files on the disk..would it be a good idea to send you one so you can test your convert app?

Once I release the Convert app source code, your developer will be able to add support for your file format -- or you can use the IHD format if you prefer.

[Jason Rodriguez]

Hey Jason, it´s been a long time..... :)
So you´re saying that the outdoors image is right?
Or the opposite?

These are linear sensors (for the most part). That means that ANY exposure is "right". The only limiting factor is noise. If you want a "filmic" image, then you're going to have to underexpose a whole lot to get enough head-room to simulate the highlight compression that film can do (or simulate a logarithmic respose to light instead of linear). Enough head-room compression so that the eye can't see the clip-point, just like with film. It's the same thing as with digital audio trying to sound like Analog-you have to go way under 0db (like 20db for the tone), and allow that top 20db to be used as headroom so there's no digital overload, the same thing to us as "clipping". I'm sure you've heard when somebody doesn't watch the DAT and lets that overload-it doesn't sound good. Same thing with digital imaging. So anything is "right", but that doesn't mean it'll look good. Now if there weren't any bright hot-spots in that image, say in a studio somewhere, then he'd have no problems, no clipping, and we'd probably be saying great things.

But again, our only limiting factor with how far we can underexpose these chips is noise, and that's why it seems the Altasens will be such a great chip, because we can underexpose a WHOLE LOT, hardly much noise, great color saturation, etc.

And we haven't even touched on things like audio synchronizatione etc.

After talking to Steve about this, I'm not really sure that's going to be a problem, because with the camera-link cameras we have very fine control of the frame rate through partial Hz frequencies and vertical blanking. In other words, trying to hit 23.976 or 24fps won't be too hard (and both those frame-rates are VERY important, along with 25fps-for PAL-29.97 and 30fps). Only those frame-rates need to be spot-on with audio sync, the others are for MOS-type stuff only.

[Obin Olson]

ok I have CineLink with full color display 24fps and GAIN, RGB GAIN, SHUTTER SPEED control with the 1300rgb...looking good...now if we could just get the 1300rgb without the smear factor this would be at the point that I could start thinking about a box design and buy all the rest of the stuff we need!

I am stuck right now...seems the smear is bad enough to halt production with that chip and the 3300rgb datarate is so high that I can't even do what I want with it unless I have a 64bit pci card..I can't get a 64bit pci card because I have been working with the 32bit card from Epix and the whole project is wrapped around that brand..Epix does NOT have a 64bit card out that may take 2-3 more months. The only other thing is the Altasense running at 720p untill the 64bit card comes out...as you all know even the Altasense is NOT out yet!...would any of you guys think it wise to go ahead and use the 1300rgb smear and all?

arrgg

[Steve Nordhauser]

Obin,
If you are already going to use the ground glass for DOF, can you use the SI-3300 in 1280x720 windows? It would run at the same speed as the SI-1300 (same clock speed and frame rate) without the smear. Less sensitive, of course, due to the smaller pixel size. Less DOF without the ground glass. The reason the data rate is so high on the 3300 is that you are using it in 1920x1080 mode and that is a lot of data.

Also, Epix swatted their last bug on the 64 bit board last night and will be going out for new boards very soon. I'm expecting 6-8 weeks for production boards.