4:4:4 10bit single CMOS HD project

[Steve Nordhauser]

Ben,
Maybe we should pay attention to the tablet PCs. Is there a very small one? Losing the keyboard entirely and gaining a touchscreen is probably the best way to go. I can't imagine an easy to use camera attached to a full laptop. There are some really nice LCD panels for around $400-$600 w/ full VGA or better displays. The RS-170 panels are way down in price but other than framing a shot they would be pretty useless.

I think a key point is the real-time compression. If you don't do it, you probably need a RAID for anything over25MB/sec with a standard drive and about 45MB/sec with a SATA drive. If you put in the processing power for RT compression, you can write to a small drive but probably dropped 100W of power to get there.

[Ben Syverson]

The smallest tablet is the Sony VAIO U70. But the micro HD inside will never keep up with the data.

These small screens can be had at 800x600 or even 1024x768 res. I have an older Sony U3 and its 6.4" screen is 1024x768...

The biggest problem with small solutions is that they don't have 2.5" drives in them, so you can't ramp up to 7200rpm. You need a full notebook/tablet for that. In my book, a tablet is every bit as cumbersome as a notebook, perhaps more so. At least you can put a laptop on a surface and read its screen -- a tablet will lie flat, forcing you to stand directly over it or pick it up.

If you want internal RAID, you are essentially fscked when it comes to notebooks. However, I've been thinking lately that it should be possible to daisy chain a few 2.5" Firewire drives together and do software RAID. Since these drives are powered over the FW bus, you wouldn't need to plug them in. Each FW bus is supposed to deliver 45w, but even if it's less, it's probably enough to drive four 2.5" drives.

The trick would be figuring out the power/speed tradeoff. If you have enough power, you could do 4 7200rpm drives. If you aren't getting much power, you could swap them out for 4200rpm drives...

- ben

[Ben Syverson]

I think it's totally feasible to do realtime compression. Here's how it would work for a 1280x720 image.

1. Read in the bayer image off the camera.
2. March through the pixels, separating the image into 3 channels -- R & B at 640x360, and G at 640x720.
3. Compress each channel losslessly.
4. Throw that data into a file.

In reality, steps 2 + 3 would be happening at the same time.

If you're shooting 1280x720 at 24fps at 10bit, you're only using 26.3MB/sec. You might not need compression or RAID to keep up with this if the Hitachi 7200rpm drive is fast enough. But if we assume we can get at least 1.5:1 compression on each channel, that drops us to 17.5MB/sec.

We can definitely handle that. Lossless compression is very fast -- if you built it into the frame-writing code, it wouldn't take too much longer that writing an uncompressed frame.

- ben

[Obin Olson]

Steve do you have a reply for the above?

[Eric Gorski]

does anyone know if recording to ram is a good idea? this would allow a laptop to be an all in one capture device?

[Ben Syverson]

Eric,

I think it's a great idea, if you can handle the limitations. The max ram a laptop can hold is 2gb. You'll want at least 256-512 allocated as "real" ram, and then you can make the rest into a RAM disk. That leaves you with about 1536mb. Recording at 26.3mb/sec (1280x720 @ 24fps, 10bit), you'll have just under a minute of shooting time. Then you'll have a delay as it writes out to disk.

A better idea might be a portable RAID. I suggested this in another thread earlier today, and I've since done a bit more research. The basic idea is to strap three or four 2.5" external Firewire hard drives together and daisy chain them. Because laptop drives can be powered from the FW bus, it could be totally portable.

2.5" laptop hard drives draw a maximum of 5 watts during start up (5.5 in the case of the Hitachi 7200rpm drive) and around 2.5 - 2.7 watts during use. The Firewire bus should be able to supply a maximum of 45 watts -- I don't know if you get less on laptops. Regardless, if you use three drives, your maximum power draw during operation will be around 8-9 watts. Hopefully the Firewire bus on laptops would provide you with that much.

Even a 4200rpm drive can write at about 10MB/sec in the worst-case scenario (random drive locations), and around 20MB/sec in the best-case (sequential drive locations). With software-based RAID 0 for 3 drives, I don't think there would be any problem reaching 30MB/sec. Burst rates (which are improved the most by RAID 0) would probably be faster than the bus could handle (50MB/sec), unless you were working with FW800 enclosures.

Steve, what do you think of all this?

- ben

[Juan M. M. Fiebelkorn]

Ben and Steve,

The Eden processor consumes less than a laptop.
If you don't believe me go check the specs of Eden and Pentium M or Athlon Mobile.
About the compression system you are right, that's the way!!
(I've been saying that since I entered this board, and now I'm trying to develop a solution for that.)
Be aware that for every normal drive you add tho the system you add around 15 watts to your power requirements, so keeping one drive and going compression is a more power friendly solution.
About displays, there are many 7 inches Touchscreen LCD displays with VGA connector, with a resolution of 1024x768 for around $300.Mini-ITX website

My Maxtor Disk, 7200 rpm says: aound 900 miliampers for 12v and 630 milliampers for 5v.



Explanation of huffyuv internals

http://home.pcisys.net/~melanson/codecs/huffyuv.txt

[Laurence Maher]

By the way, I just got a Mac G5 with OSX and FCP HD . . . you bet your butt I'd buy that camera!!!!!!

[Juan M. M. Fiebelkorn]

Explanation of Huffyuv internals

http://home.pcisys.net/~melanson/codecs/huffyuv.txt

[Obin Olson]

I jsut bought a 8in touch-screen I will keep you posted when it arrives!

[Steve Nordhauser]

On the SI-3300:
Yes, you will get a small imaging area - probably only useful with c mount lenses or ground glass- it would be 1920 x 3.2 microns in length. This is not meant to be a great solution, just a cheap one - this camera is only $300 more than the SI-1300. That would be good if the smearing goes away and you can do 1920x1080@24fps @10bit. At the high res, the imaging area is about the same as the SI-1300 so *I think* the DOF should be the same.

Juan: Yes we will have something better - the Altasens SI-1920HD. This is 1920x1080 up to 60fps, full 12 bit. 5 micron pixels.

On storage:
Someone with good system sense, armed with a compression processing benchmark needs to review:
- how much CPU is needed to do lossless and visually lossless compression
- How much power, space and $$ that represents
- How much power and $$ that saves on the disk drive/array
- How much space that saves

I'm thinking that the CPU might have to be 2+GHz for real-time compression requiring a larger mobo. You lose the extra hard drive maybe so there is a space, power and $$ savings. At the least, a few systems (not individual parts) need to be compared. Maybe an eden with a fw raid, a micro-itx with a powerful CPU and single drive, a shuttle/Epox.

The answer may be different for different people, but it could spell things out a bit.

[Obin Olson]

Altasens? at the FG company? sounds like that is moving along at a good pace


also I see a ITX MOBO for p4! this would take care of the size issue and have enough power to do compression in real-time...hmm

what your saying Steve is that you can't do some sort of pixel binning on that 3300?

[Rob Scott]

Obin Olson wrote:
what your saying Steve is that you can't do some sort of pixel binning on that 3300?

IIRC, to do pixel binning, you need an even number of pixels -- unfortunately, 1280 doesn't go into 2048 evenly. To use the full chip area you'd have to interpolate. (Again, IIRC.)

[Wayne Morellini]

I've been noticing questions and issues previously covered, but forgotten, here is a summary of some answers:

History:

Originally Steve I in the viper thread got Sumix interested in making a camera for us. In the meantime Obin got this own version of this project going with the Silicon Image camera in the Russian film camera case, and gratefully got Steve N's support.


The main project boils down to this:

Is to make a low cost camera system that is suitiable for independent film production and low end professional, and prosumer, video production.

The aim is a system that consists of any camerlink box type HD camera connected to a portable computer system, preferably in shoulder ENG and handheld casings. Rob was doing software to make the capture, compression, and storage transparent, professional and simple, with universal codec support for transparent file format, transmission and standard NLE video editing. By using this glue software, and working out the best parts, we hope to make a well integrated simple to put together and use system, not a hack. At the moment we are all focussing on prototyping on specific cameras interfaced to normal computers with specific codecs, compression and NLE's.

Sumix is planning a compression based camera, as well as a 3 chip.

Silicon Imaging would like to do a compression based camera, if somebody else provides the finished FPGA desaign. I have another manufacturer looking at the compression issue, and Obin (I think) has also approached somebody.

Sumix and SI currently think that Altsens chips are the best.

Silicon Imaging, Sumix and many others, have non Altsens cameralink cameras.

Our own compression, codecs and FPGA, are future projects after the software is setup. Many alternatives have been discussed and suggested and there is a seperate Cinema camera FPGA thread.

Gigabit Ethernet is the what we are looking at instead of Firewire. It also is forwards compatible with 10 Giga Bit Ethernet which is way above Firewire 3.2Gbit/s optical. I have also suggested the cheap consumer HDMI (5Gbit/s DVI in USB type plug) standard, USB 3, PCI-E Desktop.

With USB2, and Gigabit Ethernet, standard drivers are inefficent and won't get near the max data rate, you need custom drivers to get close to the bus bandwidth.

USB2 has been discussed extensively with Steve N of SI. The problem is that you get lost frames because the USB hardware requires a lot of extra processing power, pixels are packed in 8 or 16 bits at a time, and the burst frame bandwidth is controlled by the shutter speed. When you read 10 bits it is sent accross as a 16 bit value (I know, really poor efficency). When you use a 1/48sec shutter requires double the bandwidth, with overheads that gets close to satuation. Alltogether unreliable.

We are looking at ITX, because of cheap consumer based mini-itx, and nano-itx formfactors, and very low power requirements. There are faster processors and extra processing capabilities being developed by VIA, that might negate the use of a P4.

Or something like that. Sounds right guys?

You will find more information about components and configurations here:


3 channel 36 bit 1280 X 720 low $ camera - Viper?


4:4:4 10bit single CMOS HD project


Home made camera designs?

The detailed guide to this project is presently at:
www.obscuracam.com

I have setup some additional threads if anybody wants to use them in future:

Home Made HD Cinema Cameras - General Discussion

Home Made HD Cinema Cameras - Problems and Performance

Home Made HD Cinema Cameras - Technical Discussion

[Steve Nordhauser]

Obin:
Yes, we have running cameras for the SI-1920HD.

The SI-3300 does have subsampling but only in integer steps -
2048 x 1536
1024 x 768
682 x 512 and so on.
The Altasens is pretty unique. It has a an interline mixing mode to get down to 1280x720 at the full FOV.