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November 12th, 2004, 11:08 PM | #2146 |
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You should be fine (or at least right on the edge) with 60Mhz, as PCI 32-bit is capable of 133MB/s (theoretical).
But as David pointed out, max sustained you should expect from PCI 32-bit is around 100MB/s. |
November 13th, 2004, 01:38 AM | #2147 |
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lots of people have LCD screens that max out at 1280x1024 like all the edit stations in the office.. that is the reason for the downsize
The Epix 64bit card will be nice. With that card I could sleep at night without the worry of FIFO overflow and complete system lockups from the massive amounts of data we have to move around with this system ;) and maybe even start to think about doing overcranking! |
November 13th, 2004, 01:45 AM | #2148 |
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8-bit would be nice, but even if the gamma is corrected before going to disk, I'd love to see 10-bit images written to disk. There's just so much more to work with in postproduction (colorgrading in particular), that I think it's really worth the extra expense.
So are we waiting for PCI-X 64 bit framegrabbers to get the required bandwidth? Bar3nd |
November 13th, 2004, 01:52 AM | #2149 |
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No I am not waiting but it will allow the speed we need to capture 24fps 12bit files on-disk. At the moment I am on the edge of the limit from the pci buss and I am not sure how the new motherboard will deal with that much data. I will have to wait and see how it goes with the new microATX board I am waiting for.
I also need to order the 74MB/sec SATA disk drives so we can get upto 148MB/sec datarate going into the disks |
November 13th, 2004, 03:10 AM | #2150 |
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Obin , if by "overcranking!" you mean "overclocking!" I would say-YES!!! EXACTLY!!!
As a "HardCore" overclocker I can share some digits: A PCI Voodoo3 2000 VGA work at 50MHz PCI buss -no problems. A HighPoint UltraATA RAID controller work at 48MHz -no Problems -at 50MHz and above the information on the disk array is killed, so you need to lower the freq and build the RAID again... ...usualy a 44 MHz PCI buss is a 99,99% safe value... ONLY on intel chipsets!!! A BIG WARNING - DON'T do that if you use *SATA* HDD's - you'll lose your data!!! Also 5 years ago I've killed the partition of my C: drive at 44 MHz PCI ,but I think today's PATA HDD's are much better in that aspect (I mean HDD's from Maxtor and NOT from Seagate!...Don't know about WesternDigital) Tell me if you are interested -I have to say more... Best Regards! Marin |
November 13th, 2004, 04:18 AM | #2151 |
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"Overcranking" and "Overclocking" are two different things.
Overcranking describes a process in traditional film cameras where you "crank at over" 24fps for slow-motion effects. BTW, the other thing that can prevent these overflows, etc. is something with an on-board memory buffer, i.e., the GigE interface. |
November 13th, 2004, 07:24 AM | #2152 |
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But doesn't GigE max out at 100MBS the same as pci? I am really interested in the GigE interface but if it is riding the edge of 1080p 12bit and is unreliable at that rate it wont work for me. Steve is this problem solved with bit-packing? If so what hurdles need to be jumped in software to unpack the bits and access the files?
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November 13th, 2004, 08:03 AM | #2153 |
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Rob:
The GigE is 100MB/sec after derating - that is the real, continuous rate as long as the system bus can handle it. It does packing - 2 12 bit pixels in a 3 byte sequence. It can be stored to disk packed so the cost is when you pull it out to do Bayer and the rest of the processing. And it does have frame buffers so you can use average rates. *However*, overcranking will not happen since 1920x1080x24fps x 1.5B/frame = 75MB/sec. You could go up to maybe 35fps. Camera link (64 bit) removes that limit. Obin: We do analog gain control in real time in the camera head since you need this to get the full dynamic range from the sensor (R,G,B filters have different responses, lighting may have difference spectral intensity). Unless we are convinced otherwise, we probably won't do any other real-time processing in the CL and USB cameras. Possibly in the GigE since it already has and FPGA and memory in the data path. CL will probably always deal with pristine data.
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November 13th, 2004, 08:23 AM | #2154 |
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Marin, I was just about to post on that too. I think there is enough latitude to allow for 30fps capture at least on PCI (I hope). I wonder, how much can you overclock a Gige signal ;) (double would solve most of our problems). I wonder what would happen if we did, isolating and Pelter cooling the Gige interface accross high quality tr4ansmission lines, or maybe converting to a optical format and then converting back {:) .
To all: People have been overclocking the PCI bus for years, now days it is a bit more complicated, but this is what I can remember. That the PCI bus clock maybe used for some other system timing, like AGP, memory (or maybe even ATA) clocks may all use subdivision of some master clock (can it be subdivision of subdivision too ??), therefore all linked, and increasing master clock could max out some other system, so changing clock multiplier is the best way, and whatever on the master clock you can get away with over extended uses (without random crashes). System overclocking tolerances, what happens and how the clocks are arranged can change from baord to board. Now the card itself may also have different tolerances from card to card. I think I rember something about increasing PCI speed also producing greatly increased power draw on the card. Anyway there should be stacks of overclocking stuff on the issue on the web. The not to distant future and the way out there: What we really need is to think of the future, that means cameras with on camera buffers, on camera compression (lossless to visual lossless to quality of HDV2) and twin Gige (1GB's) links to get descent frame rates off of cameras with 12bit depth. Something not thought of is the edit Iris controll. When we have cameras that have a latitude to match big bit depths (16bit+) then a wider latitude canbe shot with more ability to play with in post. Such a shot (maybe with more than 16bit latitude) maybe my actor standing infront/to side of the sun with details of both clearly seen (though obviously the actor looking murky from the squashing of his contrast involved). Finally we will get the ability to film and show accross a large light range where the audience contracts their iris's depending on what they are focusing on. I have been thinking about this for a year or two. There is more, but I think it is possible to deliver today, if any camera had the bit size and SN ratio to match. |
November 13th, 2004, 08:27 AM | #2155 |
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After some surfing' guess what i find!! OK OK THIS may be OLD news but its bloomin new to me!! How the hell did i miss these?
(1) Olympus 8-Megapixel HD Camera http://www.cinematography.com/index.asp?newsID=3342 (2) 3840 x 2160 Hi-Res Box Camera http://www.cinematography.com/index.asp?newsID=2714 come someone comment |
November 13th, 2004, 08:59 AM | #2156 |
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i know a few months ago we talked about RECORDING TO RAM as an option for high-speed capture... will that not allow you to record whatever resolution and color depth you want?
how about stuffing a server with 20gb or ram? |
November 13th, 2004, 10:07 AM | #2157 |
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Anhar
Yes those SHD cameras, I want one with that res, I mention them a few times, that is the one with the prism that spilts the image accross 4 chips to get 8MP. The IGS ssytem is the company with that capture card I put up for everybody to evaluate and comment on a few weeks ago. They are also interested in Cinema camera stuff, and I pointed them here. <<<-- Originally posted by Eric Gorski : i know a few months ago we talked about RECORDING TO RAM as an option for high-speed capture... will that not allow you to record whatever resolution and color depth you want? how about stuffing a server with 20gb or ram? -->>> the problem is the maxinum speed the capture card can get accross the PCI bus to disk or memory. Also 20GB (try 200GB-2TB) * $ then it has to be stored. We have a intermediate scheeme of using max onboard ram to smooth things out. Thanks Wayne. |
November 13th, 2004, 02:00 PM | #2158 |
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<<<-- Originally posted by Wayne Morellini : Marin... I wonder, how much can you overclock a Gige signal ;) -->>>
I know nothing about the nature of the GigE signal ,but there is a HUGE potential for overclocking (in our case)-it's obvious-the difference in cable length! If we can put together the camera head and the motherboard-the GigE cabel should be about 30 cm and not 100meters! At the years of i386-i486 processors there was a small button on every computer case,called "TURBO" :))) ! So what about same thing here - Not pushing TURBO -you are safe,GiGE compatible,able to reach 100 m and even 110 m ... and on the other hand -Pushing TURBO you are uncompatible,limited to 30cm, but deadly fast? :) If this is possible ...then the "mini computer" could stay realy mini- with the GigE chip on board,VGA on board,RAID on board the overall height is close to 1inch ! Also If I remember correctly on intel 865-875 chipsets, there is a separate buss for the onboard Ethernet adapter and if we use RAID 0 with the help of South Bridge (ICH5R-separate buss too), then the need of overclocking PCI become unduly! Best Regard! |
November 13th, 2004, 02:07 PM | #2159 |
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Forgive me but I still cannot get the word "Overcranking". Is the word "cadence" similar?
Thank You! |
November 13th, 2004, 02:58 PM | #2160 |
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No not really. Cadence refers to a specific rythme. Overcranking is different.
With a film camera to achieve slow motion it is necessary to shoot more frames per second than usual so that when you play back at normal speed the motion is elongated - hence slow motion. For example you may shoot at 48fps and then play that back at 24fps effectively creating slow motion. |
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