Laptop for use as SiliconDVR station for SI-2K
 

OK, Mr. Bob Hart asked and I thought others could use this info as well, so here goes.

Computer
Check out the newest laptops.

The one I am now using successfully has a catchy name US-VPCCW290X-LBOM.

I ordered it custom-built at SonyStyle. Build time was reasonable, I think I got it within about 10 days delivered.

My Specs:

Intel® Core™ i5-540M processor (2.53GHz) with Turbo Boost up to 3.06GHz

2GB (2GBx1) DDR3-SDRAM-1066

Large Capacity Battery (VGP-BPL13)

Genuine Windows® 7 Home Premium 64-bit (I've upgraded it to 7 Pro, but this is really not needed for the purposes of SiliconDVR.)

320GB Hard Disk Drive (5400rpm) (Hint: although it is possible to record on it, my recommendation is to use it only for OS and programs. For data recording (video), use in DVD enclosure that replaces the stock DVD-ROM. I bought such enclosure on eBay, delivered from Asia. Sits neatly inside the laptop's enclosure, pops out when you need to transfer data to the main editing PC. Nice.)

Laptop comes with Marvel-Yukon NIC, not Intel, but still works fine as it allows for large 9K packets required by SiliconDVR.

This particular configuration allows me to record Quality4 CineformRAW at any framerate, up to the highest 150fps.

And monitor at full resolution during recording.

Since it is a laptop, the setup is inherently mobile. (My previous setup based on Taiwanese miniATX mobo in steel enclosure was much more robust, admittedly. This laptop is rather delicate. Oh well, still it does the job.)

On location: Backpack
For truly mobile applications, just put the laptop in the backpack (the outer net for ventilation, not inside of the inner partition... You don't wanna go Slumdog on it with some ice packs, do you?) I use Eddie Bauer backpack, since I'm vane. OK, that and because it turned out to be the best value despite the brand name. Got it for about $35 including tax in the Eddie Bauer retail store. Carries laptop, camera, cables, accessories, battery, monitor, lenses... then becomes a laptop sling during mobile shooting with SI-2K. (Or you can buy something like this for bragging rights :)

Field Monitor
With this setup, you want to monitor the screen over laptop's HDMI output. I use a 7inch monitor 619AH, it takes the same 12V that I feed the camera. IMO, touch screen is not really needed. You can cycle through the usual menus using right mouse programming available in DVR instead. So the monitor is regular LCD with LED backlight, not touch screen. With the screen shade, it has enough contrast in most situations for confident monitoring. I find resolution sufficient for critical focusing. You just overshoot the lense's focus ring both ways first, so to find the relatively sharpest zone in the middle. I hope I make sense.

Same monitor can be used as external monitor for Canon 7D.

Sound - mic preamps:

For sound input, I use:

- one channel: CEntrance Micro Port Pro

- if multiple input channels are needed: Echo AudioFire 4

Hope this helps.

Alex.


Thanks for that. I shall head Steve Rice in the direction of your post.

Ummm... Not so fast!

It turns out, the miniSATA connection between the laptop's mobo, and a SSD in the DVD enclosure, is not good enough.

I would get weird AV sync issues with clips longer than 2minutes, while recording like that. Especially if frame rate was over 24p.

This lead to conclusion that thsi has something to do with the bandwidth.

Recording to the SYSTEM disk had no such problem. (Note: system disk is now SSD as well.)

I will investigate further, but so far it looks like miniSATA link may be no good for this type of work. Which sucks - it is absolutely great to be able to just pop out the SSD with the recorded clips and move it between the recording and editing machines...

Alex.


Before you toss dust in the air and do the sack-cloth and ashes bit, check the SATA cable. These are close to the most frustrating and cynically dodgy product ever visited upon man since the postwar Ford 10 Prefect.

On that flat dark coloured flat plug, there is a thin face opposite the conductors. It is loaded by the spring pressure of those conductors. Add the torsion of the stiff cable and you've got customised 100% percent fail sooner or later. A corner gets a split in it which is near impossible to see but what this does is allow the plug to open up and allow an open or resistive connection on the conductors closest to it.

The problem first shows as an intermittant glitch. You may also find that your computer has to sit dead flat otherwise the HDD read/write performance falls away. Solid state drives for the operating system and data may be a viable option.

The HP computer Steve Rice tried up in Thailand would ram out if it was tilted from horizontal. There is a generation of HDD drives which use plain bearings. These seem to be sensitive to gyroscopic loadings when the computer is tilted or carried upright while operating and tasked. I don't know if the laptops have these in them or more robust drives intended for being moved around whilst running.

Turns out the problem is most likely my external SSD drive.

Replaced with the regular HDD, the problem went away and the AV sync is perfect again:

http://www.dvinfo.net/forum/cineform...eform-raw.html

The end.

(hopefully.)