That's right.

Good news: I can now record with six cameras @640x480/60ips with the "Best Quality" compression - recording the files on my hard drive (Caviar Black). The OS is still on my SSD, I suppose that it helps a bit.

What was the issue? Well, I first bought a PCI extension card that has a NEC chipset, which as you said is really slow. So I then bought a USB 3.0 PCI-E extension card. With those two extension cards + the motherboard chipset I now have enough bandwith.

Furthermore, the CPU I use (i5-760), despite being only a dual-core and not overclocked at all, handles the compression really well (80% load when recording).

I will be able to do the first tests in about a week, time to move the hardware and gain access to a room with enough space. I will certainly be back with more questions soon ;).

By the way, best compression quality is not critical. Default compression quality setting is almost as good as best. Best setting would not hurt, of course.

Priorities are: frame rate - very important; resolution - less important then frame rate but more important then compression quality; compression quality - least important.



Intel i5-760 is a quad-core CPU.

http://ark.intel.com/Product.aspx?id=48496

Oh, I feel like an idiot now :o)! I always thought it was two cores and four threads, looks like I'm dead wrong.

Thanks for the clarification about what parameters are the most important. Since it runs flawlessly with all the settings set to the maximum I wil keep it that way, as you said, it won't hurt.

There is just the "glitch" that when you are not recording it drops a few frames on one camera, but when you actually start recording no frames are dropped. But it seems to cause no problems -from what I read from several users on the forum.

Yes, that's normal. I've always assumed that when the computer is sitting 'idle', other system processes are occasionally interrupting the flow of data from the cameras; but when you're recording video, iPi Recorder gets full system priority.

Anyway, glad you got it working!

G.

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Ok, so now I am working on a basic layout for the cameras and the area of capture. I did a little layout in SketchUp to have a precise idea of the installation. Is it a good setup or can I still optimize it? And if yes, how?

http://i.imgur.com/t9dyy.png

Looks perfect.

I'm back with some questions.

First, when I record with 6 cameras I have a huge flicker, except when recording at 50i/s. What could be the issue?

Second, I have two PC, one with a 8800GTS 512mb and the other one with a 4870. What is strange is that the calibration/processing time is way shorter with the 8800 GTS, despite being an "inferior" hfx card. Is the software optimized for Nvidia's architechures?

Flicker can be related to AC frequency in your country (50 Hz in Europe).

http://en.wikipedia.org/wiki/Mains_powe ... _the_world

Most electrical lamps do produce flicker because of use of alternating current. When you record video at the same frames per second (50 fps) as your lighting flicker frequency (50 Hz) it effectively "masks" the flicker.

Paradoxically, sometimes your motion capture results can be better when you do have visible flicker on video. The problem is that you still do have flicker when you record at the same FPS as your AC frequency (because usually it is not exactly the same) , it's just less visible for a human eye because it is low frequency. Visible flicker can be considered a high-frequency noise, and it can be easier to filter out then low-frequency noise (using the Jitter Removal filter).

I recommend that you do test captures in your environment at different frames per second and compare the results to choose the best FPS setting.

Now about video cards.

The 8800 GTS is actually not that much inferior. We do not optimize specifically for NVIDIA cards, but various NVIDIA and ATI/AMD cards can have different performance trade-offs and can behave differently in iPiStudio. I can tell for sure that latest top NVIDIA cards (GeForce 560 and 580) are seriously faster in iPiStudio then latest top AMD/ATI cards. Older generations should have more similar performance.

The difference in speed can also be caused by different CPUs in your computers.

I will test all the framerates in the future. I was afraid it would compromise the shape recognition, it was a really violent flicker, making part of some frames almost dark.

And the funny thing is that the 8800 GTS is on my C2D E6300 machine and it processes more frames per second than my HD4870 which is on my i5-760 machine.

Thanks!