OT: Multi-cam live capture software? Any Free?

Post » Mon Jan 03, 2011 2:35 am

We are running Windows XP and want to capture from multiple cam... direct to disk. May be up to 8 cam's and 8 PC's.

These PC's will only be used to capture video live.

Each PC only has one firewire card and another can not be added... so capturing more than one cam on each PC may not work.

Our question:
We are looking for the easiest and least expensive software to do live capture to individual PC's at a multi-cam shoot.... as we don't need full blown Vegas on each...

Once the video is captured to the PC's hard disk we copy it all to the Post Production workstation and start editing with Vegas.

Thanks for any help or suggestions.
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Mark Hepworth
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Post » Sun Jan 02, 2011 2:30 pm

Scenalyzer ($34) would be my first choice.
WinDV is free but I don't know anything about it other than it's been mentioned here in the past.

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josh evans
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Post » Sun Jan 02, 2011 6:01 pm

Absolutely the best software for this purpose is Adobe's OnLocation [formerly DVRack]. Not free, but comes bundled with Premiere CS3 on a separate disk and separate license. So if you know people with Premiere that aren't using their OnLocations.... maybe you can strike up a deal. BTW, Premiere for Mac comes with the same WINDOWS OnLocation [no Mac version available] so it may be easier to pry a copy off a mac-head, in fact that's how I acquired my second copy of OL.
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Michael Korkia
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Post » Mon Jan 03, 2011 4:16 am

Scenalyzer is cheap, and it allows you to capture multiple cameras onto one laptop (well, two at least, although I think a few people have managed three). Remember that you can daisy chain Firewire, so even with one Firewire card, you may be able to get more than one camera attached to your computer. Also, if you have laptops, you can easily get a Firewire PCMCIA card. They cost about $10 on eBay.
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Stephanie Valentine
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Post » Mon Jan 03, 2011 4:04 am

Markertek is still listing Serious Magic DV Rack Express DV for $150.00.
The HD version is $495.00.
Needless to say, don't expect ANY support from Adobe if you go this route.

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Dustin Brown
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Post » Mon Jan 03, 2011 1:14 am

John, I have a question about Scenalizer and multiple cameras onto a single laptop. The absolute minimum I've found to be usable, with OnLocation, due to bandwidth considerations, for a single stream is 1.6GHz CPU and a defragmented 5400 RPM drive, and this is for SD, Adobe's recommendation for HD is substantially higher.. Anything less than that will create problems. Even with 7200 RPM drives you would need a substantial engine under your laptop's hood for capturing multiple streams simultaneously. Any ideas as to what they're using?

BTW, OnLocation requires separate Firewire adaptors for additional cameras [that's so you can switch cameras, but can only record one at a time]. I wonder if it's possible to run multiple instances under virtual machines in that case. And where that would stand regarding the license. I'd have no problem if required to have separate licenses, would love to be able to record 3 cameras to one laptop, even at approximately 40 GBs per hour for SD... Of course, that means 3 iso streams. If one does a line cut, then things get easier, but without the safety net of 3 separately recorded streams.
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Camden Unglesbee
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Post » Sun Jan 02, 2011 7:15 pm

John, I have a question about Scenalizer and multiple cameras onto a single laptop. The absolute minimum I've found to be usable, with OnLocation, due to bandwidth considerations, for a single stream is 1.6GHz CPU and a defragmented 5400 RPM drive, ...
Wow, something isn't quite right, if that is your minimum. I have captured to many 4500 rpm laptop drives. Also, the first computer that I was using when I started editing DV video was (and still is) a 450 MHz Pentium with a 5400 rpm IDE drive connected with 40-wire cables. And I never defragment since that is a total waste of time.

I never drop any frames on any of my configurations.

You can certainly understand why if you look at some numbers.

First of all, the CPU has almost nothing to do with the capture process because when video is transferred from a DV camera to a hard drive, it is merely copying the data. If DMA (direct memory access) is set correctly, the data should never have to be manipulated by the CPU, and instead simply copied to the hard drive. So, how fast does the hard drive need to be? This is the beauty of DV video and is why the invention of the DV compression chips created such a revolution. Prior to DV, most video editing was done on uncompressed video. The video had to be digitized and then put on a hard drive. At 720x480x24, you end up with about 1,000 KBytes per frame and therefore, at 30 fps, you need a hard drive that can sustain a transfer, when writing, of about 30 MBytes/second (that's the big "B" meaning Bytes, not bits). That's at the upper end of what inexpensive drives can do, and most cannot sustain that for sure. Thus, uncompressed video, prior to DV, and even now (for people that still deal with uncompressed) requires SCSI drives, RAID arrays, and other pretty exotic (and expensive storage) to keep up. However, DV achieves compression, both through JPEG and also by reducing the colorspace, and therefore only requires about 15% of the performance: 3.75 MBytes/sec.

If you poke around and look at drive specs, and look at the sustained transfer rates, you will see that even for a 2.5 inch IDE 5400 rpm drive, they are in the neighborhood of 40 MBytes/sec or over 10x what is needed. Thus, in theory, you could connect ten cameras to the computer before the hard drive would become the limiting factor. However, when saving multiple streams, there are lots of other factors involved, and therefore you have to have a good capture application, internal bus structure, etc.

The point is, it isn't very hard to capture two streams with any modern (last 5-7 years) computer, and you should be able to capture one stream on pretty much any computer of the last fifteen years.

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Grace Francis
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Post » Sun Jan 02, 2011 5:55 pm

I've used Scenalyzer with three cameras (SD) on one laptop. (One copy of Scenalyzer, three instances running). A Firewire hub worked just fine to connect the three cameras.

Not a single dropped frame and I got the impression that I could have captured more, but I only had three SD cameras at the time.
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Stephanie Nieves
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Post » Sun Jan 02, 2011 8:43 pm

Anybody here used WinDV or can tell me anything about it. We simply need to capture video live from our cams... while we are shooting...

Thanks for any comments.
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Post » Sun Jan 02, 2011 6:47 pm

Thanks for the reply. I learned a few things today, and was reminded of some others that had faded with time. I feel I need to add some info here, which may explain the differences.

OnLocation doesn't just capture the video/audio stream. It provides a contemporaneous display of the video, along with an audio display, Wave monitor, Vectorscope, shot clock, timecode, and a host of other goodies, all consuming CPU cycles. The recorded signal is bit for bit what the camera sends out, but there's quite a bit of processing involved for the display. The monitor applet can actually be calibrated for an accurate video display [SMPTE bars and blue gun anyone?]. Even a single button push still frame capture while the video keeps chugging along, and break the shoot into scenes without losing a frame. I can even instantly expand the video to full screen, oops, there go some more cycles.

As to a defragmented drive, I use a portable USB drive whenever possible for its obvious advantage. The few times I used the built-in drive OL constantly nagged me with the message "Drive too slow." now I keep it defragmented and no more nags. I do have to say that it never dropped a frame when I got those messages but I can't take the chance that it might..

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Tamara Primo
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