Two Camera Live Capture With One PC

[Ron Arrivillaga]

So, I've been experimenting with custom software to capture two live HDV streams on one WinXP PC. I've written a bare-bones app to test with and initial results are encouraging. Here's what I've found so far:

- "Dual capture" will not work when both cameras are plugged in to the same firewire controller. WinXP throws a low level error about "insufficient resources". This is kind of a bummer, but not a showstopper.

- "Dual capture" WILL work on systems with two firewire controllers. I had two PCI firewire cards on one of my desktop systems and by plugging each camera into a different card, testing was successful. I also have a laptop with one on-board firewire port. I popped in a Zonet 1394 PC Card, and with one camera in the on-board port and the other on the PC Card testing was successful.

- Hard drive speed will be an issue. When capturing two streams to the laptop drive (not sure, but probably 5400rpm) there were visible artifacts in the resulting stream that I assume were a result of dropped bits. When I added an external USB2 drive, it was able to handle both streams without issue. The 7200RPM SATA drive on the desktop system also seemed to handle both streams without problems. I also tested sending each stream to a different drive, and that seemed to work well (even on the laptop drive).

- The resulting streams are raw HDV MPEG-2 transport streams and are compatible with Sony Vegas 7 and every software player that I tried.

- I have NOT implemented DV support yet. It's feasible, and might not be too much extra work. It's on the to do list.

- I haven't tried to implement preview yet. It's on my to do list, but my goal is to come up with a home brewed dual capture device (preferably a tablet PC) with a small footprint. Dual preview may require too much CPU horse-power for "small footprint" devices. I'll definitely try it out though.

- This software is in raw alpha stage right now and not ready for sharing in any form. I'm not even checking for dropped frames at the moment and error handling is non-existent. I'll share a beta version (if anyone is interested) when I feel the software is more stable and a little more "full-featured". Note: software will require .NET Framework 2.0.

I'll post updates in this thread if anyone is interested in my progress.

[John Miller]

That's very interesting.

I wonder why two HDV cams on the same FireWire interface are so troublesome. For DV cams, I have successfully had three connected to a single interface (with 3 ports) and captured from all of them. That was something of a freak event, though. I can always have two attached and capture/send to tape simultaneously with no problems. I also installed a second interface and, between the two, I can capture four streams without dropped frames. Though it is all DV, the data rate is comparable to HDV.

[Lisa Shofner]

I agree, this is an interesting project.

I know DV Rack can capture live 2 cams - but only if they are on separate firewire cards, just like you mention. I've been working on a setup that will run 3 cams live, but mine is far from small footprint (3 cam mixer, laptop, 4 cam spliter for preview, tv for preview)

I'd love to test this out when you have beta working if you add in the DV feature, I have no HDV cams yet.

What language are you coding in?

[Kevin Kimmell]

I will definitely line up to test this for you. Whatever stage you want people to start kicking it around, let me know. I'm trying to get the solution handled as well. I basically want to use tapes as the backup medium and eventually be able to capture all of my cameras at live events to disk - so less PCs would be great.

-KK

[Gregg Bond]

When I do event work I would desperately love to not have to ingest 3x3 days worth of tapes, currently I use a ADVC55 to capture my "produced" output from the live mixer, which also goes to an encoder for live internet streaming.

We have an on-site NLE that does some basic work on the recorded shows and then shoves them up to the website ASAP for video-on-demand. We also use the raw footage from the cameras and some proper post-production time to make 1hr shows for TV, because it doesn't have all our branding plastered over it from the live titling system we can produce based on the customers requirements. Currently I am the only one with time to do the ingestion/logging which usually takes about a week in my drained post gig state.

You would definitely make it onto the Christmas card list if you would also allow me to test your code :)

I have 2 events in the next 4 weeks and I am more than willing to put the software through its paces.

[John Miller]

Gregg,

If you are strictly DV, our software (see my details for link) will let you capture from multiple DV cams. I have successfully captured from 3 connected to the same PC. Not a single dropped frame during 15 hours of footage. It will pay for itself by saving many hours.

Should you have a need, you can also capture to multiple computers on a local network in perfect sync.

John.

PS: How's Pompey these days? I grew up in Farlington....

[Gregg Bond]

It truly is a small world, its still good and the football team is doing better than before. I guess NC is North Carolina? If so you are a long way from home :)

The network capture is an interesting proposition and the multicam would probably shut up my NLE :) Although we are DV at the moment, we use Z1's and would like to push to HD at some point.

[Kevin Kimmell]

Ron - Have you gotten any further with this project?

Anyone else - I've successfully plugged 2 cameras into my machine on 2 different firewire cards and can view them independently via windows explorer (albeit one at a time).

I can't for the life of me figure out how to get any piece of capture software that I have to see the 2nd camera. I don't see the option to select a different camera.

WinDV comes the closest so far as it at least has a selection dialog but there is only a single camera listed (Microsoft DV Camera and VCR).

In Explorer (XP) they are listed as "Canon DV Camcorder #2" and "Canon DV Camcorder #3" and browsing to them shows each camera's view.

I've got Vegas 6, DVIO, & WinDV on this PC and they all want to show me only what "Canon DV Camcorder #3" is showing. I also have an older version of DV Rack on my laptop.

Can anyone point me (quickly - shoot is Friday) towards how best to accomplish this? I'm planning on saving out to two different USB hard drives.

Thanks,
Kevin

[Kevin Kimmell]

As a follow up to the above post, I found a product in the weirdest of places that allows for the selection of source camera. Perhaps some of you have heard of it.

It's called Windows Movie Maker :)

I've now captured video through my laptop into WMM for one camear saving out to one USB hard drive and through DV Rack for the 2nd camera to a second USB hard drive.

Granted I've only been capturing short clips of myself talking and moving with some ambient noise but I haven't seen any noticeable drops in the AVI's that are saved.

Too bad DV Rack is such a resource hog though because I don't have enough RAM to feel safe using it with something else for the live shoot tomorrow and I doubt I'll be able to get RAM in there very quickly. WMM seems to use about 40% of the CPU when capturing alone whereas DV Rack takes 80+.

Harrumph!

[John Miller]

Originally Posted by Kevin Kimmell

Anyone else - I've successfully plugged 2 cameras into my machine on 2 different firewire cards and can view them independently via windows explorer (albeit one at a time).

I can't for the life of me figure out how to get any piece of capture software that I have to see the 2nd camera. I don't see the option to select a different camera.

Our Enosoft DV Processor will do it - just select the drop down list and you will see all the DV devices attached. Furthermore, instead of the unhelpful "Microsoft DV Camera and VCR" that you see for all the devices via nearly every capture app out there, you will see the more helpful "Canon DV Camcorder #2" etc. And, with our Enosoft Friendly DV tool, you can rename them to more useful things such as "Kevin's Canon XYZ" etc. This takes the guess work out of knowing which "Microsoft DV Camera and VCR" is which.

Finally, if necessary, you can capture from two cameras simultaneously and with perfect sync. This is for DV. Ron's original post concerns HDV.

I'm not sure what your laptop is, but I'd be surprised if our software uses much more resource than WMM when capturing.

FYI, the reason I wrote these programs is because I was fed up with the very same frustrations you are having!

[Kevin Kimmell]

John,

Is this something that I could download and test in a live setting for this Friday? My laptop is a Dell Inspiron 6000 with a 1.86G Centrino processor and currently only 512M of RAM. I ordered another 1GB stick for overnight delivery so by the time of the shoot tomorrow I'll have 1.5G in the system.

I'm fairly confident that I'll be able to get MovieMaker and either WinDV or DV Rack to work tomorrow but since we'll be rolling tape too I'd love to try something simpler out.

Thanks,
K

[John Miller]

Hi Kevin,

You shouldn't have a problem with that laptop. The software was written to get real-time performance for a variety of functions on a 1.5G Pentium M (your laptop has the 1.8G Pentium M - Centrino refers to the entire chipset, just to be confusing!). 512MB will be ample.

Please see my profile for a link to our website. You can download the software from there.

Feel free to send me a private message if you have any questions.

John.

[Kevin Kimmell]

Originally Posted by John F Miller

Hi Kevin,

You shouldn't have a problem with that laptop. The software was written to get real-time performance for a variety of functions on a 1.5G Pentium M (your laptop has the 1.8G Pentium M - Centrino refers to the entire chipset, just to be confusing!). 512MB will be ample.
John.

Should I plan on outputting to two external drives or do you think with the extra RAM that I should be able to write to the system drive and one USB without dropping frames?

[John Miller]

Originally Posted by Kevin Kimmell

Should I plan on outputting to two external drives or do you think with the extra RAM that I should be able to write to the system drive and one USB without dropping frames?

Two external drives would be preferable. I've managed to capture from 3 cams simultaneously to two drives - i.e, two cams were going to one drive. RAM won't really help. Using the system drive should be avoided unless it is very large and has a lot of contiguous free space.

John.

[Eric Larson]

Are you planning on upgrading ensoft dv processor for use with HDV? At least the ability to capture two HDV streams simulataneously, not necessarily processing the streams.