Multiple MiniDV camcorders to NLE PC...

[PC Master]

Here's the current setup...

3 x MiniDV Camcorders
3 x Sets of S-Video (running over Dual RG6 Quad Shield coax, with F -> SVideo adaptors on each end) and audio (2 TP + shield into RCA connectors on each end) running to a video editing booth around 75ft away (because of orientation, some runs are longer, others are shorter)
1 x Videonics MX-1 Video Mixer (4 analog inputs, digital processing and effects, analog output)
1 x Videonics Titlemaker (analog in and out)
1 x SVHS VCR (for recording)

Ideally, I'd like to convert this into a PC-based NLE system. Goals...

1) Get video from multiple cameras into PC, where it can be edited and output
2) Maintain the highest level of quality until output stage (multiple output formats, including DVD and SVHS will probably be used depending on the setup and circumstances)
3) Must be low-cost
4) Must be easy to operate
5) Must work over 75 ft distance between cameras and editing PC (while a recording device of some sort might be placable within 25 ft or so of the cameras, the editing PC with displays will not be)
6) Move to a 4-camera setup


What I've considered doing...

1) I will build or buy a PC for editing, and a 4th camera, since I want to have a 4-camera setup. I will use repeaters and long cables to connect the FireWire cameras directly to the PC. Questions that arise...

- Would FireWire allow me to daisy chain 4 DV cameras together, or connect them to a hub, and then run a single line back to the PC? Is there an ability to do this in any fashion?

- In theory, the bandwidth shouldn't be an issue (FireWire can handle 400mbit/sec - each DV camera will use 25mbit/sec, with 4 cameras totalling 100mbit/sec, or 25% of the rated transfer of FireWire cables, leaving plenty of room for overhead). How much CPU power would be necessary for a Windows XP system to capture all of this in real time without concern of dropped frames? Has anyone tried such a setup in reality?

- Does running such long FireWire cables (with repeaters) actually work reliably? What are your recommendations for maximum lengths, usage of repeaters, etc?

- Are there cheaper cabling options that would work here, perhaps like Cat5e cable?

- The recording should be accomplishable with software that is easy to run for the semi-novice PC user. Essentially, open this program, press record. What software do you recommend?

2) Again, I'd get a PC for editing, and a 4th camera. I'd record to MiniDV tapes, and transfer to PC later.

- I've looked into MiniDV players/recorders, and all seem to cost $800 or more, while MiniDV cameras cost $250 or less. Surely there are cheaper models out there, though they might not be quite as rugged as the expensive ones, right?

- I know from past experience that there are always drop-outs on MiniDV tapes. I also don't want to spend a huge amount on tapes, as that would defeat the idea of this being cheap. Is there a good place to get tapes at low cost?

- This is a lot of extra work, so I don't particularly relish this option, but it has the added advantage of probably leaving the original tapes as a backup medium.

3) Once again, editing PC and 4th camera are purchased. This time, I'd buy (cheaper than FireStore stuff) or build tapeless recorders for each camera, connecting these to the PC for editing later.

- Is there a way to do this for under $200 per camera? I somehow doubt it. If it costs more than that, it's probably not worth the expense.

- Are there recorders that can record multiple DV sources at a time.



I'd also like recommendations for that 4th MiniDV camera. Desired features...

- 3-chip image processing. I'm told this greatly improves the quality of the image. I assume you can't make a picture look like it was filmed on a 3-chip camera just with software?

- Must be cheap (prefferably under $300, but I don't know if this is realistic). Used cameras are okay, so long as it works correctly and looks at least halfway decent.

- Must have FireWire capability.

- Should be able to run without a tape, or with a tape that has reached its end, and not shut off (at least when plugged into AC power).

- Should have a decent optical zoom (and the ability to disable the stupid digital zoom while recording, to prevent the operator from accidentally using it and degrading the picture quality).



So...comments, thoughts, suggestions, flaming, etc? Any tips or words of wisdom you have to offer would be most appreciated.

[rumplestiltskin]

One FW camcorder on the bus (turned on) at one time. While you may physically connect multiple camcorders via a FW hub, you may only control one camcorder at a time. Having more than one on the bus (turned on) will screw things up royally.

Best setup: dual-processor G5 with either iMovie (free) or Final Cut (don't remember the $$).

Camcorder: Canon ZR series are cheap but Sonys are much better for not a lot more. However, Sonys tend to need more repair. I always get the extended warranty when I buy a camcorder. I've used it a few times on a few different camcorders and have always had it honored. (Mack Camera warranty.)

[PC Master]

So what you're saying is that I'd need multiple DV busses then? Why is it that multiple cameras on the same bus won't work? Is it something to do with the addressing?

Regarding the Mac...I don't use Macs. They also cost too much, and would require a lot more time spent trying to troubleshoot when things go wrong. I've been using PCs for a very long time.

I don't suppose there's a Final Cut for Windows, is there? How does FC compare to Adobe Premiere Pro, Vegas Video, and other leading programs? In other words, if I can't have a PC-based Final Cut, which program should I get?

[rumplestiltskin]

So what you're saying is that I'd need multiple DV busses then? Why is it that multiple cameras on the same bus won't work? Is it something to do with the addressing?

Regarding the Mac...I don't use Macs. They also cost too much, and would require a lot more time spent trying to troubleshoot when things go wrong. I've been using PCs for a very long time.

I don't suppose there's a Final Cut for Windows, is there? How does FC compare to Adobe Premiere Pro, Vegas Video, and other leading programs? In other words, if I can't have a PC-based Final Cut, which program should I get?

The apps do not know how to work with multiple camcorders; that's why you don't have the ability to daisy-chain camcorders. It is possible that someone might write some kind of driver that would see the firewire chip (it has a unique number) in each camcorder and permit you to select the one you want but that doesn't exist now. Besides, 400Mb FireWire doesn't have the bandwidth for more than one DV-stream at a time...hence we're back to the one camcorder rule.

As for Macs costing too much, that depends on what it is you want to do. If it's NLE via FireWire, you're spinning your wheels with a PC. Of course, you won't want to believe this so do go ahead and throw your money at this on a Windoze box. "Troubleshooting"??? Yeah, have a ball on your PC, guy. NLE on a Mac just works. If you don't believe me, head over to a 5th grade classroom and watch them editing with iMovie. It's amazing.

You mentioned multiple camcorders so I'll assume you need multiple video tracks. Final Cut supports (IIRC) 99 video tracks whereas iMovie supports one. There's a "paste over" function in iMovie which permits a simulation of A-B roll but it's nowhere near as functional and editable as separate tracks (like FC). I think Premiere supports multiple tracks in Windoze, however.

NLE for the PC: There's AVID Free (which some swear by and others swear at). Personally, I find the app's user interface simply awful but I've been told that it's possible to get used to the 99% keyboard interface (almost no mouse support). This is supposed to speed up the workflow and I don't doubt it but it does require a rather long learning curve. No Final Cut for the PC. There's Premiere by Adobe which many folks seem to like. Finally, there's the MS Movie Maker that comes with Windows but it has this nasty habit of encapsulating the DV-Stream from the camcorder inside an AVI wrapper. Why? To make it incompatible with everything else so you have to stay with a M$ "solution". Steer clear of that manure.

Think total cost of ownership, not initial cost of the system. What is your time worth? Final Cut is used for many TV shows and movies. Collateral was videotaped (24p) at night (couldn't use film because it wasn't light-sensitive enough), then edited with FC before they added a film filter effect and transferred it to the film master for duplication. (Blackhawk Down, others, as well.)

I believe Apple has a deal with FC if you buy it with a Mac. If not, let me know offline as I sometimes have access to some deals (legit).

[PC Master]

I'm trying to understand exactly why multiple camcorders won't work. There would have to be a hardware, firewire, or other reason, or someone would have written software to do it. From what I'm reading elsewhere, I'm guessing that camcorders usually use ID #63 on the FireWire bus (instead of getting a unique ID like they're supposed to), and thus you have ID conflicts with multiple devices. If that's the case, I'd then require 4 FireWire busses to do what I want. Figuring out the software end can come later, though I don't doubt something like Premiere can possibly handle it, if someone can give me an idea of how much CPU power one DV stream would take to record.

Regarding the bandwidth, I'd really like to know where you get your information. FireWire spec says it can handle 400mbit (that is, 400 million bits, or pulses, since we're using a cable connection) per second. Cables and hardware are tested to this effect, so let's assume this is accurate, and that one FireWire bus can actually handle this much traffic. DV spec is a puny 25mbit per second. 4 DV feeds would then be 100mbit (4 x 25mbit) per second, only one quarter of the rated maximum for FireWire. In theory, if there were no overhead and you could use 100% of the bus (yes, I realize that neither of those conditions are true), you could stack 16 cameras on a single bus and it would work.

With computers, nothing 'just works' all the time. Aside from the learning curve of learning OSX and how to use it properly, there's the fact that I know a lot of ins and outs of Windows already. I know exactly how to work with files, how to do most anythign I want with the OS, etc. Not to mention that 90% of the people using this setup are Windows users. I'm not a big MS fan, but it's the best choice for now (until I learn enough Linux to switch over confidently).

Yes, I understand you're a die-hard Mac fan. What you need to understand is that I've already decided to go with a PC. You won't change my mind in that regard. What I need help with is the other things mentioned above.

If AVID is as powerful as Premiere, or close to it, it might be an option. I've long been a lover of keyboard interfaces. As for MS...if it's MS....I stay away from it unless it's called Windows or Office (and those only until I can take the time to learn Linux-based alternatives).

The total cost of ownership of a Mac is going to be, glancing at the CompUSA website, $1,800 or so for a 2GHz G5. Feel free to tell me of a better price. For that same price, I could build a top-end Athlon 64 system with double the RAM, double the disk space, and probably dual flat panel displays. Then we have the learning curve to go from PC to Mac. My time is indeed worth quite a bit, but I've seen people use Premiere Pro, and it seems pretty efficient and straightforward to me. I've never had the chance to see Final Cut in use, unfortunately.

Thank you for the previous recommendation of a camera, by the way. It looks very promising.

I don't suppose you have recommendations on any of the other items I mentioned above (MiniDV 'set top' type recorders, network multi-source DV disk recorders, small and cheap DV disk recorders, cheap DV tapes, etc)?

[Paul Glagla]

You may try to capture with the freeware CaptureFlux. One computer can run several copies of the program, and each copy can select a different DV camcorder by its index.
The real limitation is the power of the processor and the speed of the harddisks. With my Pentium 4 of 3GHz, I may capture comfortably with 3 camcorders simultaneously (not switching between them, but all 3 capturing to disk), but did nor try with 4.

http://paul.glagla.free.fr/captureflux_en.htm

[PC Master]

This looks potentially promising. A few questions...

- Have you ever tried this with an AMD setup. Will a 64-bit CPU help at all with this?

- What was the total CPU usage % with 3 cameras recording at the same time?

- Did you have any trouble with frame loss, etc?

- Since you're apparantly the author of this program, can you verify my thoughts regarding using multiple DV cameras on a single FireWire bus? Are there any theoretical workarounds for this, perhaps even something you'd be interested in attempting?

[ozymango]

You may try to capture with the freeware CaptureFlux.

Bonjour, Paul, et merci pour le programme! That's all the French I know, I hope it's "le" and not "la."

I was looking for just such software a few weeks ago, and finding it for FREE is just icing on the cake. Now to try some of those projects I've been waiting on ...

[rumplestiltskin]

You may try to capture with the freeware CaptureFlux. One computer can run several copies of the program, and each copy can select a different DV camcorder by its index.
The real limitation is the power of the processor and the speed of the harddisks. With my Pentium 4 of 3GHz, I may capture comfortably with 3 camcorders simultaneously (not switching between them, but all 3 capturing to disk), but did nor try with 4.

http://paul.glagla.free.fr/captureflux_en.htm

Are you saying that you "DO" capture 3 at a time or "MAY" as in "possibly"?

Thanks

[rumplestiltskin]

I'm trying to understand exactly why multiple camcorders won't work. There would have to be a hardware, firewire, or other reason, or someone would have written software to do it. From what I'm reading elsewhere, I'm guessing that camcorders usually use ID #63 on the FireWire bus (instead of getting a unique ID like they're supposed to), and thus you have ID conflicts with multiple devices. If that's the case, I'd then require 4 FireWire busses to do what I want. Figuring out the software end can come later, though I don't doubt something like Premiere can possibly handle it, if someone can give me an idea of how much CPU power one DV stream would take to record.

Regarding the bandwidth, I'd really like to know where you get your information. FireWire spec says it can handle 400mbit (that is, 400 million bits, or pulses, since we're using a cable connection) per second. Cables and hardware are tested to this effect, so let's assume this is accurate, and that one FireWire bus can actually handle this much traffic. DV spec is a puny 25mbit per second. 4 DV feeds would then be 100mbit (4 x 25mbit) per second, only one quarter of the rated maximum for FireWire. In theory, if there were no overhead and you could use 100% of the bus (yes, I realize that neither of those conditions are true), you could stack 16 cameras on a single bus and it would work.

Capturing more than one stream is going to be a pretty interesting trick. If it is at all possible, separate FW channels (multiple PCI cards) would seem to be necessary; certainly a FW hub would confuse issues.

Based upon 15GB/hour of native DV-stream, I arrive at a theoretical 34mbit. I think that nothing but a very high-end box is going to manage the total package, so to speak, of capture (including writing to disk which is the where failure to keep up will result in dropped frames and other bad things). RAID 0 some drives and it should help.

Please do post what result you get with the multiple streams (whether you try one channel or multiple). I'd be very interested in knowing how it works.

Sorry about the MacBigot stuff; I've been doing this for so long that I know what works (although there are other things that can work, eh?) and try to save folks some time and effort.

Good luck!

[Paul Glagla]

I have presently only 2 DV camcorders (same model from Sony) . When connecting them on two firewire connectors (on the same PCI card) and lauching capture in format DV type1 (it is the least demanding on CPU) it takes approximatively 50% of CPU time from a Pentium4 3GHz with Hyperthreading on.
I must say that the capture is with preview at the same time, and probably preview (which includes a decompression indeed) is time consuming. A similar program without preview and only capturing should be very less CPU-time consuming. Besides, the two previews are not strictly sync, this could be a problem for your project.

[edDV]

Ideally, I'd like to convert this into a PC-based NLE system. Goals...

1) Get video from multiple cameras into PC, where it can be edited and output
2) Maintain the highest level of quality until output stage (multiple output formats, including DVD and SVHS will probably be used depending on the setup and circumstances)
3) Must be low-cost
4) Must be easy to operate
5) Must work over 75 ft distance between cameras and editing PC (while a recording device of some sort might be placable within 25 ft or so of the cameras, the editing PC with displays will not be)
6) Move to a 4-camera setup

Lets go back to the multicamera need. Explain in better detail what you are trying to do. Is it 4 camera simultaneous recording to disk? Or are you trying to live switch camera feeds to one output? Or something else?

Most NLEs will support multiple cameras each with a dedicated IEEE-1394 port but only one at a time. IEEE-1394 has a max length of 4.5 meters (~15 ft) but repeaters can be used to go further (not cheap).

Give us more info on need.

[PC Master]

Yes, I will be recording from 4 cameras simultaneously. Right now we use 3, but this is for live events, and a 4th camera will help a lot. Right now we're using an analog system, basically, so we're switching, titling, and recording in real-time. This has caused substantial difficulties, and lacks the quality we want, so we're moving to a NLE system.

As for the rest...what other information do you need? I thought I explained pretty much everything in the first post.

rumplestiltskin> No worries about the Mac vs PC debate. I suppose there are benefits to each. I just prefer the PC.

As for the rest, DV is supposedly 25mbit/sec, resulting in 12.5GB per hour of recorded video. WikiPedia says it should be 13GB, and gives a complete breakdown of how it works here. In any case... 34mbit * 4 streams = 136mbit, still within the ability of the 400mbit FireWire spec. This results in about 16MB of data being written to the HDD per second. Now, I'll probably go to a SATA drive anyhow, but even ATA/66 should be able to handle it.

It seems to me that the real complexity would be the addressing and managing of the datastream.

Paul> Is there any chance you could update your software (I'll admit I haven't tried it yet - haven't got a PC with FireWire) so that there's a checkbox or something to disable the video playback, prefferably in realtime (though that's not necessarily possible, I know)? I imagine that it would reduce the CPU overhead substantially. Also, have you applied CPU optimizations? Specifically, I'd like to see a version tweaked to perform well on an AMD processor.

[Cornucopia]

Yes, I will be recording from 4 cameras simultaneously. Right now we use 3, but this is for live events, and a 4th camera will help a lot. Right now we're using an analog system, basically, so we're switching, titling, and recording in real-time. This has caused substantial difficulties, and lacks the quality we want, so we're moving to a NLE system.

As for the rest...what other information do you need? I thought I explained pretty much everything in the first post.

rumplestiltskin> No worries about the Mac vs PC debate. I suppose there are benefits to each. I just prefer the PC.

As for the rest, DV is supposedly 25mbit/sec, resulting in 12.5GB per hour of recorded video. WikiPedia says it should be 13GB, and gives a complete breakdown of how it works here. In any case... 34mbit * 4 streams = 136mbit, still within the ability of the 400mbit FireWire spec. This results in about 16MB of data being written to the HDD per second. Now, I'll probably go to a SATA drive anyhow, but even ATA/66 should be able to handle it.

It seems to me that the real complexity would be the addressing and managing of the datastream.

Paul> Is there any chance you could update your software (I'll admit I haven't tried it yet - haven't got a PC with FireWire) so that there's a checkbox or something to disable the video playback, prefferably in realtime (though that's not necessarily possible, I know)? I imagine that it would reduce the CPU overhead substantially. Also, have you applied CPU optimizations? Specifically, I'd like to see a version tweaked to perform well on an AMD processor.

What part specifically needs to be realtime?

• The recording?
  The switching?
  The titling?
  All of the above?

If it's just the 1st one, you can always record to tape, and load the tapes in sequentially afterward, like any NLE. Then do a multicam edit sequence (most all NLE's can do that, too. We just covered that in a recent thread).

If it's the 2nd or 3rd one (with or without the 1st), then you should look into something like NewTek's VideoToaster3, which is IIRC realtime (with a little processor delay). Main question here is: does a multicam-switched and titled "finished" video need to be compiled in realtime?

Currently, the weakest links in your chain are your mixer, titler, and final recorder (SVHS?)
Even going to an analog mixer of higher quality (like the Sony FXE-120 that I have in one suite) and a better Chyron-type CG/Titler would VASTLY improve your signal. Then it could be piped to a separate DV cam (NO SVHS!) Still not the best, but much better.

A main problem I see is synchronizing the cams. For seamless live switching, you really need cameras that can be genlocked. Most consumer/prosumer DV cams don't have that capability. And moving up to Pro cams (DVCam, DVCPro, BetaSP, DigiBeta, etc) is $$$$.

Questions:
Why the need for such long feeds? What's the occasion?

Did I hear right in that you are recording 3 separate instances of audio when you're recording to the master deck? If so, a much improved setup would be to have separate mikes setup and fed (with std long balanced/XLR cables) to an audio mixer, which is fed to the deck. More on this later if you're interested.

Scott

[Richard_G]

I have presently only 2 DV camcorders (same model from Sony) . When connecting them on two firewire connectors (on the same PCI card) and lauching capture in format DV type1 (it is the least demanding on CPU) it takes approximatively 50% of CPU time from a Pentium4 3GHz with Hyperthreading on.
I must say that the capture is with preview at the same time, and probably preview (which includes a decompression indeed) is time consuming. A similar program without preview and only capturing should be very less CPU-time consuming. Besides, the two previews are not strictly sync, this could be a problem for your project.

Paul and all those that are interested.

I've just tried 2 camcorders, a Sony DCR-VX700E MiniDV and a Sony DCR-TR8000E Digital8. Both connected to the same PCI TI chipset Firewire card. I can start CaptureFlux running twice and individually control both camcorders. I can capture from both but as soon as I do, the one that I started to capture from first starts dropping frames. It isn't a HDD throughput problem as the HDD activity light is not fully on, but is behaving as I would expect it to during a DV transfer. However, my CPU, a mere AMD 2500XP Barton chipset (which actually runs at 1833 MHz) is sitting at 100%. I then tried transferring from just one camcorder and noticed that, although I can transfer with no dropped frames, the CPU is at 100% just previewing the video, before I even start the transfer!

As someone else suggested, it appears to be the preview that is eating up the CPU power. If it was possible to either turn the preview off or run it in some sort of lower quality mode so less CPU was needed to process it, a successfull, simultaneous transfer should easily be possible. Obviously, anyone with a faster CPU that me would stand a better chance of success, but, in my case, it isn't keeping the DV streams separate, or controlling both camcorders through the same Firewire card, it is simply the fact that my CPU just doesn't cut it.

[PC Master]

What part specifically needs to be realtime?

• The recording?
  The switching?
  The titling?
  All of the above?

If it's just the 1st one, you can always record to tape, and load the tapes in sequentially afterward, like any NLE. Then do a multicam edit sequence (most all NLE's can do that, too. We just covered that in a recent thread).

Yes, it's just the recording that has to be done simultaneously. Doing other things in real-time (such as capturing to the PC from multiple cameras) would have 2 advantages. First, it saves time. Second, I don't have to rely on DV tapes which can have dropouts.

If it's the 2nd or 3rd one (with or without the 1st), then you should look into something like NewTek's VideoToaster3, which is IIRC realtime (with a little processor delay). Main question here is: does a multicam-switched and titled "finished" video need to be compiled in realtime?

No, I don't need a finished video available in real-time, which is why I've been looking at NLE. It allows greater control and less errors while sacrificing only the ability to give live output.

Currently, the weakest links in your chain are your mixer, titler, and final recorder (SVHS?)
Even going to an analog mixer of higher quality (like the Sony FXE-120 that I have in one suite) and a better Chyron-type CG/Titler would VASTLY improve your signal. Then it could be piped to a separate DV cam (NO SVHS!) Still not the best, but much better.

Yes. As stated, I plan to go to a PC-based NLE system where all editing, titling, and such will take place. From there, the output will go to any variety of formats, probably including DVD and SVHS (local cable company only takes SVHS for public access stuff). There have also been requests to output audio CDs and even cassettes. I'm not concerned with exactly what I'll output from the PC. I can handle that without difficulty.

A main problem I see is synchronizing the cams. For seamless live switching, you really need cameras that can be genlocked. Most consumer/prosumer DV cams don't have that capability. And moving up to Pro cams (DVCam, DVCPro, BetaSP, DigiBeta, etc) is $$$$.

This isn't really an issue though, since I'll be doing all the editing post-record.

Questions:
Why the need for such long feeds? What's the occasion?

This particular setup is for my church, which records its weekly services and broadcasts them. We also record a monthly music event which features different local (and sometimes non-local) Christian artists. The only place that is available for the video recording equipment is around 75 feet from the cameras. I wish there were alternatives here, but that's pretty much a constriction I have to work with.

Did I hear right in that you are recording 3 separate instances of audio when you're recording to the master deck? If so, a much improved setup would be to have separate mikes setup and fed (with std long balanced/XLR cables) to an audio mixer, which is fed to the deck. More on this later if you're interested.

Actually, right now, we're only using the audio from one camera. As a somewhat-experienced sound engineer, I plan to use a mix from our main sound system, added to a couple of omnidirectional hanging microphones (to get the 'ambience' of the room, applause, things like that). I'm really not concerned about how to achieve the audio quality we desire. It's really the video that I need to figure out.

Thanks for the response.


Richard_G> Does this FireWire card have more than one FireWire bus on the card (this is usually the case when using more than one port on the card)? If so, you're using one camera per bus, which is possible to do here, but not what I was getting at. I'd like to be able to run it all through a single connection if possible.




At the moment, it's looking like recording to MiniDV cassettes, then transferring them to the PC later, is what I'll have to do (which will add about 4 hours of time to production each week - 4 cameras with an hour of tape each). Does anyone have any recommendations on where to get good, cheap tapes. My thoughts, currently, are to get really cheap tapes and use new ones each time, or to get slightly higher quality ones, and use them for two or even three recordings.

This would also mean I'll need to either purchase another MiniDV camcorder (~$250) to act as a player for the PC, or find a dedicated player/recorder (those seem to run about $800 or so though).

If anyone has any additional comments on the other options, please don't hesitate to offer them.

[Cornucopia]

Ok, it's getting clearer now...

Your issue is mainly with temporary storage:

DV vs. FireStore type device vs. Firewire-to-Harddrive

It's mainly a matter of storage costs--both upfront and long-term, and quality and speed.

DV=Low upfront cost, High Longterm cost, Quality depends on brand and media usage habits, realtime speed for each input and output.
FS=High upfront cost, Lo Longterm cost, Highest quality, High speed IO.
Fw2Hd=Med to Hi upfront cost, Lo Longterm cost, High quality-depends on bus/storage/cpu capabilities (varies directly w/upfront cost), High speed IO

The crux of the matter is your DV tape buying habits. You say "cheap" and "re-use" in the same sentence with a complaint about "dropouts". Notice the relationship?
Pro DV (and DVCam, DVCPro) tapes are more expensive than consumer DV tapes, in large part because of better dropout immunity. Of course, pros usually only record on their raw tape ONCE.
I would think that with good tapes and recording only 1-4 times, you should notice NO visible dropouts.
If you record/reuse more than that and/or use cheapo tapes, you're going to have to learn to either live with the dropouts or change to another storage system (one of the 2 mentioned above), which means BIGGER upfront costs.

HTH,

Scott

[edDV]

A PC is not a live digital switcher. Nothing that I'm aware of will do live switching and titling in a PC. An NLE is not intended for doing anything live.

Your 4 camera live recording issue can be easily solved by using tape. An analog feed can go to an analog switcher for the director to call the shots (over intercom) for your live feed. A framesync would probably be needed for clean cuts.

There are many solutions that are normally used by pros for live event coverage. You need to cough up a budget number.

Probably the minimum solution ($8000+) would be NewTek's
http://www.newtek.com/vt/

PS, I would't bet the farm on this product being ready for prime time. Interview existing customers before committing to it.

Added: OK I didn't read all the posts before responding to the "live" requirement.

See next post instead. It all comes down to $$$ vs time vs quality. Toss software development skill into that mix.

[edDV]

Yes, I will be recording from 4 cameras simultaneously. Right now we use 3, but this is for live events, and a 4th camera will help a lot. Right now we're using an analog system, basically, so we're switching, titling, and recording in real-time. This has caused substantial difficulties, and lacks the quality we want, so we're moving to a NLE system.

As for the rest...what other information do you need? I thought I explained pretty much everything in the first post.

rumplestiltskin> No worries about the Mac vs PC debate. I suppose there are benefits to each. I just prefer the PC.

As for the rest, DV is supposedly 25mbit/sec, resulting in 12.5GB per hour of recorded video. WikiPedia says it should be 13GB, and gives a complete breakdown of how it works here. In any case... 34mbit * 4 streams = 136mbit, still within the ability of the 400mbit FireWire spec. This results in about 16MB of data being written to the HDD per second. Now, I'll probably go to a SATA drive anyhow, but even ATA/66 should be able to handle it.

It seems to me that the real complexity would be the addressing and managing of the datastream.

Paul> Is there any chance you could update your software (I'll admit I haven't tried it yet - haven't got a PC with FireWire) so that there's a checkbox or something to disable the video playback, prefferably in realtime (though that's not necessarily possible, I know)? I imagine that it would reduce the CPU overhead substantially. Also, have you applied CPU optimizations? Specifically, I'd like to see a version tweaked to perform well on an AMD processor.

It just isn't going to work that way. Each camera needs a dedicated IEEE-1394 feed (driver is the issue not bandwidth). Contention takes place at the PCI bus, then the HDD controller. It would be a major software engineering challenge. If it was easy someone would have a product by now.

So get real and look for solutions using proven technology. If you can't wait for DV tape to HDD transfer, put one of these on each camcorder...
http://www.videoguys.com/FireStore.html

[Cornucopia]

Alternately, you could have a dedicated PC with Firewire IO and Removeable HD for each camcorder, then just swap out HD's when needed at the NLE box.

Scott

[Richard_G]

It just isn't going to work that way. Each camera needs a dedicated IEEE-1394 feed (driver is the issue not bandwidth). Contention takes place at the PCI bus, then the HDD controller. It would be a major software engineering challenge. If it was easy someone would have a product by now.

Not wishing to disagree, but take a look earlier in the thread and it can be done. The CaptureFlux software will do it.

PC Master, I'm not sure if the Firewire card has separate busses or not. It is a cheap generic TI chipset based PCI card with three Firewire sockets. Whether they each have there own bus or merely share the same one I have no idea. All I know is that the CaptureFlux software finds the first camcorder that was switched on and displays it as Microsoft DV Camera and VCR. When the second one is switched on it displays that as Microsoft DV Camera and VCR #2. Each running occurance of the program has tape transport controls which control the two camcorders independantly.

As for DV tapes. Buy the best you can get, always stick with the same brand and only ever use them once. It'll work out cheaper in the long run.

[Cornucopia]

It just isn't going to work that way. Each camera needs a dedicated IEEE-1394 feed (driver is the issue not bandwidth). Contention takes place at the PCI bus, then the HDD controller. It would be a major software engineering challenge. If it was easy someone would have a product by now.

Not wishing to disagree, but take a look earlier in the thread and it can be done. The CaptureFlux software will do it.

PC Master, I'm not sure if the Firewire card has separate busses or not. It is a cheap generic TI chipset based PCI card with three Firewire sockets. Whether they each have there own bus or merely share the same one I have no idea. All I know is that the CaptureFlux software finds the first camcorder that was switched on and displays it as Microsoft DV Camera and VCR. When the second one is switched on it displays that as Microsoft DV Camera and VCR #2. Each running occurance of the program has tape transport controls which control the two camcorders independantly.

As for DV tapes. Buy the best you can get, always stick with the same brand and only ever use them once. It'll work out cheaper in the long run.

Actually, it's been shown fairly empirically, that tape gunking/jamming occurs when you use the same brand of tape almost all the time, but then occasionally change to another brand. Both of the alternatives will work--ALWAYS use the same brand, or ALWAYS cycle through a number of high quality brands.

Back OT, most of those cheapo Firewire cards are using 1 chip/controller/bus for all the ports. That is likely the weakest link.

Scott

[edDV]

It just isn't going to work that way. Each camera needs a dedicated IEEE-1394 feed (driver is the issue not bandwidth). Contention takes place at the PCI bus, then the HDD controller. It would be a major software engineering challenge. If it was easy someone would have a product by now.

Not wishing to disagree, but take a look earlier in the thread and it can be done. The CaptureFlux software will do it.

PC Master, I'm not sure if the Firewire card has separate busses or not. It is a cheap generic TI chipset based PCI card with three Firewire sockets. Whether they each have there own bus or merely share the same one I have no idea. All I know is that the CaptureFlux software finds the first camcorder that was switched on and displays it as Microsoft DV Camera and VCR. When the second one is switched on it displays that as Microsoft DV Camera and VCR #2. Each running occurance of the program has tape transport controls which control the two camcorders independantly.

As for DV tapes. Buy the best you can get, always stick with the same brand and only ever use them once. It'll work out cheaper in the long run.

I see multiple devices reported when each are connected to separate IEEE-1394 connectors on a given card or motherboard as well but in that case the driver is working with one device per port at a time. To Windows, each connector is a separate port.

PC Master was talking about sharing one port for multiple camcorders I thought. He was trying to make the point that each used 35Mb/s and a single link could carry 400Mb/s. The problem there is getting DirectShow to share a port for multiple camcorders.

I can capture IEEE-1394 TS streams and do DV transfers at the same time. Or I can network one IEEE-1394 port while another controls a camcorder. I haven't attempted multiple DV transfers to a single drive at the same time.

Contension would need to be analyzed at the PCI bus and at the HDD controller or RAID controller. Multiple 35Mb/s streams could be handled in theory. Best to hook up 4 camcorders and try it. If there is a problem (like you saw) a realtime PCI bus software expert would be needed to rewrite the drivers.

[PC Master]

Thanks for all the comments and suggestions. Keep them coming, please.

I guess, at this point, the next step is to buy a FireWire card, a FireWire hub, and some cables. Then I can wire it all up the way I would like to (albeit without having a long cable run and repeaters, but I'm fairly confident that will work), and test it out.

The only suggestion I've heard so far that should make this setup fail is that all MiniDV cameras use the same ID number, and thus putting two on the same bus at the same time will not work correctly. Can anyone verify this before I go spend money on a hub and such? Does anyone have a setup working where 2 or more cameras are able to be accessed simultaneously via FireWire, with only one cable running from the PC to a hub (or multiple cables, so long as you can verify your FireWire card only provides one controller/bus - check the Windows device manager for this information)?

Paul> Can you check on this? Or can you at least tell us what FireWire card (or motherboard, if it's on there) you have?

[Richard_G]

I would suspect that if you use a single Firewire cable from pc to hub and then attach multiple camcorders to the hub it will fail. I have proved that you can run at least a pair of camcorders on different sockets on the same Firewire card. I have no reason to think you couldn't run more, it's just that, although I have three camcorders and three ports on the card, I've only got 2 cables!

Has anyone tried the same thing but using different transfer software? I'll give it a go over the weekend when I've got the time available.

My Firewire card is a cheap TI chipset one made in Taiwan and marketted by a company called Mentor.

[PC Master]

Richard> Can you give me more information? What is the specific model of the chipset on your FireWire board? Can you possibly send a photo?

Most useful would be to check the Windows device manager to see if it shows up as only a single FireWire host/controller or as multiple hosts/controllers. If the former, it's quite probable that ideas will work. I'd really like to know before I go to the extent of buying things to test it out.

[edDV]

Richard> Can you give me more information? What is the specific model of the chipset on your FireWire board? Can you possibly send a photo?

Most useful would be to check the Windows device manager to see if it shows up as only a single FireWire host/controller or as multiple hosts/controllers. If the former, it's quite probable that ideas will work. I'd really like to know before I go to the extent of buying things to test it out.

PC Master you are venturing outside the design spec. I hope you are risking your own money and not others. Consider it an experiment and make sure all equipment is returnable.

Even if it works, record miniDV tapes as backup because there is high probability of data loss.

[PC Master]

How is using a hub designed for FireWire with several FireWire-compatible cameras going outside the spec?

[edDV]

How is using a hub designed for FireWire with several FireWire-compatible cameras going outside the spec?

I've never heard of a hub being used for this purpose, i.e. to connect multiple DV camcorders at long distance to a single IEEE-1394 link. DirectShow DV camera device control would have to support it or a custom driver would be needed.

It may work but don't bank on it.

[Richard_G]

PC Master> For what it is going to cost, it has got to be worth a try. I paid £15 (approx $25) for my card about four years ago. It is now obsolete but uses the Texas Instruments chipset. Device manager shows it as being a Texas Instruments OHCI Compliant IEEE 1394 Host Controller,

the Properties show Device Type: IEEE 1394 Bus Host Controller,

Manufacturer: Texas Instruments

Location: PCI Slot 4 (PCI bus 0, device 11 function 0).

Without dismantling the machine I can't tell you any more I'm afraid but I'll repeat that although two camcorders work when plugged into two sockets on the Firewire card, I suspect they won't if you are going via a hub.

Get hold of a TI chipset Firewire card and give it a try, what have you got to lose?