Slashdot Mirror
Building a Multi-Channel PVR System?
Dr.Ruud asks: "What would be good ways to build a multichannel VCR? Think of a cluster of 4 PCs, each having 4 TV-cards (with MPEG-hardware on each) and (if necessary) a separate harddisk per TV-card, and maybe a 5th PC that controls the others, holds a DVD-writer and any other necessary hardware. Could it be done in a simpler and cheaper way? See also linuxtv.org, linuxmedialabs.com and of course SouceForge-vcr-projects like Freevo." What would be the best way to go about cutting down the number of machines such a cluster would need? Could this be done by building an all-in-one-wonderbox without it getting really expensive?
I'm just trying to figure out why you would need 16 programs taping at one time... I am the only one who finds that a bit off the wall?
In theory, you'd also need an array of hard drives, because the thrashing of four or more things being recorded at once would be painful...
This would mean you'd have a maximum of 4 hard drives, unless you buy an IDE card that lets you support more, wouldn't it? (Each IDE chain can have only two devices, right? or is that outdated info now?)
An interesting idea for certain though...
http://www.babysmasher.com
http://www.openingbands.com
Well, I gotta admit, I'm baffled as to why one would want to record 16 channels at the same time. Why is that interesting to you? What's your goal here? Are you providing a service for somebody? Is this something you'd just like to do at home? Answer that for me and I might be of more assistance.
Personally, I can't help but think that 4 cards capturing at ideal quality would saturate the PCI bus unless each card directly controlled a hard drive.
Version .8 will allow you to have several machines, each taping its own channel(s), controlled by any of the machines in the network. The goal is to allow you to have one gigantic server in the basement, and 1 fan-less machine in the living room.
Far more interesting is what ramifications (if any) are there to having 2/3/4 tuner cards in one PC. After all, each tuner card probably needs its own sound card... what else is involved?
"Sometimes a woman is a kind of religion, she can save your soul & set you free from all your sins" - Bad Examples
While I see the occasional need for 2 tuners, frankly sometimes even that sounds like overkill. I find when there are two shows on at once it's a subtle message from the TV gods that I shouldn't watch so much TV.
I've also never figured out why you need the DVD burner. With so much disk in my Tivo, there is always stuff to watch, and my need for archiving stuff to watch again later is so small as to be unimportant. If I _really_ need it, a lot of it is at the video store for rent.
Is the 16 tuners so you could have a box shared by a whole LAN of people? I guess if you have the bandwidth that would make sense.
Right now the public thinks PVRs are too complex, so the big vendors will probably be working to make them simpler rather than more complex.
What we really need is a component architecture, with lots of little pieces, all with 100mbit ethernet (firewire and USB 2.0 are too "smart" for their own good. ether is the
way to go.)
Then just add what you need. Tuner boxes (OTA, digital or satellite as needed.) Decoders, mounted right on the inputs of the TV that plug in ethernet and spit out component video or NTSC. The ethernet of course leads you to drives running NFS or SMB, and an always on processor to control it all that's simple.
That way you can start simple, with just a tuner, a decoder and a controller (these 3 might be in the same box) and a networked drive or a drive-in-a-box, and add what you want.
Has it been over a year since you last donated to the Electronic Frontier Foundation
A dual 500 machine is more valuable as a PVR than a single 1.6 gig machine. Ideally you'd want 1 processor for playback and one to handle the other stuff (compression, etc...)
16 channels? Err. Okay. If you really want to capture that many at once, you'd likely be better off having one computer per card. You don't need expensive/new hardware to do that. If the card does the processing and funnels the compressed data down to the hard disk, then the processor is little more than a manager. Last I checked, a P3 500 would easily handle a PVR card with hardware compression.
If you have space considerations, go with a dual I suppose. But I wouldn't do more than 2-channels per PC.
"Derp de derp."
Same idea for for HDTV, except save the data stream.
science is a religion
Doing any of this without hardware compression is, of course, not even remotely viable. Given that, you have some serious limitations imposed by common hardware.
Many of the PVR cards use the KFIR encoder chip in conjunction with a Conexant bt8x8 video capture chip. The bt8x8 does the NTSC->PCM, and sends it to the KFIR encoder, which sends the MPEG data back to the bt8x8. The limitation comes from the fact that there is no hardware-assisted DMA for the data coming from the KFIR chip. That means the host process has to repeatedly poll the PCI memory address for the bt8x8 GPIO ports in order to capture the data.
Putting more than one or may be two of these cards in a single machine would swamp the machine so badly it wouldn't be able to do much else at all, let alone sending the video to disk or a network-attached storage device.
If you can find a PVR card (supported under Linux, good luck putting multiple *anything* in a Windows box) that doesn't blow the PCI bus to pieces when capturing, and you should be able to put quite a large number in a single machine, limited by PCI slots. The KFIR chip captures up to 12Mbps, which is 1.5MB/sec. PCI can peak at 132MB/sec, so as long as busmastering overhead across a dozen cards isn't fatal, you could put them all in a PCI expansion cage on a single machine.
GStreamer - The only way to stream!
I have a TiVo right now and it is great.
I've seen the software to do it yourself and also machines that also do it (but aren't the TiVo service).
TiVo calls up a number every night and gets the listing information, is there a way to get that for the free programs and/or other machines?
I know that TV Guide has a web page with the listings - do they have an XML stream that you can grab and parse - or someone else?
If so, I'm not exactly a power user of TiVo and that would be a nice thing to have - but I don't want it as just a VCR sort of thing where I have to manually tell it "record XYZ at 4pm every thursday" - I am spoiled by the listings intelligence that TiVo has.
If there is something out there like that, esp avail over the net, that would be a lifesaver when I move to Bermuda since they don't have TiVo there and I would love to have that or something like that there.
There are some odd things afoot now, in the Villa Straylight.
I highly doubt you'd need five PCs. What you would need, though, is four MPEG2 hardware capture cards with built-on TV tuners. Remember, a MPEG2 isn't all that big... From rough estimates in my head, any modern DMA100 IDE disk should be able to handle the bandwidth of four MPEG2 streams. You also won't need that powerful of a CPU, either. I'd say that with a little bit of special capture software (that can address four different cards) that will do tuning and scheduling and a TV-out device (Composive, S-Video, and Component) with hardware MPEG2 decoding (or a fairly fast box), you'll have all you need. If they are combination capture / playback cards, you could technically have four outs, too. Might be nice for family time. Queue it up so capture takes priority on all cards but one, or...? The possibilities are endless.
But anyway, I personally would think that you would only need two or MAYBE 3 streams at once, but if you already have software to address more than one card, why stop with just two? As long as the hard drive and PCI bus can handle it, you're set.
I recall a conversation I had with the digital cable installer awhile back. He had never heard of PVRs before, and as I was talking about them, he suggested that since the data for all the channels is coming in on the same line at the same time, it could be possible to modify a cable receiver to capture multiple channels at once. This wouldn't solve the problem of how to record them all, though I'm guessing a 8/16/(insert number of channels here) SCSI hard drive setup would work nicely.
You could try the ATC-620 from Coolermaster. Looks nice, available in silver or black. Not super-cheap, but reasonable at least. I'm leaning towards a couple of these myself for home a/v use.
BAM!
how do you plan to get 16 NTSC-composite video signals from your cable/sattelite/broadcast feed? Do you have 16 base-band converters? I'm curious.
Or perhaps are you capturing CCTV for archival? You may want to investigate how people do that (casinos capture immense amounts of high quality digital video for security purposes). The hardware is, doubtless, expensive, but it may give you some insight on how it can be done "on the cheap".
"Think of a cluster of 4 PCs..."
A Beowulf Cluster of PVRs? Sweet!
I have no great authority here, except that I have ran several linux systems, coded simple linux apps, and ran ATI's all-in-wonder (piece of crap) PVR solution for two years.
Every month or so, someone comes up with a newfangled linux PVR and posts it here and on sourceforge.
Last I looked, there were at least 4 seperate projects on linux PVRs. There was also something major wrong with each project!
One project has a cool interface but could not actually record!
One project could record and playback, but not record and playback at the same time!
Yet another project could record and playback, but even the author of the thing reported that the audio and video were badly out of sync.
Now: I don't know if the Ask slashdot question was a troll, or someone hoping to startup a dumb dot bomb that re-sells TV signals, but even a single P-1Ghz with an ATI all in wonder could barely record at broadcast quality - read: It didn't ever fully approximate broadcast quality.
I've got two coworkers who purchased PC PVR solutions, and guess what - all three of us now own: Tivo, Replay, and DishNetwork-PVR systems.
BAH. This is really stupid. Until someone hacks together something that actually works, and doesn't require a PHd in driver hacking, and syncs the audio properly, and has a 1/10^6 chance of working on someone else's build of linux/hardware, then let's not waste time discussing the *neato* applications of linux PVR. It's still a fantasy for private/OSS projects...
I like my Cooler Master ATC-600, but it looks like they have a number of other options as well (look under "Desktop"). The ATC-600 is just slightly too big for my entertainment center, but it perches nicely on top of it. Now I just need to find a reason to use the thing (now I have a high definition cable feed, the HTPC is useless for recording shows). Also, it's a Micro-ATX form factor, but if you're planning on doing an HTPC, that should be more than enough. Especially if you want the case to fit well in your entertainment center.
If that is the case he should have a look at motion it can handle multiple videodevices and even use multiple inputs on each device.
Jeroen
Secure messaging: http://quickmsg.vreeken.net/
I talked to some developers over at BeBits about the idea; one said that he had no interest in updating any of his Beos apps and that he had entirely moved over to Windows. (ugh)
The other was intrigued, but had far too much stuff going on already.
Any ideas? Anyone thought this too? I would dive on in, but I am a musician and left programming behind with Apple II basic...
P.S. Trolls: Oh yes, Beos is dead, what am I thinking, I should learn to code, I smell like cats, blahblahblah.
orichter writes: does anyone know how, with a with a few minor adjustments, you turn a regular gun into five guns?
Word to developers - what you've done so far is great, but if you want to unseat MSFT, you've gotta make it so that Grandma can install it.
If we were talking about a new version of GCC or the latest kernel, with Visual Studio.NET and Windows Longhorn as the competition, it'd be fine to moderate this comment as (-1, Lazy n00b), but you're talking about a glorified VCR, and you're going up against TiVO.
For this kind of product, User Interfaces matter. Saying "RTFSource", and "It's skinnable", won't cut it.
Likewise, dependency trees can be a formidable barrier to adoption. Saying "Well, of course it compiles fine for me, I mean, who doesn't rebuild XFree86 from the CVS source tree on a weekly basis?" isn't gonna cut it either.
PCs are cheap enough these days, especially since folks in the DIY segment might want to dedicate one as a PVR. Given the appliance-like nature of such a device, I'd say a (set of, for each supported motherboard-chipset/video-chipset combo) binaries ought to be a design goal, and I might even go so far as to say that distribution as an ISO wouldn't be out of the question.
I played with this idea briefly. Imagine a high end hotel offering "whatever" on demand for sum of cash $x. Networking to the rooms is a solved problem (see spectravision, etc.). Only question is how to get the content.
Well, that, and selling and servicing it in a scalable fashion to hotels that aren't terribly interested in giving you much of a cut.
Not a bad idea, but you run into trouble with the marketing and the amount of time you need to keep things vs. your affordable drive space. Not to mention the copyright issues the networks will come up with.
ceci n'est pas un sig.
Many people are posting things like "I can't see why you oould need 16 channel".
why would you post just that? I show a starttaling lack of imagination for nerds.
Just off the top, I can think of:
Archiving different channels takes on global events.
Perhape he is going to take 'orders' for recording, so instaed of settng your VCR, you just call this guy up and say "PLease record X for me"
Maybe he just thinks its interesting.
Perhaps he's going to hook it up to 16 continues camera feeds for security.
I'm sure some people here can think of more, and better ways to utilize this.
The Kruger Dunning explains most post on
go to SCSI 160, use at least 3/4 G Ram.
Thats what I have in mine, and it record Native just fine.
The Kruger Dunning explains most post on
Why watch less tv? So he can just put useless posts on Slashdot like yours? The guys asked for technical advice, not for gripes.
I've read all the comments about the limitations on the PCI bus, basically there's no way around the lack of bandwidth.
What if he wanted to do distributed capture though?
Think about it, you have 4 machines capturing alternating frames. Machine 1 does frame 1,5,9 machine 2 does 2,6,10, machine 3 does 3,7,11 ect.
This thought occurred to me last night while doing some kazaa downloading. Maybe a better P2p capture system would involve each client downloading 1 frame per movie, and sharing that with the world. The clients could assemble the movie from a distributed network, much like a frame server does in premiere.
The real advantage to doing this would be movies that are stored in a lossless format.
Chill. Relax. There is no need for longwinded rants with random bold words. No, the free software PVR projects are not ready for prime time yet. It shouldn't be suprisingly, they're all very new. Mozilla's few few years weren't terribly promising. Linux itself took many years before approaching general usability. For the software to reach a polished stage we need to start with the crappy first pass. There is lots of experimentation and playing around. Core components (like drivers to TV cards and MPEG encoders) are still early in the development stages themselves. Eventually things will settle down, all but a handful of projects will fold, and things will become ready for you. In the meantime, let other people do a little harmless cheerleading. We need early adopters and fans to help work out the bugs in the system, do development, and keep the developers inspired.
(If you feel a burning need to emphasize something, the <em> tag will generally give you a more subtle, easy to read result. Bold text tends to leap out, dominating the paragraph. If you really want readers to just focus on those key points, consider a bulletted list using <ul> and <li>)
Search 2010 Gen Con events
I've seen a lot of threads that say an application like this would be great for security cameras and the like.
Assuming this is even implementable (which it is not), lets look at a cost breakdown:
16 video capture cards - $100 x 16
16 120 gig hard drives - $120 x 16
4 cheap cases - $50 x 4
4 mb/proc/mem combos - $240 x 4
1 dvd burner - $200 x 1
other odds and ends - $100
which comes out to a grand total of approximately, oh, $5000
Now lets look at my solution:
16 VCR's purchased from circuit city- $50 x 16
one guy to switch tapes every six hours- $6.50/hr
$806.50.
Digital cable is basically just another way to modulate a given 6 mhz block that we call a channel. It makes this block able to carry multiple channles, dependant on the quality, and compression. A highly compressed channel can handle up to 40 channels (Of the cooking show variety), and a minimum of 4 (Die Hard quality).
But this is what I propose. You would have to get a card that is modded to recognize these blocks of channels (They all recognize the channels, but they won't recognize the individual digital channels, unless they are digital cards). BUT, take these cards, and record the 6mhz bandwith, NOT the actualy individual channels.
Lets put it this way, lets say HBO runs at the 550 mhz - 556 mhz range (Which is arrpox where it is for COX Cable Las Vegas) If we were to recorde this range, we would not just be getting the normal HBO that we want, but also all of the other channels on the same bandwith. On average thir are 8 high quality streams on any 6 mhx channel. So in this case, by recording one of these channels, we would be able to extract 8 channels, say HBO, HBO2, HBO Signature, HBO Latina, Cinemax, etc.
In this case, it might be able to record between 8 and 40 channels per tuner card. With specially modified hardware, and software to do this level of decodeing.
Also if you were to find a way to compress this data, you might be able to find an extremely efficient way to compress this data.
- Ice_Hole
"I couldn't give him (Bill Gates) advice in business and he couldn't give me advice in technology." Linus Torvalds
I'm sorry, but what is the point of 'Ask Slashdot' if the question is going to be absolutely silly? I've farted out more useful questions than this one.
A PVR that can record 16 channels at once? Get real. Unless you're operating a TV station, you don't need that many channels. And if you do operate a TV station and you're asking Slashdot how to build video equipment - you're fucked.
Here's a tip kid. Quit jerking off thinking about recording 16 TV shows at once and go outside.
[And yes, I've got Karma to burn.]
This is perfect for public access television stations. They often have 5-10 people, all needing to encode their videotapes at the same time. A multichannel encoder would be heaven!
I've been working with MNN, the public access station in New York, NY in building a cheap, open source video server out of an old TiVo. The equipment necessary to program and run television broadcast/cablecast centers is often expensive and proprietary. And unless you do web playback like indymedia or freespeechtv, you have to buy the equipment to play the game.
An open, Linux-based multi-encoder like this (accompanied by an open video server) would do wonders for the community media world!
Development is currently in the works for mythtv to do this. Hopefully 0.8 release will have this in it. Isaac and crew are working on it.
Given enough money, anything is possible.
If you want to reduce the number of nodes, you need to increase the capacity of each individual unit. One way of doing that would be to use a PCI backplane with a motherboard "card". This would give you more than the 4 or 5 PCI slots on most motherboards.
Go with a FireWire or USB2.0 capture device instead of a capture card. You can connect 4 capture devices to a 4-port FireWire or USB2.0 PCI card. So, if you only devote 3 PCI slots to your input sources, you still get between 6-12 concurrent input streams via FireWire or USB2.0. The problem is finding a TV tuner you can control via software through the FireWire and USB2.0 links. But that would solve your problem of recording alot of different shows at the same time with fewer CPU count.
If you plan on having the storage local, you'll want to go Raid. Hardware Raid would be better than software Raid.
If you use a seperate machine for storage, I'd go with NFS or netcat over GigaEthernet to a FileServer with striped volumes on mirrored or Raid-5'd disks. netcat would be better since it has lower overhead than NFS.
So, with 2 Computers, you will be able to capture from 1-12(depending on how many cards and ports you use) individual channels/sources to a very fast file server which can then serve out the streams or burn them locally to DVD(s).
ADC, Canopus, Sony, and a few others produces AVFireWire/USB2.0 adaptors, but they are for signal source and output and not for tuners/channels. Some resources listed below:
Resources
WinTV Products:
http://www.hauppauge.com/html/usb_data.htm
A USB TV Tuner
http://www.snapstream.com/buy/buy-tunerusb.htm
More USB TV Tuners...(wintv repackaged)
ATI Wonder USB
http://www.ati.com/products/pc/tvwonderusb/
http://shopper.cnet.com/shopping/resellers/0-114 36-311-3850079-0.html
ATI usb tuner card...
Basically, they are USB tv tuners which captures to MPEG1 or MPEG2... if you're running under Linux anyways, you can re-pipe through Mjpegtools to resize and recompress to MPEG2 format for use with DVD playback on the fileserver.
But yeah, it's doable. :)
Good luck and have fun!
Winged Power Photography
You would want 16 channels recording at the same time so you could retro surf ....
... at least for the stations that are being recorded.
So as you surf around and you see something you like, you could rewind to the begining of the show.
I have Tivo now, and often I will turn on the tv and realize that the show that is currently on, is one that I wish I had seen from the beginning. Since my Tivo was on that station, I can rewind a half hour back in to the buffer, but when I change the channel each channel doesn't have a buffer, so I'm for those I am out of luck. 16 tuners all being recorded would fix that problem
If you want to edit video on a computer, you need to "digitize" or "capture" it to the computer. Hook up multiple VTRs and capture multiple tapes at once. There are systems that exist to do this, but they are high dollar. This might not be cheep, but I'm sure there would be some free clock cycles to use.
Say you do a political talk show. You want to do all the research you can. The major networks all have good political shows on Sunday morning. With this you could record them all and watch them later. Yes you could just use VCRs, but that applys to ALL PVR applications.
Many public access stations are actually multiple channels. PEG (Public, Educational, and Government) is the standard for Local Access pretty much. You could record the station live from the past so many days and stream it online to catch recent programming.
Say you have a large tape archive (the station I work at has beein archiving for under a month and has over 300 tapes) and want to store in a digital media. You could use the captured video either to make DVDs or store in low-res on a server for preview. With IDE RAIDs becoming less and less expensive, a terrabyte fileserver is now an option in the four figures.
And thats just what I can think of off the top of my head...
CitrusTV (http://www.citrustv.net): the Nation's Oldest & Largest Entirely Student-Run Television Station
Also, I am curious why you would want to use MPEG encoder cards to record your video. If you've ever tried this, you would quickly realize MPEG is a REALLY bad format to use if you plan on editing your video. I assume you will be editing your video right, I mean who and the hell would want to burn TV programs, commercials and all, straight to DVD with no editing. Anyway, editing MPEG video, no matter what you use is a bad proposition.
My system, which is two low power PCs with various large (300GB+) multidrive RAID arrays, firewire cards, 1 Canopus ADVC-100 on each system and Sony Satellite receivers. The Sony are important since they have a 9 pin serial connector which connect directly to the PC for changing channels and controlling the satellite receiver.
This system works flawless and I have recorded around 1,500 TV Shows since late 2001. My Linux based recording solution prior to this was moderately reliable but the quality was not good enough for DVD. With this setup the quality of the burned DVDs are almost indistinguishable from the broadcast source. In other words, very good. Oh by the way, my interface for scheduling is custom web interface using Mysql for storing data.
Now I suppose if you were hell bent on it, you could put multiple cards in a few machines and run multiple capture processes to grab your insane 16 channels, but that would be one busy machine. I would recommend a more sensible soultion, one like mine would probably work nice.
My setup includes 2 machines for grabbing video straight to disk in DV format (very high quality, does not degrade with editing like other lossy compression methods). Now these machines also double as mpeg encoders too, but don't do much else. They stay pretty busy with just those two tasks. I have another 3 machines that are dedicated MPEG encoders, using mjpegtools as the encoding software. My desktop machine is where I edit the video, using Kino. I also use my desktop to run dvdauthor, which masters the DVD-Video folders prior to burning them to disk. This machine sometimes encodes MPEG too. On some days I have as many as 6 or 7 MPEG encoder machines going. And I have yet another machines that actually burns the DVDs.
So I guess you could do it with a few machines, but you'll be sorry once you've got a bunch of video to encode or master and only a few CPU to do it. Make your capture machines the cheap, slow CPU type and your encoder, editing, mastering machines of the fast type and you might be all right. I'd still love to know why you would want to record 16 channels. Also, I assume you are doing this with Cable TV, which sucks for quality and regular cable too, since digital cable requires a box for each individual channel you need to watch at the same time. I can't see anyone paying for rental on 16 cable boxes. Even worse I can't see anyone spending that much money on 16 satellite reveivers. I have 6 satellite recievers and I almost cried when I had to pay for them.
Oh by the way, my system is 100% Linux end to end, so the poster who posted a comment above who says there is no Linux PVR solution that works, has no idea what he is talking about.
-Aaron.
1. Obtain a copy of the Broadcast Transmissions Summary Document, colloquially known as "TV Guide."
;)
2. Use the stylus to systematically eliminate programming choices that cannot be realistically maintained in the desired timeframe.
This ought to do it.
Honorary Member of Jackie Chan's Kung Fu Process Servers
An array of PVR's? What in the world are you going to watch? There aren't enough good shows on on to keep a single PVR busy let alone an array of them.
Me? I'm going to build an array of vacuum cleaners. My idea sucks too, but will cost less.
-=-=-=-=- osjedi uses Debian GNU/Linux. -=-=-=-=-
This is only slightly related, but here goes. Does anyone out there know of a way that I can use some combination of computer programs/scripts and hardware to control my dish network receiver from within a program? I have dish network and cable and I'd like to use something like freevo (modified) with the guide features, but I would like to be able to do all of my channel changing through one interface. For example, if I selected a channel that I got through the satellite only then I could send a command to the satellite to tune to that channel. It would give me a seemless interface into all the channels I receive, and the person watching wouldn't have to know that to watch FOX you use the regular cable channel and to watch TLC you have to turn on the satellite and put the tv on channel 3.
I feel confident that this could probably be done using some infrared transmitter, but does anyone know of a way that might be able to send commands directly to the satellite receiver without just acting like a remote control?
What is it with this anti-TV religion that some people seem to have joined? It's not just that they don't watch TV, they insist that nobody else should watch TV either. If you watch TV you're an inferior person! They interrupt conversations to make sure that everybody knows they don't watch TV. They are insanely PROUD of the fact that they have never seen an episode of Farscape, or didn't watch the 6-o-clock news last night.
At what point did "not watching TV" become such a huge achievement for these people? Is there a similar group of anti-readers? Imagine some nutjob interrupting a conversation about an Asimov novel to make it clear that he never reads novels and in fact doesn't even own any novels! You'd rightfully think a person like that was mentally deranged, yet this bizarre behaviour is proudly proclaimed when the medium is television.
To all you idiots repeating the tired mantras of "I never watch TV!" and "You TV watchers should get lives!", I say that you are the people without lives if you think not watching TV is some sort of achievement.
You would be far better off using DirectTivos for the capture boxes. You can then 'hoover' the recorded shows onto a massive central server by using the Turbonet cards and simple protocols. This is better for multiple reasons:
1) You get the direct satellite stream without going through the decode-reencode step that reduces quality. This results in a huge increase in picture quality.
2) The Tivos can pull double duty as playback devices and capture devices. You'd just need a minor first step to make sure what you want is transferred from the server before playback.
3) If you want you can build a diskless, (fanless?) box with a 100M ethernet connected to a switchport on a switch with a gig ethernet to the server. This would give you better control over the output, especially if going to an HDTV ready TV.
4) The Tivos can act as backup devices for what is recorded when the server goes kaplonk. Still playable! This increases the WAF (Wife Acceptance Factor) greatly.
Good luck with whatever you are doing recording sixteen channels simultaneously.
Well, a lot of motherboards come with onboard RAID now, in addition to the regular ATA, so you could fit 8 IDE devices on one board.
That being said, you'd probably want to add a RAID Controller anyways. From my experience, they perform better than onboard chips which are usually stripped down. Either way though, you definately want to RAID the drives in at least RAID 0 if not RAID 5. Not only do you get a larger logical drive out of it, but the performance boost can help as well.
And, yes, as others have said, it varies VERY much by how much quality you want. Native DV (the defacto for "online" video editing) uses 40/3 GB/hr. That's roughly 30 Mbit/s based on my quick calculations. MPEG I/II/IV all offer various bitrates at various qualities. But, what you save at the harddrive you lose at the CPU there.
Something to remember is that many people are using theoretical maximum bandwidths when calculating the number of streams. When I run no-load write tests on my Video RAID, I usually only get 50-60 Mb/s. Granted the drives need some defragging and there are background processes running, but that's the real world.
We just got a Canopus DVStorm2 (roughly a $1200 real time editing card) at the station. It will allow you to simultaneous capture 3 streams into DV. I haven't tested it yet, but I'd assume I'd want to set each stream to its own drive to maximize performance. Probably could get away with two to a drive without headaches. I really wouldn't want to try all three without fear of losing a frame over an hour. Point is, be reasonable with your expectations from an IDE drive.
CitrusTV (http://www.citrustv.net): the Nation's Oldest & Largest Entirely Student-Run Television Station