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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?
... needed in order to record shows off of HBO, HBO2, HBOMovie, and HBO Brasil all at the same time.
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 or is that outdated info now?)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...
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Is there really that much 'good stuff' on tv to watch, let alone save?
Jim Harry
On a semi-related topic, does anyone have good recommendations on PC encosulres (or complete systems) that are suitable for a home a stereo rack? I'm looking for something that is both functional and esthetically pleasing.
Thanks in advance.
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.
When in the history of television has there ever been 16 decent things to watch on TV ?
You probably wanna buy a T3 as well and basically make copies of everything on DirecTV...
mind you you'd need 16 receivers, and like well thats a little out of anyone's leagues since the remotes would be insane (but cool)...
Anywho if you were actually able to find that much stuff, you would basically turn yourself into the pirate TV capital of the world! That would be the only reason i see (but my tiny brain is unable to comprehend anything other than "stealing" stuff. Good luck buddy! The evil empires are going to your house right now to brainwash that idea out of yer head hehe!
I tried to think of a good sig, and this wasn't it.
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."
VCRs are cheap. Buy 16 of em...goes without saying.
Same idea for for HDTV, except save the data stream.
science is a religion
Can you imagine taping 99 channels at the same time with a Beowulf cluster of these?
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!
And then you'd have time to watch all this recorded content? Most us have trouble finding time to watch just one show, and you're recording 4 at a time _and_ burning dvds.. Isn't there something better to do in life than watching tv shows for most of the day (and night)?
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 setting up a machine with 4 scsi drives 4 pci tv capture cards and 4 seperate virtual machines like vmware or some other virtual machine software.
Now be quiet.
...just watch less TV?
Not that you'll have trouble cutting down with the amount of utter garbage out there.
Honorary Member of Jackie Chan's Kung Fu Process Servers
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!
Of course, this doesn't help with the fact that you'd still need eight of these things (and you'd saturate the PCI bus, as someone else mentioned), but it would (possibly?) cut the number of cards needed from 16 to 8.
Karma: pi (Mostly due to circular reasoning in posts).
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 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.
I have DirecTV with Tivo Dual Tuner, and it's great. I can watch two channels at the same time, and thanks to the built in buffer I get to scroll back in time and see what I missed. Great for sports. The problem is that I have a nice TV with dual video inputs that wants to run PIP, but the Tivo doesn't have dual outputs. If tivo were to either add dual outputs or make their own pip control I'd be living large. There are only a few times where I want to watch more than 2 channels at one time. It would only happen the one week when all 4 sports are happening at the same time. ESPN ESPN2 CBS ABC ESPN NEWS FOX SPORTS TBS WGN that's 8, I could see up to 12 for extreme fans, or if you buy one of those full court passes or NFL or NBA or what have you packages then maybe you'd want more.
because I have been enjoined by this Holy Office to abandon the false opinion which maintains that the Sun is the centre
I know this is offtopic, but its the fastest way I can think of. Will everyone be so kind as to beat the hell out of my server: [pyroxpro.com][pyroxpro.com] so I can get a quick stress test? I have no paid ads, or popups, or crap like that, just want slashdot effect stress tested. *PLEASE*
orichter writes: does anyone know how, with a with a few minor adjustments, you turn a regular gun into five guns?
Doesn't Ultimate TV already do this, the multi channel that is. Get 2 and I'm sure you're still cheaper then 4 computers, though if you need to tape more than 2 channels I think you should really watch less tv
"Not knowing when the dawn will come, I open every door." - Emily Dickinson
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.
There's a couple of good stations in Austin, and they both run shows that I'm interested in at the same time on Sunday.
So, I multi-channel FM stereo recorder would be a good thing.
In the course of every project, it will become necessary to shoot the scientists and begin production.
ATI might sue you under the DMCA for using the terms "building" and "all-in-wonder" in the same sentence...
Buy the President
With needing nearly 4 gigabytes per hour of TV recorded at that rate, a 160 gigabyte HD would only yield 40 hours of recording time, or 10 hours per tuner card.
Writing to a HD at 60 MB/sec means that you're probably not going to be reading from it at the same time to watch something that you have previously recorded. Therefore, you're going to want to break this out into multiple IDE channels, perhaps one drive per channel.
Something seriously has to be asked here -- if you're recording 4 hours of TV per hour, when are you going to watch all the stuff? Even assuming that you're skipping commercials (turning a 30 minute program into a 22 minute program), you're still going to be falling behind at a good clip.
If you're doing that with four machines, 16 hours per hour of realtime, what the hell are you going to do with all the data? I think the editor has been trolled with this article.
No text
There's no decent or even marginally workable channel guide software currently available for a "roll your own PVR". A PVR without good guide software is best a PITA and at worst a door stop.
I've researched it pretty thoroughly and both Replay TV and Tivo have the PC-based systems beat hands down. The only one that comes close is Microsoft's Media Center XP, and it's not scalable and is locked down to specific hardware. It won't meet your needs.
Your best and cheapest bet is to buy a few Replay TV 4k or 5k's. They locally network to each other, so you can each record a discrete video stream on each one and you can watch streams live from the other units. They share over the net, copy shows to PC, use your PC as storage space, burn to SVCD or DVD etc...
Buying a few Replay TV's is probably far cheaper than the parts cost of the custom unit you plan to build, not even counting your labor costs.
Once your labor costs are in there, there's no competition.
Interesting concept if it is being built for multicamera systems like security in vegas and to come in at a reduced cost.
...has for years included the "full bandwidth VCR", something that would basically record everything that's on the cable. Playing it back would allow you to change channels just like you were watching TV, just at a different time.
what's so funny 'bout peace, love, and understanding?
It would be cheaper to just live with a single PVR for day-to-day recording, and buy DVDs and/or VHS tapes of the content you want. You might not be able to catch all of your desired programs, and it might not be possible to order all of the content you miss on DVD or VHS, but it certaingly is more simplistic and cheaper then building a friggin cluster and hacking code in order to tape stuff off TV.
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.
1)new lindows boxes being sold at wall mart for $99 + 2)said mpeg capture cards + 3)bonded(coupled...?) ethernet connections for a virtual 500-1000mbps bandwidth = huzzah!! possibly cheaper than tivo pvr able to run open/free guideware, allowing tivo like ease of use, but the media sharing capabilities of a computer. oh yea, anyone know anything about proggress being made in "black box" emu's or descrambling algorithms??? last i checked the few ones that existed worked only for PAL signals(asian? european?), not NTSC. the signal format american cable providers and televisions transmit and recieve=(or is it the other way around...?). although unethical in many ways, for some this would make the homebrew solution a much more attractive alternative. i'm not suggesting or encouraging piracy or thievery, just pointing out reasons some may choose a diy option. also, is there anyone looking into uploading descrambling algorithms or emulators into tivos themselves? Just a few thoughts.
Galen
Err, this may be a silly question, but where are you going to get the CPU power from to encode 4 video streams?
My 1Ghz Athlon is at 80% encoding HALF-frame video into MPEG4 and it drops seriously large numbers of frames if I try and encode at the native resolution (720x576 for UK PAL).
I tried using MPEG2 but that uses up seriously massive amounts of hard disk space, just to get it up to VHS standard.
Unless someone makes a hardware MPEG4 encoder, I can't see how you can easily encode 4 video streams at once unless they're done in a fairly low quality/resolution.
Nick...
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
in Germany we have mostly digital tv. And many people use "dbox2"-type SetTopBoxes. We put Linux on them, and they have an ethernet interface so u can directly record anything u want at a touch of a button. Of course directly taken after the demuxer. Mpeg Cards is a pain in the ass, tv today should be(is) digital, and so no digitizing and recompressing (both means quality loss) is needed.
a perfect combination here would be a dbox2+linux and an xbox+linux. record all u want, play all u want.
To save some money, I would use 4x diskless PCs connected each to a dedicated 100MBit card in a central NFS server with lots of disk space.
Put up to three none-MPEG DVB-S card (if you are lucky enough to be able to use that) in there, a single DVB-S card with MPEG decord, and be done with it.
Also, you will need some switches for your digital signals to be distributed to each of the DVB-S cards.
Oh, before I forget: Get a live. Why 16 programs add once?
Something seriously has to be asked here -- if you're recording 4 hours of TV per hour, when are you going to watch all the stuff? Even assuming that you're skipping commercials (turning a 30 minute program into a 22 minute program), you're still going to be falling behind at a good clip. And thats a long time with no /. Can you handle that??
Check out Taiwanese vendor http://www.provideo.com.tw/ . They sell a variety of video capture PCI boards and USB boxes. They have surveillance systems that use single or multiple PCI cards to monitor and capture up to 16 sources simultaneously. They also have a new four-port MPEG-4 based PCI capture card that they claim supports Linux. However I don't think these boards include tuners, just line inputs, so you would need an external source to do all the channel tuning.
I seem to remember reading about a guy who was recording the signal before it got to the tuner. Then he played it back into the tuner and selected the show he wanted to watch. He had recorded all the available channels at once.
I read about this a long time ago. Probably back in the 1970s because I think it was when VCRs were coming out and the idea of recording a show was a new idea.
One reason I can think that you might need this many channels would be if you were streaming a feed to a corporate or dorm LAN. OK, so the poster didn't mention streaming they mentioned PVR, but lots of people are asking "why do you need that many?". Well, that's a reason.
Now, can anyone point me towards a decent media streaming solution for Linux please? (I'm serious!)
Thanks, Matt
The software is fairly cruddy, although useable, but there are some (non-free) solutions out there that are reported to work quite well. Also, the RF remote is a killer app, especially when combined with a wireless keyboard and gyro mouse.
How much RAM did the machine in question have? Im curious what could be causing the poor performance.
If you want multiple program capability you'd probably need multiple hard drives whether they're in one "superbox" or a cluster. Because of this you might want to have one machine possibly without a hard drive as the piece that sits under the TV and provides the user interface and is networked to the cluster or superbox located in the basement or closet.
That way your fans/hard drives aren't drowning out your soaps.
...is a Beowulf cluster of PVRs?
sorry, but it had to be said.
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.
I spotted one of these at CompUSA, although, now that I see the price, it is quite expensive. Very slick, though: all metal, with doors that are held closed with magnets like an upscale stereo. Now you just have to find room for the watercooling kit.
"I assumed blithely that there were no elves out there in the darkness"
Get a life.
There is one Project that realy delivers PVR to linux. Video Disk Recorder (http://www.cadsoft.de/people/kls/vdr/) is aimed at people with DVB satelite or terrestial cards. The DVB cards also have a very nice open source driver :) The cards them self are rather expensive for now, but the "budget" cards (without the tv-out and mpeg2 decoder) is around $150. VDR can easily control 3 or more DVB cards and automaticaly choose which can recieve a timed recording. It can even pause live TV with a single DVB-S card (Something the windows version of the DVB software can't :) Electronic Program Guide is integrated. You do need a big hard drive tho as the recordings are in DVD quality. They can be converted into SVCD or DivX after they have been recorded of course.
More on the DVB cards: http://www2.arnes.si/~mthale1/dvb_english.html
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>)
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Because if it is, just save the whole transport stream to disk. This may require some electrical engineering and custom hardware.
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
He could tape all the frames of one show, and distribute the show, while 3 other people can do the same with the other shows?
My local cable company is trying to move everyone to digital cable. I don't believe that capture cards support digital cable. Might be wise to wait until there's actually a tuner for digital cable before trying to build a MONSTER pvr (which I'm all for btw). There's always the usb capture devices as well, might cut down on the pci slots you would need.
I told you on the last Tivo story, "Imagine a beowolf cluster of these."
You all kicked my ass but see... He listened.
I wish there was some there was some way that I could be outside playing basketball, in the rain, and not get wet.
The question suffers from a lack of definition. What source of video is being used (CATV|DirectTV|Broadcast Satelite Feed)? What quality are we looking for (D1|DV|320x240)? How much programming is being recorded (24/7 per channel|Selected scheduled programs)? What is the destination for the recorded media (Direct View|Streaming|DVD Archive|MPEG-4 Sharing)?
The solutions would result from the answers to these questions. Sony makes an excellent line of MPEG video servers for broadcast environments. It costs big bucks, but you can put together a video capture/agregation/distribution setup worthy of a DBS broadcaster that way. That's the high road.
Middle of the road, and for the poorer video sources (DirectTV and CATV) would probably be best served by a half-rack of 1U systems with MPEG-2 or -4 capture cards. I would avoid using 4 cards per system becaue the cost/density/stability equation doesn't work. Why get raid or extra hdd controllers to make a system work when you can have a nice stable single-stream system? And no worries about PCI bandwidth/latency/conficts. Depending on output format you can have the systems encode directly or share to a separate encoder / dvd mastering system. Also, consider using professional pre-filtering hardware to reduce noise and improve video quality before the capture/encoding phase in order to reduce the load on general purpose processors that have trouble handling the full datarates of video in real time.
If your goal is just to get it done and do it cheap (and your goal isn't 24/7 or real-time streaming) I would suggest that a stack of DirectTivos would be the best bet. At $500 for 2 simultaneous recordings, I doubt you'll beat the price point, stability, and program guide availability, and using a control box and some scripting with available TivoWeb and mpeg offloading utilities, you'll get good results without having to do all the engineering yourself.
That's just a couple of ways to do it. Probably as many routes as there are users of such systems. And we haven't even scratched the thorny stuff like de-interlacing, multi-system (PAL/SECAM), HDTV and HDCP!
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.]
how come when i watch tv there is nothing on. do you really need to record 16 programs at once. I don't think so.
SCREW FLANDERS
hmmm, i'd suggest the following.
..the only difficult part would be the apps...either run 4 copies of freevo or mythTV
1) four good capture cards
2) SCSI U160 (or U320) RAID system
each card would write to its own set of..say 3
striped disks (total of 12 disks). add
into this the system disk and a hotspare.
14 SCSI disks...you'd need either a nice big tower
or a couple of external disk boxes.
or write in the new functionality yourself.
Any chance to sample and store the entire frequency spectrum on the antenna, and then filter out the desired channel later in software?
-Max
Since most people are looking at this from the consumer angle, I'm going to back-track a bit. The television 'channels' are bands of specified width and position in the UHF/VHF spectrums. A tuner uses simple demodulation, which filters out all other frequencies, and allows the single band to pass through and be converted to a digital signel (modern ones do, anyway).
If archival is what you want, you can capture whatever size band you want and demodulate it later, rather than converting every band seperately to mpeg or whatever. I'm no expert, but I can tell you hardware that can do that will be specialized and probably pretty expensive. The cost might be less, though, than a rack full of computers, and the captured waveform should take up about the same amount of space (compression should work), or maybe less. Perhaps someone else here can better answer those questions, or you can google for 'demodulator tv' - I got lots of hits w/products - or something like that.
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!
......a small, minor, but very important
issue is that you MUST have the low latency
patches for the Linux kernel installed. too
many people seem to just dump the PVR flavour
of the month onto their Linux box and see sync problems. this is where , as someone else mentioned, OpenBeOS (or BeOS original) would
come in interesting...or even QNX with its realtime base. hmmm, perhaps AmigaOS 4.x will
find the niche it needs? 8-)
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.
I mean, come one, that one was obvious.
-Looking for a job as a materials chemist or multivariat
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
I see much point in recording like 16 channels at once, it is not the case that I watch the TV and there are 3 simultainelus (grr.. spelling) shows I would like to watch, as many here pointed. It is about having the archive of the last week TV programing. Those machines would be running round the clock recording and storing last 80-200 hours of TV on all channels. So in case I miss something 2 days ago I could always get it form my mega media server. IMHO this should be public service, everyone could login and get the show he missed. If I eventualy build one I'll share it with at least all my friends so it got used a little bit.
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
One way, perhaps to speed this transition, which I would consider a form of activism, would be to set up such a grand TV ripping station and every week let's say, burn a few CDs/DVDs for different types of people. A disc of cartoons, some friends are mine are into sports so we'll burn one for them too, and of course the news, and C-SPAN and whatever else we feel like. Not to mention of course, all the movie channels.
This would of course, be highly illegal and expensive and make no money, but I think it would be a grand gesture in the fight against intelectual property. Cheers, Joshua
When in danger or in doubt, run in circles, scream and shout!
YOu just need a really large bandwidth converter, then you could record the entire spectrum and when you play it back later, you can tune in different stations. Not remotely practical today, but in a few years, who knows?
JET Program: see Japan, meet intere
The PC would be used to control the boxes over the network (I think you can remotely schedule anyways) and to archive off the video (if you really wanted to). I think that would be cheaper and easier to assemble than to put together the computer and software to do what you are asking.
"You can now flame me, I am full of love,"
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.
Use btaudio instead.
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
So you could have one motherboard and 12 drives if you wanted, the case is the issue then, and cooling.
I have used MythTV and I have to say that it is the most promising opensource PVR project I have seen so far. And I have tried most of the others.
Maybe he intends to save all the news streams produced in the upcoming media event/war in Iraq. There was talk of trying to make sure of keeping all the different footage from 11/09/2001 if I remember right. Or maybe it's just for a Simpson/Futurama/Family Guy marathon. Either's good.
Use USB video input devices. With USB2.0 capture devices you will need 2 channels and two hubs for the 16 input heads. With USB1.0 you will need 3 extra USB cards so each capture head has it's own port. USB capture heads do MPEG compression in them. Probably less than 30MB/sec for the whole set. One drive could probably handle it, but go for 2 to spread the load.
Freevo is horrid. It interfaces with the wrong applications and is incredibly difficult to get ANY kind of support on. I had to learn Python to get it working with my card (Matrox G400 Marvel).
Better off using Perl + Xawtv and designing a little menuing system for it in tcl/tk. It'd be easier.
Freevo, christ.
I'd get a Radeon(flavor of the month) All In Wonder, 2 TV wonder cards(Does it have hardware MPEG encoding support? if not, substitute both TV wonder cards and Radeon All in Wonder for 3 cards that do plus one really kickass video card), an IDE controller card(Go with a mobo with decent onboard SCSI or likewise an external SCSI adapter if you have gobs of money to throw around), 3 really fast and rather large hard disks(This is where the SCSI optional comes in.), 1 rather slow and small IDE hard disk, a high end 5.1 capable soundcard(I'd suggest Soundblaster Audigy but I hear it's XP/2k drivers are a dog...), a gob of RAM(1GB+), and 1 DVD-R. Load the entire thing onto your choice of Mobo/CPU combo, and go with it. And of course, the necessary wiring. Enough coax from the wall to the system, a 3 way splitter, and soforth.
here's the only problem, how do you capture from three seperate sources at once? Maybe you could rig the ATi multimedia center to run several instances each pointed towards the different capture boards? Maybe ditch windows all together and find a linux solution?
Non impediti ratione cogitationus.
I've heard about most cable and wireless companies now offering the option to rent Setop DVR boxes. Get as many as you want/can.
--"The perfect example of the man of action is the suicide." - William Carlos Williams
Instead of ripping on this guy for watching too much TV, maybe you should think about what else this could be used for. I myself looked into setting up something similar for my frat. Basically we wanted a web-driven on-demand video system. The outputs would be RF modulated and spit over unused channels on the pre-existing coax cable. Basically a pirate CC TV station with 24 hour Simpsons, Futurama, and Family Guy.
:(
Unfortunatly it turned out to be cost prohibative at the time (2 years ago) and we just fell back to a bunch of samba shares and watching TV on computer
I used a Lian Li PC9300 case for my entertainment centre machine. It's not the same width as my other components, but it looks appropriate.
Bear in mind though that any case suitable for a home theatre system will be cramped... this particular case is pretty small, I had trouble finding the right power supply to fit inside it.
Incidently, my system works perfectly - if you're serious about setting up such a machine, I'd strongly advise buying a Realmagic X-Card, and a copy of Jove Player (www.8dim.com I think). That's what I use, and I barely ever have to switch back to the Windows desktop for anything.
(Complete system includes a Yamaha RX-V995 amp, custom built speakers from Equinox, Jamo sub, centre, and rear speakers, 80cm television, etc. My shelf unit DVD player hasn't seen any use since I finished building this particular PC).
I work in the testing department of a game development company. When we test console (Playstation) games, we record all gameplay on VCRs so that we have a video record of bugs. You would not believe the amount of video tape we use. Then, it's a PITA to capture the video you want, etc.
A system like this would be invaluable to us.
Which TV tuner card(s) with hardware MPEG2 encoder are actually supported under Linux? That is a big showstopper as far as I can see...
___
If you think big enough, you'll never have to do it.
You'll have something which just about performs the same as a VCR does now, but still doesn't have consistent, reliable, international scheduling information which means no season passes, wishlists, channel highlights, suggestions.
Yah, it all makes sense now.
Government of the people, by corporate executives, for corporate profits.
but multiple tuner cards in each, and use IDE or SCSI RAID for storage. OR, if you can find a PC-on-a-card with a tuner on-board, get your self a 20-slot passive backplane box. Each PC-on-a-card should have it's own hard drive. use a separate pc for the dvd burning. or take paxil for your obsessive-compulsive disorder.
Since HDTV covers all major channels in my area (9/12 of all local channels terrestrial) I plan on only doing HDTV tivo. Reason? easier, better picture, and no de-interlacing issues.
/May/ be able to do it with a 1+ghz, but I'm playing it safe)
:-) Power of running 1 system 24/7 in my power district is about $15/mo. Having 4 systems, over 1, would be an extra ~$450 a year in power costs.
A P4 2.6Ghz (You
128MB ram
80+ gig
4 HDTV tuner cards (There is someone who is making some for Linux, about about $180 or less/more. The cards get the TS stream from the broadcast/card and can put it to disk, or to an NVidia geforce4-440 that has hardware mpeg2 decoding).
Optical out AC3 card
Geforce4-440
All near silent fan's
Total cost? about $1.2k
It will be hard to beat that if you don't do HDTV. The main problem with current TV/interlaced is you can burn all CPU on a dual system trying to de-interlace and clean up the image, and that's not doing real-time encoding of the video and audio, and dealing with sync issues.
Many people have been talking about having to have multiple soundcards, or one that supports several inputs. If you use HDTV, you have the sound in the TS stream, and don't need even a real soundcard. Each HDTV TS stream is max 19.6Mb/s That's 80Mb/s for 4 hdtv streams. But, you can always select "alternative" ts streams for lower res/bandwidth/disk space. Today's MB bus's and disk drives can support 80Mb/s (10MB/s) sustained.
I'll see about posting a story to slashdot when I have my system built. The HDTV cards for linux are a few months away or more from being done. I don't mind since the cost of P4 2.6Ghz will drop too.
My experience for the last month in researching is you can hack and play all you want, but in the end the cheapest route is spending more and doing it right. It's true that regular TV tuner cards are $40 but you'll spend more on the other parts (CPU) to try improving all those. You'll see many projects (mythtv) now supports clustering/network encoding. I personally don't want a cluster of systems.
That's my $.02
But it's likely out of your price range. Take a tour of the Armed Forces Broadcast Center in San Bernardino. Five satellite feeds from live feeds and a room full of hard drive arrays and seven figure automation equipment. World's largest PVR. Takes up a whole room. Not enough room in this forum to explain how it all works. Anything is possible with enough money. Before anyone goes off the $500 hammer deep end, this system replaces a few hundred world wide stations with >1000 staff. All the major networks likely have similar setups. MPEG-2 for 'normal' programs, MPEG-4 for HDTV.
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. -=-=-=-=-
It seems that a lot of people are assuming this guy wants to record sixteen channels of Television at once - but to me it seems that the obvious reason for this system is to monitor/record from a multichannel video surveillance system, which could easily exceed 16 cameras depending on the size of the site. Perhaps the poster should search for pc controlled multiplexors (which have like four video in ports and do most of the video compression on board). Try looking at home automation/security sites (NOT x10.com), sorry no links, but I'm sure I've seen such cards on the web before, although they cost ~$1200 for four channels.
Well, maybe not, but it would be cool. Just hook up your (satellite/cable/antenna) directly to a really fast A/D converter and use GNU Radio tools to demodulate/decode/decrypt as many channels of TV as you want and save it right to your disk. Unfortunately, this would require an obscenely fast A/D converter and more processing power than you would want to imagine (hmm... I wonder if a Beowulf cluster...).
For the uninitiated, read about GNU Radio here.
Many VCRs and VHS tapes seems to be the solution here, based on this web page at least.
I dunno about using TV tuner cards, which have been a real pain-in-the-butt when I had to deal with them, but I did find it easy to hook up my DV-camcorder to my PC through a Firewire (IEEE 1394) card & then essentially save the video stream from the camcorder directly onto my harddisk. The camcorder would also automatically send any analog video source I hooked up to its video inputs straight to the Firewire connection, real-time.
The camcorder provides the video stream in MJPEG format (which would probably need to be reencoded to something a little more standard, but that could be done at leisure and perhaps other machines).
If you've got a powerful-enough PC, it should be able to handle a couple of simultaneous Firewire streams. There's probably some way to do the video/audio->Firewire conversion w/o a camcorder too. There might also be video/audio->USB converters (as long as your USB connections have a high enough bandwidth to handle a decent quality stream).
The main thing that the gentleman was speaking of is entirely true. I mean one of the big things is for Linux to someday become a alternative OS for other users (at least that is what I would like to see) but how is this possible when there is no windows alternative programs? I built a PVR with a ATI card and used windows 2000. I decided to try and install linux on it as I have used linux for four years now and have reverted back to windows on the machine because it does record and it does play and record at the same time. Linux and pvr's are just not kickin right now and thats how it is....unless I pick up a book and learn C++ or whatever language and write the programs myself.
Well, here's one idea. If you have a hardware (or really fast software) DV compressor(s) that can do multiple bit rates you could interleave the data with data from other tuner/compressors. That way, you would be able specify a maximum data rate, and you could record as much video as you wanted, although quality would go down as you started to record more and more channels. You could split the video signal again later.
Here's what I would do if I was designing hardware. I would have 'nodes' with a tuner and a variable compressor. Nodes could be Firewire devices or something like a PCI card. Cards or cartages would be better, because if you had a ton of devices it could get to be a mess of wires and such. The host computer, which the nodes are plugged into would then interleave the data stream and record it to the hard drive. The device would also have a network interface (say Ethernet) so that it could coordinate with other hosts on the network. The thing would almost certainly have enough CPU power left over to some management software, so one would be delegated 'master' roll which would coordinate all the nodes. Theoretically, you could record as much data as you'd like without any practical limit (since the control data is just stuff like 'channel 3, 6-8pm').
autopr0n is like, down and stuff.
I have to call BS on this post. You are a dirty dirty liar. Let's summerize the hardware you have mentioned: Two low power PCs - $500 each? With "various large (300GB+) multidrive RAID arrays" - Okay, $100 a pop for the SCSI cards, minimum. Let's say you have 3 100GB SCSI HDs in each, with no redundancy, and we're talking, what, $150 each? Two firewire cards - $100 each. 2 Canopus ADVC-100s - $300 each. Then you have 6 Sony DSS Receivers (I assume) at $200 a pop each. Oh yes, then there's the 3 MPEG converting machines, let's say $800 each, if we include a hardware encoding card. Or was that "6 or 7 MPEG encoder machines"? Make up your mind. Is it 3, 6 or 7? Let's pretend it's 7 after all. (Let's not forget the crying fit inducing 6 satellite bills, which for all of the extra channels would come in around $80 each every month. Yeah, 80 x 6 x 12 = $5760 per year on cable bills.) Your magic video editing system would have to cost at least $4000. So the bill comes in at a whopping $13700.
Okay, so let's assume that you're mister moneybags, and you go ahead and set up a system for this. My only question is: Why? Are you a big-time pirate? If so, why would you be advertising the fact? You're lying, and everyone knows it. Plus your website http://www.mp3smuggler.com/ doesn't go anywhere.
Fake. Liar. Troll.
Have a nice day.
I'm not much of a server geek, but don't some rack mount systems allow for a one slot PCI riser? If you go that route (slightly older rackmount systems can be bought for ubercheap), each can hold one tuner (and capturing video should be decent, since other than transferring data to the file server, they won't be doing anything else), then use one desktop system for the heavy stuff (encoding, controlling the individual recorders), and one that can act as a RAID file server for all of the recorders.
As for the rackmounts, IIRC, those have built in VGA outputs. Connect those to a bunch monitor sharing blocks (4 to 2, then the 2 to one monitor, so on and so forth), and you can switch from live to recorded on the fly. This is assuming, however, that you want to watch everything on the monitor, and not the TV.
Of course, with the pricing approaching ludicrous numbers to build such a beast, you'd be better off buying a few Tivos.
Just because you can mod me down, doesn't mean you're right. Shoes for industry!
the tuner/soundcard connection is just there so the tuner can dump audio to the speakers in real time without using the host computer.
autopr0n is like, down and stuff.
To the contrary... I've been using MythTV for a while now, and it has been mature enough to be useful for quite some time. The current release does not have any of the problems mentioned in the post with the random bolded words... it supports recording to mpeg4, has a pretty (and themable) interface, and it would take quite a bit to get me to switch to another PVR project. Current CVS (0.8 release is nearing) even supports TV over Network. MythTV is already capable of most of the things mentioned in the article. And I close with,
IN SOVIET RUSSIA, MYTHTV WATCHES YUO!
Restating the obvious since nineteen aught five.
One solution is tuners with hardware M(J?)PEG compression. Are there any that are supported under Linux?
Troll? My post was modded as Troll? Are you daffy?! The parent asked for recommendations on cases that would fit well (size and visually, I presume) in an entertainment center. I told him what I own and like. I mentioned a few issues I had with the case I own. In short, I answered his question with proper and relevant information alongside my own experiences with said product. So where, pray tell, did I troll?
Imagine if you had spent all that time and mental something, anything, more important then spending more of your life in front of the tube.
autopr0n is like, down and stuff.
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?
When I first heard about PVRs as they are now known it was a time shifting device. I know that sounds simples, let me explain.
Now in the UK we have 5 analogue free to air broadcast channels.
What someone had done was to build a machine that could continually record the 5 channels to a disk array and play one back. There was enough disk space to cope with 24 hours of TV.
Now the big difference with this approach to the one that modern PVRs do is subtle - a modern PVR is just a smart disk based VCR - this monolithic apprach means you don't have to set schedules, pay for download guides, or have your viewing information passed back to your cable provider - it just means you can watch any TV that was broadcast in the last 24 hours.
Your favourite shows are on at the same time - no sweat watch one after the other - you may think you do this with any PVR but unless you have 2 recievers you can't timeshift both programs - you have to watch one live and record the other.
Three of your favourite shows overlap - no sweat.
Your mate tells you about a great program that was on the night before - no sweat its on the array.
You see how this is different to most PVRs now.
Spool forward to now (I saw this idea about 4 years ago) and its not practal to record everything from your STB - but I guess you may watch 16 channels most of the time - and these days you can probably keep 3 days worth on a reasonable disk array.
Oh - and I've thought of another. If you were making low budget films wouldn't it be cool to be able to hook up 5 camcorders and record the feed from them all in perfect sync for editing later?
If you can find a TV capture card with decent drivers that allow more than one card to co-exist in a device, you're half way there.
For analog TV, you will need cards with hardware encoders, so all the heavy lifting is offloaded to a specialized chip - away from the CPU, on the other side of the PCI bus (i.e. not effecting either of those resources with high bandwidth requirements).
For digital TV, it's even easier. When the decoder captures the ATSC stream, it is a compressed ~19Mbps MPEG2 stream. The CPU just has to do a few DMA transfers to pull the stream & send it to disk. This is very low overhead. I have an HDTV PCI card today, when capturing, it's barely a blip on the CPU meter.
The PCI bus is irrelevant at this point, because it could theoretically handle over 20 of these ATSC streams simultaneously (32 bit / 33 Mhz PCI is ~1Gbps). If you think you need more headroom, go with a server board, with 3 peer PCI-X busses, they are not expensive.
The Hard drive performance should also be a non-factor. Hard drives are rated in MegaBytes per second (a decent one is ~40MB/s). So, you can fit plenty of 20 MegaBIT/s streams into that pipe.
Hard drive capacity is a bigger issue.. Slap in a few 200-250GB disks in a RAID array, and you're all set.
...that there are four things on TV at the same time that are worth recording.
The movie Timecode does something like this.
I am a dirty, dirty, dirty whore.
I have to say though, isn't this really just an extremely striped down variant of MPEG style compression, or at least a similiar idea to Motion Compensation?
CitrusTV (http://www.citrustv.net): the Nation's Oldest & Largest Entirely Student-Run Television Station
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.
The only drawback to this idea is that it sounds pricey...
I've had a DirecTivo for nearly two years, and bought a second one a few months back. If you have DirecTV, this will allow you to record two shows at once (which is a godsend). Even better, is that it's recording an already compressed stream, so you don't have to worry about losing any signal quality (other than the already heavily compressed streams of some DTV channels).
The unit will set you back about $350 and do about 35 hours of video. The good news is that on the Sony models that I've bought, I've already been able to add a 80 gig drive vs the original 40 (and it even has an extra power plug and bracket if you just want to double your drives).
I've also talked to some people who have networked these machines, and I'm personally going to investigate installing either a removeable HD or perhaps even a DVD-R.
Great resource for things like this is the TivoCommunity
Dr. Wu
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
Don't forget that your typical TV crops about 20% of the image and ignores half frame. There's a reason why bugs are positioned at the top of the "lower third" of the frame.
CitrusTV (http://www.citrustv.net): the Nation's Oldest & Largest Entirely Student-Run Television Station
So who's saying it has to be a Linux solution?
If all you have is a hammer, everything looks like a nail.
The best way to get MPEG-4 video with high quality and a low bit rate is to you two-pass encoding. Its very hard to do two-passes in real-time, seeing as you have to finish all of pass one before pass two begings.
Let's not forget where MPEG-4 got popularised: the Divx that was sold as rental replacement. The whole idea was to fit an entire movie in studio quality video on what was effectively a souped up CD. That was done in a process that was anything but realtime.
And you're absolutely right. Its not feasible at this time to encode 4 MPEG-4 streams at once given present technology in real-time. As per MPEG-2 being massive, that all depends on your perspective. To me it saves space compared to DV.
CitrusTV (http://www.citrustv.net): the Nation's Oldest & Largest Entirely Student-Run Television Station
check out the VIA EPIA Mainboard, with a built in 933MHz VIA C3 processor, 5.1 channel audio, video, tv-out, hardware mpeg decoder, 10/100 LAN and more.
All for a measly price of approximately $150 or so.
All you need is a tv tuner card (note: this mobo only has 1 PCI slot).
More info here
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Now I
It works! I have a post that is inargueable!
http://www.tiltrac.com
Sure there $50,000 but why re-invent the wheel?
iRepairIT - iPhone, Mac, & PC Repair
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One PC to bring them all and in the darkness bind them!
Sorry, couldn't resist.
I also tried to build a PVR based on linux. Suckage. Duy a TiVo. I did. Then I upgraded it. It rocks. The DirecTiVos can record two channels at once. My PC? Am trashing the All-In_wonder for A GeForce 4 with DVD/DivX/VCD/MP3/OGG/CD/Emulation box.
I noticed that one of the electronic retailers had JVC S-VHS recorders for $89 last week. A S-VHS recorder with S-VHS tape is pretty close to the standard digitized stuff. The only trick to using four of them is to figure out how to make the remote control only one at a time. You could probably spend less than $100 to rig up something that would work. So, for around $500 you've got four machines that will record six hours of stuff each. Of course the individual VCR's won't record and playback at the same time, but nothing is perfect.
If you have a ganders here. You will see that Pace have released a box that allows you to watch one channel while recording another on to hard disk. Plus this box sells officially for £299, but I've seen it on sale locally for £249. If a two tuner box can be launched for such a low price, I can't see cost being the barrier to a 4 tuner recording version. Surely its only a case of getting faster hard disks, before a 4 channel recording version becomes available.
I'm quite happy to stick with my Tivo, but when they launch a box that can record two channels at once I'll jump for it. I'd love to be able to record The Kumars at No 42 and The News at the same time. I give it a year or two before such a device hits the market.
As for the current I am able to view two channels at once on my Mandrake box using two Hauppauge cards, I can only record on one though as the HD strains when I try both. There is a windoze product called PowerVCR and it is made by CyberLink, this compresses video in to MPEG for recording to disk, thus the main bottleneck is processor power and RAM, not HD speed. That is what is needed on Linux, a good realtime analog to MPEG encoder as a stop gap before recording the digital stream directly to disk is possible (drivers, copyright etc).
Actually, TiVo is planning a software update to do just that.. That is why when you look at their new remotes (on the website or when buying a TiVo2) they have a "Window" button for that express purpose. :-)
how'bout u take one of them xilinx chips that can have 4, 8, even 16 little CPUs, instead of programming CPUs, program TV tuners. voila!
go buy two low-end hi-fi stereo VCR's. attach each one to an FM receiver, set the timers to record for you, and you get up to 8 hours of stereo audio. i've done it before for long concert broadcasts.
Thi swould be impossible with new digital TV service we have in Canberra Australia.
TransACT streams your selected channel from their HQ directly to your set top box via high speed ADSL (this same link also contains high speed internet).
So recordign more than one channel at once, or even watching on eand recording another becomes a problem.
Martin
I would assume you mean 12 channels of cable because it would be impractical with satellite and pointless with broadcast tv. I suppose you could try to build your own 12 channel demux/decrypt for satellite but you would need an awfully large crack pipe. Even if you had satellite, cable and broadcast antenna to feed this monster who the hell will have the time to watch all the content you are recording. You would be far to busy administering your mini-headend and working a second job to pay the electric bill. Perhaps you should just start off with single PC with 4 capture cards. You could even purchase an IDE raid to store even more crap. You could impress your friends by playing every episode of Aqua Teen in high quality digital video but beyond similar efforts I don't see much use in 12 record channels.
The truth suffers more from convictions than from lies.
Nothing like mass piracy to promote Linux.
Maybe we can promote Linux to accouting firms that practice Arthur Anderson style accounting and get Saddam to use Linux too. Hey, North Korea could use Linux with mysql+apache to have a webapp for tracking their nuclear missiles.
video, because you're going to have to have a lot of storage. Put it this way, at 720x480 w/ stereo audio, you'll need about 15GB/hr uncompressed (well with some loss-less compression).
Golden rule - Don't make any assumptions about hardware. Build a prototype, test it, clone it. Test 2 before you buy more. I have a system to do more or less what you're thinking of built around 5 Shuttle SV25 and 1 Shuttle SV24. I got my prototype going on the SV24, bought the 5 SV25s because SV24 was obsolete, and found out that a chipset change between two very similar models meant I couldn't rip CDs on the SV25 (still not fixed by 2.4.20 I'm told, I run 2.4.19, but I'm told Windows works fine - sigh). Since there's only one PCI slot per machine adding an IDE board fixed it for one SV25, but the others don't have a free slot. I have 3 Pinnacle DC10 analogue video in/out boards, all worked beautifully, then I bought one for another different setup and got ghastly grey diagonal lines interference that needed a hardware soldering hack (electrolytic decoupling capacitors) to fix - that could have been an expensive ~$200 mistake. I bought 3 instances of a respectable brand CDRW/DVD drive that had issues playing the first track of VCDs that two other brands do not.
Given that Digital TV is already compressed, what about just capturing to disk (or tape or whatever) the raw channel data as an RF stream and then "downloading" it vi RF back to the decoder when you want to view it or process it or whatever.
:-) TV owner with good normal TV reception will tell you, the compression artefacts in DTV are there for all to see. The big advantage, and it is advantage enough to get my $1.00, is that the quality of image does not "degrade" with signal strength in the same way that normal TV does (oh and they can pack many more channels into the given bandwidth :-). Sure it gets a bit blocky when things go awry but overall you get crystal clear images all the time (compression artefacts apart).
I know there are _lots_ of channels, I am not suggesting that one should/could collect all the channels (is that even feasible), but the channels are all frequency modulated are they not? So just a bit of frequency channelling hardware and you should be able to record as many channels as you like without requiring multiple decoders.
As an aside, the big scam, IMHO, of the (non HD) digital TV business is the description of it as higher quality pictures, which is just wrong. As any (PAL
"The first thing to do when you find yourself in a hole is stop digging."
This article and many of it's responses reminds me of when I asked my teacher what temperature is needed to boil water. Naturally, he couldn't answer until he first found out why I wanted to boil water and suggested several alterntives to boiling water like not heating it all, switching to boiling other liquids, etc. Of course, it wasn't until I explained to him that I wanted a readily available liquid to scald people who want to know answers to questions without laying down a really good reason for needing the information first that he was able to answer me. 8^}
Guns don't kill people; Physics kills people! - John Lithgow as Dick Solomon on Third Rock From The Sun
I'd be happy if I could find a cheap way to combine four or five directv boxes into one cable like signal.... Say each one is dedicated to one of these channels... ABC, CBD, NBC, FOX, UPN, WB.
They are all transmiting to channel three or four, I'd like to combine them so any t.v would get all five stations using channels 2-6 if hooked to a splitter..
But that so far eludes me.
I know this is a little OT but just I couple days ago I set out to find the best PVR software for Windows. Yes I know Windows sucks *nix rocks and everything but the fact is I'm stuck with Windows for now and would really like a decent PVR program. Anyone have any suggestions? btw. MythTV looks amazing, I wish they had that for Windows...
Build a bunch of fanless EPIA 5000 mini itx mobo's into a single box. They come with onboard sound and a pretty good video chip and as they're only 170mm square it should still be manageable in size and cheap.
Then install the linux clustering distro of your choice (the boards run RH disto's out of the box, and there are a couple of RH based clustering projects out there).
M
T
---- It puts the lotion on its skin or else it gets the hose again. It does this whenever it's told.
What would be good ways to build a multichannel VCR? Think of a cluster of 4 PCs, each having 4 TV-cards?
More to the point, how to we get the gene engineers to redesign the human frame with several extra ocular inputs and a quad-cameral consciousness so they can absorb all this TV you seem intent on capturing?
Da Blog
[ ] You have ever heard of vdr (http://www.cadsoft.de/people/kls/vdr/) and its plugins.
3600 seconds/hour * 16 MB/second gives almost 40 GB/hour/channel. Considering the size and throughput of modern disks, you may be able to capture a few channels for an hour or so before you would have to process the data. Hmmm, I guess you could do this for almost any bandwidth if you had the appropriate frequency shifting setup. Starting to sound like a softare radio...
science is a religion