Make Your Own TiVo?

seanldunn asks: "Currently I am looking at digital video recorder solution to help flesh out my home theater, I've taken a look at the two consumer boxes that I know of, RealplayTV and TiVo"> link however their stance on not being able to upgrade their hardware without taking it into the shop doesn't float my boat. After all, why should I pay them $300 for a 30gig IDE hard drive, when I can buy one off the shelf for $180, and I can get a 60gig for about $200 in a year? Currently I'm am thinking about adding a few components to my personal web/file server running Linux... I'm looking at grabbing a video capture card supported by bttvgrab and some sort of mpeg decoder card with TV out, maybe a Creative Labs Dxr2. Quite frankly a software decoder with a TV out converter doesn't sound good for playing on a P-133... Anyone know if there are any better/cheaper solutions then this?" Interesting thought. If such a solution were put together, how would it compare in quality with the comsumer solutions?

Special Hardware

[maggard]

Just a quick note - the hard drives used in these applications aren't the cheapie ones avialiable at your corner screwdriver-shoppe but rather "AV" models. These are designed to stream data without interruption. Most of the other drives are built to periodically recalibrate themselves which of course would lead to an interruption in your "Powderpuff Girls" viewing pleasure.

Re:Cheapie Tivo

[bonehead]

An NTSC VCD is 352x240. However, to get the best quality, you need to capture at 352x480. This is due to the fact that NTSC video is interlaced, so you need to capture at double the verticle resolution in order to capture both fields. Once you've got that, a high-quality resize algorithm will effectively de-interlace the clip and combine the fields.

Re:what's quality like on TiVo?

[Rombuu]

I purchased a TiVo about 3 weeks ago and am very impressed with the product. As for the quality at the highest quality level (which will eat up your "30 hour" disk in 9 hours), the quality is identical to the input coming in on my (shitty) cable. The medium quality provides about 16 hours of recording which is more TV than I'll ever get around to watching at one time.

The gear as I understand it is somewhat "standard" in that you should be able to buy it off the shelf, but it is not the sort of thing you'd have lying around. PPC chip, AV hard drive, MPEG card, 56K modem, etc... The real value in the unit is in the TiVo service so that you can tell it "Tape all showings of Space Ghost" without having to program those in.

Anyway for a total cost of $598 ($399 for the unit, $199 for the "lifetime" TiVo service), I think you would have an extremely hard time rolling your own at this point, unless you time isn't worth much, or you just want the challenge of it all. In a few years, which people are throwing out CPU's that have the horsepower to do real time MPEG-2 compression and you are wondering what to do with your puny 75G hard drive, throwing together something like this may be a lot more feasable.

Re:what's quality like on TiVo?

[Rombuu]

The lifetime of the TiVo unit, not your lifetime, or the lifetime of any nearby stars or anything...

Re:No Special Hardware

[Anthony Kilna]

From what I understand of it, the "AV" associated with a drive today means something else. One of the big drive manufacturers (Quantum?) has released technology that allows the drive to both read and write simulateously... this means you can be watching one show and recording another as long as you're overwrting the old show, or some such.

Same idea: Dishplayer

[XenonOfArcticus]

I have had Echostar/DishNetwork service for many years and have been quite happy with it. This weekend I bought a new receiver/dish setup (with two LNBs) so I could get the Denver broadcast stations. I bought the JVC/Echost ar Dishplayer 7200 [dishnetwork.com]. Aside from being a WebTV unit as well (whoopee) it's darn cool, and has great program guide, unattended scheduled recording, pause, rewind, fastforward and record live television and lots of other cool gizmos.

Specs:

• 56k software phone modem
  
• 17 GB hard drive(Model 7200, about 12 hrs)
  
• 16Mb RAM
  
• 67 Mhz QED 5230 processor (aka MIPS R5000) with 4Mb ROM
  

According to this page [reser.org] you can easily upgrade the HD in the Dishplayer yourself, and Echostar at least tacitly permits this (though they disclaim it completely, and you take your warrantee into your own hands).

BTW: User interface and video quality is excellent, given that it is all digital MPEG from the head end to your hard drive. The system price is about $400 with the dual-head dish and the 17Gb HD (about 12 hours of recording time).

time for a new hd

[eap]

Those IBM 70G hard drives that appeared on /. a few weeks ago are starting to look small now.

No Special Hardware

[SwellJoe]

While it's true that many drives in the past experienced problems due to thermal recalibration, most drives are now able to weather those monentary lapses without significant interruption to the data stream. Back in the day, I went out of my way (and paid the 20% premium) for AV drives, but I haven't had to bother when I bought my last few drives.

Multitrack audio is a hobby of mine, and I've found that with drives less than 2 years old, there are no problems with streaming huge amounts of uninterrupted data from non-AV drives.

In fact, I'm not even sure that many manufacturers still make a separate line called "AV" drives, anymore. Most have just improved their normal line to behave properly when streaming data. Not to mention that drives have gotten faster since the AV drives were so common. A single video stream at DVD quality is not difficult to sustain even from a UDMA 66 7200 RPM drive (which are dirt cheap these days).

Re:what's quality like on TiVo?

[fedos]

Define "lifetime".

Satellite Compatibility/DirecTV/Control-S?

[Helix150]

I am thinking about building something like this... the only problem is that I want to be able to get programming from DirecTV (a satellite TV company). My sony DTV reciever has a 'smart card', which I am not sure could be adapted to this unit unless it just descrambled everything in software. But the DTV box has a thing called Control-S. This uses a simple serial connection which allows the DTV to control my current VCR, tell it to turn on, record, stop and shut off at the correct time. In theory, could you rewire it to a standard PC serial port? For those not familiar with Control-S, it uses a standard mono minijack audio cable as a connection. I believe it could be used two-way (to control the DTV)... I am currently using a sony SAT-B2 DTV box and a Sony SLV-770HF VCR.

Re:Ya need a Slink-e

[Helix150]

thats perfect... a bit expensive though. any cheaper solutions? ways to rewire the RS232 directly to the slink? Also, what about satellite decoding?

Ya need a Slink-e

[Randy Rathbun]

Check out the Slink-e [nirvis.com]. It will let you control S-Link, Control-A, Control-S and infrared stuff over an RS-232 port.

Nope.

[Randy Rathbun]

DirecTV is not going to give out how to decode stuff. The only way to do it is to record from the video out using a TV tuner card or some such.

S-Link stuff is sent serially, but trying to figure out what the signals are is going to be tough and probably not worth your time considering what the nirvis product does and the price.

what's quality like on TiVo?

[eries]

Anyone know first-hand what the quality is like on those new TV boxes? Do they have some kind of neat custom gear or are they just standard parts marked up like crazy for stupid people?

Want to work at Transmeta? MicronPC? Hedgefund.net? AT&T?

"Roll your own TiVo"

[m0nkeyb0y]

This was a thread during the whole TiVo hacking topic. Jim Buzzbee [mailto] was cool enough to post [slashdot.org] with a link to a wonderful individual who hacked together his own TiVo/Satalite reciever with full menus and even a remote. The plans are here [cadsoft.de]. I really wanna make one if I can scrounge up the money!!

Current tech is so close, yet so far

[Vito]

I've been doing research on this for the last month or three, and the news isn't entirely good. First, you need to figure out exactly what you want your TiVo-esque set-top box to do. "Personal TV" features like live pause and live rewind? Digital, full-frame recording? MPEG1, MJPEG or MPEG2 compression? Channel guides and automatic VCR programming? CD playing? DVD playing? Lastly, what will you put it all in?

Let's start with personal TV features. You can currently record live, full-resolution video and audio onto your HD without dropping frames -- assuming you've got at least a 500mHz processor and a fast HD. That's just a live dump to a raw AVI, and you'll fill up your HD pretty fast that way, at roughly 1-2 meg a second. But if you can blow 4gb for an hour of programming to be able to do a live pause/rewind for a while, then that's not too big a deal. But what if you want to include digital VCR features, not just live pause/rewind?

Now, things get a little more expensive. The crux of the problem is to do live, full-frame MPEG2 video and audio encoding in software, you need at least ANOTHER 500mhz of horsepower, and a single 1gHz processor won't cut it. MPEG1 quality blows if you're recording off satellite or even decent cable TV (if you want the low-end, though, the Broadway [datx.com] MPEG1 encoder is cheap, around $800), leaving you with just MJPEG or MPEG2 video. MJPEG is much larger than MPEG2, because it doesn't have temporal compression, but you can get consumer-grade hardware MJPEG encoders on Matrox hardware, so for a build-your-own box, if you 2-3x your HD size, you should be okay. But to do it right, you want full-frame D1 MPEG2 encoding (half-D1 MPEG2 is MPEG1 resolution, but MPEG2 quality), like you have on DVDs. And to do that in hardware will cost you over a thousand dollars, and may not include an MPEG DEcoding solution!. Yuck. Darim's MPEGator2 [darvision.com] can do full D1 encoding for (only) US$1800, VisionTech's MVcast [visiontech-dml.com] is US$1995, DV Studio's Apollo Expert [dv-studio.com] is US$1995 and includes both encoding and decoding, making it possibly the best buy. I have no idea if Linux drivers are available for any of them, but the price alone puts that sort of tech out of the realm of most people's hands.

With that sobering realization in mind, let's forge forward to channel guides and VCR programming. Channel guides are easy. Just have a Perl script rip and reformat any of the listings from the online providers, including Excite TV [excite.com], Ultimate TV [ultimatetv.com], GIST TV [gist.com] (which also provides the Yahoo TV [yahoo.com] listings), Ask TV [asktv.com] (in the UK), Click TV [clicktv.com] (what TiVo uses), TV Quest [tvquest.com], TV Grid [tvgrid.com] or TV Guide Online [tvguide.com]. And once you have this set up, it's not much farther to program an IR transmitter to sit in front of your VCR's IR port to have it automatically record shows for you.

CD playing in a set-top box is a nice feature. Pop the CD in, and have it hit CDDB for the disc info, and give track options. Shouldn't be too hard.

DVD playing in a homebuild Linux-based set-top box is nearly possible now, too. As of this weekend, I believe that you can now put a DVD in the drive, and play it, entirely software decoded, no ripping VOBs or copying to a HD, full-screen, full-frame, with real-time AC3/48kHz audio downsampling to 44kHz, and audio/video sync is probably only a few hours of coding away. Now all we need is hardware MPEG acceleration in the ATI Rage chipsets, and maybe that attractive Apollo encoder/decoder.

Lastly, what are you going to put this monstrosity of open-source software engineering in? What we've just explained above is that for around $3000, you can build a combination cable box (we'll ignore the open source software cable descramblers for the moment), real-time MPEG2 digital VCR, timeshifting personal TV player, channel guide, CD player and region-code-less, restriction-less DVD player, that utterly blows the quality of anything else on the market out of the water. This is what TiVo WANTS to be. But what are you going to do? Stick a fat, ugly, beige desktop case on top of your TV? Bah. T-A-C-K-Y. Even the recently rediscovered BookPC (aka NLX) cases still look like PCs. But most people can't afford to mint custom cases, yet you want something that doesn't look like a PC. How about a 1U or 2U black rackmount case, sans locking front panel and rails? 19" wide makes it a bit wide for small TVs, but that's okay. You've got a bay for a floppy drive or small LCD panel, a DVD drive, and enough room inside for at least one HD, and in some 1U cases, both the TV card and the MPEG card! Otherwise, just go 2U, which isn't TOO much larger. Whee.

I think that's it. I don't know what the state of TV input on Linux is, but I assume it's pretty good, or you wouldn't even be able to consider this project, so that's not a big deal. And even through you can record in real-time, without compression, straight to AVI (bleagh!), I left out the possibility to post-process the AVI to MPEG, because really, that's so tacky. That's like having to play DVDs by copying them to a HD first. Do it realtime, and Do It Right(tm). Lists of MPEG hardware encoders I got from a Canadian distributor called BernClare Multimedia, Inc. [bernclare.com] Seems like a nice place. Other URLs I used for reference (no, my personal project doesn't have a site; I just posted most of my knowledge here!) include the still-conceptual LinuxVCR [pp.htv.fi] project, the LinuxToday article on How to Build Your Own 1U Rackmount [linuxtoday.com], the Calibri 300R [calibri.net] 1U rackmount Linux-based router, and LCDproc [omnipotent.net] for that LCD display you know you'll need on the front to perpetually blink 12:00.