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HDTV via GNU Radio
NortonDC writes "High Definition TV has been successfully captured in its native data stream from an over the air broadcast by a software defined radio that is Free and open source from the GNU Software Defined Radio project."
HDTV is either 1920x1080 (1080i) or 1280x720 (720p). Where did the 2730x1088 resolution come from? It's obviously wrong (the images are obviously scrunched vertically).
Why does the image exceed 1920x1080? Isn't the highest HDTV resolution 1080p?
How much does the card that they used cost? Is it reasonable?
Is anyone else really confused about what has been accomplished here? What does GNU Radio do? The site's not too helpful.
I've tried various google searches for terms like MC4020, MC4020 data acquisition card, MC4020 data card, etc., and the only results that actually refer to a data acquisition card of some kind are on either the gnu radio page, or the MC4020 Linux kernel driver mailing list archive. I can't find pricing or distributor info anywhere.
If it costs less than $400, though (which is unlikely), I'd pick up an MC4020 instead of a traditional HDTV tuner card.
Does anybody know if atsc_rx can be run realtime?
A solution to the problem with music today
Definitely looks cool, but I couldn't find any information about how long it takes to process each HDTV frame. I doubt it is nothing near real time!
The images on the site are at 2740x1088 resolution, but HDTV at max resolution is 1920x1080. You can tell from looking at the images that they're horizontally stretched, so something weird is going on.
A Linux-friendly HDTV recording solution is definitely needed. Unfortunately, it seems that in order to record HDTV you need a $1300 Analog Input Board.
Can anyone with more knowledge about this project please post a less expensive solution if one exists?
What exactly do I need to buy to start playing with this?
I'm more interested in the radio part than the TV part, but either way, the site doesn't give any indication of whether this is within the reach of the average geek or not.
What do we need, a TV tuner card with FM, or no card at all (is that why it's called software radio)?
If a card is needed, which cards satisfy BOTH of the following two conditions: 1) the card works under Linux/BSD and 2) the card is actually still available on the market today. (I ask that last part because of experience with old cards being supported, but not available in stores, for other functions like video and networking). And how much does the card cost? Is an antenna required? How much does everything cost?
Someone please clue us in. Thanks.
Looking at the images and seeing that huge ugly NBC bug in the lower-right corner. You'd think that at HD resolution the least they could do is make it smaller, but no. At least this was on the original broadcast network. When I watch The Daily Show on Canada's comedy network they plaster their opaque bug on top of the original comedy central one, and as a result I every so often miss out on something that the bug is crawling over. Is there any hope of HDTV killing these things? If it's a digital signal couldn't they transmit the bug out of band and let the TV reconstruct it when people change channels or something?
Man, I wish the Gnu folks would build their own hardware card rather than the card they are currently using - it's quite expensive.
I'd love to see them put a decent FPGA, an Intersil 50216 4 channel digital downconverter, and a nice 60 Msample/sec 12 bit flash A/D converter on the card - they could do that for a bill of materials of about US$200, and have enough power to do the capture properly.
Before you say "Fine - why don't YOU design it?": I'd love to get more involved in GnuRadio, but I'm afraid of potential conflicts of interest both ways - contaminating GnuRadio with my professional work and possibly exposing my employer to problems with GPL infringment.
Also, is anybody big in the Gnu Radio project going to be at IWCE (International Wireless Convenention and Exposition) March 10 - 14? If so, where? I'm getting in on an exhibitor's badge - maybe I could get pictures?
www.eFax.com are spammers
Bascially the aim is to drastically decrease cost and increase flexibility of radio signal reception and decoding by replacing lots of specialized electronics with software.
Now instead of a very expensive ATSC decoder for your HDTV-Ready TV, you will now have a box with an antenna, maybe a preamp, and a powerful DSP running in software.
The cool part is, you can reprogram or adjust the software as needed to create other capabilities, use other frequencies, or increase performance even after the product is shipped.
I'm sure I drastically oversimplified this, and probably don't realize the full scope of the benifits. Read up on it, use google.
But as applied to HDTV, this is an AMAZING accomplishment. We might soon have open-source HDTV decoding. I for one, would love to have the ability to directly access the native format of the TV signal, stream it to disk, multicast it on my home lan to the living room, whatever. COOL STUFF!
I found out by downloading the kernel driver source code that the name of the board is actually Measurement Computing DAS4020/12, and costs $1300. Thanks to the other posters for also mentioning this.
A solution to the problem with music today
It's the only one in this branch so far that actually has its facts about software radio straight.
The Canadian sattelite company, StarChoice, has receivers that are produced by Motorola and General Instruments. The encryption algorythm used to encode the video was produced by Motorola under the name "Digichiper II," which was a step up from the previous "Digichiper."
I am wondering, has anyone decoded the encryption process? As well, would I be able to decode the information via my TV tuner?
In my world, the phrase 'minimal hardware' does not include a $1300 PCI card...
True, for now, but in theory the price would be able to be brought down to less than the current HDTV tuner cards (and act as an 802.11 card to boot).
oh yeah, it also gives you TV/HDTV/FM/AM - maybe even satellite radio (but that's probably encrypted).
This is a *universal* radio - you just have to write software to make it do what you want.
Yes, that would be like making tubing and hairspay illegal because you can make a potato gun. Or like banning code to read a DVD because you might be able to read a DVD that the RIAA didn't want you to read.
Specifically, forces in opposition to a free society are considering FCC rules that would require all commercially available radio receivers to have some sort of "tamper resistent" properties. This won't affect you and me because we will build our GNU radios from chips sampled or purchased, or get them in El Paso from those Mexicans who already manufacture cable boxes across the border. But it will effect your mother, your friends, and others, because they will pay more to see less on the TV.
If you keep voting ignorant testicle-less corporate serfs into office, you will live in a society which resembles IBM's or EDS's corporate culture EVERYWHERE, not just in the workplace.
Maybe it *will* be illegal in your country.
.au care to comment on the current digital transmissions?
But eventually Supply and Demand will kick in - someone will want to tape "Friends, 2009", so presto! the means will appear. Soon enough you'll be able to buy the equivalent HDTV VCR from China for $120 that "mistakenly" ignores the broadcast flag, a-la DVD zoning.
Pity it means that some other country's tech industry gets the "3) Profit!".
Side note:
Sure won't be worrying about how illegal it is in my country (Australia) for a long while yet.
Is "the switch" happening in 2008? And have we sorted whether we're going for SDTV or HDTV?
Anyone with a set-top DTV box in
Anyone? Anyone? Bueller?
You are in a twisty maze of processor lines, all alike.
There is a lot of hype here.
This project isnt just for HDTV but any radio signal one can capture, convert and sample to extract data. This software could be used as an XM radio or possibly a digital cable descrambler. All you need is a decent A/D card (one that can handle the bandwidth of the signal you wish to decode) and associated tuning circuitry. All the signal processing is done on the computers CPU. With SMP boxes, x86-64 and other CPU technology on the horizon the possibilities of building software recievers for most any digital signal is definatly something worth looking into.
Another thing people have to realize is that its just a reciever, the digital stream has to be decoded by another program making it perfectly legal. The program that might have to crack encryption or remove/ignore copy protect bits to record or view that data stream is what will be illegal.
As are your neighbor's cordless phone, GSM/TDMA mobile phone traffic, police CB, and your garage door opener. Next.
Its size makes it impractical for anything like a Tivo. Until I can either get a realtime MPEG-4 encoder to compress these streams or get the data on the next DVDs its unlikely I'll be seeing any HDTV on my computer in the near future. I can barely afford to process and store all my regular NTSC video. Can you imagine how long it would take to compress a 2-pass 1280x1024 2-hour movie into an xvid/ogg file?
I've got a PVR; I leave it on all the time so when I walk into the room and I'm interested in what's on, I can rewind and watch it from the beginning. Unfortunately, that only works for the one channel that the PVR is tuned to. If I change the channel and see something interesting, I can't rewind it. What I want is is PVR that records the last hour or two of every channel that I get.
GNUradio is the receiver for that PVR. The PVR records the unfiltered signal from the antenna. That gives you all the channels at once. When you want to watch a show, the GNUradio software reads the raw data and filters out the channel you want. If a show looks interesting, you can rewind and watch it from the beginning. Even if there are two or more interesting shows on at the same time, you can filter them both in parallel and re-record one or more while watching another.
Nothing for 6-digit uids?
Thanks for the info. I've only used BitTorrent a few times (last Sunday my ReplayTV didn't record the 300th Simpsons for some reason, so I was able to get it from the Internet and was happy with BitTorrent even though multiple instances blue-screen my Windows 2000 box).
I didn't realize it had these problems. I've never used IRC or Usenet to get binaries. And as far as special formats, the shows I've gotten from BitTorrent have been in .mpg or .avi format, I didn't need to do any conversion.
From what I've read there are upload-restricted clients available but I haven't investigated them. I will look into K++ though. Thanks! (Here's a link -- K++ is KaZaA Lite.)
I feel fantastic, and I'm still alive.
Where do I learn more about this, other than the obvious BS in EE option?
Do your math homework... and if you're not in school, just pick up, read, and do the exercises in a bunch of good calculus and linear algebra textbooks. (The key is to actually *DO* the exercises, math is not a spectator sport!) If you've been away from it for a while, I recommend Sylvanus Thompson's 1910 classic, Calculus Made Easy. Chapter 1 is titled, "To Deliver You From The Preliminary Terrors". The book is still in print.
Calculus sounds terrifying, and most people think of it as a weed-out course. But if you do the exercises, any idiot can get an A+ in it. Only the intelligent see the sheer beauty and elegance of Newton and Leibniz' greatest contribution to the world. And you'll find yourself using it everywhere - calculus is the mathematical equivalent to the speedometer in your car. You could calculate your speed by looking at the odometer and your watch, but the speedometer essentially takes the derivative (finds the rate of change) of your position.
Most of these modulation techniques are based on the mathematical manipulation of sinewaves. You have to have a good understanding of trigonometry, complex numbers and multivariable calculus. Then, Fourier is your Big Friend In High Places.
With the mathematical basis in place, the modulation schemes themselves might be best left to a math degree rather than an EE - though, in my program, the double-degree was only a two credit option.
(Bachelor of Mathematics is also fun; mathematicians are almost always crazy, and it's really great to see how frightened or awestruck Joe Public gets by someone who has a degree in math. Even with "just" the iron ring, you can tap it incessantly on the boardroom table every time the boss says something stupid.)
And I have to tell you - I can't say that I understood all of what the original poster said - I didn't. I stick with EM and power more than the rather abstract modern modulation systems.
"I've balanced the budget for you, but I had to take the square root of a negative number to do it."- Quoted by memory from Dilbert cartoon e-mailed to me after I described an incident where a friend of mine *actually did that* to our former boss.
Fire and Meat. Yummy.
KaZaA Lite is a really good program but can be abused too easy. It lets you "cheat" with the system so that you can be a bandwidth hogging leech if you really want. I find its useful for when i need to locate a file that otherwise i would be blocked from downloading becuase of ratios. This does not mean i am a leech. K++ lets me find files that are hard to get which i then share openly to others. I know that if i were to not share to p2p then im doing my part in killing something which i would like to use again.
So despite KaZaA's drawbacks of being abusable i still think it is better than BitTorrent which sounds like abuse waiting to happen to me.
unzip; strip; touch; finger; mount; fsck; more; yes; unmount; sleep