HDTV On Your PC And Hard Drive

Jack Kolesar writes: "So, you want to watch HDTV but you don't want to shell out thousands of dollars for a new television. Well, AMDPower.com has a review of the AccessDTV HDTV tuner card. Not only does it let you watch HDTV, but you can also record it on your harddrive. Yes, the full 19.4Mbps stream of 8VSB is stored in raw format. Now, if somebody out there could just make some linux drivers for it ..."

Comments

Re:HDTV Protections?

[thud2000]

According to the article, the recorded video is in fact encrypted - only the specific card that did the recording will be able to play back that particular stream.

They encrypt, folks; you don't get raw format

[A nonymous Coward]

A bunch of posters haven't bothered to read the article and wonder why the MPAA etc don't clobber them. This card encrypts using its serial number, so it can only be played back by itself. If this encryption and decryption happens in the hardware, it might not be feasible to reverse engineer it and get the raw stream.

Re:They encrypt, folks; you don't get raw format

[apnar]

Some work is already underway to reverse the encryption scheme. Check out http://groups.yahoo.com/group/AccessDTV. Not too much activity, but there were some decent things figured out already. Mainly that it looks possible to pull the unencrypted stream from the file.

Also there is another card that does mostly the same thing (no PVR functions) but doesn't encrypt the stream at all called the HiPix

Re:They encrypt, folks; you don't get raw format

[Noehre]

Have you ever tried taking a screen capture while playing a DVD?

All you get it a black box.

What the DVD Consortium decided what that a DVD video is sent directly to the video card as an overlay. Basically, the DVD is invisable to the rest of the system. You can't bypass the video somewhere inbetween the disc and the monitor.

I'm sure they can/will/already do something like this with HDTV.

Hard Disk Space

[JohnHegarty]

As this is a 19.4Mbps raw format file. I persume that bits.

So.

19.4 x 1024 = 19865.6 Kbps
19865.6 x 1024 = 20342374.4 Bits Per Second

Now lets divide by 8
20342374.4 / 8 = 2542796.8 Bytes Per Second
2542796.8 / (1024 x 1024) = 2.425 Mega Bytes Per Second

Now, I would like to record a move of 2 hours

2.425 x 60 x 60 x 2 = 17460 MB
or 17460 / 1024 = 17.05 Gb

Thats alot of space , evan for a 80mb hard disk.

Just a question someone might be able to answer, how well will this compress ?

If its a good level of compression, will it allow a new way for the napster type people to break into a new medium.

Re:Hard Disk Space

[imuffin]

Yeah, 17.05 GB is a huge file for a 80 mb hard drive. You'd need over 200 of those drives just to fit one movie!

The video is as compressable as you want it to be. Using mpeg 4, you can get a pretty decent looking 2 hour movie in a gig and a half, so I'd guess that if you wanted to preserve the HDTV look, it would be somewhat larger than that... But just like you can choose quality settings on a tivo, or like you can choose SP, SLP, or LP on a VCR, you can choose the bitrate and compress it to whatever size you want with a quality tradeoff.

I think its a wonderful idea, and I can't believe there hasn't been something like that for the PC yet. A 5 gig compressed movie may sound huge now, but in a few years it'll be like storing an MP3 album as hard drive sizes increase.

And once you're playing video on your computer, how long could it possibly take before someone finds a way to break the encryption and then compress the raw stream?

Re:Hard Disk Space

[bowb]

MB with a big B is megabytes
Mb with a small b is megabits

kB is kilobytes
kb is kilobits

(I don't think it matters much whether the K is big or small, but the convention in the sciences and engineering is to use a small k for kilo, big M for mega, and big G for giga.)

Also note that hard drive makers always use multiples of 1000 for their units:

1kB = 1000B
1MB = 1000kB
1GB = 1000MB

(RAM of course is always measured in multiples of 1024, e.g. 1GB = 1024 * 1024 * 1024B . And before anyone starts whining that the HD makers are ripping you off of those extra bytes, remember that using multiples of 1000 is an older convention in engineering.)

I'm glad I've got that off my chest. Now that you understand these conventions, I WON'T HAVE TO COME OVER AND KICK YOUR ASSES.

If I have an HDTV...Can I....?

[swordboy]

If I was to purchase an HDTV, could I use it as a 1920 x 1080 (1080i standard) monitor? I have seen that some of the high end units have DB15 inputs on the back. This would make for the ultimate entertainment center when equipped with any of the new high end Dolby Digital sound cards.

Re:SGI

[steve_bryan]

Jeez, ten years ago the format currently called HDTV did not exist. So what are you smoking? Still steamed because no one cares about your over-priced hardware which is swiftly sinking into obscurity? Let me take a wild guess -- it isn't possible now and it never has been possible to buy a $500 board that would enable a SGI workstation to receive HDTV over the air? Being a Mac user myself I'm not particularly a partisan of the PC world but the implication that PC are about 10 years behind workstations won't survive any reasonable scrutiny.

Re:Hauppauge?

[cmowire]

Yes, but the Hauppauge card doesn't decode the full HDTV stream. They just convert it to NTSC and let you see that.

Hauppauge Linkage inside

[Argyle]

Here is the Hauppauge WinTV-D (pdf) linkage.

It appears to do the same thing.

Re:Hauppauge?

[Quickening]

yes, hauppauge has had the wintv-d and wintv-hd for a while now. I use the wintv-d to watch dtv on my hdtv.
In fact there are several on the market now - see www.digitalconnection.com. I have yet to see a card tho that will actually output full ATSC video thru component outputs to an hdtv. When they say "full resolution" they mean vga to a computer monitor.
hauppauge claimed to provide hard drive recording of the mpeg2 streams with their latest drivers - but I have never been able to get it to work - nor have they answered repeated requests for technical support.

Digital TV/Radio musings

[Aztech]

Just like the Hauppauge DVB boards... I have one here in the UK and the kick ass, Linux TV not only produce Linux drivers for them but a whole suite of utilities that do PVR functionality, time shiting and 'dvbstream' that actually lets you redirect the MPEG2 transport stream to various other PC's over the network.

On a related note, I picked up a DAB (Digital Audio Broadcasting) digtal radio receiver the other day, I can save the MP2 baseband strem directly to disk... no loss of quality, you can actually record all the stations within the same multiplex at once since they all come through the same COFDM transport stream. The datacasts are pretty smooth (and quick) too.. take a look at radio, if they get this into portable devices then this will give 3G a run for its money when it comes to rudimentary information like news, sports scores etc :)

Re:SGI

[lupetto]

I used to work exclusively with SGI hardware and software in a broadcasting environment. HDTV output is fairly new in the SGI world - I'm thinking it came out about two years ago. This HDTV input/output board was made only for the very high end servers (only onyx2 servers afaik). Information about the HDIO card is here.

It is not supported in the most common machines used at TV stations, the Octane and the O2. There have been rumours that an HDTV card was being developed for the Octane, but as far as I know it hasn't been released.

SGI hardware is, IMO, overpriced. We usually would buy a barebones system (no memory, no monitor, etc) and then buy the parts from third party vendors. At the same time, SGI and the Irix operating system offers much more than you can get out of a standard windows or macintosh system, such as really fine grained scheduling control, guranteed I/O and frame rates, which is very important to engineers.

PC's are improving (and in many areas surpassing), but are not yet at the level of SGI servers for specialized broadcasting environments.

Why can't we build our own?

[dschuetz]

Everyone's bemoaning the fact that these HDTV cards don't have linux drivers and use encryption. Well, is there any reason why we can't just build our own cards?

If the people at SlimDevices can create their own network-based MP3 player with off-the-shelf chips, why can't they (or someone similarly talented) create a little device that takes off-air HDTV signals, feeds it into standard chipsets, and outputs compressed (MPEG-2?) HDTV video over ethernet? Get the little thing responding to simple commands over IP (maybe port 80, just have something in your browser that can handle video/mpeg-2 streams), and you've got a great thing going.

Make 'em cheap, put a few of these in your basement, have 'em all stream to a big RAID box, and then all you need is for the same guys to build a nice ethernet-to-video box for the set-top.

Seriously, though -- how available are these chips? Could someone easily build something that takes "GET CHANNEL 37.3" on an IP port and streams MPEG back? If I recall correctly, off-air HDTV streams are *not* encrypted, right?

Re:Hauppauge?

[ddennedy]

I have a WinTV-HD. Yes, it outputs full ATSC through component output. The big difference between WintTV-HD and WinTV-D is that the -HD has a hardware MPEG-2 decoder so it is not dependent upon the CPU for decoding and so it is not dependent upon the video card for the proper video out signal.

The PVR function of the WinTV-HD software is quite weak, but I can record MPEG-2 transport streams to the hard drive as long as I do not use the component output mode. Instead, I must use the RGB output mode. I can not hear sound while capturing unless I use the direct AC-3 SPDIF output to my amp, but my amp only has one connector, which I usually leave connected to the digital out connector on the Soundblaster Live for
DVD playback.

IIRC, The Telemann HiPix also records standard MPEG-2 transport streams to the hard drive.

I purchased a 34 inch, 4x3, direct view (tube) HDTV monitor for $1495 from a maker called Sampo. It has VGA input and can display computer RGB output at 1024x768. I run my WinTV-HD at 1440x1080i with the component output.

The biggest problem I have is with reliable reception even with a decent powered antenna in the attic. Some channels never work unless there is a low pressure weather system.

Adam Williams' Linux mpeg library can decode MPEG-2 Transport Streams that he can record using a WinTV-D that does have Linux drivers.

Its Broadcast, not encrypted.

[El Camino SS]

They make their money on advertising...

They are not going to encrypt it. Watch all the commercials you want.
I work in TV. It is based on free watching and commercials. Regular TV is not going to become pay-per-view. Because if it was, then someone would come back and give it away for free. That is not how the system will ever work. Anywhere.
If there is encryption, it is a hardware issue... not the transmissions themselves. I think you might be confusing compression with encryption on this one.

Guess how much most cable companies pay for CNN?
Nothin. Find the satellite. Just run the advertisements, please.

I'm usually very polite on /. but whoever made this "Insightful" was an idiot.

More than 2 HDTV Cards available

[Anonymous Coward]

I am surprized that noone mentioned the Hipix-200 from Telemann.

There are currently three HDTV cards:

AccessDTV This one encripts its data and attempts to get you to subscribe to their TV Listing service

Hauppage This card does not encript the data, but its software sucks.

Telemann This card does not encript the data, and the software doesn't suck. It aint perfect, but it is usable.

There is more info at www.avsforum.com where useres of these boards are discussing their merrits.