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TiVo to support HDTV by "Year-End"
JMorgan in Seattle writes "TiVo has (finally!) announced support for HDTV. It's a ways off (end of the year), but at least we know that HD TiVo is on the horizon. In two separate press releases, we learn that TiVo will support both standalone and DirecTV hi-def PVRs. TiVo is really on a roll--first Rendezvous support, and now this. Now if only DirecTV would add more HDTV channels..." I've been waiting to get an HDTV receiver for this. Joy.
Just a heads-up, if you are currently a DirecTV subscriber, you will need to get the triple-LNB dish to receive all the HDTV signals.
It will still depend on the resolution at which TiVo stores the video, no matter what the original quality was for the master transmission.
Using the same compression algorithm to get the same file size, the better video quality you start with, the better the compressed version will be.
If TiVo stored the HDTV stream uncompressed, then that would take a heck of a lot more storage space, even more than DVD video takes on a 4.7 gb DVD (about 3 DVD hours=4.7 gb?).
$8.95/mo web hosting
That's 2.5MB/sec.
You'd need ~9GB per hour. So the largest harddrive available currently would give a whopping 20 hours of recording.
TODO: Something witty here...
Toshiba DVD-R + Tivo box
Remote scheduling, intra-tivo video sharing, and MP3/JPG display on Series2 Boxes
"TK-421, why aren't you at your post?"
The subscription is only for the program guide data. You can still pause/rewind/fast forward live TV, and schedule recordings manually, without a subscription.
There are ways to get the guide data into the Tivo without a subscription, from third-party sources, though I've never tried to on my unit.
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Let me throw some facts into this mix. Your analysis is right on, but you need more info.
Uncompressed HDTV requires about 1.3 Gbps of bandwidth to transmit. That's the SMPTE 292M standard for serial digital 4:2:2 YUV 1080i HD. Nobody outside of the TV studio ever sees uncompressed HD.
When a network sends its broadcasts to an affiliate, it's not unusual for that signal to come down at about 45 Mbps over an OC-3. So the signal has already been compressed one time before it ever gets to your local TV station.
The 8VSB transmission standard for broadcast HDTV calls for an effective bandwidth of about 19.3 Mbps between the TV transmitter and your house. So before the signal hits the airwaves, it gets compressed a second time.
So the most your TiVo will ever need to store for over-the-air (OTA) HD is about 19.3 Mbps. That includes the 1080i signal and the Dolby Digital 5.1 audio.
For satellites and (eventually) land-based cable, the facts are a little different, but the gist is the same. I believe DirecTV is currently broadcasting at about 15 Mbps on its various HD transponders.
So all HDTV programming is compressed at least once and down to at least a ratio of about 70:1 before it ever gets to your house. This can be made to work for two reasons. First, your HDTV can't resolve all of the detail in an uncompressed HD frame. The set just isn't capable of it. Second, a good HD encoder can produce a 19 Mbps signal from a 1.3 Gbps signal that is free of visible artifacts. Note that I said a good encoder. Last week's broadcast of "Any Given Sunday" on ABC looked like hammered shit because it had been run through a poor encoder. Macroblocking everywhere. Virtually unwatchable.
So let's say your TiVo stores the incoming signal without additional compression. OTA HD (19 Mbps) requires about 2.5 MB/s of storage space, or about 8.25 GB/h. So a TiVo with an 80 GB hard drive could store nearly 10 hours of HD content, and considerably more SD content. Given that 320 GB hard drives are available, it's easy to imagine a high-end or upgraded TiVo that has room for as much as 70 or 80 hours of HD content. Not half bad.
So to sum up: "uncompressed" HD (meaning HD that is not compressed further once it gets to your house) requires slightly more than 8 GB per hour. Additional compression applied to the OTA or satellite signal is likely to result in very objectionable artifacts, unless TiVo spends a lot of money on their encoder hardware. Since people who buy HD equipment are currently on the high end of the market, it will make more sense for TiVo to spend the money on additional storage and simply omit an HD encoder from the device completely.
A 10-hour TiVo (note that these are 19 Mbps HD numbers only; SD capacities will be four to six times higher) will require one 80 GB HD or two 40 GB HD's. The upgrade path could possibly include adding 80, 160, or 320 GB hard drives to get to a final capacity of up to 80 hours (rounded up) for a few hundred dollars over the base price. Not too bad.
I write in my journal
TiVo is adding support for USB->ethernet connection in April this year. It will come with the new software that all Series2 TiVo users will get.
,#401 and it will use ethernet instead of the phone line. VERY nice.
That's when the OFFICIAL support comes out. Unofficially TiVo can use a USB->Ethernet adaptor now. You set your dialing prefix to
Also, this confirms with the information on what people will be able to record from HDTV signals. The plan in the above article stated that there would be no restrictions on recording over-the-air broadcasts (read: your local stations), while you could only time shift PPV events by 90 minutes and not save the recording. I'd suspect that other cable stations, basic and premium, would have some restrictions between those cases.
"Pinky, you've left the lens cap of your mind on again." - P&TB
"I can see my house from here!" - ST:
- reboots spontaneously, even while we're watching a program.
- mysteriously turns itself off at random times (like Wednesday afternoon), and doesn't come back up. You can't record anything if it's not powered on.
- Let's say you want to watch something that it's currently recording. Like, say, an episode of Farscape that's been running for half an hour, but hasn't finished yet. When you tell the box to start watching the show, it dumps you at the END of the recorded portion (aka LIVE TV).
- That, we can fix. Just rewind back to the beginning of the show. Slight hassle, but not horrible. Then, when the RECORDING ends (irrespective of where in the program YOU are), it dumps you back to the live feed. Not horrible for regular programs, but it sure sucks when you accidently see the final score of the basketball game you were watching.
- So you're halfway through a show, and you go run an errand. While you're gone, your SO watches something else. When you return to watch the rest of your show, the TW box starts at the BEGINNING, not where you stopped watching.
- TiVo has a function where you can record beyond the end of your show. College hoop, for instance, tends to run long, so you can tell it to record an extra half hour to make sure you get the end (and OT, if applicable). The TW has a similar function that you can program, but it doesn't work.
TiVo does all of the above admirably, with a user interface my technology stunted inlaws can use. That $500 never made so much sense, and the TW box is going back when I get a spare moment to do it.ceci n'est pas un sig.
TiVo's lack of support for standard-definition digital cable is no big deal, but HDTV is another matter.
Digital SDTV is a maximum of 720x480 (or 704x486 (704=22x32) or something else close) which is similar to VGA's 640x480 but the pixels are narrower than they are tall. PAL digital SDTV is 720x540 with almost-square pixels.
This maximum is the same as DVD and also known as CCIR-601. However, digital cable might have lower resolution to save bandwidth. TCTI/AT&T/NuevoComcast uses 352x486 on most channels on the HITS satellite and it's likely the content is softened (low-pass filtered) a bit before real-time-encoding.
Therefore, re-digitizing and re-encoding the standard-def analog stream coming out of your digital cable set-top box is only moderately horrible. Motion artifacts will be a bigger issue than resolution because TiVo encodes in real time so can't go back & choose keyframes more wisely later. It also costs 1/100th of the encoders used by HITS and DirectTV do.
Real-time-encoding of SDTV by a sub-$500 box is a reasonable thing in 2003. HDTV is another matter and the digital cable boxes I know of (Scientific-Atlanta Explorer 2000HD) only have analog video outputs (YCrCb component for HD). Pinnacle Systems makes a system where the HD option alone is $1000. HD on PCs now is where SD was 10 years ago- intra-frame (Motion-JPEG/DV-style) or no compression, using oodles of disk space (even with today's 180GB drives). Uncompressed HD @ 1920x1080x30x12bpp (4:2:0) is 90 megabytes per second. That means burning through a 180GB hard drive in about 1/2 hour.
As the poster suggests, you want to get the MPEG-2 stream & just slap it on a disk instead of trying to recompress. For Over-the-Air HDTV broadcasts, this should be no problem. For cable systems that keep OTA in 8VSB...
(something boxes were required to do a few years ago even if the provider doesn't support it- they have to pass through 8VSB with enough bandwidth/low enough noise that a receiver can still demodulate&decode it)
an 8VSB-in-only HDTV PVR would work. Many systems are demodulating 8VSB and re-modulating at QAM64. If they also apply their conditional access (CA), it gets really sticky.
The fact that there aren't digital-cable-ready TVs like there were(are) cable-ready TVs is something the industry, their Cable Labs group and the FCC have been working on for years. The biggest obstacle is Scientific-Atlanta and General Instrument (now Motorola)'s incompatible systems in the US. It's possible to run both on a single network under an agreement called Harmony, but they still see CA as the crown jewels.
POD (point-of-deployment CA, rented from the cable company) was supposed to solve that by putting all the proprietary stuff in a PCMCIA-like card & making the boxes or TV's or VCRs or PVRs use standard interfaces.
Google terms: PowerKEY (SA's system), DigiCipher (Motorola's), Conditional Access.
Other sources: Multichannel News and Communications Engineering and Design (CED) Magazine