TiVo Community
TiVo Community
TiVo Community
Go Back   TiVo Community > Main TiVo Forums > TiVo Series3 HDTV DVRs
TiVo Community
Reply
Forum Jump
 
Thread Tools
Old 11-27-2009, 04:45 AM   #1
wmccain
Custom AV Consultant
 
wmccain's Avatar
 
Join Date: Dec 2002
Location: Palo Alto, California
Posts: 124
HDCP Head-Scratchers

I was a very early adopter of TiVo — my first standalone was activated in October 1999. Went through a number of standalone and DirecTiVo models. A few years ago, the Rupert Murdoch era at DirecTV forced me off TiVo and onto DirecTV's own DVR boxes. Recently, the dispute between DirecTV and Comcast over Versus prompted me to get Comcast installed, buy a new TiVo HD, and insert a Comcast M-Card (so now, for the time being, I have both Comcast and DirecTV).

In the course of fiddling with my new TiVo HD toy, I discovered a few puzzling aspects of TiVo's implementation of HDCP over HDMI.

1. I noticed (using a status screen on my A/V pre-pro) that the TiVo HD asserts HDCP on all channels — even OTA channels, as well as every single Comcast channel, copy-protected or not. I confirmed this with a "support article" that I found on TiVo's Web site, in which it states that the (now-discontinued) original Series3 asserts HDCP on copy-protected channels only, whereas the newer TiVo HD models assert HDCP on all digital channels. See:

http://support.tivo.com/app/answers/detail/a_id/146

Why? Anybody "have a clue"?

For comparison, my DirecTV DVRs work like the original Series3 — they do not assert HDCP on OTA channels or on any non-copy-protected satellite channels. Not even on premium channels like HBO. Only PPV channels are ever HDCP-protected by the DirecTV DVRs.

2. An annoying (but solvable) issue that results from the TiVo's constant assertion of HDCP is that the "Viewing is Not Permitted" message can pop up if (for example) you have one TV connected via HDMI and another TV connected via component cables — and you turn off the HDMI-connected TV set. (This can also happen if you switch the HDMI-connected TV to a non-HDMI input, but that depends on the TV set. Some models continue to support HDCP on the HDMI input when you are viewing another, non-HDMI input. Some don't.)

The "Viewing is Not Permitted" message says that you must unplug the HDMI cable. Indeed, that (extremely inconvenient) solution works, and after the HDMI is unplugged, you can then view the TiVo successfully via component cables on the other TV. A better solution is a to install an HDMI splitter and run HDMI cables to both TV sets.

Conjecture: This nuisance appears to result from the constant assertion of HDCP together with a (presumed) inability of the TiVo HD to disable its HDMI output jack internally (while leaving the component jacks active). That is, HDCP requires the TiVo to get an HDCP key from the TV set. Since the set is turned off, there is no HDCP key. So, to meet the HDCP standard, the TiVo must disable the HDMI output — but the only way that the TiVo knows how to turn off HDMI is to make you unplug the HDMI cable!

Anybody out there have a better explanation?
__________________
William C. McCain
Palo Alto, California

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
wmccain is offline   Reply With Quote
Old 11-28-2009, 10:19 AM   #2
wmccain
Custom AV Consultant
 
wmccain's Avatar
 
Join Date: Dec 2002
Location: Palo Alto, California
Posts: 124
Question: Why in the world does the TiVo HD assert HDCP constantly over HDMI, whereas the original TiVo Series3 asserts HDCP only when required (that is, only for copy-protected programs)?

Speculation: Maybe it was cheaper that way. The main difference between the HD models and the original Series3 is the drastically lower manufacturing cost — which enabled them to drive the retail price all the way down to $250 (from $800). In large part, that cost reduction was due to newer, less expensive chips (more highly integrated, and higher production volumes now that HD has become a "mass market" item). Perhaps the HD models use an HDMI chipset that is hard-wired to always do HDCP?

In other words, maybe there is no way to turn off HDCP in the hardware design of the HD models ...

The only other functional difference between the original Series3 and the HD models (of which I am aware) is the support for both tuners by a single M-card. That difference favors the HD models, and most likely it is purely a software issue. But who knows — maybe there is something about the original Series3 hardware that makes M-card support difficult or impossible.

(I seem to recall that TiVo promised that the original Series3 would support both tuners with one M-card, but that promise was never kept. I don't really blame TiVo for that — it was probably some "gotcha" in the CableLabs specifications.)

Now Here's a First: When I had Comcast installed two weeks ago, I told the installer that I would be replacing their cable box with a TiVo and an M-card. And the installer advised me to be sure to get the TiVo with the front-loading card slots, because the rear-loading version required two cards!

Furthermore, when I called Comcast to request the M-card, they advised me that it would cost me $30 if they delivered the card, but I could return the cable box and pick up an M-card at their service center without paying any installation charge. And so I did.

Times have changed in the cable business!
__________________
William C. McCain
Palo Alto, California

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
wmccain is offline   Reply With Quote
Old 11-28-2009, 09:35 PM   #3
qz3fwd
Registered User
 
Join Date: Jul 2007
Posts: 241
Could be the content owners pressuring CE's to "secure" their content like the analog sundown (2011?).
Im suprised the Comcast even knew what a cablcard was, et alone allow you a self install. Over 3 years & 3 visits none of the Comcast techs had a clue-even when the Manager came out to supervise!
qz3fwd is offline   Reply With Quote
Old 11-29-2009, 07:29 AM   #4
84lion
Registered User
 
Join Date: Jan 2009
Posts: 53
wmccain, I think you've covered the Tivo HD HDCP situation well. I found out that the Tivo works that way when I tried to use the HDMI and another output and found as you did that if something is plugged into the Tivo HDMI port and there's no handshake the Tivo provides no output. For that reason I simply eschew the HDMI port and use the component outputs. Currently I split the component outputs and am perfectly pleased with the results. I couldn't tell a difference on our 37-inch LCD HDTV between HDMI and component. With a larger HDTV, YMMV, I would think.

I too am surprised Comcast allowed a self-install on the cablecard. They don't allow this in metro Atlanta.

I didn't know that a Tivo HD with rear-load Cablecard slots existed - or was this a typical case of a misinformed Comcast tech?
84lion is offline   Reply With Quote
Old 11-29-2009, 10:59 AM   #5
AndrewScott71
Registered User
 
Join Date: Oct 2007
Posts: 10
All outputs blocked when HDCP is not enabled

Tivo really needs to do something about these CP issues. Most other DVR's let you watch your recorded content on other tv's in the house. And now, if you have the component and HDMI inputs connected on one device you need to have the HDMI tv on in order to get a pic. Why couldn't they just disable the HDMI output when an HDMI HDCP connection isn't made? Why are all the outputs disabled? This is just another issue that is turning me and many others off to TV. I have been a Tivo subscriber for 10 years and these issues are pushing me towards a Windows Media setup with XBOX360s streaming the saved content.

PLEASE ENABLE OTHER OUTPUTS WHEN HDMI HDCP IS NOT CONNECTED.
AndrewScott71 is offline   Reply With Quote
Old 11-29-2009, 11:22 AM   #6
dianebrat
Uncontrolled Force
 
dianebrat's Avatar
 
Join Date: Jul 2002
Location: boston'ish
Posts: 7,721
Quote:
Originally Posted by 84lion View Post
I didn't know that a Tivo HD with rear-load Cablecard slots existed - or was this a typical case of a misinformed Comcast tech?
The OP didn't say it was a Tivo HD, and he's correct, the original Series3 has slots on the rear, the Tivo HD and HDXL have them on the front. The comcast rep was knowledgeable that there are two different models with different needs, this is a step up for them.

Diane
__________________
"There is a distinct difference between having an open mind and having a hole in your head from which your brain leaks out."
dianebrat is offline   Reply With Quote
Old 11-29-2009, 06:03 PM   #7
wmccain
Custom AV Consultant
 
wmccain's Avatar
 
Join Date: Dec 2002
Location: Palo Alto, California
Posts: 124
Quote:
Originally Posted by dianebrat View Post
The comcast rep was knowledgeable that there are two different models with different needs, this is a step up for them.
You are correct. When the installer said "rear-loading model", he was referring to the original Series3, and of course "front-loading" refers to the newer TiVo HD models.

He did get one thing wrong, though, which I did not mention before. He said there were two rear-loading models and one front-loading model — whereas, in fact, it is the other way around. Still, I just may have had the good fortune to get the world's most savvy Comcast installer!

As for picking up the M-card at the Comcast service center (and thus avoiding a $30 "truck roll"): Apparently, that policy varies a lot across the Comcast universe. I am located in Silicon Valley, home to TiVo and a lot of high-tech engineers (myself included). So it is not terribly surprising that Comcast's policies here are more "enlightened" (and their installers are more knowledable).
__________________
William C. McCain
Palo Alto, California

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
wmccain is offline   Reply With Quote
Old 11-29-2009, 06:19 PM   #8
wmccain
Custom AV Consultant
 
wmccain's Avatar
 
Join Date: Dec 2002
Location: Palo Alto, California
Posts: 124
Quote:
Originally Posted by AndrewScott71 View Post
Why couldn't they just disable the HDMI output when an HDMI HDCP connection isn't made? Why are all the outputs disabled?
Most likely, they do not disable just the HDMI output because they can't. To simplify the design and reduce the chip count, the TiVo HD models probably lack the ability to turn off the HDMI while leaving the analog outputs active.

Note that (except for a few remaining analog cable "stragglers") all TV channels nowadays are digital, and the digital signal is what gets output from the HDMI connector. The analog signals (component, S-video, and composite) are derived from the digital signals by means of DAC chips (digital-to-analog converter chips). It would take at least one additional "gate chip" to shut off the digital data stream to the HDMI connector while still sending that same signal to the DACs.
__________________
William C. McCain
Palo Alto, California

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
wmccain is offline   Reply With Quote
Old 11-29-2009, 06:53 PM   #9
wmccain
Custom AV Consultant
 
wmccain's Avatar
 
Join Date: Dec 2002
Location: Palo Alto, California
Posts: 124
The Real Mystery

Cost-reduction is a satisfactory explanation for the inability to selectively disable the HDMI output while leaving the analog outputs active. The real mystery, however, is why the HD models assert HDCP on all channels and all programs (and even on the TiVo menu screens) — whereas the original Series3 "did it right" and asserted HDCP on copy-protected programming only.

I can think of three possible explanations:

1. Cost reduction — although it is less obvious that "constant HDCP" saves on chips (as compared to the "all outputs tied" issue). But maybe, just maybe, there is a cheaper HDMI chip that always does HDCP and doesn't let it be turned off.

A more subtle (and more technical) version of this theory: The HDMI chip has a "pin" that is set to 0 or 1 to disable or enable HDCP. That pin can be hard-wired in the circuit board to "enable HDCP" at essentially "no cost". But to control that pin via software would require a processor-controlled "I/O port". There are only so many such ports available on the processor (or its supporting chipset), and maybe no I/O port was available (without adding more processor-support chips).

2. TiVo's software engineers said "Let's just do it that way, because it simplifies our code."

3. CableLabs pressured TiVo to "go overboard" on copy protection.
__________________
William C. McCain
Palo Alto, California

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
wmccain is offline   Reply With Quote
Old 11-29-2009, 07:10 PM   #10
solutionsetc
Registered User
 
solutionsetc's Avatar
 
Join Date: Apr 2009
Location: Northern Sierra Nevada
Posts: 658
One more half-assed TiVo implementation... seems my list is ever expanding.

Thanks for this thread. Boy am I glad I did not discover this the hard way when I was considering using component-cat5 baluns to distribute to another room (I ended up getting a second TiVo).

I'll cross this possibility off of my list as, until now, I thought it a viable solution for the CCI byte issue with MRV should that ever plague me.
solutionsetc is offline   Reply With Quote
Old 11-29-2009, 08:11 PM   #11
CrispyCritter
Purple Ribbon Wearer
 
Join Date: Feb 2001
Location: North Potomac, MD
Posts: 3,637
Quote:
Originally Posted by wmccain View Post
The Real Mystery

Cost-reduction is a satisfactory explanation for the inability to selectively disable the HDMI output while leaving the analog outputs active. The real mystery, however, is why the HD models assert HDCP on all channels and all programs (and even on the TiVo menu screens) — whereas the original Series3 "did it right" and asserted HDCP on copy-protected programming only.

I can think of three possible explanations:
There is one more possibility and that is that they didn't "do it right" in the released S3. Complaints about the S3 refusing to output anything if an HDMI connected HDTV was turned off started as soon as the S3 was released, as far as I can remember. Certainly there were complaints and workarounds (monoprice switches) long before the HDTiVo was released, and copy protections wasn't an issue in those discussions. Aside from the article you found (which I admit is strong evidence) is there any evidence that the S3 and HDTiVo are different in this regard? I haven't seen anybody ever bring up that possibility here, before now.

You definitely understand the issues much better than I do, but the S3 had much the same problems that you are describing, and it seemed to be a general problem, not something channel specific. Am I missing something?
__________________
CrispyCritter
TiVo Roamio:Felix TiVo Premiere:Bob TiVo XL4:Fred TiVo HDXL:Sharon TiVoHD:Susan
CrispyCritter is offline   Reply With Quote
Old 11-29-2009, 08:16 PM   #12
wmccain
Custom AV Consultant
 
wmccain's Avatar
 
Join Date: Dec 2002
Location: Palo Alto, California
Posts: 124
Quote:
Originally Posted by solutionsetc View Post
One more half-assed TiVo implementation... seems my list is ever expanding.
Not entirely fair. If they are going to drive the retail price down from $800 to $250, then newer, more highly-integrated, mass-produced chips will only go so far. Some cost-cutting must be achieved by means of "design compromises". Some items on the "nice to have" list will get "left behind".

On the whole, I am much happier with the TiVo HD than I was with my first high-def TiVo box, which was the DirecTV HR10-250 (released nearly two years before the original Series3). The HR10-250 had limitations that the Series3 and later models do not have:

• No native mode HD output. You had to choose a fixed output resolution from a list.

• No concurrent HD and SD output. Only one or the other could be active — the composite and S-video outputs were active only when the fixed output resolution was set to 480i.

My understanding is that these were limitations of the HD chipset that TiVo chose for the HR10-250 (and they were common limitations of most HD chipsets available in those bygone years).
__________________
William C. McCain
Palo Alto, California

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
wmccain is offline   Reply With Quote
Old 11-29-2009, 08:45 PM   #13
solutionsetc
Registered User
 
solutionsetc's Avatar
 
Join Date: Apr 2009
Location: Northern Sierra Nevada
Posts: 658
Quote:
Originally Posted by wmccain View Post
Not entirely fair.
Granted… but it seems you are working off the assumption that the hardware is responsible for this. It is tough for me to believe that anyone that would be successful enough to market a mainstream chip would have it flawed in such a way. I don't have any HDMI appliances that behave this way; even some really cheap ones. Unfortunately, my past experience with the quality assurance of TiVo supplied software does not compel me to give them the benefit of the doubt that you, most graciously, are willing to grant them.

I may indeed be wrong on this; and I have been wrong many times before and not afraid to admit it when proven so, but until then, I have to maintain my TiVo conditioned assumption that this is another QA oversight and not a limitation of the hardware.
solutionsetc is offline   Reply With Quote
Old 11-29-2009, 08:54 PM   #14
wmccain
Custom AV Consultant
 
wmccain's Avatar
 
Join Date: Dec 2002
Location: Palo Alto, California
Posts: 124
Quote:
Originally Posted by CrispyCritter View Post
Aside from the article you found (which I admit is strong evidence) is there any evidence that the S3 and HDTiVo are different in this regard?
I don't have an original Series3 to test, so I can't verify that it does HDCP differently than the current HD models. But TiVo's "support article" that I linked above seems to be very clear about it.

However, even if the original Series3 does HDCP only for copy-protected programs, as stated in the article, it is still quite possible that, like the current models, the Series3 always makes you unplug the HDMI cable if the HDMI-connected TV is turned off. The Series3 probably shares the current models' (presumed) inability to turn off the HDMI jack internally, while leaving component output active. And they may very well have decided to make you unplug the HDMI cable, even when tuned to non-copy-protected programming, just in case you might later change to a copy-protected channel.

Note that HDCP could "suddenly" become necessary for a number of reasons, even without the user changing channels manually. A copy-protected program could start on the channel currently being watched (PPV?), or a scheduled recording (or two) could be copy-protected. So they may have decided that it was "best" to make you unplug the HDMI cable whenever the HDMI-connected TV is turned off, just so they don't have to interrupt you later.

I gotta admit, though, this is an extremely annoying design characteristic of the TiVo Series3/HD models. And it is a characteristic not shared by the other high-def DVRs in my house (three DirecTV HR20-700 DVRs). To "work around" this problem, I spent more than the price of the TiVo HD on a Gefen HD splitter and some more HDMI cables. (I was, however, planning to migrate the other TVs from component to HDMI eventually anyway. This just "moved up" the changeover.)
__________________
William C. McCain
Palo Alto, California

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
wmccain is offline   Reply With Quote
Old 11-29-2009, 09:13 PM   #15
wmccain
Custom AV Consultant
 
wmccain's Avatar
 
Join Date: Dec 2002
Location: Palo Alto, California
Posts: 124
Quote:
Originally Posted by 84lion View Post
Currently I split the component outputs and am perfectly pleased with the results. I couldn't tell a difference on our 37-inch LCD HDTV between HDMI and component. With a larger HDTV, YMMV, I would think.
Agreed. I have LCD TV sets of 20, 22, 26, and 32 inches and I can't tell any difference between component and HDMI on any of them.

On the other hand, my "big ticket" set is a Sony front-projector with a 135" screen — and on that set, the difference between component and HDMI is overwhelming. Not so much in "detail", which seems about the same. But the HDMI picture has better contrast and more color saturation. (This could, however, be mainly due to shortcomings in the component video circuitry of the projector.)

But there are other reasons for moving off of component video and standardizing on HDMI. Both of my Blu-ray players (Oppo player and Sony changer) limit their high-end HDMI support when they are set to also support component video. No support for 1080/24p, for example.
__________________
William C. McCain
Palo Alto, California

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
wmccain is offline   Reply With Quote
Old 11-29-2009, 09:51 PM   #16
wmccain
Custom AV Consultant
 
wmccain's Avatar
 
Join Date: Dec 2002
Location: Palo Alto, California
Posts: 124
Quote:
Originally Posted by solutionsetc View Post
Unfortunately, my past experience with the quality assurance of TiVo supplied software does not compel me to give them the benefit of the doubt that you, most graciously, are willing to grant them.
Apparently, you have never tried a Motorola or Scientific-Atlanta (now Cisco) DVR. Compared to them, TiVo is generally regarded as the "gold standard" in DVR software.

When DirecTV added high-def in MPEG4 on new satellites that could not be received by my TiVo-designed HR10-250, I was forced to migrate to DirecTV's own DVRs. They were quite buggy at first, and they downloaded new software once a week for the first year. In effect, their entire customer base was helping them do a Beta Test. They are still being updated about once every two months (more than three years after the initial release).

By now, however, the DirecTV DVR software is reasonably stable and robust. Unlike most of the others, DirecTV licensed TiVo's patent portfolio, and maybe they even had access to some of TiVo's source code (due to their past and future relationship). So they had help!
__________________
William C. McCain
Palo Alto, California

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
wmccain is offline   Reply With Quote
Old 12-01-2009, 02:58 PM   #17
windsurfdog
Hoof Hearted?
 
Join Date: May 2009
Posts: 105
VERY interesting thread.

Like 84lion, I, too, have abandoned HDMI from my THD to my Denon HTR. In my particular application, I tried connecting both the component and HDMI from the THD to the Denon with the idea that I could at times use the HDMI connection for normal audio/video from the THD and, at other times, use the component for video only from the THD and audio generated from the Denon...a nice setup for me to enjoy whatever THD video source...photos, football games, etc...while listening to Rhapsody through the Denon...or any other audio source for that matter. Abandoning the HDMI takes care of any handshake issues plus, like 84lion, I see absolutely no diff in video quality on my Samsung 46" LCD.

As for standardizing on HDMI, as wmccain mentions, I certainly see it coming as my Denon blu-ray player only has a single HDMI output.

And, heck, with HDMI 1.4 rolling out, who knows...the implementation may be so bad that you can't do anything if you lose your internet connection!
windsurfdog is offline   Reply With Quote
Reply
Forum Jump




Thread Tools


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Advertisements

TiVo Community
Powered by vBulletin® Version 3.6.8
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
vBulletin Skins by: Relivo Media

(C) 2013 Magenium Solutions - All Rights Reserved. No information may be posted elsewhere without written permission.
TiVoฎ is a registered trademark of TiVo Inc. This site is not owned or operated by TiVo Inc.
All times are GMT -5. The time now is 11:10 PM.
OUR NETWORK: MyOpenRouter | TechLore | SansaCommunity | RoboCommunity | MediaSmart Home | Explore3DTV | Dijit Community | DVR Playground |