Friday, November 28, 2008

Good Deal on Sony PlayStation 3

Q.: The Sony PlayStation 3 (left) is:

1. A video game console that also plays Blu-ray discs and DVDs
2. A Blu-ray/DVD player that also plays video games
3. Both of the above

A.: 3. Both of the above (Yes, it was a trick question!)

This CNet review says the PlayStation 3 is about the best Blu-ray player around. The new Panasonic DMP-BD35 gives it a close run for its money and, at its roughly $250 street price, may nominally be the better value, if you have little interest in games. The PS3 with 80 GB of storage usually costs $150 more, at $399.99 MSRP.

But wait! Sony is offering this deal on a new PlayStation VISA credit card. Sign up for the card between now and the end of 2008 and you can use it to buy an 80 GB PS3 for $399, after which you will receive a $150 credit on the card! The net cost of the PS3/80: "as low as $249.99."

Update: OK, I pulled the trigger and applied for the PlayStation VISA card today. Got instant approval ... but I missed a trick at that point and failed to note my new card's account number and the CVV2 number. Had I done that, I could have immediately gone to this page at the Sony Rewards website and bought my PS3 without waiting to actually receive the VISA card in the mail. The VISA account number and magic CVV2 code that lets you use the card online were apparently given on the confirmation page that came up after I submitted my application and it was approved, according to this blog entry about the PS3 offer.

However, I didn't catch on to that fact. I closed the browser tab instead. Now I can't retrieve the vital information, no matter how creative I get with my browser's history window.

That means I'll just have to wait until I get the card in the mail.

If you want to do it the right way and not my way, you can click here to see a version of the offer that lets you (a) apply for the card first, then (b) redeem the offer immediately, as soon as approval has been granted. Just remember to note your VISA account and CVV2 numbers.

BTW, if you don't redeem the offer right away, and/or for some reason you don't want to buy your PS3 from the Sony Rewards site, you supposedly can use your new card to buy it at any authorized
PlayStation dealer, and the $150 credit will just show up on your PlayStation VISA billing statement. OK, fine, but I'm not exactly sure how, if you buy it at (say), the credit card people know you bought specifically a PS3 and should get the $150 credit. I plan to use the Sony Rewards site and sidestep any doubt in the matter, so I may never know.

Update #2: I just discovered that the PS3 doesn't come with a true remote to control Blu-ray play! You can use the game controller, but it's awkward.

This is from the CNet review:

Our only real complaint with the PS3's movie playback is the remote control issue. Accessing Blu-ray and DVD menus with the PS3 controller is functional, yet a bit awkward. Unfortunately, you won't be able to program a standard universal remote to control your PS3 as it lacks an infrared port. Thus, it needs to receive commands via Bluetooth. Not coincidentally, Sony offers a Bluetooth compatible remote for $25. Other options have surfaced to combat this issue, such as the Nyko Blu-Wave Infrared Remote and the USBIRX3 from

I've just ordered the Sony remote from Amazon for $20. (BTW, the Bluetooth approach of the PS3 beats the usual Blu-ray player's infrared-type remote in that Bluetooth does not need to a clear line of sight to the PS3.)

Update #3: I received the Sony PlayStation VISA card in the mail today, activated it, and ordered my PlayStation 3 80GB at the Sony Rewards website. This involved becoming a member of the website, which allows you to buy Sony stuff for reward points. Each reward point is worth a cent, so my $399.99 PS3 cost 39,999 points, minus the 50 points I got for joining, which came to 39,949 points. The shipping on the PS3 cost 3401 points, or $34.01, so the total for the transaction was 43,350 points. I had to buy the points, and so $433.50 was charged to my PlayStation VISA. I expect to get a $150 credit on the VISA account for the PS3 promotional discount. My final bill should be $283.50.

Update #4: Above I mentioned that I had failed to exercise the "redeem now" option on the Sony PlayStation card offer ... because the offer I was looking at was similar to this one, and did not include a "redeem now" option. I now find that purchasing the PlayStation 3 on my new card at the Sony Rewards website is not enough, all by itself, to trigger the $150 credit/rebate automatically. Today I have called 1-877-865-SONY (7669), the Sony Rewards contact number, and am now waiting for a callback "within two business days" from someone who can help me.

It boggles the mind, trying to explain why my use of my brand new Sony PlayStation card to purchase a PlayStation 3 at the Sony Rewards website did not automatically result in a $150 credit or rebate on the purchase, but that's what happened!

Apparently, the "Complete instructions [for the $150 card credit] will be sent upon your approval for the PlayStation Card via email" fine print on some of these offers is not true. I have received the card itself, but no email instructions as to how to obtain the $150 credit.

Update #5: I have finally received the instructions for how to get the $150 rebate. See Getting My PlayStation 3 $150 Rebate for details.

Sunday, November 23, 2008

TiVo MRV — Use a Second Wrapper?

Recently, in TiVo Multi-Room Viewing (Yet Again) and earlier TiVo Multi-Room Viewing entries to this blog I indicated my disappointment that my second TiVo DVR can't share recordings with my first TiVo if the recordings are copy-protected. I suggested that digital watermarking might be used on TiVo video recordings to enable tracking of the account from which a recorded program has been copied from one TiVo to another using Multi-Room Viewing (MRV).

I now have come to believe watermarking isn't the answer. I'll go into what the answer to the problem of using MRV on copy-protected material later in this entry. First, more about why watermarking isn't such a good idea.

In the following sample of a graphic image that has been given a watermark ...

... the identity of the image's creator has indelibly become part of the visible image. I suggested that something like this could be done with the video images associated with a TiVo recording when the recording is copied (a) to another TiVo using MRV, or (b) to a computer using TiVoToGo (TTG). The watermark could represent the 10-digit Media Access Key (MAK) of the recording TiVo(s) on a local home network, or else it could contain the user name on the TiVo account associated with the MAK.

After posting my last entry on the subject, I began to worry about whether a watermarking scheme to protect MRV is even feasible, so I started rummaging about in Google to see if watermarking has ever been seriously proposed for TiVo recordings.

It seems that the answer is only a highly qualified yes. In 2005, TiVo Inc. issued this press release indicating it would be using watermarking for TiVoToGo:

To discourage abuse or unlawful use of this feature, TiVo intends to employ "watermark" technologies on programs transferred to a portable device using the TiVoToGo feature that would enable tracking of the account from which a transferred program originated.

In other words, the "low-cost software [that users need to purchase] to facilitate the [TiVoToGo] transfer of content from the PC to ... portable devices" such as an iPod supposedly will watermark the transferred and reformatted content. For example on a Mac, Roxio's Toast Titanium software transfers a TiVo recording from the TiVo to the Mac, optionally decrypts it — since it is received in encrypted form — plays it on the Mac, makes a standard DVD of it, and/or converts it to a format compatible with an iPod.

I have made iPod-compatible copies of TiVo recordings in this way. I can't confirm that they're actually watermarked. They're certainly not visibly watermarked ... but watermarking can also be done invisibly.

Even if watermarking of TiVoToGo conversions is being done invisibly, it seemingly is not really what I'm looking for. The problem I've been fretting about with watermarking MRV transfers, as opposed to TTG conversions, is that in the latter the MPEG-2 video in the TiVo recording has to be decoded and then re-encoded in MPEG-4/h.264 format for (say) an iPod. The watermarking can be done rather easily between the decoding step and the re-encoding step.

But with MRV there is no decode/re-encode process. (Nor is there in TTG, prior to the actual format conversion which is the optional final step.) Instead, the intact MPEG-2 program stream as recorded on the TiVo, complete with the "wrapper" that the recording TiVo has added to the stream in order to encrypt it and keep it from being used in the absence of a TiVo-authorized decryption algorithm, is copied to the receiving TiVo as is. There is no convenient opportunity to watermark the video, visibly or invisibly.

So, if watermarking is out, what is in?

Watermarking is out, I repeat, due to the need to burrow down to an inner level of the information in the MPEG-2 program stream — the digitally encoded video information itself — decode it, add a watermark to it, and re-encode it. Such a process is difficult and time-consuming, and decoding and re-encoding lossy MPEG-2 video compression sacrifices quality.

If the burrowing-watermarking approach is a non-starter, then perhaps the right way to approach the MRV problem would be to add something to the very outer level of the MPEG stream.

Keep in mind that a TiVo already encases each MPEG-2 program stream that it records in a "wrapper" which in effect encrypts the stream. Unless the playback software or hardware knows the Media Access Key (MAK) of the recording TiVo and knows precisely how that MAK can be used to decrypt the stream, thereby removing the wrapper, playback is impossible.

Still, for better or for worse, that particular TiVo encryption/decryption algorithm has been hacked. Software known as tivodecode is available which can decrypt a .TiVo file that TiVoToGo has transferred to a computer from a TiVo DVR. This software is independent of the official software used with TiVoToGo, such that an average computer user can learn to decode any .TiVo file he has by providing the recording MAK as a parameter to tivodecode. Once the .TiVo file is decrypted, it can be used in any number of ways — including reformatting it to MPEG-4/h.264 for an iPod, with no watermarking whatever!

That means that authorized MRV copying of copy-protected programs needs an extra, better, layer of protection.

I envision it working something like this: when TiVo B wants to receive an MRV copy of a copy-protected program that has been recorded on TiVo A, B uses a secure network connection to send A an encryption key. This key is one which B has made up at random; it is not the MAK which is shared by the two TiVos.

The ad hoc encryption key would be generated by B, the requesting TiVo, at the time the MRV request is initiated. In fact, it could be (based on) a number representing the precise time and date, down to the millisecond or nanosecond, that the MRV request occurs.

The ad hoc encryption key would be transmitted by the receiving TiVo B to the sending TiVo A using something like a "secure socket layer," a type of safeguard against digital eavesdropping that is familiar to all those sending credit card numbers across the Internet.

Once it received the ad hoc encryption key from TiVo B, TiVo A would use it to add a second "wrapper" around the requested program stream, in addition to the wrapper already being used that depends on the MAK. This second wrapper would represent an additional layer of encryption. Only TiVo B, the receiving TiVo which has requested the MRV copy and which has provided the ad hoc key, could remove the second wrapper and play the copy in the customary way.

This strategy of using a second wrapper would apply only to Multi-Room Viewing, not to TiVoToGo. TTG would still not be able to transfer copy-protected programs. Only MRV would be able to do that.

The general idea here would be that the only real threat to digital rights management posed by TiVo MRV has to do with eavesdropping. If two TiVos, using nothing but approved methods, send copies of copy-protected programs between themselves on a home network in a way that is completely secure from eavesdropping, there is presumably no possibility of illicit activity.

An assumption here is accordingly that the elaborate new authentication protocol that, I am suggesting, ought to be used for MRV would make the process unhackable — that is, the MRV "handshake" between two authorized TiVos (including, but not limited to, the secure transmission of the ad hoc key) could never be faked by a computer hacker programming his computer to pretend to be "TiVo B," the requesting TiVo. Hence, the only way the hacker could get access to the copy-protected MPEG stream being transmitted on the network would be by "listening in" to its MRV transmission, while it is in progress. But that would only get him an encrypted program stream that he lacks the ad hoc key to decrypt.

Monday, November 17, 2008

TiVo Multi-Room Viewing (Yet Again)

Recently, in TiVo Multi-Room Viewing (Again), I indicated my disappointment that my new (second) TiVo DVR can't share recordings with my first TiVo if the recordings are copy-protected.

I have a home wireless network. Both of my TiVos are nodes on it (in addition to my two Mac computers, a cable modem, and assorted Apple TV and AirPort networking devices). After a TiVo makes a recording, in theory that recording can be copied via the network to the other TiVo, in what the folks at TiVo Inc. call "multi-room viewing" or MRV. The only problem is, an awful lot of the programs are copy-protected: their digital bitstreams contain a flag bit that says, "This program can be copied once, i.e., only for a single generation. The copy cannot then itself be copied."

Owing to how TiVo Inc. has chosen to comply with an agreement it has entered into with CableLabs, a consortium representing the cable TV industry and, indirectly, the providers of copyright-protected programming to cable channels, that flag bit is in fact honored by not letting a copy-protected program participate in MRV.

Note that no programs on channels that are broadcast locally over the air and then carried on cable are copy-protected in this way, only many (but not all) programs on cable-only channels.

If a copy-protected program on the first TiVo could be viewed on a second TiVo, then the way that would happen is this: it would be copied to the second TiVo. Thenceforth, it could be watched on the second TiVo ... or the original could still be watched on the first TiVo.

But, no. TiVo Inc. chooses instead to not allow MRV copying of "copy once" originals. As far as I can tell, the main reason is the fear on the part of the cable industry and program copyright holders that the original bitstream could be intercepted and have its copy protection stripped while a legitimate copy is being made across the home computer network.

In theory, at least, TiVo Inc. could go to CableLabs and ask for special approval of a (presently unspecified) scrambling or encryption method that, if used by TiVo DVRs for MRV, would nullify the piracy threat. However, the granting of said approval is not something that has happened ... yet.

The present way of doing MRV ties the original version of a copy-protected program to a specific device: the actual TiVo DVR that made the recording. A non-copy protected recording is, on the other hand, tied to a specific home network, not a specific device on that network. I believe any "fix" for the present inability to share copy-protected programs among multiple TiVos on a single home network would need to make such programs network-specific rather than device-specific.

I believe it was the original intent of TiVo Inc. to do exactly this, but the CableLabs agreement got in the way.

TiVo Inc. apparently intended to base MRV authorization on the TiVo's Media Access Key (MAK). The MAK is a unique 10-digit number that identifies every TiVo. It can be brought up on a TiVo's associated TV screen by means of the Messages and Settings menu hierarchy of the TiVo. Once you know what your TiVo's MAK is, you can (for instance) enter it into TiVo Desktop/TiVo Transfer software on your computer to enable TiVoToGo.

TiVoToGo is the ability to copy (again, non-copy protected) recordings from a TiVo to a computer. Once the copies are on the computer, they can be viewed and/or decrypted, then converted to other video formats such as for use on an iPod.

The decryption of a computer file with a .TiVo extension, once it has been copied from a TiVo DVR to the computer via TiVoToGo, requires that you enter the MAK of the originating TiVo into the computer software doing the decrypting. (That is, the MAK needs to be specified both to copy the recording and to decrypt it. The latter may be done by the same software as the former. If it is not, the MAK has to be specified to both.)

Details of the TiVo encryption-decryption system are hard to come by. Apparently, the TiVo DVR takes the "MPEG-2 program stream" which contains the TV show's video and audio information, as recorded in digital form, and it puts some kind of digital "wrapper" around it. For the original video and audio to be played, the wrapper must first be removed. This is something that cannot be done properly unless the software knows the MAK used by the originating TiVo DVR at the time the wrapper was created — at the time the show was recorded by that DVR, that is.

When a recording is copied from its original TiVo to a computer or to a second TiVo, the wrapper comes along with it. The resulting copy of the original recording cannot be played unless it can be unwrapped first — which can't happen unless the computer or second TiVo knows the MAK.

As I found out when I added a second TiVo to my home network, all TiVos on the same home network share the same MAK! (A TiVo on a different home network, though, has a different MAK.) Clearly, if the MAK is the basis for unobstructed MRV'ing of material on a local home network, all TiVos on the same home net should be able to participate in unobstructed MRV sharing of copy-protected material, in particular. TiVos not on the same network, since they do not share the same MAK, couldn't share the recordings. Neither could computer software applications that have not been supplied with the original MAK.

I suggest as a possible solution to the current MRV impasse that the MAK might be used as a digital "watermark" which the recording TiVo (or any other compliant DVR) visibly embeds in the video of a recording that is being shared via MRV.

Below is a sample of a watermarked image:

In the simplest implementation, "watermarking" would indelibly stamp the copied video recording with the identity (MAK) of its source DVR, which, as I have said, is actually the MAK of the home network. Any DVR with the same MAK (because it is on the same network) could compensate for the watermark and effectively "erase" it from the video as it is being legitimately played back. Watermark "erasure" would be done for legitimate playback only. The watermark would remain a part of the original recording and all copies made of it. Moreover, if a third-generation copy were made from a legitimate second-generation copy, it too would bear the watermark. No matter how many generations of copies were made, every generation's copies would duly inherit the watermark.

In a more elaborate implementation of the watermark strategy, instead of using the actual MAK as the watermark, the watermark could be an encrypted version of the MAK that could be matched for purposes of "erasure" during playback only by using that same encryption key (or a closely related one) to manipulate the supposedly identical MAK which is known to the playback device or application. More on that possibility later.

Or, instead of using the (encrypted or not) MAK as the watermark, the recording TiVo could use the user name on the account to which the TiVo belongs. Because every TiVo on the home network has access, via the network, to the TiVo Inc. database, it could (based on the MAK) fetch the same user name when doing MRV playback of a copy-protected recording. The retrieved user name, instead of the MAK itself, could be used as the basis of "erasing" the watermark for playback.

In any implementation of MRV watermarking, the MAK would be crucial in three ways. First, the MAK would need to be specified by the receiving TiVo to the recording TiVo in order for the latter to gain access to the recording TiVo's Now Playing list. Second, the MAK would be required for the receiving TiVo to be able to "unwrap" the copied recording. Third, the MAK would be required for the receiving TiVo to know how to "erase" the video watermark at playback time.

Similarly, if the destination device were a computer and not another TiVo, the same three mandatory uses of the MAK would apply. All legitimate uses of a watermarked TiVo recording would be MAK-dependent in three interlocking ways.

If a watermarked video recording were intercepted and diverted in an act of piracy, all protocol-compliant computer software, or any protocol-compliant home-entertainment hardware such as a TiVo or another DVR, could simply refuse to play it if that software or hardware were not privy to the same MAK. Alternatively, protocol-compliant software or hardware could go ahead and play it in the assurance that the watermark would show up on screen and effectively ruin the playback.

Non-compliant software/hardware might also play it ... but the watermark would be constructed such that only protocol-compliant software/hardware, on the same network with the recording DVR and therefore privy to the same MAK, could successfully "erase" it during playback. Non-compliant software or hardware accordingly would be able to play the video only in a "ruined," visibly degraded way, owing to the presence of the uncompensated visible watermark.

In the scheme I propose, the watermark, which would show up on a TV or computer screen that was trying to play an unauthorized copy of an original recording, would be in some way based on the MAK of the recording DVR. The MAK uniquely identifies the TiVo account of the owner of the recording TiVo, whose responsibility it is to see that his personal recordings don't show up in someone else's hands. As a legitimate TiVo user wanting to avoid the consequences of having "my" recordings show up in "your" (illicit) hands — I might face de-authorization of my TiVo account, or worse — it would accordingly behoove me to make sure my home network was secure against piracy.

In a worst-case scenario, a video pirate might supply a customer with (a) a watermarked video recording derived from someone's TiVo, along with (b) playback software or hardware that is capable of "erasing" the watermark during playback, but only if given (c) the MAK used to watermark the recording.

That scenario could be averted by encrypting the watermark, as suggested earlier. That is, instead of having the watermark be the MAK itself, it could be an encrypted version of the MAK that would be matched for purposes of "erasure" during playback only by using that same secret key (or a closely related one) to manipulate the original MAK and "erase" the watermark. Our pirate (or his customer) would thus have to know the actual MAK of the recording TiVo, not just the encrypted version thereof which shows up as the watermark. He would also have to know the key used to encrypt the MAK for purposes of creating and "erasing" the watermark.

Such an encrypting key might at some point be discovered by the piracy community and compromised. Because TiVos are regularly updated from TiVo Central by means of an Internet connection or phone line, the encrypting key in question could be changed any time it was compromised. If that happened, MRV copies made with the old key would no longer work.

That is, unfortunately, unavoidable. Occasionally, blameless users would be irked to find a legitimate copy they made only yesterday no longer works today. But that's far better than the current situation, in which legitimate users can never make MRV copies of copy-protected TiVo recordings.

Note also that if the MAK-based watermark were encrypted, casual users who stumble across a pirated video online would be unable to learn the MAK of the source TiVo — which is a good thing. Yet TiVo Inc. or any other authorized watchdog, being privy to the original encryption key, would be easily able to identify exactly whose TiVo the pirated copy originated from.

I realize that the ideas I'm broaching herein are sketchy and provisional. They need to be vetted to make sure they are reasonably watertight. The various interlocking concerns who are involved in this issue do have a right to protect their programming against piracy. No one who says otherwise is going to win that argument.

Still, the key word in that preceding paragraph is "reasonably." It is generally recognized that dedicated pirates will find a way around any copy-protection system, given enough time. The aim is to make it very, very hard for them to do so, since making it absolutely impossible is impossible.

That said, any sketchy proposal such as this one needs fleshing out and thorough vetting by all concerned who would be betting their "family jewels" on the success of the methodology. Such fleshing out and vetting ought to be done in the context of developing a full industry-standard protocol for MRV and "to go" usage of copy-protected recordings made by home DVRs and potentially used by other DVRs/hardware devices/computer applications.

It is the present absence of such a multi-industry protocol and accord which is really to blame for my not being able to MRV my copy-protected recordings of TNT's "The Closer."

Tuesday, November 11, 2008

TiVo Multi-Room Viewing (Again)

Recently I got a TiVo HD digital video recorder:

It joins the TiVo Series 3 I bought two years ago:

You can read about my experiences with the TiVo Series 3 in earlier installments in my TiVo series of posts. In particular, this post gives more details about my main topic herein: TiVo multi-room viewing.

My new TiVo HD hooks to my new living room TV — see My New Samsung LN52A650 TV. The old one hooks to my two-year-old Sony KDL-40XBR2 upstairs in the bedroom. The new TiVo, like the old one, digitally records cable TV programs, including digital channels, analog channels, high-def channels, and premium channels.

One of the nice things I can do with either TiVo is take advantage of TiVoToGo capabilities (see my TiVoToGo series). Programs that have been recorded on a TiVo (if they are not copy protected) can then be transferred via a wired or wireless home network to a computer, where they can be stored or converted into videos playable in iTunes or on an iPod.

Another nice thing I can do, now that I have two TiVos, is "multi-room viewing." MRV (click here for an official description; click here for a FAQ) lets you transfer shows between two or more TiVo DVRs.

Say you have recorded an episode of "House" on your bedroom TiVo but want to watch it on the TiVo in your living room. You go to the Now Playing list on the living-room TiVo — that's the list of programs that have been recorded locally on that TiVo — and scroll down until you reach an entry for, say, "Bedroom TiVo." Selecting the entry brings up the Now Playing list of the remote TiVo in the bedroom!

From that list you select whichever program you want to watch in the living room and then select "Transfer this recording," and the show begins streaming from the bedroom TiVo to the one in the living room. (This assumes, by the way, that you have both TiVos on the same wired or wireless home network.) After you initiate the transfer, you can optionally begin watching the transferred copy as it is being made.

After the transfer has been completed, you will have two copies of the program, one on the bedroom TiVo and one on the living room TiVo. The new copy is for all practical purposes identical to the original, and you can watch it as often as you like, set it up either never to be deleted or to be eligible for deletion after so many days, and do whatever else you are accustomed to doing with "live" TiVo recordings. The only obvious difference is that the new copy does not show the channel, time, etc. of the original recording — though the program information you can pull up by pressing the Info button on the remote is the same.

That being said, there are (as always) some gotchas.

(1) One gotcha is that watching a show in "real time," as it is being transferred, TiVo to TiVo, can be an iffy proposition. If your home network can't keep up speed-wise, then the real-time viewing process can bog down. I have a wireless 802.11g network that I find can keep up nicely with a transfer of a standard-def TV program, but with high-def material it bogs down. HD material uses more bits per second and requires higher bandwidth than my network can manage in real time. As a result, when I am watching an HD transfer in real time, the receiving TiVo frequently goes into pause mode and requires me to hit the play button on the remote to continue. The transfer, meanwhile, continues normally, and after a while, even if I never restart the viewing process, it finishes — at which time all the viewing glitches go away.

(2) Another gotcha is that you may not want to create a permanent second copy. There are two variants. One, you may want just to watch the program stream from the bedroom TiVo on the living room TV, without having the recording copied permanently (until it's deleted, that is) on the LR TiVo. Or two, you may want the permanent copy to stay on the LR TiVo, while that on the bedroom TiVo goes away, automatically and immediately, once the transfer is done.

TiVo multi-room viewing supports neither option.

TiVo MRV does not have a "stream without copying, for viewing only" mode. Possibly this is because many home networks are too slow to make this a viable option.

Nor does TiVo MRV have a "move" mode that allows automatic and immediate deletion of the original recording, once the transfer has been done. And this leads into the next gotcha ...

(3) Copy-protected shows that have been recorded on, say, a bedroom TiVo cannot be transferred in any way to another TiVo. They can't be copied, they can't be streamed, and they can't be moved.

Cable companies use a set of flag bits in a byte called the Copy Control Information, or CCI, to invoke copy protection. This byte is present in all digital broadcasts and cablecasts. Depending on how it is set, it can limit the amount of copying that can be done. You can visit this thread in the TiVo Community Forum to find out more about how CCI, copy protection, and "digital rights management" (DRM) affect TiVo usage. The official TiVo Inc. policy regarding copy protection can be read here.

Basically, if the CCI code represented as hexadecimal 0x02 is set by the cable company, it means "copy once" (or "copy one generation") is technically permissible — as opposed to CCI 0x03, "copy never." "Copy once" should accordingly permit MRV transfers. However, the agreement TiVo Inc. has signed with the cable industry won't let digital recorders transfer CCI 0x02 programs between themselves unless CableLabs, a consortium which represents the cable industry, approves the way the recordings are encrypted while they are being transferred. In the absence of such approval, a company like TiVo Inc. is expected to fall back on not letting such transfers take place at all.

And that's exactly what TiVo Inc. does.

Technically, this restriction applies only to TiVos that have CableCARDs — credit-card sized objects that when inserted in a TiVo Series 3 or TiVo HD allow the TiVo to receive scrambled digital channels. Consequently, shows that are received on analog channels or "clear" (unencrypted) digital channels can always be transferred from one TiVo to another.

CableLabs' "DFAST Technology License Agreement for Unidirectional Digital Cable Products," which sets forth in legalese the copy-protection constraints applying to CableCARD-enabled TiVos, can be accessed by clicking the hotlink above.

So, what programs are copy protected, and what programs are not? First of all, I have found that anything that I receive on premium channels like HBO is protected. Likewise, episodes of many series, such as "The Closer" on TNT (or TNT-HD), that are shown on cable-only digital channels are protected.

On the other hand, anything that is aired on a local digital or high-def TV channel and is retransmitted over cable is, by law, required not to be copy protected. So, for instance, "House" on Fox is always copyable (even in HD!).

Unfortunately, the number of programs that are legally copy protected on cable may be growing. I have found that some series on some cable networks that used to be copyable are no longer copyable. (Of course, the episodes recorded before copy protection went into place are still copyable.)

The use of copy protection may vary from one cable provider (mine is Comcast) to another. It is generally believed by those concerned with the issue — but I can't confirm this — that cable companies have been signing agreements with program providers that require the cable companies to use copy protection on certain shows or certain channels.

Now for some editorializing on my part: I believe TiVo multi-room viewing should be allowed for "copy once" programs.

Specifically, I don't think copying, streaming, or moving copy-protected material from one DVR to another constitutes a basic violation of copyright law. Rather, it qualifies as "fair use" of copyright-protected digital material.

However, a cable-TV program provider (such as a Hollywood studio) who holds a copyright has a legitimate worry: that a show such as "The Closer" could be pirated en route from a "source TiVo," during an MRV transfer, to a receiving device. The digitally transmitted stream could be forced to make a "detour" into someone's personal computer. For example, the PC could conceivably masquerade as a TiVo and receive the digitally transmitted stream from the source TiVo. The received program stream's CCI byte could then be set to 0x00. Then the resulting copy could be distributed over the Internet.

There are at least two ways to guard against such a scenario. One is to insist that a robust scrambling/encryption method be used during a TiVo-to-TiVo transfer. The other is to make sure that the "handshake" between any two TiVos prior to initiating a transfer is sacrosanct and can't be mimicked by another device.

In the present state of affairs, apparently CableLabs is emphasizing the robustness of the encryption method and paying less attention to the sanctity of the handshake. Because TiVo Inc. has not obtained approval of the encryption method used for all files on its TiVo boxes as satisfying the CableLabs requirement that would allow at least a "move" operation for copy-protected shows, MRV is currently being crippled with respect to the fair-use rights of TiVo owners.

If the cable industry would allow "copy once" programs to be moved (or copied, or at least streamed) from one DVR to another solely on the basis that the sacrosanct handshake between the two DVRs is valid, and would waive the requirement that in such a scenario the encryption method used for the transfer must be specifically CableLabs-approved, some progress could be made.

In short, there is room for compromise.

Such a compromise could, and probably should, include establishing an MRV encryption/scrambling method that would be acceptable to the cable industry and to DVR makers. Presumably, such a method would have to be more robust than the simple encryption TiVo uses today for recordings on a TiVo box. Yet it would not necessarily have to be as robust as HDCP, the elaborate method used to encrypt video for transmission over an HDMI cable. The reason: if HDCP were an acceptable option from the point of view of DVR makers, then, since it is already included as part of the CableLabs agreement, TiVos and other DVRs could use it for MRV right now! That they aren't doing so implies that HDCP is too elaborate (and probably too dependent on costly hardware add-ons such as computer chips) to be used in this way.

If DVR makers could formally agree on handshake and encryption requirements, multi-room viewing of "copy once" material could become a reality. What's more, the agreement might enable TiVos to "talk to" other DVRs such as those built into some cable boxes, and to exchange programs with them.

So I say to the respective industries: c'mon guys ... put your heads together and come up with a mutually satisfactory way to let me watch "The Closer," as recorded on my bedroom TiVo, on my living room TV.

Monday, November 10, 2008

LCD Flat Panels: Uneven Backlighting

I have two 1080p flat-panel LCD HDTVs, a new Samsung LN52A650 (52") and a two-year-old Sony Sony KDL-40XBR2 (40"). They both exhibit a problem with uneven backlighting, the Samsung to a very minor degree, the Sony to a more noticeable (but still hard to spot) extent. Research on the web indicates that this and related problems — "cloudy" backlighting, a "flashlight" effect, "leaky" backlighting, "mura" (a Japanese word) — are not uncommon on large 1080p LCD flat-panel HDTVs.

Click here to see an official thread about the clouding/flashlighting problem with the Samsung LNxxA650 model HDTVs. Click here for a similar thread about Sony LCDs.

Here are some pictures showing what the problem can look like when an artificially solid black/dark image (or a "regular" image with a very dark background) is on the screen:

To test your TV: some TVs will give you a solid black screen if tuned to an unused input; or, you can use an appropriate image from a DVD, such as the end credits from many movies.

The number of individual TVs about which forum posters have complained concerning this type of problem is so large, it has to be said that the uneven backlighting problem is not confined to just a few unfortunate set owners. This sort of problem is showing up on a great many high-priced LCD flat panels from Sony and Samsung, and perhaps from other manufacturers as well. For Sony and Samsung, there seem to be similar problems with successive generations of LCD flat-panel HDTVs; for instance, the current Sony KDL-nnXBR4 and XBR5 models seem to be affected, and not just the older XBR2 and XBR3 models. Multiple Samsung models over the last few years are also known to be prone to the problem.

Many buyers have replaced their original LCD sets by exchanging them at the store where they bought them or by taking advantage of the manufacturer's warranty, and found the replacement TVs too often have the same problem, if to a greater or lesser extent.

There is little reliable information on what causes the problem, or what solves the problem.

There is some unscientific, anecdotal evidence that the problem stems from mechanical or heat-induced stresses on the LCD panel itself. (This is the theory I personally subscribe to.) An LCD panel works by using electrical signals to tell molecules in individual pixel-sized locations in the panel to block light from a large fluorescent backlight from passing through the panel and reaching your eyes. Ignoring details concerning how this is done separately for the red, green, and blue components of the color TV picture, the basic idea is that as certain light-blocking molecules (the "liquid crystals") twist and untwist, light from the backlight passes through the panel unobstructed or is blocked to one degree or another. The three-dimensional geometric alignment of all the pixel-sized cells containing the twisty light-blocking molecules has to be absolutely uniform. Otherwise, you get "uneven backlighting" and see "clouds."

If there are uneven mechanical or thermal stresses on the LCD panel, perhaps coming from physical distortions transmitted from the frame of the TV assembly, the panel can warp, dimple, twist, crumple, etc., to a very minute degree. Now the twisty light-blocking molecules aren't squarely in front of the spots of light which they are intended to control. The effect is similar to what happens when you view an LCD flat panel from off-axis and see increased overall brightness and reduced overall contrast. The difference here is that only certain spots on the screen are, in effect, being viewed off-axis, owing to the warping, dimpling, and distorting coming from uneven mechanical or thermal stresses that have been applied to the physical LCD panel.

At least, that is the theory. Giving it some support is the fact that some people have reported being able to reduce the severity of the problem by slightly loosening some or all of the screws holding the TV assembly together, after carefully laying the TV face down on a soft cloth covering a perfectly flat and level floor. (This is a procedure that can cause major problems if botched, and it may void your warranty, so don't try it lightly.) Many who have done this have suggested leaving the TV in this face-down position, powered on so that it stays at normal operating temperature, for hours or days before re-tightening the screws to a lesser degree than they were originally tightened.

Other people have reported that their uneven backlighting problems have gone away or diminished on their own after several weeks or months of TV use, presumably because the cumulative effect of cycles of heating/cooling the TV over and over again has eliminated or minimized the mechanical stresses the TV assembly as a whole puts on the LCD panel it houses. Yet other people report that the problem either appears or disappears (depending on the individual TV) each time the set warms up, after not having been used for a while.

All of these reports tend to confirm that mechanical/thermal stresses on the LCD panel are the prime culprit.

There have been, in addition, reports that the cloudiness/unevenness problems tend to vanish if you simply turn down the LCD backlight — not contrast or brightness, but "backlight" per se — as you can do from the onscreen menu systems of these TVs. Sony, moreover, has apparently issued a firmware upgrade for some of its XBR models that will apparently do this automatically when the scene on the screen is dark. (I have ordered the upgrade but have not tried it yet.)

It stands to reason that reducing the backlight intensity would camouflage the problem, which is basically that too much light is leaking through in certain spots, in dark scenes. Lower the amount of light that the backlight produces, and there is consequently less light to leak through.

As a sheer guess, it may be that keeping the backlight low also generates less heat, reducing thermal stresses on the LCD panel.

So far, there appears to be little hard evidence that these problems derive from poorly manufactured LCD panels per se. I had the panel inside my Sony replaced under warranty, and the new one turned out to be exactly like the original, insofar as this problem was concerned. It looks as if the installation of the new panel inside the TV assembly created the problem all over again. This is more evidence that the problem has to do with mechanical/thermal stresses coming from the TV assembly as a whole.

Some posters to the threads mentioned above have tried to assign blame for the problem to certain ranges of the manufacturers' series of serial numbers, or to certain specific months of manufacture, or to what country the TV was assembled in. I have seen little hard evidence that any of these factors is important.

Nor does there seem to be any correlation between this problem and that of "dead" or "stuck" individual LCD pixels — which are defects in the manufacture of the LCD panels themselves.

It also needs to be noted that this problem is typically hard to spot. Unless you are looking at just the right kind of image on the LCD screen and the "cloudiness" just happens to catch your eye — or possibly you have made a point of trying to find it — you may in fact have the problem and never become aware of it. Some people, once they have discovered it, pretty much dismiss it from their minds as relatively unimportant. Others become semi-obsessed with it. I have personally found that it is better to be in the former group than the latter ...