Consider a TiVo or other personal video recorder (PVR) attached to your TV. If something should happen tragically to one of these devices, such as system or hard drive failure, it’s certain that any recorded content on the device will be lost (once you finally get it back from repair). From a broadcaster’s perspective, the content on such devices is transitory and not permanent (even though many people tend to keep recordings around for a long time). This is especially true for protected content, where a protection scheme (DRM) is used to lock the content to that specific device or limited other devices within a home network. For these dedicated consumer electronic (CE) devices, users tend to expect loss of their recordings should some evil befall the unit.

Now consider a Vista PC with digital cable tuner (generically referred to as OCUR). Just like a PVR, content recorded and stored on the PC hard drive is considered transient by broadcasters. Unlike stand-alone PVRs though, a PC is much more susceptible to system failures (although hopefully this is much improved with Vista) because of buggy software, viruses, etc. where end users might re-install the OS to recover from a poor state, or even worse have to replace a major component like the motherboard. Just like a PVR, if a Vista PC enters such a tragic state, all recorded content will be lost.

Some specifics are in order:

• If your content is on a hard drive that crashes, you can’t do anything about that anyway. Your recordings are gone. This isn’t an area where I expect users would be surprised to have data loss.
• If you re-install the OS, even though your recorded content is on another drive or partition, your recordings will be worthless
• If you replace your motherboard (of course with one from your OEM that supports OCUR), even though nothing else about the system has changed, your recordings will be worthless.
• Replacing the processor, hard drive, RAM, or other system components will not impact your recorded content.

The reason your recordings will be worthless is because the process used to protect the OCUR-recorded content is based in-part on the system security identifier (SID) and is also tied to the OCUR capable motherboard BIOS. Hence, if you re-install the OS, the system SID changes and all bets are off. Likewise, if you change the motherboard, the BIOS also changes, so all bets are off.

I personally do not know all the detailed CableLabs legal requirements for a certified Vista PC, but not being able to recover a DRM key in a limited secure way is a problem for PC users. Heck, Vista has a built-in backup program that users likely expect can recover their recorded TV, but doesn’t (make note: your recorded TV files *will not* be backed up by the Vista backup application). Take for example the BitLocker feature which makes use of a secure Trusted Platform Module (TPM) built on to certain motherboards to encrypt the entire OS file system. This solution enables users to backup the necessary keys to Microsoft’s online Digital Locker for recovery. A similar solution for DRM keys seems within the realm of possibility (but again, I am not sure of all the intricate legal details). While Vista provides a parity experience to a TiVo in a system failure situation, as I’ve said before, I believe Microsoft has a responsibility to ensure these scenarios make sense for PC users and not just accept how things currently work in existing consumer electronics offerings. I suspect, though, that folks within eHome are thinking about this for improving the experience over time. I hope so anyway.

What do you think?

I’ll be in Denver the week of 3/19 - 3/23 for Digital Living Network Alliance (DLNA) meetings. If you’re in the area and want to shoot the breeze, let me know.

Meet Heather (left) and Jennie (right); I have no idea who that guy in the background is. While it may appear so, I really don’t have them in a headlock

I’ve seen a couple sound cards on the market that incorporate two sound processors, one for decoding a premium digital audio bitstream (Dolby Digital for example) and handling the digital-to-analog (D/A) conversion, and another for encoding the analog output of the first processor into various formats like MP3 or WMA. In effect, these cards rip the track by using the analog loophole of content protection schemes, whereby the then non-protected premium audio is directly routed (looped) into an encoder for output into another format. This is generally referred to as transcoding, but the analog piece is the “clever” addition.

This got me thinking about my Demystifying Audio Options for DVD and HD-DVD post and the new lossless 24bit/96kHz per-channel audio formats (this also applies to DVD-Audio and SACD). Because high-quality components are used in these new class of sound cards, and there is no “wire” between the two sound processors, the loss by doing a D/A conversion (then back to digital) would be minimal. Certainly the resultant sound would be better than CD quality. The only interesting thing which I’m not sure any of these solutions provide, is maintaining channel separation (surround sound rather than simple 2-channel). WMA for example supports up to 7.1 channels, and Microsoft provides freely available tools (and APIs) for combining multiple discrete channel PCM files into a single multi-channel WMA file. Assuming there are no legal restrictions I am not aware of, it wouldn’t be much of a stretch to produce a solution which:

• Removes DRM for discrete multi-channel audio output
• Decodes lossless audio bitstream into multi-channel PCM
• (via analog loopback) Encodes multi-channel PCM into multi-channel WMA

While it may be possible to do something like this using the analog loophole to get better-than-CD quality sound, at minimum, licensing of the premium audio codec (decoder) would be necessary. If everything was to be done in hardware on the card, the WMA (if WMA was the format of choice) encoder would also have to be licensed.

The value for all of this? DRM-free high-quality sound. I do what to share a couple important thoughts though:

First, content owners have the option of specifying in the digitally encoded bitstream that a copy-protected output is required, i.e. no analog output. This is common for video, but I’m not certain whether this also applies to premium audio. Speak up if you know. If such a flag exists now or in the future, if this new class of card ignored it, that would be illegal. Second, if licensing of the decoders/encoders is happening already to make this solution work (legally), why not just skip the analog hole, which will likely be plugged in the future anyway, and do a complete digital transcode? Heck, I’m betting the majority of folks (who are high-end audiophiles anyway) would also settle to have Windows Media DRM (WMDRM) applied to the resultant file to get access to a lossless multi-channel WMA file that they can play back from any Plays-For-Sure device (that understands the WMA lossless codec) or Media Center Extender connected to a surround sound system.

Am I off my rocker or missing something important? Something like this could really make DVD-Audio or SACD relevant again (or maybe just online music marketplaces could sell these multi-channel tracks for a premium). There is a precedent for this already in the HD-DVD specification, it’s called managed copy.

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Lossy vs. Lossless

Throughout this post, I use the terms lossy and lossless, where the former means the sound is not the exact original (has loss), and the latter means the sound is the exact original (has no loss). By way of example, a lossy sound format is MP3 and a lossless format is WAV (otherwise referred to as PCM or Pulse Code Modulation as this is the most common use for WAV).

HD-DVD sound parity with DVD

Both DVD and HD-DVD support the lossy Dolby Digital (DD) and DTS surround formats which have a max bitstream of 1.5Mbps. There are four interconnects with enough bandwidth to output this lossy surround signal from your source player to an audio/video receiver (AVR):

• Discrete analog outputs
• Digital Optical (S/PDIF)
• Digital Coax
• HDMI (which will also carry video)

If the discrete analog outputs are used, the digital-to-analog (D/A) conversion happens in the source player rather than the AVR. For all digital outputs (including HDMI), the maximum 1.5Mbps bitstream is simply sent over the digital interconnect to the AVR for D/A conversion.

The only time sound quality would be better using the discrete analog outputs of your source player would be if the analog pre-amp and D/A converters in the source player were better then in the AVR. This is generally not true except for the higher end players (or you have a poor quality receiver).

High Definition Multimedia Interface (HDMI)

HDMI is a single cable high-bandwidth solution for transporting both audio and video. There are three versions: 1.1, 1.2, and 1.3, with 1.1 or 1.2 being in almost every piece of recent consumer electronics equipment today. 1.3 is brand new and adds some new value, but to be explicitly clear:

YOU DO NOT NEED HDMI v1.3 TO EXPERIENCE THE NEW HD AUDIO FORMATS. Both versions 1.1 and 1.2 support the bandwidth necessary for 7.1 channels of 24bit/96kHz audio (discrete analog outputs is also an option if HDMI is not). For the eager minds, 24bit/96kHz is better than big budget Hollywood films which master at 24bit/48kHz, and ordinary films which typically master at 16bit/48kHz.

Speculation as to why pre-HDMI digital interconnects weren’t revisioned

I’m fairly certain digital optical (S/PDIF) and digital coax were not revisioned to support the higher bandwidth needed for the new lossless formats because a single cable for carrying audio and video is a preferred setup experience. HDMI had this promise already, and also supported a copy protection scheme supported by content owners. While it may have been possible to revision existing digital interconnect to meet bandwidth and copy protection needs, receivers would also have to be updated (hopefully just a firmware update), and consumers would still be forced to connect two separate wires and deal with potential synchronization issues between audio and video. In the end, the value of HDMI far exceeded the cost of not sticking with existing interconnect. If a reader has more background on this, I’d love to hear it.

HD-DVD sound advancements beyond DVD

Unlike DVD, HD-DVD also supports two new compressed lossless surround sound formats: Dolby TrueHD and DTS-HD Master Audio. As a side note, typically the compression schemes used that can still achieve lossless reproduction are a 2:1 ratio (compressed to half the original size). Additionally, uncompressed lossless multi-channel PCM is supported. As fate would have it, there are also two new lossy formats with improvements over Dolby Digital and DTS: Dolby Digital Plus (DD+) and DTS-HD High Resolution Audio.

All HD-DVD players are required to support every Dolby format; with the two new DTS HD formats as optional.

Additionally, all HD-DVD players are required to decode all audio formats (including the legacy ones) in the source player into multi-channel uncompressed PCM (so it can be mixed with picture-in-picture and menu sound effects), which is far to big to fit over digital optical or digital coax (in reality, the physical cable has the bandwidth, but the standards which govern how the bits are sent over the interconnect do not support the necessary throughput). The uncompressed lossless multi-channel PCM format can; however, be sent over HDMI (any version) or have the D/A conversion happen in the source player and output over the discrete analog outputs.

So, if any of the new lossy or lossless audio formats are used by the HD-DVD source content (what’s on the disk), and a digital optical or coax interconnect is used, the resultant multi-channel uncompressed PCM is automatically re-encoded on-the-fly by the source player (to Dolby Digital or DTS) to fit over that interconnect. In effect, the value of lossless sound is lost and DVD sound parity is the result. Importantly though, you’ll still get great sound, even if it isn’t as great as it could be.

The only way to achieve full fidelity lossless reproduction of the new lossless HD sound formats (or any of the new lossy HD formats) is to use the discrete analog outputs, or HDMI (remember, you don’t need v1.3).

What’s the confusion around HDMI 1.3?

Simple: the HDMI website clearly says that v1.3 is required for the new HD lossless formats. This is true only in the sense that v1.3 allows for the raw Dolby Digital TrueHD and DTS-HD Master Audio bitstreams, as opposed to the uncompressed multi-channel PCM bitstreams, to be sent over the interconnect. This is extremely misleading. Note that sending the raw bitstream would also require the AVR to support the corresponding decoders, but would have the additional value of enabling product differentiation by higher-end digital components and processing of the streams. At the end of the day; however, whether the bitstream is the raw compressed lossless format, or the uncompressed multi-channel PCM format, the audio transfer is lossless (bit for bit the same audio). Importantly, you don’t have to upgrade your AVR or use HDMI v1.3 interconnect to get HD sound. You could in the future upgrade your AVR and have HDMI v1.3 interconnect for potential improvements by way of processing enhancements, but there is no reason to wait.

Conclusion

• If your AVR has HDMI inputs (and processes the sound rather than simply providing interconnect switching) and your HD-DVD player has HDMI output, you can get benefit of all new formats.
• If your AVR has discrete analog inputs (most do) and your HD-DVD player has discrete analog outputs, you can get benefit of all new HD audio formats.
• If you don’t have, or can’t use, HDMI or discrete analog interconnect, you’ll get DVD parity sound (the HD-DVD player will trans-code on-the-fly automatically).
• Your AVR does not have to understand any of the new required HD audio codecs (remember, the receiver sees a linear PCM bitstream).

Let me know if you have any questions or want me to expand more on the topic.

P.S. Thanks to all the bright folks at Microsoft who helped me understand all this voodoo.

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The editor of Linux Today wrote a fabulous article about The Next Hurdle for Desktop Linux being HD. I highly encourage you to first read my post about The Real Deal on Vista’s HD Restrictions to better understand the requirements, then the above article. In short, the key points of this article are:

• The Feb 19, 2009 US deadline for moving from analog to digital broadcasts is quickly approaching, creating a vehicle for the nascent HD content market
• PC users also want access to HD content (or be a hub for whole-home distribution)
• Video card manufacturers are signing-on to support industry *required* DRM schemes to enable premium HD content on the PC platform
• Lack of revenue from Linux users doesn’t provide incentive for video card manufacturers to author native Linux drivers
• Without DRM, content providers require down-res of content (from HD to SD)
• Software in-between the video card driver and display must also support protecting the HD content, and hacks to bypass content-owner restrictions are illegal
• GPLv3 places restrictions on DRM use, which may inhibit end-to-end solutions

The Linux Today editor who authored the article says it best:

Looking at the future of digital content, will the GPLv3 forever keep Linux relegated to servers and older machines that don’t have HD video requirements?

I am confident the open source community will step up to this challenge, hopefully in a legal manner, but it will be interesting to see what the impact to GPL will be.

What do you think?

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I recently read this article titled A more secure OSX before Leopard, aimed at hardening the default installation. The important thing to me about this article is that each approach taken to harden OSX Leopard is what Windows Vista employs out-of-the-box.

Operate as a non-root user:

Windows Vista by default employs User Account Control (UAC) to address this issue. In past versions of Windows client, the default user has administrative privileges, but in Vista, even administrator is not a true administrator without user elevation for certain system operations. The process for creating a new non-root user in OSX is not without pain, but a step in the right direction. And, what do you know, the new non-root user is prompted for root credentials whenever certain system tasks are attempted, much like the default Vista behavior.

Enable the network firewall:

If you can’t find the firewall configuration in OSX, that’s because it is non-intuitively placed in the sharing preference pane. The author points out that even if you enable all of the options, you still have some work to do using the command-line ipfw tool. Not consumer friendly. Apple has not innovated at all in this area, and the default firewall settings do not provide consumer-friendly insight to end users, but enabling the defaults is definitely a step in the out-of-box Vista direction.

User comments to the article provide other valuable information for making OSX more secure, so I encourage folks who aren’t booting their MacBook into Vista to take the steps to be more secure.

Windows Vista does do a good job of being secure out-of-the box, but looking forward, there is a lot of work ahead to improve/balance usability in the face of such security improvements.

Quite simply, those of us who have built our own MediaCenter PC are out of luck when it comes to CableCARD; at least for the near future anyway (I’ll get to this later). Vista has shipped, but there are no OEMs offering CableCARD support for their MediaCenter offerings yet. This is mostly due to the heavy weight CableLabs certification process (which I won’t get into in detail). So what are your options for getting CableCARD for premium digital cable (including HD) in the near future?

(1) Purchase a Vista MediaCenter PC today from an OEM who promises you an upgrade path (make sure it’s in writing too). Note that I’m not aware of any OEMs who have explicitly said they provide an upgrade path for customers who have purchased a Vista-Capable logo’d PC. In all honesty, while it may be possible for an OEM to get CableLabs certification for a particular MediaCenter PC model that was shipped prior to general Vista availability, i.e. with a Vista-Capable logo, I’m not sure whether this will happen or not. My feeling is that if the option is feasible, only the most customer caring OEMs will do so due to the significant cost of certification (note that this certification cost is per unique system). If such a loving OEM does exist, the process would have to be one of the following:

• Purchase a Digital CableCARD Tuner from them when they become available, and download the necessary system updates that enable the digital tuner to work. Of course, you would have had to install the Vista upgrade first.
• Send your MediaCenter PC back to the manufacturer for all necessary upgrades.

The second option seems the most feasible considering that OEMs likely don’t want the system updates getting distributed illegally (not that I’m sure option-2 would thwart such a thing anyway). This option does have considerable cost though, both monetary for shipping the PC, and in terms of customer loyalty because they’ll be without a PC for some time. This option will likely only happen for an OEM that has sold a lot of these MediaCenter PCs and are willing to cover the costs to slightly ease customer pain. My intuition is that I doubt either will happen, but we’ll see if an OEM steps up to do the right thing. 

(2) The other option is to wait for OEMs to start shipping their CableCARD ready machines. This will probably be in full swing within the next few months. Obviously, this option has less unknowns and is the safer bet.

Let me know what you think about all this, and considering the restrictions, what OEMs could do to make you feel better about whatever decision they make. Also, if you have any thoughts other than “there shouldn’t be any restrictions”, I’d like to hear them.

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