A Brief History of ATSC in Media Center

In the beginning there was NTSC in Freestyle (Media Center 2002), and it was good.  Media Center supported the #1 market and proved that computers could do a great job recording television, pausing Live TV, and organizing recordings.  With support for one tuner under our belt and an enthusiastic user base, we moved forward with Harmony (Media Center 2004) to a more mature, flexible and polished product that supported dual NTSC or PAL tuners, opening up the European, Asian and Australian marketplaces.  A few intrepid souls figured out how to hack together ATSC support into Harmony using little-known interfaces and scarce hardware like the VBox 110.

Between the release of Harmony and Symphony (Media Center 2005), ATSC demand increased by leaps and bounds, though still smaller than the NTSC base by far.  To this day, only a very small percentage of Media Center users actually use ATSC, although it's a matter of some discussion whether that number is small because the number of HDTVs is small, or because Media Center's support is... less than optimal.  In any case, by the release of Symphony the user community was clamoring for ATSC support without hacks, and was disappointed when Symphony shipped without it.  An update quickly followed, though, and Symphony Rollup 1 with HDTV Support was released as a free update through Windows Update and the Microsoft Download Center. The changes in Emerald (Rollup 2) and Diamond (Windows Vista) did/will not not substantively change the architecture of ATSC, so what we have today will more or less be the way it works for another couple of years.

••• design decisions

When we (speaking in generalities here, since I was not a member of the team at the time) first investigated how to include ATSC into the product, there were several major hurdles standing in the way.  The first was a consequence of our decision to use the VMR (Video Mixing Renderer) instead of the deprecated Overlay Mixer for rendering video.  Overlay rendering differs from mixing in the way that video is prepared for display.  In overlay mode, the video is literally painted over the top of whatever else is being rendered.  In mixing mode, "surfaces" with video or other graphics are blended together, either in software or hardware-accelerated, prior to rendering on the monitor.  The advantage of mixing mode is greatly increased flexibility in what you can display at the cost of performance.  It takes a lot more horsepower to process all those pixels, especially with alpha (transparency) and 3D effects.  99% of the video hardware on the market today uses a form of overlay mode, which drastically reduces the hardware requirements (e.g. no 3D hardware required), but hamstrings them when viewed side-by-side with the sort of effects you can get with mixing.  The semi-transparent menus on top of video that you see in Media Center that give it such a cool look are just not possible with overlay mode.  All that alpha blending and those 3D effects come at a hefty cost, though.  Media Center has to work many times harder to get the video to the screen, even when no special effects are on-screen at the time.  That, in a nutshell, is why Media Center requires not just an OK video card to shine.  And a faster CPU.  As a result of the increased power needed to render video, and with the hardware available to consumers in 2000-2002, it wasn't really feasible to offer HD with the first couple of releases.

Even if the video could keep up (which it could on higher-end systems, even in 2002), there was another difficulty: Guide data.  The problem is that when you get multiple lineups (the term we use for the programming information associated with the set of channels available on a given medium in a geographical area), merging them into a single lineup and making it easy for the user is not an easy solution.  The decision was made to punt it until demand was increased, and to stick with a simpler homogenous lineup, rather than the more advanced heterogeneous lineup that would be required to support both NTSC and ATSC on a single system.  The market of people that have more than one TV provider is, after all, not that large, and we wanted to get it right for the most people we could.

••• support for ATSC gathers steam

A vocal minority of the user community, along with a large majority of the eHome TV product team, were not pleased with the lack of support.  We got the funding to put ATSC in the product, as long as we could fit it into the schedule and without major risks to the architecture of Media Center's TV and PVR functionality.  With compressed schedules the norm, and the development and testing staff already deeply into a bad work/life balance, many options were considered for getting ATSC out to users.  What was finally implemented is a good first stab at doing it, with a few facets that are, um, less than what we'd like them to be.  Since we did not have ATSC-specific listings available through our Guide data provider for many, many areas, we looked instead at reusing the data available from existing analog lineups via "mapping".  Since ATSC channels are in a completely different format (like 13-1 or 9-5), and to avoid putting a new button on the remote (requiring a redesign), ATSC channels are renumbered in the UI.  The scheduling/PVR conflicts were just ignored, leaving it up to the user to say "only record this channel", omitting support like "record this in HD if you can, but get it in SD if not".  The end result was a pseudo-heterogeneous lineup support that we have today.  You do get the additional ATSC lineup merged into your Guide, but the analog source is still required--you cannot have ATSC without NTSC today.

••• the current state of things

During First Run (the initial Media Center setup wizard), or TV Signal Setup, we detect whether you are in a region that supports ATSC, and then detect if you have a compatible ATSC card installed (or for Emerald, up to 2 ATSC cards).  After configuring your SD tuner, ATSC is configured as an adjunct to the "primary" analog tuners.  If you choose an analog, sans-STB (set-top box) cable lineup for your analog tuners, then that data is what's available to ATSC to map to its channels.  The same goes for satellite or OTA (off-the-air/broadcast) lineups.  Only with digital cable lineups do you usually get the full Guide data to assign to your ATSC channels.

To assign listings to the ATSC channels in the lineup, we run a heuristic match against the available channel metadata, and try to get a "best-fit" match for existing channels to the new ATSC channels.  For example, if there is a channel "KOMO-DT" in the primary lineup, it can be matched to the known ATSC channel KOMO-DT on 4-1.  In some areas, the match can't be made automatically, but you can go to the Guide settings (Settings-->TV-->Guide-->Edit Digital TV Listings) and manually associate the listings of an existing channel to the ATSC channel.  Basically what you are doing is saying "this channel that exists on my "primary" lineup has identical programming to that ATSC channel".  It works best with digital cable lineups because they carry all of the local OTA ATSC channels on their networks (due to Federal must-carry laws).  To get the minor channels (where the "minor channel" > 1, e.g. KCTS-DT2 on 9-2 in Seattle), you have to add them to your lineup manually using Add Missing Channels, and then map them to listings using Edit Digital TV Listings.

The end result of all of this is a unified lineup that can be presented to the user in a single Guide grid.  ATSC channels are assigned numbers like 1041 for channel 4-1, and slotted in where they fit best.  If your primary lineup already has a channel 1041, we look for another block of numbers to put the ATSC channels.  A side-effect of this is that if your primary lineup is changed--like if Comcast decides to add a channel 1000 to their lineup--the ATSC channel numbers may get reassigned to another empty block.  Personally, I'd like to implement a better solution, but as I've said before, we Americans are unnaturally attached to our channel numbers.  Most would just give you a blank look if you suggested that we don't even really need channel numbers at all.  Not when you have a good enough search/filter mechanism, anyhow.

••• the days to come

For the Diamond release, we have announced support for OCUR (OpenCable Unidirectional Receiver) tuners, which will allow native tuning of digital cable signals, with CableCard support (for premium channels like HBO).  This includes HDTV signals, which should be good news to most users.  More people pay for TV service now than don't, and if you own a Media Center, you are about 20 times more likely to have cable or satellite service than not.  Roughly.  OCUR support probably means (definitely, for Diamond) that we won't be supporting heterogeneous lineups anytime soon, which is a shame, but hard to make a business case against.  Why spend time and treasure on something that most people won't use, and could possibly destabilize the entire product?  That's a little hyperbolic, but the onus is on the people who want the feature to justify it.

We announced a deal with DirecTV where we will directly support their newest STB in Media Center, just like--or very similar to--the OCUR does with digital cable.  The field is finally opening up and we're getting to a point where we can offer our users very attractive options for "traditional" TV services.  The European market, or more precisely, the non-U.S./S.Korea/Japan market, has already standardized (for the most part) on a fairly sensible broadcasting standard--DVB--which we are improving our support for with every release.

Non-traditional video services are also booming in popularity, with Online Spotlight partners offering more movies and other multimedia content for free (in many cases) or on an ala-carte basis, directly competing with PPV services offered by traditional TV providers.  Apple has changed course on its "we'll never get into the PVR business" policy with iTunes video (and their toe-dip product Front Row, which is a pretty spiffy little QuickTime automation script), and The Market is scrambling all over itself to get on the bandwagon.  Internet TV is coming, just as soon as we (as in "we the market", not necessarily "we at Microsoft") figure out what Internet TV is.

Comments (26)
  1. Ian Dixon says:

    Great post, good to see that DBV support is going to be improved

  2. Stuart Anderton says:


    A real shame that Diamond (that’s Vista, yes?) won’t support heterogenous lineups.

    I’m in the UK, and a very common scenario here is to use MCE with a Sky TV STB. As they charge extra for a second box, many folks would like to combine an analogue card connected to their Sky box with either a DVB-T card or a second analogue card connected to normal OTA TV to allow dual recording. Many of the most common channels are in common between the two.

    I can have two different sources connected to my TiVo with no problems (I can only record one at a time) but the EPG is fully integrated, and it’s annoying that I can’t do that with MCE.

    There seem to have been a few unfortunate design decisions taken with the EPG from a completely US perspective without realising how it world work in the rest of the planet. We still don’t have a fully working EPG here in the UK, partly because of the problems stretching a structure designed for US cable tv to our system. Sky TV are about to do a complete channel renumbering, and on past experience it will render MCE boxes useless for weeks – we have our fingers crossed though!

  3. Josh says:

    I am in a definite minority. I have Cable, DirecTV and ATSC.

    I originally had DirecTV and a cable modem for internet service without any cable TV. But they my cable modem provider decided to tack on a $10 charge per month if you didn’t have any TV service. Basic cable was $11 per month. HD with a cablecard was just $6 more. So, I could either pay $50 per month for just the cable modem or pay $57 per month and get cable TV service with HD and the cable modem. No brainer.

    But I couldn’t record HD. My TV has a cablecard slot, but no way to record it.

    Enter ATSC (ATI HDTV Wonder) and Media Center. I only use Media Center to record HDTV, nothing else. I have 2 Tivos to record DirecTV SD (HD isn’t worth it with DirecTV just yet). I happen to live near Boston, and the ATSC channels are fantastic. If only I could get the guide data for 2-2 (PBS-HD) and 44-2, 44-3, and 44-4 (WGBX stations).

    I was getting PBS-HD guide data via a cable operator in my state that happened to carry it. That is, up until the release of Rollup 2! After that, the ability to map a sub-channel to a channel that is different from the main channel completely disappeared! Oh, it looks like you can. But the data never shows up in the guide. So, despite mapping 2-2 (1022) to PBS-HD on Comcast Cable, it still manages to give 2-2 the same guide data as 2-1 (WGBH).

    Guide support for sub-channels isn’t just bad, it actually got worse with the last release. Please fix this bug quickly! 🙂

    I would love to unify my recording using Media Center to record ATSC, DirecTV and Cable via a Cablecard. Bring on Fiji, and don’t forget about those of us with multiple services!

  4. ShapeGSX says:

    A bit more info. For some reason, Zap2It is horribly slow at adding channels to lineups. In addition, they frequently get the incorrect guide data for new channels. But there seems to be no way to get it fixed. I’ve emailled them over and over, but it still isn’t fixed.

    For example, go to http://www.zap2it.com and enter zip code 01602. Select Charter Digital. Now go to channel 782, which should contain guide data for WGBH channel 2-2, which is PBS-HD. Instead it contains the same guide data as analog channel 2, which is completely wrong.

    And, if I am not mistaken, this is where Media Center gets its guide data, correct?

    If I bought a box such as the new LG LRM-519 PVR Media Center recorder and had no recourse to get guide data fixed, I’d be more than a bit angry.

    Don’t get me wrong! I love Media Center! But the unfortunate fact is that hacks around the guide data really limit its effectiveness.

    Incidentally, I see that a fix is coming for sub-channel mapping. Thank you! But why is it taking 6+ months for us to get it? 🙁

  5. BrettRobi says:

    Excellent post Peter. I love this kind of background. It allows us bitchy end users a little more insight into the decisions made by MS that we all live with. A little understanding goes a long way.

    Great stuff. Keep it up…

  6. Griffon says:

    I still don’t see why a legacy, physical, analog card is needed though, the system really should just be able to lie to it’s self to enable a digital card directly. Or like in the case of Fusion HDTV USB device that do both just leverage that, usb tuner add-ons are really fast growing aftermarket segment.

    Come on, your guys data is pretty sketchy as far as what people are actually using to capture with… MCE can’t be bought directly but most OEM’s are selling with tuner or some other piece of hardware, so you have no true clue what most home brew folks are buying to make it all work… Many of the largest channel partners, HP etc sell the boxes with NO tuners, creating a huge market for simple, no box opening, add-ons… yet to use them somebody has to crack the box to stick in a crappy analog tuner? Come on, this is just bad legacy design and needs to be cleaned up. It’s just a little shameful that vista (diamond) is shipping in this same sad state.

    Also not to put to fine a point on it but Nealson still says most of America get’s their cable OTA, not through cable, or satellite. As ATSC tuners in plug and play format, that can also do analog, become much more common, even standard, so will the demand. Why not be ahead of the curve?

    It’s likely to be a good while yet before folks can go get those cable cards, and longer still before DirectTV rolls out anything. These providers do things measured in decades, they HATE change that doesn’t make them a buck per transaction, your rush will never be theirs, so in the short term you guys should throw the rest of us a bone and dump required analog support. Sadly of course none of this is your direct call , just saying…

  7. Jason Pearce says:

    I live in the UK. In my region, terrestial tv signal (both analog and digital) is extremely poor and unlikely to improve.

    I wait in eager anticipation for proper dvb-s support – I have a firewire dvb-s tuner, I just can’t use it with MCE 🙂 – its the one key missing piece for me

    Free to air support would be a nice starter ….

  8. Mark G says:

    Nice article.  However I live in anada and receive a large of atsc channels over the air.  Microsoft made the unfortunate decision to disable HD OTA in Media center for 2005.  Certainly at the time this made sense.  No canadian broadcasters were utilizing atsc.  Things have certainly changed in 2006.  HDTV sales have exploded.  Most canadians are able to receive numerous atsc channels of both canadian and american origin.  Please MS enable OTA DTV for Canada.

  9. Joe says:

    Could you possibly provide a little more insight into the DirecTV deal?  Is a "tuner card" a possibility?  Can Vista’s secure path be used to secure the signal off the PCIe bus?  Would that then pave the way for a PCIe sat. tuner that would take a DirecTV smartcard?  If not, are we looking at something akin to a USB or 1394 connection to the box to exchange data?

    One would think it would be wise for DirecTV to support Vista MCE with a tuner card.  They currently subsidize so much of the STB expense that transfering that to consumers via OEM or even BYO HTPC builders seems to make great business sense.  Those users also probably correlate very highly with valuable subscribers and are likely to lock in to long subscriptions to validate their HTPC investment.

  10. GBK says:

    Although I  understand the reasons it’s too bad that Vista after being delayed so many times is still going to be a patch up job for the Media Center.. I might just have to forget about getting it now that I know it won’t offer anything new at all. by not having the guide data correct you can never record PBS because of their 3hr delays… I agree with Griffon there is no need to have analog junk in the system you’re using the crap guide data anyway so what’s the difference what card is in there as long as at least one tuner is?

  11. PeterRosser says:

    Joe – I cannot comment on the deal, since a) I’m not actually privy to the details, and b) if I *were*, I couldn’t share them.  What was announced at CES is all that is public at this time.  The business guys are working all the stuff out… I’m just a lowly developer.

  12. PeterRosser says:

    GBK – Vista is going to offer a ton of new stuff, including Digital Cable + CableCard support.  Have you seen the screenshots and demos?  You can get in on the CTP and run it for yourself free to get a taste, too.  Vista is going to be sweet.

    Even if you weren’t going to get Vista specifically for the Media Center changes (although for me that would probably be enough), it’s got so much more going for it that for anyone who uses their computer more than a little bit it’s a no-brainer.  LUA as default (more secure), Aero Glass (3D acceleration everywhere), user-mode sound with per-application mixing (finally! the sound stack can’t crash Windows!), Avalon GUI engine (cooler-looking apps), smart folders, Windows Explorer rearchitecture (wait til you try the new navigation UI… it rules), Windows Search (about time it was included in the OS), SideShow and better Away Mode… there’s tons more.

    Just in the tiny little corner of Windows called Media Center we have smart thumbnails (not just the first frame of video… we ANALYZE the content to find a "good" frame to use), support for more tuners (lots more… can you say dual 4-tuner cards?), totally reinvented UI that’s easier and faster to use, mini-guide, PIP, auto-favorites, the list goes on and on!

    Sure, we wanted to support more standards, but that stuff can get added in when the business deals are ready.  People say "why don’t you support X?", and most of the time it’s because someone else owns the patent or copyright on it already, so we need to partner with them to get permission.  There’s a lot of scrutiny on everything we do, so all the I’s have to be dotted, and the T’s crossed, or the big bad ** Commission (name ommitted because I’m paranoid) will try to slap another huge fine on us.  Or we will lose the partner.  Or both.  So we’re working on it, okay?

    Everyone on the team wants it just as badly as you do.  We live and breathe this stuff, and it kills us to not directly support everything right now.  The reality, though, is that short of breaking the law there is no way for us to do so.

  13. Griffon says:

    In what way exactly would you be breaking any law to support OTA HD directly :)?

  14. GBK says:

    Peter, are you saying that I could run CTP now and have HDTV tuner support? does Vista have AverMedia A180 driver built in? if not point to someplace that does and I’ll gladly try it until then it’s all vaporware and we have to believe what you say which of course is subject to change.. 🙂 just like WinFS etc that was supposed to be part of this 6 yr in the making OS.

  15. GBK says:

    Oh I forgot to say how is using NTSC in Vista a good thing?  NTSC is dead end of life in 2009 (would have been in 2007 if it weren’t for idiots in Congress) your OS should be future looking instead we’ll have to depend on a service pack that will most likely break everything since it won’t be done from the ground up but rather another patch.  Or are we going to have to buy a whole new OS by 2009 only 2 years after Vista?  btw I may not be eloquent with my words but I do know how much works goes into developing something like this which is why the choices of NTSC do not make sense to me at all.

  16. PeterRosser says:

    Griffon – We wouldn’t, of course (except for the RRT stuff, which is silly IMHO, but that’s another topic).  I was referring to support for satellite.

  17. PeterRosser says:

    GBK – It does have HDTV support, but unless you use an OCUR tuner you still need the NTSC tuner to bootstrap the ATSC.  I think that the OCUR is still very much under tight control by the cable co.s, so getting one might be tough.

    I’m not sure whether the AverMedia A180 is in-box or not, I’ll ask the driver guy in the next-door office.  Even if the driver isn’t in-box, I know they’re on the matrix and should work.  The driver model for tuners in Vista is pretty much the same as XP (unlike graphics cards).

  18. PeterRosser says:

    Responding now to GBK’s 2nd posting there 😉

    NTSC is *not* "dead" in 2009 by a long shot.  It’s only dead for OTA broadcast.

    We have not announced what we plan to do about sans-analog ATSC support in Media Center.  Just speaking technically, it can be done with a moderate amount of work.  Whether it makes economic sense to do so, that’s what mgmt needs to decide.

  19. GBK says:

    Thanks Peter.  

    If A180’s are in-box I will give it a try.  I think the only reason I can’t test the parts I want is because of lack of drivers support which is obvious for a beta OS but I go off what Peter Thurrott saw and posted on his site.  Sorry I’m picking on you but the whole NTSC tuner thing is silly in my opinion as a requirement for ATSC tuners.  How is this going to work with OTA? NTSC for OTA goes away what is going to fill in the guide data if I choose not to do cable (no way I’m paying them for 15 home shopping networks)? and having NTSC tuner in there when there is no need (in my case) just takes up a slot which I wish I could put a 3rd HD tuner into 🙂 Also the OCUR tuner will require CableLabs Certification correct? which a home built system will never be able to get.. So it ticks me off as a consumer I don’t want to buy a Dell etc with their junk support and hardware… basically I’m stuck OTA and IPTV unless I choose to pay 3 times for a machine that has inferior hardware then what I can put together.

  20. PeterRosser says:

    Here’s an update on the in-box drivers situation:

    We have not announced any of the tuner drivers that will be brought "in-box" for Vista, so I cannot tell you what will or will not be shipped alongside the OS.  What I *can* tell you is that tuners that do not have in-box drivers will still likely have Vista-compatible drivers.  "In-box" just means that the drivers ship on the same CD as Windows, and get updated via Windows Update.

    For comparison, *no* tuner drivers are in-box today.

  21. GBK says:

    Thanks Peter; for the in box driver support I meant it more for testing. I know that vista won’t support *all* tuners (any) out of the box. I don’t believe we can get our hands on any tuner drivers out there now so testing Vista’s MCE is essentially impossible at this point. Also heard rumors that 5270 build expired MCE portion on Jan. 1 Then the next CTP on Feb 17 or so… if it had some rudimantary tuner support it would be possible to test otherwise the general public can’t test it very well.

  22. toadmazter says:

    I’m a little late in participating on this topic, but wanted to throw my comments/question in.

    I am *ALMOST* a 100 percent satisfied MediaCenter customer.  I have a dedicated MCE 2005 "server" with a dual analog tuner and two FusionHDTV5 Gold cards. I use two (soon three, once I find one more) XBOX360’s (one per TV viewing location) as extenders to watch and manage content.  My remaining frustration is the lack of true ATSC support in MediaCenter.  As an example, I can not get MCE to tune my local CBS HD affiliate.  But the software that comes with the Fusion cards displays it great!  After countless hours of research, driver tweaks, and conversations with CBS engineering, we have determined it is a PSIP issue at the station… but nobody can tell us what the issue is and it remains broken.  Every other OTA ATSC settop box known to man works… just not MediaCenter.  Can you point me to some helpful info that I can provide the CBS engineers?  This is the last issue (I even have DVD’s streaming to my 360’s to my wife’s satisfaction) I need to resolve before I can return my Comcast HD DVR’s.  

    Thanks for reading!


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