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Why was simultaneous SD-HD output stopped?

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by wipeout, May 8, 2012.

  1. May 8, 2012 #1 of 62

    wipeout Icon

    Jul 15, 2003
    Does anyone know the reason Directv has done this? I have a HD tv in the living room and a SD tv in the kitchen. Now the only way to watch both at the same time is in SD. I do not wish to go through the process of buying additional equipment to get around this mess. Does anyone out there know why this has been done to the viewers?
  2. May 8, 2012 #2 of 62

    Davenlr Geek til I die

    Sep 16, 2006
    They said it was because the box would be to slow trying to display both resolutions at once.
  3. May 8, 2012 #3 of 62

    KSbugeater Godfather

    Feb 17, 2005
    Well, technically it's still displaying 2 res at once... it's the rendering of both HD and SD GUI (Graphic User Interface, such as the guide, list, even the progress bar) at the same time that would quagmire the processor.

    I've found that I can kinda limp along for short periods of time without downrezzing. The nasty box goes away after a few seconds, so live TV like sports works pretty well if you know the channel number. Even recorded programs could be started on the HD display and then watched from the SD monitor... 30 sec skip does NOT bring up the nasty box, nor does 10 sec replay.

    Having said that, I'd rather have the option to turn the GUI to SD but leave the video HD. The HD GUI looks great but has no operational advantage over the old SD GUI (until they add columns to the guide... HINT HINT)
  4. May 8, 2012 #4 of 62

    hamltnh Cool Member

    Jan 8, 2006
    Maybe it's also related to the recent change that creates an HDCP secure content nag screen if you're using the HDMI connection with any of the analog connections--somewhat related?
  5. May 8, 2012 #5 of 62

    TomCat Broadcast Engineer

    Aug 31, 2002
    You are exactly correct on this one.

    On this one, not so much. Its not that it would be hard on the CPU, its that the DVR does not have the physical capacity to produce both SD video with a SD graphics overlay along with HD video with a HD graphics overlay all at the same time.

    The DVR overlays graphics on video to create the GUI. Since the video resolution may vary both on input and output, it needs scaler circuitry to match the resolution of the GUI overlay to the video resolution chosen at the moment (along with interlace/deinterlace capability).

    Scalers are usually in hardware because they are cheap and ubiquitous and the math is relatively simple and unchanging from a few separate but fixed algorithms, and they also then do not tax the CPU. Another reason they are in hardware is because they have to push (recalculate the luminance, chrominance, and physical position for) up to 63 million pixels every minute. IOW, simple fixed calculations, but a heck of a lot of them in a short time span. Hardware is the only practical way to do that.

    And there are 3 scalers built into the legacy DVRs.

    Scaler #1 is a cross-scaler that is the one that is invoked when "Native" is turned off ("Native" is a 1:1 pass-through). It is used when you want to set an output resolution different from the input resolution. If the input and output rez are the same, it also operates in a 1:1 pass-through mode. It's really there for compatibility with older TVs that might not accept the conventional HD resolutions that have become ubiquitous on post-2004 FPs.

    Scaler #2 is used to scale the graphic overlay rez to the chosen rez of scaler #1, which allows the overlay. If the rez were different between the two, overlay would be impossible. Back in the day of SD graphics, it was typically used to up-rez the graphics to HD for overlaying the HD video (unless the input rez was also SD). With the advent of HD graphics, it is typically a cross-scaler because the chosen rez is also usually some flavor of HD.

    Scaler #3 is a down-scaler, which accepts various input rez configurations and outputs an SD rez. It is there mainly to serve the composite/S-video (if available)/analog audio outputs that make the unit compatible with devices that don't support HDMI or component.

    So there are constantly 3 outputs to support; two are HD and of the same HD rez, and one is SD.

    When the GUI was SD, it was a simple matter to overlay that downstream of the downscaler (since it was of the same rez) which provided the SD output along with the GUI.

    But now, the GUI is HD, which means you can't overlay the SD output without downscaling the GUI as well. To do that simultaneously with an HD main output you would need yet another scaler circuit. But hardware doesn't download over the satellite, so they are stuck with 3 scalers instead of the 4 that are needed.

    So how do you retrofit a DVR that was never designed or built with the hardware to accomplish this? The way they solved the problem was to use scaler #1 to put the video output in a SD rez, which also placed the GUI into a SD rez for the main output (remember, scaler #2 always duplicates the rez of scaler #1 to allow the original overlay). Then they simply send that, SD video with SD GUI, to the SD analog output.

    This skips the step of having to downrez the HD video for the analog SD output, and it also skips the step of having to downrez and overlay the HD graphics separately on top of the SD output, which is the part they can't do with the existing hardware.

    To make it all work without totally befuddling the user, they downloaded a gif or some other graphic still into ROM that can be invoked on the SD analog output whenever the main resolution is not converted to SD. That's the mind-numbingly stupid "your cables are not in HD!" nag screen we have all come to love so much.

    A clever idea, sort of clumsily implemented.

    Bottom line, it is not a matter of them being concerned about the CPU cycles; CPU cycles aren't even in the equation because the scalers are all hardware-based. Its a matter of not having enough hardware scalers on hand to do both HD and SD outputs simultaneously and still have graphic overlays on each.

    I could not agree more. But as you can see from how they do it, having both SD and HD GUIs available would be a retrofit nightmare at best, and probably neither practical nor possible.

    It is what it is.
  6. May 9, 2012 #6 of 62

    wipeout Icon

    Jul 15, 2003
    Excelent information, thank you.
  7. May 9, 2012 #7 of 62

    hamltnh Cool Member

    Jan 8, 2006
    So why not create a nag message that says, "SD Guide is unavailable when receiver is set to HD" at the top of the screen that clears in a few seconds?
  8. May 9, 2012 #8 of 62

    bobcamp1 Icon

    Nov 8, 2007
    The cable Tivos use the same chipset. They have no problem with the GUIs, and can output HD and SD GUIs on all ports simultaneously. HOWEVER, the SD TV output is not scaled from 16:9 to 4:3, so everything looks squished in on the SDTVs.

    It's the same problem, just a different way of handling it. But at least the GUI is shown on the SD TV so you can change it to 4:3. Of course, the HDTV will also change to 4:3, but both outputs support the GUI so you can figure out what's going on and fix it from either TV.
  9. May 9, 2012 #9 of 62
    Stuart Sweet

    Stuart Sweet The Shadow Knows!

    Jun 18, 2006
    The reasons are complex but it boils down to making the menus look as good as possible on a single TV. The overwhelming majority of people use one receiver per TV.
  10. Laxguy

    Laxguy Honi Soit Qui Mal Y Pense.

    Dec 2, 2010
    And as sets die and get replaced, or upgraded just because fewer will put up with any SD, and HD sets are increasingly cheaper (and way smaller), the problem diminishes over time. Possibly fairly rapidly.

    These shorts are for a younger person, wouldn't you say?
    [Whimsical tag line on Sprint commercial. Non-sequitor for amusement purposes only.]
  11. TomCat

    TomCat Broadcast Engineer

    Aug 31, 2002
    Yes, indeed. Why not?

    I posted earlier that it should have buttons for "yes, change resolution to SD for now" or "no, don't change", and then leave you alone for the next 2 hours and automatically change back automatically after a 4-hour timeout with no input from the remote.
  12. TomCat

    TomCat Broadcast Engineer

    Aug 31, 2002
    I think that is an astute observation. Or maybe an "A-Stuart" observation :).

    But is seems to me, anyway, that it could have been handled a little better, even if they were directed by their overlords not to expend a lot of energy on the project (and probably for the reasons you state--SD on a HD box is sort of going away).
  13. Kerry

    Kerry Mentor

    Jul 17, 2008
    bottom line the hd guide(joke) is not wort it. Its slow as mud and ruins my experience waithig around for it to work. and all the changing back and forth is a tee total pain in the ass direct tv can take a very fast hr31 and turn it in to a copy of a suck hr21 with the hd guide. ahh the miricals of tecnology. righ out of the stone age.
  14. allenn

    allenn Icon

    Nov 19, 2005
    D* could fix the firmware, but my bet is the future DVR models will have only the HDMI output port. This is merely conjecture based on output ports disappearing starting with the HR20 which lost the RF output. Best wishes!
  15. bobcamp1

    bobcamp1 Icon

    Nov 8, 2007
    SD on an HD box can't go away! I live in an MPEG4-local area! I can only use HD boxes. Please don't forget about us!

    Simply put, the box is deigned to work with just one TV (although the manuals aren't clear about that, and the installers will do anything if you pay them under the table). There are other providers who don't have this issue -- mainly most of them except D* and Tivo. Dish actually touts this feature. So if it's important, I'd start looking around.
  16. Jon J

    Jon J Grouch Extrordinaire

    Apr 22, 2002
    Music City, USA
    FYP. ;)
  17. jes

    jes Icon

    Apr 20, 2007
    The "box" is designed to work with simultaneous A/V outputs. All outputs are on and display/supply a signal, all the time. AFAIK, in the past, D* has never said this is an unsupported feature. Many of us have set up our systems to take advantage of the feature. It was not until the HD GUI "update" that this started to be a problem with video output. It's a D* software decision.

    Would you still be so accepting to this attitude if say the analog audio output presented an audio message, "Please connect your audio system using a digital cable or turn off Dolby® Digital", every time the audio was digital? :eek:
  18. RBTO

    RBTO Legend

    Apr 11, 2009
    +1 to that !!!!!! Pointy-haired boss decision????
  19. TheRatPatrol

    TheRatPatrol Hall Of Fame

    Oct 1, 2003
    Phoenix, AZ
    And obviously that wasn't the case as some of the boxes are still slow. ;)
  20. ThomasM

    ThomasM RF Engineer

    Jul 20, 2007
    Milwaukee, WI
    I disagree and the zillions of posts just here on DBSTALK from people complaining about this same issue seem to support my opinion. Why pay $6 a pop for more "boxes" when many households have many rooms (and TV's) but not that many TV watchers?

    I have many friends with DirecTV and other TV providers and each and every one of them watches the output from a receiver/cable box on multiple TV's using RF remotes or IR senders to transmit the remote control signal back to the "box".

    In fact, I watch the output from one of my R15's on THREE different TV sets!

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