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Multiple input streams to HTPC

Discussion in 'Desktop & Laptop Computers Forum' started by Jagsta, Apr 9, 2003.

  1. Jagsta

    Jagsta
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    Hi,

    I'm considering my options at the moment regarding a HTPC. What i'd like to achieve is to channel all my inputs (STB, DVD,STB2) via the PC, render the stream as I want it displayed (progressive scan output into VGA module of a loewe tv PAL/NTSC), whilst providing me with digital recording etc.

    I haven't decided on the platform yet, i'd like to do it in Linux, but i think I need dscaler, and I don't fancy porting it!

    My question is how best to take more than one input stream into the PC, or is this not easily done without switching boxes/unplugging things? Are there graphics cards or addon cards that I could use to accept more than one input?

    I guess that S-video is the likely candidate for the input.

    Thanks,
    Jagsta.
     
  2. owain_thomas

    owain_thomas
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    You could use the svideo switching of a HC amp to do this into one svid input on a capture card (assuming you are using a HC amp with svid switching ;) )

    Owain
     
  3. Jagsta

    Jagsta
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    Thanks Owain, this is soemthing i've been looking into this morning. I have an old Yamaha DSP-A590 which has s-video switching, so this is definitely an option it seems. Shame I don't use it for audio anymore!
     
  4. owain_thomas

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    Other ways of doing it might be:

    Using multiple versions of the same input card (capture card) would add extra physical inputs, but I think this may well be a "more hassle than it's worth" way of going about it. Not tried it myself though, so might be worth a look.

    A card like the HOLO3D has both component and svid inputs which might give more flexibility, but costs ~£600 for the card alone.

    what type of amp are you using for your sound at the moment?

    Owain
     
  5. Jagsta

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    I've moved onto integrating my existing hifi into my AV setup. I have a Musical Fidelity X-A2 Pre/Power Amp, and X-Ray CD Player and a pair of Dynaudio Audience 52 speakers (a truly outstanding speaker IMHO). The 5.1 output from DVD player/PS2 is going into a yamaha DSP-E800, front pre-output to the existing hifi, rear output into wharfedale bipolars, centre is a crappy leftover until I can get hold of a decent centre speaker.

    Eventually I'd like to only use the DSP-E800 for pre-output, and get hold of 3 monoblock power amps, then switch the X-A2 to the rear channels and independently amplify the centre and front L/R. Time and money permitting as usual! My main priority is getting progressive scan input into my Loewe, which means the VGA module upgrade and a bit of work on a PC!
     
  6. owain_thomas

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    I'm using a DSP-800 as well, that has svid switching, doesn't it?

    That would be the simplest solution, have the video inputs matched to the right sound inputs and when you change to the DVD audio input (for example) the svid out will output the right signal to your HCPC.

    I've got a Tosh Tv so I'll be using one of these to send a 720x480P signal to the component inputs.

    Owain
     
  7. Jagsta

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    Doh - yes it does have s-vid switching, what am i thinking! Doing it in this way definitely seems to be the simplest and cleanest solution.

    Thats a nice solution, with the keystone breakout to component. I'm lucky that the Loewe has the VGA input natively, although I am seriously struggling to get enough info about the VGA module to truly know what it is capable of displaying (Conflicting info abounds in this respect). I think that my chassis will support both PAL and NTSC progressive inputs, but this is all a bit new for me atm, so I expect it to be a rocky road!
     
  8. owain_thomas

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    Know what you mean, seems like I've been planning this thing for years now. I'm just waiting (hoping :) ) to see if the back pay I'm dependant on actually comes through. Still the enforced wait has allowed me to gen up on a lot of stuff and avoid some potentially costly mistakes, also the price of stuff is coming down all the time.

    I'm thinking of getting one of these sound cards, the DAC is supposed to rival that in much higher-end stuff than my DSP-800, so might well bring a nice improvement in audio as well as video quality.

    Have a look at this front-end software, it's still not in beta form yet, but is incredibly stable and powerful, it will almost certainly form the main access to my HCPC when it gets a little more functionality.

    Have you had much thought as to what other components you will be going for?

    Owain
     
  9. Jagsta

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    That sound card looks interesting, I think to begin with i'll be ignoring sound from the PC point of view and just using it for processing video. When I buy an internal DVD player, i'll have to worry about this but I had originally intended to simply get a card with digital output for 5.1, then using the existing kit. What you say about the DAC is interesting, although the noise levels in the PC may not be too favourable for audiophile performance?

    With regards to components, i'm just digging into the threads for recommendations, however at the moment my main priority will be to get it up and running, using cannibalised bits of my other PCs, to get a taste of what can be achieved. If things look good i'll start replacing the component parts with those of a better quality. It seems like a minefield to be honest.

    I'd still dearly like to get this going on Linux, from a stability and maintenance perspective, but it seems early days for HCPC on this platform. (Interestingly there is an application called tvtime on Linux which has potential it seems as a dscaler equivalent).
     
  10. Gerbil

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    Jagsta, just for info I've had mine running at

    640x480@60Hz (Loewe quoted resolution)
    848x480@60Hz (with Powerstrip)
    720x576@50Hz (with Powerstrip)

    I think the latter resolution is only likely to work if you've got the newer 2500 chassis. I haven't tried anything else, but I can send you the timing info for Powerstrip for these resolutions if that's any help.
     
  11. Jagsta

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    Gerbil,

    thanks very much for that info - just what i'm looking for.

    I do have a Q2500M chassis on my Vitros, so its hopeful that the PAL resolution you mention will work too.

    The timings would be excellent, if thats ok.

    Also, at the risk (more like a certainty) of sounding stupid, the output resolutions you mention for NTSC and PAL are to output a widescreen format?

    Jag
     
  12. Gerbil

    Gerbil
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    You should be able to paste the settings below into Powerstrips Custom Resolution section

    848x480=848,32,96,48,480,10,2,33,31643,1
    640x480=640,16,96,48,480,10,2,33,25200,7
    720x576=720,43,96,77,576,12,4,38,29484,1

    Since the Loewe doesn't have any auto scaling or seleactable presets for the VGA input all of these will produce a full screen 16x9 image. For the 4:3 resolutions (ie 640x480 and 720x576) you'll end up with a slightly distorted Windows desktop. DScaler can cope though as you can set the aspect ratio of your output display device and if you use Zoom Player for playing DVD/media files you can compensate easily.

    For example I use the 720x576 setting almost all the time. If I'm playing DVDs then I set ZoomPlayer to disable aspect ratio adjustment (fit to window) and things work perfectly. If I'm playing media files (AVIs) etc. then Zoomplayer has an aspect ratio adjustment function which when set can compensate for the fact you're displaying a 4:3 resolotion on a 16:9 device in which case I set Zoomplayer to use the derived aspect ratio.
     
  13. Jagsta

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    Gerbil,

    Finally got my PC up and running last night to try this out. I have a nvidia GeForce 1 card that i'm using to output to the Loewes VGA module.

    I had mixed success with the resolutions you mention above, I was wondering if you see the same things I do?

    At 640x480 the geometry is good, I can center the image using the Loewe VGA Geometry menu.

    At 720x576@50Hz I get a picture, but the geometry is beyond the scope of the menu to repair - I don't know if I can use powerstrip to correct this, I don't seem to be able to

    At 848x480@60Hz the results are similar to the 720x576@50Hz res, except there is less flicker in the image, geometry is still poor though.

    I've tried using both the powerstrip resolutions you kindly supplied and the predefined powerstrip resolutions as there is one defined for both PAL and NTSC progressive, but the results are the same I think.

    Have you had any more success with these resolutions?
     
  14. Jagsta

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    Another thought on this - The graphics card driver will have a difference on the output geometry I think, so it may be worth my while trying the vendor supplied driver for the card instead of the nvidia reference driver. Also a different card might be worth a try, I am considering getting an ATI radeon 9000, as these seem well liked.

    Gerbil - if those resolutions you mention look ok on your set, which card are you using to output to the Loewe?
     
  15. Gerbil

    Gerbil
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    Jagsta

    Sorry to hear you're having problems. I wouldn't say the geometry is perfect via the VGA interface, I can detect a slight curvature in vertical lines that isn't really correctable via the Loewe VGA geometry settings.

    Its possible if centering and width/height are the main things causing issue then you might be able to play with the front/back porch settings under the advanced timing options in Powerstrip. If you do this then be careful and make sure you know the hotkey for resetting Powerstrip back to defaults otherwise you may find the picture goes so bad you can't find the button to undo the changes. I had to play with the settings to get a picture that was centered enought to be correctable with the Loewe controls.

    My previous PC was using a Geforce MX 200 to drive the Loewe and the current one is using a Radeon 9000 so I don't think the card is your issue. I'd play with Powerstrip a bit more, there may be enough differences between our two tellies for the settings to need a bit of tweaking.

    The flickering is always going to be an issue as 50Hz is a low refresh rate for a monitor and shows up badly when running a Windows interface, however I wouldn't expect the flicker to be noticable when actually playing a DVD.

    Edit:

    Just seen your other post regarding display resolutions e.g. 720x576 displaying on a 16:9 screen. I really wouldn't worry, the limitations of the Loewe VGA module is the main problem. If you can get 720x576 working (or 768x576 if you're brave) then you can compensate for the horizontal stretch using Zoomplayer. The latest version even has a handy little calculator. You input the aspect ratio of your display device (16:9 for the Loewe) and the resolution you're driving it at and it calculates a 'Source Relative Stretch' for you which is basically how much stretch to apply to the vertical image.
     
  16. Jagsta

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    Thanks Gerbil, I think i'll have another bash tonight with powerstrip. To be honest I think that i'm being very harsh about the output, with a windows desktop there was noticable flutter (like a waving left and right) on some things, like outlook.The image was bowed at the edges consistently. I'm used to the Loewes other inputs though so it looked bad on first impression.

    I am going to try and evaluate the differences I see between playing back a PAL dvd at 720x576 and at 640x480 display resolution - I would expect the 720x576 image to look better as its the same res as the image encoded on the DVD, but with the geometry I may end up preferring the 640x480. I guess this would introduce stutter problems with the refresh rates being different.

    The only source I have to try at the moment is my PS2 via S-video (composite though :() into a hauppauge wintv-pci card, through dscaler and into the loewe - which is not ideal for comparing the output.

    I'm a little confused about the dscaler settings I need to use - I've set the display to 1.78:1, it autodetects the input res, so is there anything else I need to do with Dscaler to render the output correctly? I assume I then go full screen in dscaler and thats it!

    Thanks for your advice Gerbil, appreciated.
     
  17. Gerbil

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    I have to say I've never used Dscaler much, but that sounds about right, so give it a whizz.

    It's worth investing the time in playing with Powerstrip. I wouldn't say my geometry (and by that I mean curvature of what should be straight lines) is any worse running at 720x576@50 than 640x480@60 so keep trying. I got my original settings from a post by Karnis on HDTV resolutions over at avsforums, and I ended up tweaking them in Powerstrip to get the image centered enough for the Loewe controls to cope.

    I don't have any R1 DVDs so I was determined to get a 50Hz resolution working. It also enable you to play with the Reclock filter which supposedly eliminates 'micro-stutters'. I think the jury is still out on this one, I'm undecided as to whether I can tell the difference.
     

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