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> 01 - DVB-t, Frequently Asked Questions
darro
post Jul 2 2004, 04:56 PM
Post #1


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Card: VisionPlus DVB-t


Please post into this thread if you want to add anything. The more people adding stuff, the better :)

NOTE: Once posts are consolidated into the main FAQ they will be deleted. Please don't be too offended

The Forum This forum has been set up and is run by a owner of a DVB-T card. Almost all members are, like you, users of these cards and their software. This is not the official support site for these cards. If you have specific problems with the card, you should contact the vendor you purchased the card from.
    [*] DVB General
  • Common DVB-T Questions
  • Common Vision-Plus Questions
  • Common Problems [*] Common Vision-Plus Problems
  • [*] This FAQ isn't answering my question. Where can I find more help?
  • Useful Links New

    General General Information about Digital TV and PC DVB-T Cards
    What is Digital TV?
      Fundamentally Digital TV is the broadcasting of Free to Air programming via a digital rather than analogue signal. It is sometimes referred to as DVB-T, Digital Video Broadcast - Terrestrial. There is also DVB-S (satellite) and DVB-C (cable)

      There are two digital formats, Standard Definition (SD) and High Definition (HD), the main difference being the quality of the picture and sound.

      AUS In Australia all broadcasts should be in Widescreen format (16:9) and will appear letterboxed on standard 4:3 televisions. Each Network has one HD channel, and may have several SD channel(s).
      Each Network is approaching DVB-T in a slightly different manner, so there are differences in what each network is providing on DVB-T. All current free to air programming for each network is transmitted on one of the network's SD channels. Some networks have chosen to only broadcast HD transmission when the program is available to them in a HD format. At other times they broadcast a HD demonstration tape.

    What is DVB
      DVB is short for Digital Video Broadcasting, it is a suite of internationally accepted, open standards for digital television. The core standards of DVB are DVB-S (satellite), DVB-C (cable) and DVB-T (terrestrial). All these standards are all based upon MPEG-2 (DVB-MPEG) for audio and video coding.

    What is a DVB-T card?
      A DVB-T card is PCI card that can receive a DVB-T signal and display it on a PC monitor (or TV)

    Common DVB-T Questions
    Can I use my existing antenna?
      If you are getting average analogue reception do not expect DVB-T to make things better.
      There have been reports of antennas in Unit blocks that have had problems. It maybe that these installation are using boosters, which assist in analogue but not necessarily digital reception.

    Can I copy captured data to a DVD?
      While both DVD and DVB-T are MPEG-2 files, there are some incompatibilities between the two formats. One of the main differences is that the packet size is different 188 bytes VS 2048 bytes. Some older players / codec's do not handle PVA streams well. Although the latest V5.X of InterVideo's WinDVD or CyberLink's PowerDVD should. So no, a DVB capture saved onto a DVD will not play in a normal DVD player. There are many applications and processes that will convert the file so it then may be authored onto a DVD for playback.

    On a Non-Widescreen TV (4:3), why do some programs look so small?
      All DVB-T broadcasts in Australia at meant to be in 16:9, widescreen format. Of course much of the old programming, and that from countries that do not use widescreen is still in the original 4:3 format. For this material to be transmitted in digital it must fit within the 16:9 format. This places black bars on either side of the picture, otherwise known as pillarboxed. So on a standard 4:3 TV not only is the image letterboxed (black bars top and bottom), but also pillarboxed. So the picture is shrunk in the middle of the screen.

      Is there anything that can be done about this ? Yes, if the application you are using has a zoom feature it will expand a pillarboxed picture so it will fill a 4:3 screen. Not all DTV viewing applications have this feature though. VisionDTV does not but DigiVision and DigitalWatch do.

      Amusingly, some TV advertisements recorded in 16:9 have been given to the networks in a letterbox 4:3 format. When transmitted on Digital, they are reduced further as they are a letterbox, in a pillarbox, in a letterbox.

    There appear to be several channels for each network. What are they ? (AUS Only)
      Each network has been given a certain amount of space (bandwidth) to work in. How they use this space appears to be up to the individual network (although commercial networks cannot use these for different programming). As mentioned earlier there is generally one SD Channel, transmitting the equivalent of the current analogue and one HD Channel, but there is room for several more channels in the bandwidth allocated.

      Following are some examples of what the network use these extra channels for. Nine, Seven, Ten, and SBS have a TV guide channel that display the days programming, this is not to be confused with an EPG (Electronic Program Guide). Seven used a channel during the Rugby World Cup to display match statistics. Network 10 use some channels to broadcast SD with AC-3 (2 Channel, not 5.1) audio instead of the standard audio stream. It is reported that networks may use these other channels to show different camera angles during sporting events etc.

    Can I watch TV and record at the same time (or visa-versa)?
      Note this answer is based on having only one card. More than one card in a machine is not yet supported by any of the vendors. Some forum members have more than one card using some third party software.

      Two answers, and to some extent this is the reverse of a VCR.

      A. You can record live TV and watch something that you have previously recorded, although you may need to use two difference applications to do this.

      Remember, as the broadcast is already a MPEG2 stream there is no encoding etc to be done. Recording a live DVB broadcast is really just a matter of buffering the data to a file on the hard drive. Watching a previously recorded program does not require the card at all, it is simple a program reading a data file. Some DVB applications may not let you do this at the same time due to internal application limitations.

      In some cases if you had very slow hard drive access then having one file being written to the disk and another being read could be a problem, but there have been no reports of this.

      B. DVB cards can only lock onto one frequency at a time.  This frequency can contain a number of programs or channels, you could in theory capture more than one program at a time.  Software is only now starting to address this situation.
      AUS In Australia, each network has been given one frequency (in Metro areas anyway). So you can functionally only record on network at a time.
      UK In the UK, it has been reported that a couple of networks share each of the frequencys, BBC and BBC2 for example.

    What are BDA drivers that I keep hearing about?
      BDA (Broadcast Driver Architecture) is a MS standard (read that as you will) for how a TV card device driver should be written. It is part of the MS DirectX family of APIs and is the core of how TV is implemented in their Media Center Edition (MCE) of Windows. More information on it can be found here http://msdn.microsoft.com/library/en-us/di...a>

      The practical upshot of this will be that any BDA compliant software, should work on any BDA compliant hardware. It should be possible to mix and match the hardware and software used. This is of course in a perfect world, and we all know which one we live in !!!

      This is the problem. There is not a lot of BDA compliant software today other than MS' MCE, which is only available with a OEM PC, and is not available is Australia. Quotes you will have seen here are from people with access to the developer version.

      As for compatibility. There are a least two major digital broadcast standards DVB and ATSC. Within the DVB standards there are also some variations, like what we have here in Aust. The software would need to know a fair bit about all standards to work with them correctly.

      The BDA drivers (third party, not offical) for the VP card have been around for quite a few months here. Software is now being developed to use these drivers.  

      Nova-T (and it's cousin the DPandA) and the DVICO card have BDA drivers, Twinham have also released beta official BDA drivers. That leaves AverMedia and Nebula. No doubt they will be providing drivers at some point, as without them they cannot play in the MCE space.

      Given that BDA is in it's early phases of adoption, there appears that not all BDA drivers are create equal. There are reports that the shortly to be released kworld card will ship with BDA drivers, but that these are not fully BDA compliant and may have issues.

      Although vendors are releasing BDA drivers, this does not mean that their software will support other cards. At this point in time the software is one of the main competitive advantages the vendors have. Although hopefully we will see a number of third party vendors supporting BDA, such as showshifter etc.

    Can I listen to FM radio with any DVB-T card?
      No.

    Can I listen to digital radio with any DVB-T card?
      Yes and No.

      In Australia there are some digital radio channels being broadcast by the ABC and SBS that you can listen to with this card. However, you cannot listen to the DAB (Eureka 147) transmissions that the ABC and SBS are trialling in Sydney and Melbourne.

    What is Digital 44, and can I get it?
      AUS Check here (and scroll to the bottom). At present it appears only to be in Sydney. It is being transmitted on UHF-35 (578500Khz). It consists of about 8 channels that are a mix of news, sports and parliament.

    What software can I used to edit captured video
      Note This is not a complete guide for video editing, there is a lot of good information here and elsewhere on the web on this topic.

      There are many applications both commercial and free that can edit captured material. There are a number of good articles in this forum and on doom9.org . On the commercial front, members have had success with Wobble's MPEG2VCR and TMPG's TMPGEnc DVD Author. On the freeware front there is ProjectX and Mpeg2Schnitt (MPEG2Cut in German) to name a few.

      Just be aware that the application needs to specifically know how to handle a MPEG2 PS file (Program Stream), this is slightly different format than a DVD MPEG2 file.

    What is this Interactive TV I hear about and can I used it?
      These interactive services use standards known as MHEG and MHP. A overview and description of these standards can be found on the CommDesign Web site. Basically they are standards for delivery and presentation of data and applications within the TV data stream.

      Currently no DVB applications support these services. There are reports that one of the Teac STBs does support MHP. Nebula have this feature on their development roadmap.

      AUS In Australia the Nine Network uses this service when broadcasting some sports events.
      UK In Britain the BBC are providing news, sports and weather updates.

    Can I hook my DVB-T card up to my Cable/Satellite service?
      Short answer is no. If your DVB card has analogue inputs (such as Nebula or Dvico), or you have analogue inputs on your video card (VIVO) you could connected the output of your pay TV STB to your computer. There is some discussion of this here. There are satellite and cable versions of the Twinhan card. Note, this will not work with the new Digital cable services such as Foxtel Digital in Australia, no CAM's / Subscription card's are available for VideoGuard NDS encryption system they use.

    What is DXVA?
    A good definition of DXVA (DirectX Video Aceleration) along with may other HTPC terms can be found here. For DXVA to be of any assistence it needs to be supported by both your video card (and drivers) and your video codec.
All Radeon 9xxx series cards support DXVA, and most Nvidia FX5xxx and higher so long as you have the lastest drivers. DVXA needs to be enabled in your codec.  For Cyberlink (Powerdvd) this can be enabled via HKEY_CURRENT_USER\Software\CyberLink\PowerDTV\UIUseHVA=1 (Dword).  This key may be in several locations so you may want to search your registry for the UIUseHVA key. For Intervideo (WinDVD) try the following registry key - HKEY_LOCAL_MACHINE\SOFTWARE\InterVideo\Common\VideoDec\DXVA=1

What software can I use to watch and/or record TV?
    There are two main GPL applications Webscheduler and DigitalWatch. Webscheduler is a recording scheduler with a web interface and EPG capabilities. Digitalwatch is for viewing live TV and offers a lot of control over codecs used.
    More details on these and other software can be found in the Third Party DVB-T Software section of the forum. A great guide for installing and configuring Webscheduler can be found here
    In addition to this some comercial developments can now be used with BDA compliant drivers.See ShowShifter for the VP card, or Fusion card.

    Common Vision-Plus Questions
      What is this VisionPlus DVB-T that everyone is talking about?
        The VisionPlus DVB-T is a PCI digital TV tuner card from Twinhan. It is known to be compatible with the Euopean and Australian stanards

      Where Can I Get One?
        They are now being stocked in many stores.
        AUS Lako Pacific are the Australian distributor for VisionPlus products.

      Can I plug my VCR into this card?
        No. The VisionPlus DVB-T does not include an analogue tuner, composite input, or s-video input. If you need to watch or record from your VCR then you will need another capture card.

      Can I get TeleText / Captions (subtitles)?
        VisionDTV is the only software that has support for Teletext. There have been reports that it is quite slow to access.
        There is some development on a Directshow teletext decoder here , this has been tested with DigitalWatch
        AUS As per analogue transmissions, TeleText data is only transmitted on Channel 7 and its affiliates (Prime etc). Caption data is on all channels, again this can only be accessed with VisionDTV. There have been no reports of this working correctly.

      Can I have more than one DVB-T Card in one machine?
        Whilst you can have more than one card, at this point in time no commercial software supports the use of two cards at one time. Nor can two cards be used by two applications simultaneously. A new version of the drivers/software to support multiple cards is in development. It is unclear when this will be released.
        Some members are running one card natively with the supplied software, and a second cards with BDA drivers to capture with the BDA version of Webscheuler.

      What other software can I use with the USB version?
        All third party software in this forum was written using either the Twinhan SDK or against Spectrum's BDA Drivers. Neither of these work with the USB version of the card. There are some Linux programs that appear to work with the USB model See here.  There are some reports of Twinhan testing a set of BDA drivers for the USB model.

      Common Problems
      How do I tune in channels?
        Tuning channels is different for each application. Some have automatic scanning which should find all the channels you can receive for you, others require that you know more details about the frequencies and Program ID's.
        AUS : Visit the DBA website for frequency information: http://www.dba.org.au/index.asp?sectionID=...;/a> To find PID information you can use an application, such as the WinDTV SDK sample application, or DigitalWatch's Scanchannels.exe, to scan a frequency.

      When I'm watching TV the video stutters. How can I fix this?
        There are a few different kinds of stuttering which have been experienced. Here are some things that have worked.
        • Set your display refresh rate to a multiple of 25. (ie, 50, 75, or 100)
        • Upgrade the video card driver to the latest version, or if you're already using the latest version try downgrading to an older version. Some versions are known to cause problems.
        • Improve your antenna and cabling.
        • Drop the display resolution to 1024x768.
        • There are reports of interference with Wireless Network Cards. These have mostly been resolved by moving the wireless antenna further away from the computer. See this post.

        General consensus is that you need around 95% in the quality stakes for a reliable picture. It appears that the strength is not so much a problem.

        Some have reported success on less, but not many.


      When I playback a file in my Directshow based player why does it die after a few seconds?
        Directshow tries to automatically figure out which filters are needed to play a file. When it tries to use the MPEG-2 Demultiplexer filter to split the stream, this problem of stalled playback occurs. If the MPEG-2 Splitter filter is used then the problem goes away.

        To fix the problem you need to force your application to use the MPEG-2 Splitter filter. Some applications, such as Windows Media Player, do not support this.

        Media Player Classic
        • Go to View/Options
        • Click on Filters/Overrides
        • Click "Add Filter"
        • Select the "MPEG-2 Splitter"
        • Once selected check the "Prefer" radio button option for this filter
        Zoomplayer version 2.x or 3.x pro
          Use a .filter file with this line in it
            LoadFilter({3AE86B20-7BE8-11D1-ABE6-00A0C905F375},MPEG-2 Splitter)
          Zoomplayer3.x standard does not support manual media filters. This post show how to use radlight's filter manager to raise the merit of the MPEG-2 Splitter. (thanks to Imit for this one)

      I can pick up some networks fine, but not others.
        Like the analogue transmission, each network may be transmitting its signal from a different tower. This is particularly the case in capital cities. You may not be getting an adequate signal from the network you are having difficulties with.

        Also see the following post

      When I capture a program there is a lot of corruptions in it.
      NOTE: This answer is based on being able to watch live TV without errors. If you also get errors with Live TV look this is not likely to be you problem. There have been problems reported when recording to SATA drives, particularly when these are connected to an On-Board SATA controller. See this post

      Common Vision-Plus Problems
      I can't get my VisionPlus DVB-T to install. What am I doing wrong?
      Some conflicts with other BT8X8 chipset devices have been noted. If you have one of these cards then you might need to remove it and it's drivers to get the VisionPlus DVB-T to install.

      IRQ conflicts have also been known to cause problems. Try moving the card to a different PCI slot.

      If there is a hardware issue the drivers seem to think the card is a satellite model, rather than terrestrial. If VisionPlus seems to be in satellite mode have a look at this post. It is almost certain that the card is faulty.

      Why doesn't the remote work?
      See the HOW TO: Troubleshooting the IR Receiver thread.

      I see a fuzzy line (white dots) at the top/bottom of the picture.
      This is data in the DVB broadcast that is used to adjust aspect ratio.

      One possible resolution in DigitalWatch is to increase the default Zoom by 1-2%, making the picture large enough that these signals are not seen on the screen without losing too much of the picture.

      This FAQ isn't answering my question. Where can I find more help?
      Also, many issues have been discussed on this forum. Try searching for what you are after, Remember that the default search is only for the last 30 days. If that fails then post a thread in the appropriate section of the forum and wait for someone helpful to point you in the right direction.   Please remember to provide as much information as possible.  Information like hardware and software specs, any diagnosis you have done so far and how the problem can be re-produced.

      Links - Some useful links

       Updates
      • 13/03/2004 - Divided up sections to cater for other cards.
      • 28/04/2004 - Added TV/Record and BDA section
      • 08/06/2004 - Edited 4:3 viewing, kworld BDA, Filter Management, VP Drivers issues. Added File editing, Digital 44
      • 16/07/2004 - Edited: DVD conversion. Added: VP USB support, DVB-T and Cable, MHP Support.
      • 22/08/2004 - Edited: Video Stutters, VP USB. Added: Recording Corruptions
      • 01/09/2004 - Seperate out some AUS info,  Added Links
       
        Maintained by darro. Send him a PM if you want something added.
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      Guest_Big Richard_*
      post Jul 12 2004, 11:04 PM
      Post #2





      Guests






      Thank you, thank you.

      I bought a VisionPlus Vision DTV Ter card yesterday and wasted many hours with the thing giving me a frame grab of video every few seconds and very broken audio - despite very good signal strength and quality indications. I tried newer drivers and older ones, moved PCI slots, changed BIOS settings, disabled swapfile, changed video card settings, etc, etc.

      The following snippet from your FAQ has saved me much more frustration, hair-pulling and lack of sleep: "There are reports of interference with Wireless Network Cards. These have mostly been resolved by moving the wireless antenna further away from the computer."

      My wireless router normally sits on top of my PC. To install the VP card I moved the router to just beside the PC to allow removal of the PC's metal cover. I inserted the card into a slot and knowing that these things are never straightforward, left the cover off the PC - with the router about 40 cm from the VP card. Of course this must have been transmitting piles of 2.4 GHz straight into the card!!!! Turned off the wireless section of the router and I have got perfect pictures and sound now. I reckon it will probably be OK once I put the lid back on the PC to re-enable the wireless network - it is a good quality case with got EMI protection.

      Once again thank you biggrin.gif smile.gif
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      darro
      post Jul 16 2004, 05:15 PM
      Post #3


      Forum Regular


      Group: FAQ Maintainer
      Posts: 458
      Joined: 30-September 03
      From: Sydney
      Member No.: 168
      Card: VisionPlus DVB-t


      Updated the FAQ 16/7.

      Many thanks to Joey for some of the answers above

      Let me know if anything is wrong or a least wildly inaccurate!

      Cheers
      Darren
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      darro
      post Jul 16 2004, 05:19 PM
      Post #4


      Forum Regular


      Group: FAQ Maintainer
      Posts: 458
      Joined: 30-September 03
      From: Sydney
      Member No.: 168
      Card: VisionPlus DVB-t


      QUOTE (Big Richard @ Jul 12 2004, 11:04 PM)
      Thank you, thank you.

      The following snippet from your FAQ has saved me much more frustration, hair-pulling and lack of sleep: "There are reports of interference with Wireless Network Cards. These have mostly been resolved by moving the wireless antenna further away from the computer."

      Big Richard,

      Glad to it was of some use to you.

      Sorry for taking so long to approve this post, I did not get any notification that a message was waiting and I was too slack to check!

      Cheers
      Darren
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      darro
      post Aug 18 2004, 05:32 PM
      Post #5


      Forum Regular


      Group: FAQ Maintainer
      Posts: 458
      Joined: 30-September 03
      From: Sydney
      Member No.: 168
      Card: VisionPlus DVB-t


      Hi Guys,

      We are looking at reworking the FAQ section and separating it out a little more. So I need a bit of feedback from some of you.

      1/ Anyone from outside of Australia who want to add or highlight anything different about how DVB-T is implemented in their country. Things like is DVB implemented as widescreen in your country, does each network get more than one channel?????. If someone could make some notes and send them too me that would be great.

      2/ Can I ask if someone with a fusion, v-stream, or nebula card wants to put together some question and answers. I am quite happy for format it all out.

      3/ If anything is wrong, misleading or out of date in the current FAQs, or if you have seen a post that you feel should be included in the FAQ drop me a note

      4/ For those guys who feel they are forever answering the same question, drop me a note and I can link to one of your better answers.

      5/ I have started an FAQ for DigitalWatch, anyone feel up to doing one for WebScheduler?

      Cheers
      Darren
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      darro
      post Aug 22 2004, 06:30 PM
      Post #6


      Forum Regular


      Group: FAQ Maintainer
      Posts: 458
      Joined: 30-September 03
      From: Sydney
      Member No.: 168
      Card: VisionPlus DVB-t


      Small update to the FAQ.

      22/08/2004 - Edited: Video Stutters, VP USB. Added: Recording Corruptions

      Cheers
      Darren
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      darro
      post Sep 12 2004, 12:17 PM
      Post #7


      Forum Regular


      Group: FAQ Maintainer
      Posts: 458
      Joined: 30-September 03
      From: Sydney
      Member No.: 168
      Card: VisionPlus DVB-t


      Update to the FAQ

      Added links and DXVA section. Minor updates

      Cheers
      Darren
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