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onboard video cause of sync issues?

Discussion in 'Video capturing from analog sources' started by rcglider, Aug 7, 2004.

  1. rcglider

    rcglider Member

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    I have two systems. In short, one gives good direct DVD burn with no sync problems. Specs:
    Abit NF7-s
    Barton 2800
    1gb ram
    ati 9700 pro
    Winfast 2000 xp deluxe


    The other however does not and will get severely out of sync while using DVD Direct Burn. System specs are:
    Abit NF7-M
    Barton 2500
    512mb ram
    onboard nvidia video
    onboard sound (using Realtek drivers)
    Winfast 2000 xp deluxe

    Am I asking too much out of this for smooth recording without sync issues, or does it need an AGP video card to eliminate the problem? I'm using the lates Winfast drivers and PVR. Is the onboard audio ok if using a decent video card? Or maybe I just need better software to correct the out of sync problem?

    thanks
     
  2. Minion

    Minion Senior member

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    Most sync problems are Caused from the time Lag between your capture device and your Sound Card...
    Your Capture device has it"s own Built in Clock so it knows how long a second is and How many frames to capture every second ect...Your sound Card also has it"s own Built in time clock so it knows how long a second is and many Audio samples to capture in a second...
    The problem occurs when the Two devices use a Time clock that is not exactly the same, It might only go out 1 second per hour but with a 2 hour Capture the audio can go out by 2+ seconds which is a Bad sync problem...Most Good Capture Programs Can compensate for this Time lag by either adding or Dropping Frames to keep sync with the audio or to Dynamicly re-sample the audio durring capture as to Keep sync with the Video....
    The First Method of Adding or Dropping Frames to keep sync with the audio is not a Good Method because because adding and Dropping frames changes the Frame rate so if you encode this file to Mpeg or another format it will go back out of Sync...
    The Best method is to Dynamicly resample the audio so it syncs up with the Video...

    I guess the Capture program you are useing doesn"t have a method for keeping sync or it uses the Method of Dropping and adding Frames....
    If you are captureing Directly to Mpeg2 then I suggest trying "Intervideo WinDVR 3.0" to capture because it can properly compensate for the Time lag..
    And if you are Captureing to AVI then I suggest something like Virtual_VCR and set the "Master Stream" to "Video" ....or any Capture program that has a "Master Stream" setting can properly compensate for the Time lag if you set it to "Video"...

    You can also get a Better sound Card which will help but even the best Sound Cards and Capture cards will have a time lag to some degree.....

    Cheers
     
  3. rcglider

    rcglider Member

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    Thanks. It's a bit frustrating purchasing a TV tuner only to find out it doesn't work as advertised. Direct Burn DVD using Winfast PVR was the major selling point and kept within the budget. Now to discover another $80 is needed in order to correct the audio/video sync is nothing short of disappointing to say the least. I wanted to keep it simple to use as it was built for a friend that needs it as simple as possible, plus he only has a 30gb hdd so Direct Burn was a good solution.

    Thanks for your time.

     
  4. Minion

    Minion Senior member

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    Well there has been a lot of Posple who have Complianed about the WinFast PVR software because they were getting Sync Problems so I suggest a different Capture Program, One I know that Captures extremely high Quality mpeg2 files is "Intervideo WinDVR 3.0" and it also properly Compensates for the Time Lag between the Audio and Video and there are a couple other Programs that have the direct DVD Burn feature like "WinDVD Creator" but it"s capture quality isn"t as good as WinDVR 3.0....

    Cheers
     
  5. chowskip

    chowskip Guest

    I have been battling with A/V Sync for months now. I have had the best luck with VirtualDub. It is free and is has options to compensate for the problem.
     

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