Divx to VCD - synch/video problems

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  • synchron
    Junior Member
    Junior Member
    • Nov 2001
    • 28

    Divx to VCD - synch/video problems

    Was wondering if I can get some help here:

    I use 2 PC's to go from Divx AVI to 2 VCD's in regular MPEG-1 format. The Home PC which contains the divx is an AMDK6-2 400 Mhz, just barely within spec to watch the clip and do nothing else. The faster work PC is a PIII 1.1Ghz that I use to do the encoding. I use AVI split/Nandub to split the Divx to burn to a CDRW since my home burner cannot handle CDRW's that are 700MB, just CDR's. I decompress the audio from the Divx and use TMPGenc on the fast PC once copying the 2 AVI's to harddrive and load the NTSC Film Template since that is the source of the original, usually. I encode/burn (ala Nero) both files and they play perfectly on both PC's with decent quality. The problem arises when I bring these VCD's back home and play on my DVD player - basically audio/video sync problems where video jumps ahead of audio and then corrects itself. It is not the typical audio/video starts out good and gets worse later in the film. This is constant random video jumping always going ahead of the audio and then "fixing itself", definitely an unusual phenemenon and only when the source was Divx.

    Since they play fine on any PC, one must think it is my DVD player but since the player plays everything else flawlessly (DVD, MP3, homebrewed VCD/SVCD, even MiniDVD) before I consider replacement, is there any way this is in the Encoding process?? I have received encoded VCD MPG files also and they play flawless on the DVD player as well so there could possibly be an improvement I can make in the encoding process. Any suggestions??

    TIA, synchron.
  • setarip
    Retired
    • Dec 2001
    • 24955

    #2
    "Since they play fine on any PC...is there any way this is in the Encoding process?"

    You appear to be defying logic. If the burned VCDs "play fine" on any PC, other than your home PC, it doesn't seem plausible that there could be an encoding problem.

    On another point, what is the audio format of the .AVI , that necessitiates you converting it to uncompressed format?

    Comment

    • synchron
      Junior Member
      Junior Member
      • Nov 2001
      • 28

      #3
      The resulting VCD plays fine even on the home PC - it is the Divx that plays borderline. I know that it's probably a flaw in the DVD player, which is an Apex 703 using one of those cheap ESS chips, but since other d'led already encoded MPG's play fine on the Apex also, it could possibly be in the way I'm encoding it with Tmpgenc. I basically use all of the settings of the VCD NTSC Film template and just check the "soften block noise" which is at 35.

      Another similarity is with DVD Ripping: using Smartrip/DVD2AVI/Tmpgenc I see the synch problems sometimes. Using Dvdx to go from DVD to MPG on the fly, I never get any synch problems but the tradeoff is that the quality sucks with their internal VCD encoder and if I use Tmpgenc on the fly ala their AVIsynth frameserver support, the audio of the resulting MPG crackles.

      Back to Divx: the audio stream is your typical 48000Hz 2 channel 0-bit precision Fraunhofer MP3 codec. I thought that the golden rule of converting/encoding is to always decompress the audio to avoid synch problems because the audio/like the video is variable bit rate and decompressing makes it constant, thus allowing Tmpgenc to analyze/work properly.

      Synchron.

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      • setarip
        Retired
        • Dec 2001
        • 24955

        #4
        "Back to Divx: the audio stream is your typical 48000Hz 2 channel 0-bit precision Fraunhofer MP3 codec."

        As long as it's standard MP3 (not VBR), there is absolutely no problem feeding it to TMPGEnc...

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        • synchron
          Junior Member
          Junior Member
          • Nov 2001
          • 28

          #5
          Well I think I get the synch problems because the original is VBR MP3, I can tell this by Saving WAV in VD and playing it in Winamp. I see the bps thing jumping around, therefore its variable. This is why I decompress audio.

          I purchased (or "borrowed") another brand DVD player and I still get synch problems so this is definitely an encoder problem. Interesting how a PC MPEG decoder (in software) can handle an MPEG-1 better than a DVD's processor/video chip in hardware/firmware since all of these play fine on a PC. So now I'm thinking that a VCD player likes the standard 29.97 NTSC format a lot better than the 23.97 Film format, which leads me into thinking I should use the standard NTSC template and select the 3:2 pulldown in Tmpgenc. Will this work? What exactly happens when you choose this option??

          Comment

          • setarip
            Retired
            • Dec 2001
            • 24955

            #6
            Reduce the audio rate to 44,100...

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