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Audio/Video desync with VirtualDub-MPEG2

Discussion in 'DivX / XviD' started by R.Spark, Jun 6, 2003.

  1. R.Spark

    R.Spark Guest

    I'm trying desperately to convert some MPEG2 videos into divx format (to distribute them via the web), but I get always an audio/video desynchronization with VirtualDub...

    I know, I hate to ask what looks like a question already asked a thousand times, but in many posts I did not manage to find a solution that satisfied me. Please read below!

    * Input video: MPEG2 (from a sat-TV capture card)
    * Output video: Divx (no matter what version)
    * Tools: Multidec -> PVACut -> PVA2MPG2 -> VirtualDub-MPEG2 (release of may 25th)

    I found in VirtualDub-MPEG2 an excellent tool that suited my needs (offers much control and remains simple). The only drawback I see is this audio/video desync.

    I think this problem comes from Virtual Dub, because the MPEG2 original file plays perfectly (in PowerDVD for example), and so
    does the ouput file in AVI/divx format when encoded using Vidomi. But Vidomi doesn't have filters etc...

    There are solutions to resynchronize the audio with the video :
    - the audio skew correction option in VD : in some tutorials, the value to put in the 'delay' field is like a "magic" value for me; personally I find this is not an easy task! :-/
    - the tool 'SimpleSynchronizer' (by SuperTrax) helps but is maybe too simple... in some videos, it's no use previewing since there is no navigation, and there are only one place or two in the middle, where you can see the lips moving and detect audio desync...

    Furthermore, some videos I resynched in an "almost acceptable" way for me, appeared to be more out of sync than I thought when
    viewed by others, with other hardware configurations.

    Isn't there a means, instead of *re-synching* audio and video (visually) afterwards, of *not losing* sync during the encoding process with VirtualDub ? And thus achieving a perfect synchronization fo *all* users, whatever their harware may be ?

    Thanks in advance,


  2. R.Spark

    R.Spark Guest

    Please could someone give me an answer ? At least tell me there is no other solution than the ones I mentioned. I have described my problem in every detail, haven't I ?...
    Besides I'm always forced to do this synchronization manually (and blindly). I always manage to get a good result, but I spend too much time with audio synchronization only...

  3. pst

    pst Guest

    I also had problems of this kind,and found a small glitch in the original .avi video that threw out the sync,used avifixjoiner(search in google)to fix the file.Check the framerate with virtual dub,if it is 23.976 you need to change content of video to film movie,in tmpgenc.(page2 of project wizard)
  4. R.Spark

    R.Spark Guest

    There are probably several causes of audio desycnhronization in VD, because I also tried to join 2 avi files with VirtualDubMod (not VirtualDub-Mpeg2), and the second joined part was also out of sync.
    But now I'm only trying to convert 1-piece mpeg2 files, recorded with Multidec and a DVBs Nexus TV card, into avi files. I verified, framerate is 25.000, and it plays ok in PowerDVD and WMP9... The values I have to enter in 'audio delay' are different at each time (for different recording sessions): -1150 ms, -250 ms, -650ms, etc...
    Very strange !
    I'll try avifixjoiner (in other circumstances)...so thanks!
  5. roddy20

    roddy20 Guest

    try pvastrumento (www.offeryn.de)
    or DVD2AVI to detect the correct audio to video delay.
    DVD2AVI creates audiofile as ****-118msec.wav
    -118 is the required value
  6. R.Spark

    R.Spark Guest

    well done, Roddy20!! After struggling during 1 month with that problem, I found exactly at the same time the (or at least one) solution ... using DVD2AVI! But I manage to generate a .mpa file only, don't know why it does not generate a .wav file directly... No matter...then I convert it to a .wav file with BeSweet, and import that result into VirtualDub-Mpeg2 (all other things unchanged, except for delay = the one that appears in the filename).
    In other words : instead of processing sound with VD, I use another "path" : DVD2AVI (->mpa), BeSweet (-> wav), import wav in VD + delay... that's all!
    And believe me, the result is much more different !
    I really hope that this thread will avoid some trouble to other newcomers.
    Thx! Robin
  7. roddy20

    roddy20 Guest

    "don't know why it does not generate a .wav file directly"
    it is DVD2AVI, not DVB2AVI :-(
    so it works with AC3 sound ,not with MPA
    but the value of delay is OK for any format

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