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Sync and framerate issues HELP!

Discussion in 'MPEG-1 and MPEG-2 encoding (AVI to DVD)' started by aligroves, Apr 28, 2005.

  1. aligroves

    aligroves Member

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    Hi I have a problem that just will not fix, i have tried so many things I'm running out of ideas, please help if you can!

    I have an avi that I'm trying to convert to dvd. On a straightforward conversion using either santa, vso or avisynth or a myriad of these it comes out out-of-sync.

    So, I tried the extracting audio method using virtualdub to select audio in full processing mode, no compression, save as wav. Then opened TMPGenc and mixed the avi and wav file together into an mpeg. This solved the audio but i then discovered the playback was jerky, caused by framerate issues.

    The framerate is 23.976 and I am trying to create a pal dvd with 25fps.

    So, I then tried two things. 1) Going back to the original avi, demuxing the audio in virtualdubmod and saving as a wav. Then opening in besweet and changing the framerate, resaving as a wav. Opening avi in AVIFRATE and changing framerate. Mixing together in TMPGenc. The result being out of sync.

    Then tried (sorry i am getting to the end) The original audio process of opening the avi in virtualdub, saving the wav as non compressed and opening this in besweet to change framerate. Avi framerate changed in AVIFRATE and mixing together in TMPGenc. Still out of sync and out of ideas.

    The original avi audio codec is 0x0055(MP3, ISO) MPEG-1 Layer 3, with an Xvid vedo codec and a frame rate of 23.976.

    I can give you any other info but im guessing people may have stopped reading already due to the excessive length of this message!

    Thanks

    ali
     
  2. aldaco12

    aldaco12 Active member

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    Usually the 'gradually un-sync' is caused by the use of VBR MP3 compression, not by 'framerate issues', by what I know, because the fremes per seconds do not change the length of a movie (a PAL movie is as long as a NTSC one). But I might just be ignorant.
    Therefore, from my knowledge, the sound should be constantly un-sync, if you used the uncompressed WAV stream as 'audio input' (this happens when one converts back an AC3 stream without keeping into account the constant delay which it has with respect to the video stream [usually some tenths of ms]).
    If this is the case, and the sound stream must be delayed, you could convert that uncompressed WAV stream again into WAV (it will become 'name2.WAV') by adding a constant delay , e.g. with HeadAC3he. You don't have to change the 'destination format', you have simply to convert it by checking the 'delay ... (ms)' box which lies below the input file name. Otherwise you can 'anticipate' the sound by deleting a piece of the WAV at the beginning, to anticipate the stream (do this with Exact Audio Copy: Tools___Process WAV --> File__Cut).
    Unless that WAV was kept sampled 48 kHz instead of 44.1 Hz (but I'm not even certain that the AVI's sound stream must be sampled 44.1 kHz , like the (S)VCD, or can be even sampled 48 kHz, like the DVDs). In this case, just to be sure, check, during the conversion you make with HeadAC3he, the 'resample to 44.1 kHz' box. In this way you'll have a MP3 sound stream 44.1 kHz, as it usually happens in the AVIs.
     
    Last edited: Apr 28, 2005
  3. aligroves

    aligroves Member

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    Thanks for the reply. So, i followed this process:

    I first syncronised the failed mpeg to find the delay (400ms). I
    put the uncompressed wav file into besweet to change the framerate, then put it into HeadAC3he and added the 400ms delay rate and resampled the file as you said with the 44.1hz, although it was already at this sample rate.

    I then put the reframerated avi (used avifrate) into tmpgenc with the new wav file, loaded the dvd template.

    Unfortunately, this has not solved it, its the same sync problem. The framerate appears to fix, but i still have the wonky word problem.

    Any further suggestions welcomed!

    ali
     
  4. aligroves

    aligroves Member

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    Hello again!

    Just to say, thanks for your help,

    I tried as you suggested with the time delay again, but using besweet to change the framerate and time delay in one swoop, which seems to have done the job,

    no more wonky lips!!! Finally I can move forward with mmy life.

    Thanks

    ali
     
  5. aldaco12

    aldaco12 Active member

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    There's something I can't manage to understand. Why do you say 'change the framerate'? I've always thought the framerate is a [bold]video[/bold] issue, it's not an [bold]audio[/bold] one. On a NTSC DVD (region 1, framerate = 23.976) you usually have english audio only (region 1 = U.S., U.S. Territories, Canada, and Bermuda), on a PAL DVD (region 2, framerate = 25) you can have any country of Europe's audio [english audio, french audio, italian audio, german audio, spanish audio...], japanese audio, any country of middle east's audio, any country of Africa's audio and so on.. and the movie's framerate is always 25; it depends on the TV system, not on the audio trace you listen to...
     
    Last edited: Apr 29, 2005
  6. Minion

    Minion Senior member

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    This is an easy Problem to Fix if you know how to use AVISynth...

    Forst Decompress the audio in your AVI file and then write an AVISynth Script to Frameserve the 23.976fps AVI file to Tmpgenc But add this Line to the Script:

    AssumeFPS(25,True)

    This will speed up the Video and Audio to 25fps which keeping it in Perfect Sync and when you encode it in Tmpgenc in Pal Format you will not have the Jumpy effect from the Frame Rate conversion because AVISynth is Doing the Conversion for you, This is the Best Method of Frame Rate conversion....

    Cheers
     
  7. aligroves

    aligroves Member

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    I'm not sure why the framerate affected the audio, as you say they were effectively two different problems. Being a noob, I didn't realise about the framerate issues until I had worked out how to fix the audio sync and was checking it out on a dvd player. Then, once I fixed the framerate issue, it did seem to have made the audio sync back to square one, hence the need to add a delay rate that previously wasnt required.

    Still, glad i've at least got that issue solved!

    thanks again

    ali
     

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