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audio mpg is ok, but dvd is out of sync?

Discussion in 'MPEG-1 and MPEG-2 encoding (AVI to DVD)' started by frozzy, Apr 18, 2005.

  1. frozzy

    frozzy Member

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    Hi,

    Please need some help.
    I have the following problem.
    My goal is to convert an indian xvid movie to dvd. These were my steps:
    - audio was VBR, so I converted the audio in Virtualdub to PCM, 44100hz, high quality by saving as .wav
    - then I started up Vitualdub as a frame server, because I wanted to add permanently subtitle to the movie
    - In Tmpg I refered the video input to the frame server file (.vdr), and the audio input to the .wav file. The .avi movie is 29,97 FPS. So I used the DVD NTCS (16:9) template. Must be noticed that I used external progs (Lame and TooLame) for the audio.

    My output file .mpg is ok. Audio is in sync.
    But when I demultiplex the streams in DVDLab, audio is about 8 sec longer. I thought let me at least try to compile this to DVD, you never know. But no luck. You can see / hear that the longer the movie plays, the audio is getting more and more out of sync while
    the beginning of the movie looks ok. I also tried to compile the DVD without demultiplexing; same problem. I tried DVDMaestro, also same problem. And I also tried the encoding without external progs for audio. The strange thing is that I don't have this problem with English movies, only with Hindi movies. These movies are most of the time between 140 and 160 minutes and 29,97 or 23,97 FPS. The last movie I tried was exactly 143 minutes.

    And another question: why is Tmpg ecoding the movie first from 29,97 to 23,97 FPS (inverse telecine)? Is this neccesary?

    Thanks in advance.


    Frozzy
     
  2. rebootjim

    rebootjim Active member

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    DVD Audio must be 48khz, not 44.1khz
    Take your saved .wav and transcode it to AC3 in ffmpeggui.
    Encode ONLY the video in tmpgenc (frameserved).
    Load the m2v and ac3 into dvdlab.
    2:3 pulldown depends on the source framerate.
    If the source is 23.976, then encode in tmpgenc to 23.976 with pulldown. If the source is 29.97, encode it as such.
     
  3. frozzy

    frozzy Member

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    Hi,

    I did everything as sugested above.
    Finally I managed to create a hindi DVD from xvid.
    Thanx rebootjim. Many thanx.
    But still some questions.
    When I import the audio.ac3 and video.m2v in DVD-Lab
    The movie is still shorter than the audio (in time 9 sec).
    But thought again: you never know, let's compile the DVD!
    And yes, audio is still in sync in the DVD.
    But isn't it strange that the time lenght audio and video in DVD-Lab differs. The time length of the audio is equal to the orginal movie.avi length. Could someone explain this? And also a question about the pulldown mentioned before. I really don't understand what this is. Is it correct that the pulldown relates to the encode mode in TmpgEnc? I can't find the 2:3 pulldown. The encode mode setting for this movie was non-interlace.
     
  4. rebootjim

    rebootjim Active member

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    Because of the nature of a compressed avi, being encoded to a different compression mpeg, the movie may, or may not, have video with no audio, at the beginning, end, or both.
    When playing the avi, it just sync's up.
    When playing a straigh converted mpeg, it may not.
    If you rip the audio out, it removes any offset/delay/blank from the beginning and the end. Transcode a whatever frequency audio track to 48khz, and more changes happen.
    Generally, if there is no delay at the start of the audio track, then doing audio separately in ffmpeggui will keep it in sync, even though it's 9 seconds shorter. That just means the video has about 270 extra frames at the end, with no audio, probably blank.
    Some videos are encoded to avi at 23.976fps, and pulldown is used to make them actually play back at 29.97fps. An avi doesn't know what pulldown is, so it just plays. An mpeg can be encoded at 23.976 _IF_ the source is 23.976 and use pulldown during encode (yes, look in "Encode Mode" box in tmpgenc) so that it plays back at a normal 29.97fps, and isn't jerky.
    Because each source file is different, especially on downloaded stuff, I always use Gspot to find out the properties of the source, then I know if I should use pulldown or not, during the encode.
     
  5. frozzy

    frozzy Member

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    Shit,

    Once again your help.
    When I wanted to play the dvd on a stand alone player the movie doesn't play. It plays a second and then freezes with a beep sound.
    Forwarding is possible, but aigain the movie freezes with a beep.
    It is not the media type I use, because I never have these kind of problems with these media types. I think it has to do with the way the movie is encoded. I have this also with some dvd's from my friends while they play on other stand alone players.

     
  6. rebootjim

    rebootjim Active member

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    If they play on most players, but not yours, then I would guess it's your player.
    Never had a problem with a tmpgenc encode, ever, nor one authored in DVDLab Pro.
    Check that it can play your media type (-r +r), and that it can actually play DVDR5's.
    Older Panasonic, Toshiba, and others, cannot play some burned disks, whereas newer cheap ones, even the $35 Koss or whatever, can play just about everything.
     
  7. frozzy

    frozzy Member

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    Problem solved!

    It seems that my stand alone dvd-player doesn't support the audio.ac3 file encoded by ffmpeggui. What I did is I encoded the audio.wav file to audio.mp2 by TmpgEnc using external program Toolame. And imported this file in DVD-Lab as audio file.
    And compiled the .m2v and .mp2 to DVD. And it works.

    I want to come back on the pulldown.
    So is it correct that when the .avi is 23,97 FPS that I should select the 2:3 pulldown ? And is 2:3 pulldown the same as 'inverse 3:2 pulldown'? I only can select 'inverse 3:2 pulldown', 'non-interlace' and 'interlace'. And in case the .avi is 29,97 FPS should I then select 'non-interlace'?

    Please tell me which encode mode I should select in case .avi is 23,97, 25 and 29,97 FPS.

    Thanks!
     
  8. rebootjim

    rebootjim Active member

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    It's rare that a player won't take AC3, but no matter. Ffmpeggui can also do mp2, or you can do it in tmpgenc as you have.

    If the source is interlaced, choose that, unless the source is interlaced 23.976, then choose 3:2 pulldown. If it's 29.97 interlaced, encode as such, if it's non-interlaced, encode as such.
    "Inverse" just means that the encoder will encode it one way, so the player inverses it again to play it properly. Ignore the terminology...when someone says, "use pulldown" they mean Inverse or 3:2 or whatever you want to call it.
     
    Last edited: Apr 19, 2005
  9. frozzy

    frozzy Member

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    Normally I don't have problmes with .ac3 on my stand alone player.
    I'm sure it has to do with the encoding from .wav to .ac3. And what I understood is that this file is not really an .ac3 file.
    But nevermind, some how I managed to play the dvd on my player.

    I tried to check some info refering to encode mode of 1 xvid movie in Gspot.
    The 'PROG' and 'I/L' are both grayed. I red that this means that for that part no information is available. But I also checked 5 or 6 other xvid movies, and also both are grayed. Am I missing something?
     
  10. rebootjim

    rebootjim Active member

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    Nope, that's normal.
    I/L if lit, means the source is Interlaced. If it's grey, and the Prog is lit, the source is progressive.
    If neither is lit, it means that Gspot can't tell.
     

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