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does virtualdub mod demux ac3 at a standard rate?

Discussion in 'MPEG-1 and MPEG-2 encoding (AVI to DVD)' started by yellowsam, Mar 22, 2005.

  1. yellowsam

    yellowsam Member

    Sep 3, 2004
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    after demuxing ac3 and compiling DVD the sound was wayyyyy out
    Now i Know this is a common problem and i was wondering can you control what rate (like you can with frame rate) the ac3 is demuxed???
    the avi was in 23.976fps i tried converting the mpv stream at 23.976 in cinema craft encoder and in 25fps both were out. any positive help would be much appreciated
  2. aldaco12

    aldaco12 Active member

    Nov 6, 2002
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    No. If you demux the AC3 sound, unless you have an AC3 decompressor, you demux it 'as it is', e.g. you cannot save it as WAV (even if te button is lit, you save it 'as it is'). After that you can 'play' with it with BeSweet + BeSweet GUI or, if you have an AC3 plugin for TMPGenc, do everything with TMPGenc.
    Careful; if you encode it with BeSweet, be careful of its settings (I hatd to encode tha sound using the profile 'MP2 for SVCD', decoding the AC3 for DVD (48 kHz) to 224 kbps audio 44.1 kH, downconverting the sample rate, that foas, for DVD, 48 kHz. To had set the output sample rate to 44.1 kHz I had to manually change the settings for SSRC, even if I checked the box 'downmix sample rate in the main screen'). Maybe it's better to use HeadAC3he, to be sure the output file has the corect form.
    Last edited: Mar 22, 2005
  3. shiroh

    shiroh Guest

    for dvd just dump the ac3. no conversion needed.
    only do it for svcd/vcd.

    you don't need to convert the frame rate. that will just make it worst.

    just like aldaco said demux it as it is
  4. Minion

    Minion Senior member

    Sep 28, 2003
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    Well if you encode a 23.976fps File at 25fps in CCE the audio will go out of sync because CCE doesn"t support any Frame rate conversions accept the Newest version does 2:3 pulldown....

    AC3 files demuxed useing Virtual-Dub are not quite Proper AC3 files because they contain a wav header which needs to be Filtered out..(Actually Virtual-Dub adds the wav header to the AC3 file)

    To remoove the Wav header you need to use a program Like "AC3Fix" or what I use is a tool called "BeSliced" which Fixes the AC3 files header and should hopefully Solve your problem....


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