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  • Dolby AC3 encodes way too low a level

    Posted by Rick Hughes on June 3, 2015 at 8:07 pm

    Movie Studio Platinum 12

    Want to create standard DVD with 5.1 surround sound tracks.

    I have the original file, edited as necessary and the sound level is fine (5.1)
    I am rendering audio & video separately
    The resultant Audio file is reduced is volume dramatically – too low to be used.

    The error occurs with the Render – I chose:
    Render As > Dolby Digital AC-3 studio
    Then the template “5.1 surround DVD
    or “Stereo DVD

    The same result on both .. sound is down by at least 80% … i.e. normal slider settings would be around half way and give loads of volume (and is this way in MSP) …. once rendered with the AC3 encoder the slider has to be at maximum and still way too low.

    If I render with .wav or similar sound remains at correct level.
    There are no settings option for Dolby audio to adjust.

    I have aslo tried the AGC versions – no difference

    Aaron Star replied 10 years, 11 months ago 4 Members · 5 Replies
  • 5 Replies
  • Bob Peterson

    June 3, 2015 at 9:35 pm

    One of the standard bits of advice for Dolby is to set “Dialogue normalization” at -31db to keep audio levels up. However, it looks like you need the Pro version to do that. The Studio version does not allow you to adjust the settings in the template. That would be a deal breaker for me.

  • Norman Black

    June 3, 2015 at 11:36 pm

    Yes, the Pro AC-3 encoder which comes with DVD-A Pro, does have more options. Here is a Vegas help topic on the subject of low encoded audio, which only Pro supports.

    https://www.sonycreativesoftware.com/webhelp/vegaspro/13/ENU/index.htm#FAQ-Exporting_a_Vegas_Project_to_DVD_Architect.htm#kanchor90

  • Rick Hughes

    June 4, 2015 at 1:10 pm

    I did see a few posts where there were template settings for AC3 for Pro users.

    I don’t have Pro … (I’d like it but it would be 15x the price I paid for MSP – based on Sony web site upgrade price )

    As they include the Dolby AC3 encoder ……. you would expect it to work ?

    I’d use another format if it can maintain 5.1 and comply with DVD spec

  • Rick Hughes

    June 4, 2015 at 7:50 pm

    OK found the reason (or cause at least)

    When I watch video on PC I use VLC or Splash ……… having rendered the ac3 audio and created a DVD ‘prepare’ project.
    I normally play audio & video there to check all sounds OK.
    This 80% drop in volume was immediate and very apparent …. could be heard in VLC or Splash.

    It I encode with wav or anything else there was no drop in volume ………….
    However this it seems is NOT a fault of MSP ….. as when I burned a DVD the audio was back at correct level.

    It appears that desktop PC players cannot handle the AC3 file correctly (something to do with lack of handling DialNorm )

    So this was a bit of a hunt for a non-problem.

  • Aaron Star

    June 6, 2015 at 5:03 am

    You could try just encoding to PCM on the DVD, there is no real need for AC3 in general. If you are just producing non pro content or a simple stereo DVD, PCM is all that is needed. PCM is included in the DVD standard and so players will play the disc just fine. PCM is what you hear is what you get.

    AC3 has certain technical characteristics that make is best for professional work, like compression and >2 tracks. AC3 is basically just Dolby licensed multi-track version of mp3. If your AV bit stream will fit on disc without the audio compressed, there is no need for the compression.

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