Wrong audio AC3 5.1 channel assigment with voukoder

  • As I say in an other thread, there is a problem with channel assigment of audio 5.1, not the same between AAC and AC3 output.

    After a lot of tests, I have understand the problem :

    Adobe change the 5.1 channel assignment during import and on time line since version CC2014.

    It was L, R, Ls, Rs, C, LFE, in versions CS6, CS7

    It is nows L, R, C, LFE, Ls, Rs in newer versions

    With voukoder :

    Export/Import in AAC format conforms to these spécifications

    Export/import in AC3 only conforms to CS6 spécifications, it is wrong in later releases.

    I have make a clip with music only on suround channels, and audio recorded on front channels

    Images attached shows the layout in source monitor (same as timeline)

    Please check this (with the other clip provided in zip) and

    as voukoder is now the best way to export to AC 5.1, thanks in advance to provide a correction.

    Thank Olivier

  • Thanks for this detailed analysis. I will look into this once the floating point audio bug has been fixed. Unfortunately I had to disable AC-3 in the latest test release.

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  • I think I found the cause of the problem:

    it's not Voukoder at all that puts the fuss in the order of the audio channels, but another Rovi Totalcode plugin, which I re-activated to accept clips with audio in AC3.

    Indeed, I had already used this plugin in CS5-CS7 versions, while Premiere did not support Dolby Digital.

    Then I had abandoned it in the more recent versions since Premiere included as standard the support of the AC3.

    In version CC2018, Adobe has removed this support (under the pretext that it is standard in Windows 10), but working on Windows 7, so I re-activated this plugin, but it has been developed for CS6, where channel order was different, it is no longer suitable for CC2018 and inverts some audio channels.

    So that's the explanation of the difference in the order of the channels in AAC and AC3.

    Fortunately Premiere allows to modify this order on each clip (Modify: audio channels). I just have to check if we can do it on a set of clips in one hand.

    I'm sorry to have blamed the Voukoder plugin, but the cause of the problem was not easy to highlight.

    Thanks again


  • Vouk

    Added the Label Not a bug
  • Vouk

    Added the Label 1.x