4 Replies Latest reply on Feb 26, 2009 7:09 AM by rjf7r

    audio aliasing distortion in CS3 output when sound effects applied

      Hi, I need assistance for fixing the problem with sound output. I am trying the Premiere CS3 version, with which I tried to output mpeg2 video format for DVD movie. I am hearing nonstop aliasing distortion or may be worse (squeaks,whistles,edginess, a lot of extra queazz and pops) all the way 'til the end of the output video.
      It occurs whenever I applied sound effects: namely Multiband compressor. while I was editing in the timeline, everything sounds perfect, distortion only happens in the rendered out product video.
      I tried undo Multiband compressor and rendered another video, it sounds perfect. Not alone with Multiband compressor, I have experienced the same result with the pitch shifter effect. I suspect it's the sound card problem, I wonder if Adobe Premiere CS will have certain features to coordinate with specific sound cards?
        • 1. Re: audio aliasing distortion in CS3 output when sound effects applied
          Webshark2000 Level 1
          You said you're exporting as an mpeg2, are you separating your video and audio (exporting a separate wav file), or are they combined? What are your audio compression settings?
          • 2. Re: audio aliasing distortion in CS3 output when sound effects applied
            Level 1
            The way I use the multiband compressor effect is by means to apply a digital simulation equivalent to a mixer's compressor in analog sound processing, I do not know if the 'compression' of digital data actually happened.
            But I'll try to show what settings I made in the Multiband compressor sound effect:
            low freq attack time: 0.10 millisecs
            low freq release time: 144 millisecs
            Compressor Ratio: 2.5
            Threshold: -35dB
            mid freq attack time: 0.10 millisecs
            mid freq release time: 145 millisecs
            Compressor Ratio: 2.5
            Threshold: -38dB
            High freq attack time: 0.10 millisecs
            High freq release time: 144 millisecs
            Compressor Ratio: 2.45
            Threshold: -40dB
            Some details of my video format: The video and sound are captured in combined format via firewire from HDV source, edited and exported as mpeg2 720x576 combined video and audio (no separation). The timeline sound is noise free, only the exported video contains the noise, pops, squeaks, etc.
            I have exported the video and audio together in Adobe Media Encoder, settings as follow, video I created VBR 2 pass, 5 for quality, 25 fps progressive, level/profile main, bitrate as follows: 2 min 4 Target 6 max, for sound settings: format mpeg, layer II, stereo, 16 bit 48 kHz, bitrate 224 kbps
            • 3. Re: audio aliasing distortion in CS3 output when sound effects applied
              Level 1
              I think I found the solution. Here's the trick I realize after numerous experimenting. It is concluded that not to nest a sequence, say sequence A, where you already applied sound effect, into another sequence, name it sequence B. If you use sequence B (containing sequence A in it) to export video, you'll get unclean sound whereever the portion you've applied the effect. So just export directly from the sequence you have the original footage or video footage, try not to export from a sequence that contains a sequence /sequences, if sound effects are applied.
              • 4. Re: audio aliasing distortion in CS3 output when sound effects applied
                rjf7r
                I can confirm that I have found the same (very annoying) problem. Nesting a sequence containing audio compression into another sequence produces very poor quality audio (sounds like over-driving/clipping to me) in exported output (playing the second sequence in Premiere sounds OK).