6 Replies Latest reply on Apr 15, 2011 1:46 PM by PuuhaJimi

    Audio popping after burning blu-ray in 5.1

    Mag2124

           Just as a disclaimer, I am fairly new to Adobe Premiere and I am running Premiere Elements 8 on a Sony Vaio with an Intel Core i5-580M processor, ATI Mobility Radeon HD 5650 GPU, 8GB DDR3-SDRAM-1066 and Windows 7 Home Premium 64bit.

       

           I am attempting to create blu-ray disks in full HD and 5.1 surround sound. Source video is full HD 1920x1080 with .M2TS extension. When I have Adobe Premiere Elements 8 check the properties for my videos, it says the source audio format is "48,000Hz - compressed - 6 channels" and the project audio format is "48,000Hz - 32 bit floating point - 6 channels". This is despite the fact that the source should be 5.1. However when editing videos "5.1" shows up next to audio 1 on the timeline. I read something about this issue and I assume this isn't the cause for any poor audio after a blu-ray burn.

       

            I create new projects using these settings:

       

                     NTSC-AVCHD-Full HD 1080i 30 5.1 Channel

       

           After some quick editing I burn a blu-ray disk with the H.264 1920x1080i NTSC Dolby preset. When checking the quality of the burn the video looks great, but audio has a distinct popping or crackling occasionally that is not in the source files at all. Anyone have any ideas why a burn causes these audio blemishes to show up? I have never had any issues with 2 channel burns and I will probably just end up sticking with 2 channel audio if a solution can't be discovered. Also of note, the audio output is much lower from the burned copy than it is when played back from the source file. This will happen even when the clip volume is set to the max of +6.0dB. Thanks for any help.

        • 1. Re: Audio popping after burning blu-ray in 5.1
          the_wine_snob Level 9

          First, PrE cannot Burn, or Export/Share DD 5.1 SS Audio. Even PrPro needs the additional Minnetonka Audio SurCode DD 5.1 SS plug-in, to Export that Audio stream. PrE can work with DD 5.1 SS in many Project Presets, but will need to mix-down to 2-channel for Export, or Burn.

           

          Now, when one makes Cuts on Audio files, and butts them up, and the Cuts are not at "zero-crossings," there can be pops, or big ticks. This is due to the lack of continuity in the Audio waveform - not at zero-crossings. Usually, adjusting those Cuts to match zero-crossings will eliminate the pops and clicks.

           

          Good luck,

           

          Hunt

          • 2. Re: Audio popping after burning blu-ray in 5.1
            Mag2124 Level 1

            Thanks for the quick response, I suppose I should have known that. It appears the program tricked me when it gave me the option to open a new project that uses 5.1 audio. It seems the popping occurs even in areas where I don't make any edits. I suppose this is because it is converting the audio to 2 channel? Are there any techniques or perferred methods to mix down to 2 channel before I try to export so that I can confirm the audio is good to go, instead of wasting another BD-R. Thanks again for the advice, and Merry Christmas.

             

            Mark

            • 3. Re: Audio popping after burning blu-ray in 5.1
              the_wine_snob Level 9

              Mark,

               

              Usually the down-mix in PrE is very good, and totally trouble-free. I have not seen instances of PrE introducing transients (pops, clicks, etc.) into the mix-down.

               

              One of the first things that I would look at would be the Waveform Display of the troublesome Audio Clips (the source Clips), with the display zoomed in quite a bit, and look for "spikes" that would indicate transients.

               

              If the source files are perfectly clean, then I would bring the down-mix files into an audio-editing program, like Audition, or the great, free Audacity, and study that closely. Do you see the transient spikes there, after Export?

               

              When faced with transients, I use Adobe Audition, a separate, full-featured audio-editor, as it has special settings for "cleaning up audio." This ARTICLE will also give recs. for other programs. Though the article was written more for removing ambient noises from audio, one program, Audio Cleaning Lab by Magix, that program works well with ticks, clicks and pops too.

               

              Good luck,

               

              Hunt

              • 4. Re: Audio popping after burning blu-ray in 5.1
                PuuhaJimi

                Hi,

                 

                I happened to run into same situation that was described at the first post of this thread. Any chance of sharing what caused the audio popping at unedited videos? When I try to import my AVCHD-video (with 5.1-soundtrack) to Premiere Elements 9 everything looks otherwise ok, but this clearly audible popping happens every two or three seconds at the preview and also at the final, rendered video.

                 

                There is no difference if I choose project settings to be 5.1 or stereo audio.

                • 5. Re: Audio popping after burning blu-ray in 5.1
                  the_wine_snob Level 9

                  Welcome to the forum.

                   

                  If you play the file in, say MediaPlayer Classic HC, or another good AV file player, and listen carefully with a good set of headphones, is the Audio portion perfectly clean?

                   

                  When you look at the Audio portion of the Clip, and zoom in on the Timeline (both vertically and horizontally), do you see spikes (tranisents) at the points of the "pops?"

                   

                  If you rip the Audio from the file, with a program, like the free Audacity, do you see those same transients - this is for the original file, and not one output from PrE?

                   

                  Good luck,

                   

                  Hunt

                  • 6. Re: Audio popping after burning blu-ray in 5.1
                    PuuhaJimi Level 1

                    Thanks.

                     

                    If I play the original mts-file with Media Player Classic, the audio appears 99.9% clean. Using my headphones and 30 second test section, I could locate one barely audible "pop". PrE timeline zoom couldn't show any spikes or anything else suspicious, so I looked into this by extracting audio channels with Mediacoder to wav-file and checking how it looks at Audacity. One channel appeared to have this small step which caused the "pop". This is best described by following picture:

                     

                    tracks001.png

                     

                    Then, when I export the video (or just audio to wav-file) I get dozens of these similar steps which sound like "pop". Sometimes it is just on one channel, sometimes on both channels. They appear at every 2...3 seconds or so. For comparison, this is how the "pop" looks like when exported from PrE:

                     

                    tracks003.png

                     

                    Any further suggestions what might cause this increase in "popping" or how to fix it?