8 Replies Latest reply on Mar 29, 2012 3:34 PM by Dave LaRonde

    Audio pop at the end of renders

    CVWmedia

      Hello, I have been having this issue for several years now, and I have work arounds that work fine. I'm posting here to see if anyone else has had this problem, and if so hopefully find a more permanent solution.

       

      The problem in a nutshell is renders from After Effects having a loud audio pop at the very end. I am always rendering to Uncompressed AVI, or Blackmagic MJPEG AVI. The audio pop occurs with both formats on a regular basis. This issue is very hard to troubleshoot as I can not recreate it... Meaning the same project can be rendered multiple times and only have the audio pop on one of the renders. The pop has shown up even with audio layers trimmed well before the end of the video.

       

      So I realize this is very hard for anyone here to troubleshoot. But if anyone has had this issue, or has any ideas to help narrow this down the problem I would greatly appreciate hearing from you!

       

       

      I have anwsered provided some information below from the FAQ post. Most of this will not apply I'm 99.99% sure, but what the heck.

      Current AE Version: CS 5.5 10.5.0253

      Current OS: Windows 7

      Other software normally running: Trillian, Chrome/Firefox

      Third party codecs: Blackmagic

      Third party plugins: Optical Flares, and most Red Giant plugins available

      OpenGL: No

      "Does the problem only happen with your final output, RAM preview, or both?": Only on final output.

      Are you using Render Multiple Frames Simultaneously multiprocessing?: No, I am not.

        • 1. Re: Audio pop at the end of renders
          Dave LaRonde Level 6

          This is why it's not wise to use mp3, AC 3, or any kind of compressed audio in AE, including audio tracks of a movie clip: they too may have been compressed.  Change the audio to aiff or wav, and life gets better.

          1 person found this helpful
          • 2. Re: Audio pop at the end of renders
            Mylenium Most Valuable Participant

            Dave has a point, but you might wanan inspect your files in an audio editing app. These pops are sample distribution issues because the files are a tiny fraction too long or too short and AE fills in the blanks or just chops it off. the randomness may relate how specific CoDec options further quantize samples at the wrong frames and/or how invalid volume ranges in thge sources amplify disturbances in the output. It's a complex topic, but suffice it to say that AE is less than ideal for encoding and manipulating audio in the first place....

             

            Mylenium

            1 person found this helpful
            • 3. Re: Audio pop at the end of renders
              CVWmedia Level 1

              Thanks for the responses! I actually swore off MP3 files years ago, so I work solely with wav files. Mylenium's comment is pretty far over my head, so I will have to do some research on this before I can say anything else. Thanks again!

              • 4. Re: Audio pop at the end of renders
                Dave LaRonde Level 6

                Glad to hear you don't use compressed audio, but Mylenium makes a good point about scrutinizing the source audio in your comp. 

                 

                At my TV station, our dear departed station announcer would email us MP3's of voice sessions, which we dutifully converted to AIFFs.  No matter what we did, there would always be a snapping sound at the edit points.  We had to use 2-frame crossfades and 2-frame fades to silence to overcome them.

                • 5. Re: Audio pop at the end of renders
                  CVWmedia Level 1

                  Hello again! I did a lot of troubleshooting and finally got to the bottom of this issue. Here are some details about the problem for anyone interested. My work around solution will be listed below as well.

                   

                  -Only occurs when rendering to:

                  • Format: AVI
                  • Codec: None

                  -Only occurs with a 29.96 frame rate.

                  -Occurs when the project is greater than or equal to 26 seconds. So for clarification, 25 seconds and 29 frames will not have a pop.


                  *Changing the audio from 16 bit to 32 bit also fixed this issue. But wasn't an option for me to do on all videos.


                  Anyone interested in re-creating this issue can simply make a composition of any size, make it 30 seconds long at 29.96 frame rate and render to the format listed above. The audio pop will be at the very end (let the video play through all the way if you don't hear a pop the first time). And again, this has been occuring on the past few versions of Windows as well as the last couple releases of After Effects, but feel free to look at original post for current computer information.

                   

                  Solution: I started using a new uncompressed workflow to skip this problem. This should be a viable work around for just about anyone.

                  • Format: AVI
                  • Codec: Uncompressed UYVY 422 8bit

                   

                  Thanks for all the responses, and I hopefully this helps if you are having the same issue!

                  • 6. Re: Audio pop at the end of renders
                    Dave LaRonde Level 6

                    You seem to have been very thorough in troubleshooting, and very accurate in the information you provide.  In which case, you have nothing to fear.

                     

                    If this bizarre problem only manifests itself 29.96 fps, you shouldn't have to deal with it.  The correct NTSC frame rate is 29.97 fps.

                    • 7. Re: Audio pop at the end of renders
                      CVWmedia Level 1

                      Hah, yeah... My bad, I am in fact using 29.97, but I always remember it wrong for whatever reason. Sorry about that!

                      • 8. Re: Audio pop at the end of renders
                        Dave LaRonde Level 6

                        You know, I STILL don't think you have much to worry about if you edit together your footage in an NLE prior to After Effects work.  The good audio is there, and you can render out of AE video-only. 

                         

                        I'll admit your problem is certainly annoying, and my workaround may not work for you.  I share the same suspicion as Mylenium: the audio was recorded that way.