8 Replies Latest reply on Feb 22, 2012 1:23 PM by Dave LaRonde

    Fps creating an audio sync problem

    mrj7511 Level 1

      Ive looked all over but havent been able to find am exact answer. i use footage from a webcam at 15fps and then render the composition at 24 fps. sometimes during the video the there are sync issues between video and audio. is the difference in source and output fps creating this? thank you in advance.

        • 1. Re: Fps creating an audio sync problem
          Rick Gerard Adobe Community Professional & MVP

          Drop your 15fps footage in a 24 fps comp and audio will stay in sync but you'll have some motion artifacts between frames as the frames are blended together.

           

          Render a 24 fps file from 15fps footage and you'll have some motion artifacts between frames as the motion in the frames as frames are doubled up and the audio may or may not stay in sync depending on the codec of the audio.

           

          If the audio is sometimes in and sometimes out of sync you may be rendering to an uncompressed or nearly lossless production codec which requires a higher data rate than most computers can't handle.

           

          I don't know enough about your project to tell you more than that. There are dozens of ways to do what you're trying to do. Most work without problems. There are also dozens of ways to screw it up.

          • 2. Re: Fps creating an audio sync problem
            mrj7511 Level 1

            thanx for the reply here are the rendering spects i have been using:

             

             

            Main Options:

            Format: H.264

            Post-Render: None

            Channels: RBG

            Depth: Millions

            Colour: Premultiplied

            MainConcept: H.264 Video

            Bitrate 6.00 Mbps

             

            H.264 Options:

            Basic Video Settings- Profile High. Level 5.5

             

            Audio

            Audio Format: AAC

            Codec: AAC

            Audi Quality: High

            Bitrate Settings: 192

            advanced Settings- Precedence: Birate

             

            Audio Output:

            48.000 kHz

            Stereo

             

            If there is anything important I left out please tell me and i wll find i, i would really appreciate any help I can get to fix this issue.

             

            here is my latest video with the problem: http://www.youtube.com/watch?v=qiE-z8fRH4I

             

            at the 2:37 mark you can see that the auido/video are no longer in sync (it coincides with another auido graphic i use)

            and then at the 9:50 mark the audio slows down tremendously.

             

            again anything anyone can do to help out would be great thanx.

            • 3. Re: Fps creating an audio sync problem
              Rick Gerard Adobe Community Professional & MVP

              Use Adobe Media Encoder to transcode your webcam footage to something other than a mpeg stream before you try and edit it. Render the project to a production codec or use AME to render your AE project to a delivery codec directly. That should solve the audio issues.

               

              You never mentioned which version of AE you're working with. I'm guessing it's CS4

              • 4. Re: Fps creating an audio sync problem
                mrj7511 Level 1

                OK i will give that a try, im using CS5

                • 5. Re: Fps creating an audio sync problem
                  mrj7511 Level 1

                  You said to render the project to a production codec, is that in After Effects or AME? If it is in After Effects how do I do that?

                  • 6. Re: Fps creating an audio sync problem
                    Rick Gerard Adobe Community Professional & MVP

                    A production codec is any lossless or nearly lossless codec. Animation QuickTime, Jpeg QuickTime, Black Magic, Pro Rez, Avid all have production codecs. A delivery codec now days is an MPEG stream.

                     

                    You can render with the render cue or your could load your clips directly in the AME and render them to any production codec. You'll have to set up the encoding manually.

                    • 7. Re: Fps creating an audio sync problem
                      mrj7511 Level 1

                      Sorry, to be a pest, if I wanted to work within After Effects how would I go about doing this, if it is possible.

                      • 8. Re: Fps creating an audio sync problem
                        Dave LaRonde Level 6

                        You'd render out the individual clips by adding comps to the Render Queue, then rendering.  You can create a custom Output Module to use your codec of choice, and make it the default.

                         

                        But in terms of conversion time, Adobe Media encoder probably would be faster.