12 Replies Latest reply on May 2, 2013 11:48 AM by Alka_line

    Audio clip desync issue

    Alka_line

      Hello everyone,

       

      Been having a bit of a problem with one of my video clips. All of my footage was filmed on the same camera, and then converted to FLV with media encoder. I'm just trying to cut and stitch them together into a video, and everything was going great, until this one clip.

       

      I tried importing the file the same way I'd been doing all of them. When I try and play the file however, the audio is out of sync, but about 2 minutes. I've tried reimporting, re-converting from its original format, restarting AE, restarting PC, checking frame rate.

       

      If someone might have a solution to this, I'd love to hear your suggestions. Also, if you have any questions about the files, I'll answer them the best I can.

        • 1. Re: Audio clip desync issue
          Rick Gerard Adobe Community Professional & MVP

          FLV is absolutely the wrong format for working with video. It should only be used for delivery to flash. It does not surprise me that your footage has gone out of sync.

           

          You should either use the original footage in your project or transcode it to a Production coded. Why in the world did you pick FLV?

          • 2. Re: Audio clip desync issue
            Alka_line Level 1

            I switched to FLV to keep down on file size. I've never had issues with it. It doesn't explain why only this one video doesn't work though. They are all identical in formatting, yet only this one has out of sync audio. The video plays perfectly fine in a video player, it just doesn't work when I bring it into AE.

            • 3. Re: Audio clip desync issue
              Rick Gerard Adobe Community Professional & MVP

              Storage is cheap. Ridiculously cheap. FLV is a delivery format based on h.264. It is the source of your problem. The frame rate and audio interleave get all fouled up. It can be the total number of frames. It can be one frame dropped. It can be about anything in a GOP compression scheme like FLV.

               

              Any production format is going to give you better results. Stick with FLV if you want but I wouldn't touch it with ten foot pole. Delivery formats are not suitable in any production workflow. If you have been getting away with it then you don't know what you are missing.

               

              Try rendering your problematic clip to jpeg quicktime and check the audio then. Try using the camera original. (what kind of camera by the way?). Both will work.

              • 4. Re: Audio clip desync issue
                Alka_line Level 1

                The footage was filmed on a Canon T2i Rebel. Not a dedicated video camera, but a DSLR that can shoot HD. By no means am I in a professional setting, but gotta use what's available. Converting to jpeg quicktime still has desynced audio. I do have an external audio file that I can work with and sync manually, but I still would like to know if there is a reason that just this one file is giving me issues.

                • 5. Re: Audio clip desync issue
                  Dave LaRonde Level 6

                  Well, at the moment the few things we know for certain is that you shoot on a T2i, you're on a PC (OS?), you run AE (version?) and you posess some kind of external audio.

                   

                  The solution may be as simple as deleting and re-ingesting the problem clip.  I'd start there -- it's so easy.

                   

                  No joy?  We'll need a boatload more information,  because it could be any one of a gazillion different things.

                  Here's a litany of diagnostic questions concerning AE problems.

                   

                  But at the moment, who's to say the problem lies in AE, and not somewhere else?  Expect more questions.

                  • 6. Re: Audio clip desync issue
                    Alka_line Level 1

                    Yes, for sure I should provide more info. This is my first post and I should have read the faq first.

                     


                    I'm running after effects 5.5 (10.5.0.253) on a PC with Windows 7. The original format was .MOV, and I've converted them all to FLVs with Adobe Media Encoder. The only reason I'm saying the problem lies within AE, is because the file plays perfectly synced in VLC and any flash player.

                     

                    Unfortunately, I don't have the source MOVs currently, as they are not on my hard-drive.

                     

                    Please let me know if you need more info than this.

                    • 7. Re: Audio clip desync issue
                      Rick Gerard Adobe Community Professional & MVP

                      I use canon original files all the time. They work great and there's no need to transcode for most operations. If you do transcode you should not further compress the footage. This will always lead to problems. A dedicated transcoder like MagicBullet Grinder is a preffered tool because it will preserve the original info better than running it through any kind of compression.

                      • 8. Re: Audio clip desync issue
                        Alka_line Level 1

                        Is it common to have an anomaly like this when changing formats? If it was every file that was off, I could understand that it's not a good idea, but the fact that it is only this one...

                        • 9. Re: Audio clip desync issue
                          Rick Gerard Adobe Community Professional & MVP

                          All it takes is one mis read of a GOP by the deocder. One little hitch in the data stream and you've lost sync. NEVER throw away your original footage unless you never want to use it again.

                          • 10. Re: Audio clip desync issue
                            Alka_line Level 1

                            Well thank you everyone for your help. I've definitely learned my lesson the hard way. Luckily I have that backup audio, or I don't know what I'd do.

                             

                            The reason I wanted a smaller file size, is my computer isn't super powerful, and it's far less of a strain on AE to work with smaller files.

                            • 11. Re: Audio clip desync issue
                              Rick Gerard Adobe Community Professional & MVP

                              Alka_line wrote:

                               

                              is my computer isn't super powerful, and it's far less of a strain on AE to work with smaller files.

                              Not true at all. It's much easier for AE to decode any production codec than it is to decode highly compressed sources. AE works internally totally uncompressed. Sending AE a FLV or other mpeg source file requires AE do decode the file, fill in the missing frame information, and create uncompressed frames to work with. It's not only file size, it's the CPU load to decode the files and turn them into pixels.

                              • 12. Re: Audio clip desync issue
                                Alka_line Level 1

                                Thank you, that's good to know. I'm not too knowledgable as to how AE handles these things. I'm more on the creative side of things.