Why is After Effects adding a space/silence to the beginning and end of the audio in my file

[mohalia]

I am trying to create a video that is a seamless loop in both the visual and audio. After I export the file from after effects, the visual plays in a seamless loop, but the audio does not - there is a tiny space of silence in between. I imported the file into Adobe Premiere, along with the original audio file, and the waveforms are different. There is silence at the beginning and end of the waveform in the After Effects file, in addition to the waveform being slightly off throughout. I cannot figure out why AE is doing this or how to fix it. Any insights are greatly appreciated!

[mohalia]

I just tried exporting the file from Premiere with the original audio (with audio from AE file muted), and Premiere seems to be doing the same thing! Adding a tiny bit of silence at the beginning and end! Aghhhhhh

[Rick Gerard]

Nothing wrong. There are a few frames before the audio starts and ends. Open the audio clip in Audition to verify. Nothing wrong except the expectations. 

[mohalia]

Yes, there is something wrong. In AE, the audio starts on the first frame. When I bring in the exported AE clip to Premiere, the audio starts a few frames after. I am trying to make a seamless loop - the altered audio file ruins this. As you can see in the screenshots, the original audio file (on bottom) starts at the very beginning while the AE audio file does not. Why should I expect the exported file to have different audio than what I put in?

[mohalia]

After many hours of stress, I have found a workaround, in case anyone has this issue in the future. I read on another forum that the way that adobe compresses the audio will always result in this glitch and there is no way around it. They recommended using Handbrake to convert the .mov file. I tried handbrake with default settings and still got the gap in the audio at the end of the file, but not the beginning - very weird! I kept playing around with the settings and was able to export the file as .m4v (with AC3 audio codec) and keep the original audio intact. From there, I changed the extension of the file to .mp4 and all was good. 

[Scrantastic]

Thank you for the update @mohalia - I've been struggling with this for days. Can you please walk me through your process? Are you exporting from After Effects to Media Encoder? I can't seem to find the format to make an m4v with an AC3 codec.