I am running Audacity 2.3.1 on Mac 10.14.4.
I edited a sound track in Audacity from an MP4 video file. My aim is to use the edited audio tracks in a Final Cut Pro X video project.
I used a limiter in Audacity to prevent any clipping. I then exported the edited audio tracks as an AIFF (Apple signed 16 bit PCM) file. When I import this AIFF file back into Audacity it has many clipped segments.
Please help me sort out what I am doing wrong.
Check that the track “Gain” slider is set to zero before you export (Audio Tracks - Audacity Manual)
The track Pan and Gain sliders are applied when exporting the mix, so if the Gain slider is above zero, and the waveform level is high, then the exported file could be clipped.
Are you seeing that from the red vertical line clip indicators? Note that those indicators do not necessarily mean that the audio is actually clipped, but just that the audio reaches zero dB (which happens when the audio is clipped, but can also occur when the audio is absolutely maxed out but not actually clipped).
Given that your final video file will use a compressed format, your audio should ideally be normalized a little below 0 dB to allow for compression approximations. Before you export from Audacity, “Normalize” to a bit below 0 dB (say around -2 dB).
Dear Steve,
That was exactly my problem. I realized it a while after I submitted my posting. I tried to delete it but could not find a way to do so. Once the two sliders are in the center the problem goes away.
I appreciate your taking the time help me to address the issue.
Many thanks,
Francisco
Super 
I’ll close this topic as “Solved” as it may help other users that encounter the same problem.