Can I remove the filler track at once for all the clips?

Solution

No, filler tracks cannot be removed for all clips simultaneously.

Reason  

Filler tracks are automatically applied when the clip’s narration track length and the video track length differ. It helps to fill the gap when the narration track length is longer than the video track length. Since each clip has a different narration and video duration, the filler track length varies for each clip and must be adjusted individually. 

Steps

1. Click on the Advanced Editing

2. Navigate to the Filler track 

3. Change the filler track length to "0" and press the Enter key. 

Note: Setting the filler track length to “0” will remove the filler track from the clip.

1. Click on Save changes. 

   Now the filler track will be removed.