Problem
Exported vertical video has unintended pillarboxing because source scaling and sequence scaling are both active.
Solution
Root Cause / Diagnostic:
When creating 9:16 vertical video (1080x1920) for Shorts or Reels, compounding spatial scaling settings triggers unintended letterboxing or pillarboxing. If the source clip's scale interpretation is set to 'Scale to Frame Size' while sequence preferences or output scaling are configured to 'Fit', the NLE fits the 16:9 horizontal image inside the vertical frame with black bars on top and bottom, and then nests or re-scales it again. This produces black pillarbox bars on the left and right borders of the exported vertical file.
Actionable Fix:
1. Set Sequence Settings dimensions explicitly to 1080 horizontal by 1920 vertical (aspect ratio 9:16) with square pixels (1.0).
2. Select the clip on the timeline, open Motion properties, and set Scale to 'Fill' (or manually increase scale to ~178% to cover the entire 9:16 canvas).
3. Review the export preview window to confirm that footage fills the entire vertical frame without any black borders or pillarbox padding.
Pro Tip:
Utilize Premiere Pro's 'Auto Reframe' or DaVinci Resolve's 'Smart Reframe' to automatically track the primary subject and maintain centered framing throughout the vertical crop.
When creating 9:16 vertical video (1080x1920) for Shorts or Reels, compounding spatial scaling settings triggers unintended letterboxing or pillarboxing. If the source clip's scale interpretation is set to 'Scale to Frame Size' while sequence preferences or output scaling are configured to 'Fit', the NLE fits the 16:9 horizontal image inside the vertical frame with black bars on top and bottom, and then nests or re-scales it again. This produces black pillarbox bars on the left and right borders of the exported vertical file.
Actionable Fix:
1. Set Sequence Settings dimensions explicitly to 1080 horizontal by 1920 vertical (aspect ratio 9:16) with square pixels (1.0).
2. Select the clip on the timeline, open Motion properties, and set Scale to 'Fill' (or manually increase scale to ~178% to cover the entire 9:16 canvas).
3. Review the export preview window to confirm that footage fills the entire vertical frame without any black borders or pillarbox padding.
Pro Tip:
Utilize Premiere Pro's 'Auto Reframe' or DaVinci Resolve's 'Smart Reframe' to automatically track the primary subject and maintain centered framing throughout the vertical crop.