[John Greene]

the cause of this is, I believe, discrepancy between the ‘sequence’, ‘preview’ and ‘export’ settings.

i have just started turning out IGTV videos which are 9:16 by rule. When setting up a suitable seq preset, in this case 1078 x 1920 the ‘preview’ setting automatically jumps to 607×1080 because the I-Frame codec used to make previews has a max height of 1080 (as it would having been designed in a pre iphone world ☺ )

The resultant ‘preview’ is NOT useful or operational for ( as a previous writer wrote somewhere) it does not divide by 8 !!
In order to fill the gap created PrPro adds the pink/green bars of doom !

Solution in this case is to set all 9:16 video previews to 540×960 (1/2 of 1080×1920) The result is not great as a preview but it cannot go higher !

REMEMBER when exporting DO NOT TICK THE USE PREVIEWS BOX
The codec used to export is much better than the I-Frame preview one anyway
It’s only time !
Hope this helps