  The optimization of viewers' quality of experience (QoE) in 360 videos faces
two major roadblocks: inaccurate adaptive streaming and viewers missing the
plot of a story. Alignment edit emerged as a promising mechanism to avoid both
issues at once. Alignment edits act on the content, matching the users'
viewport with a region of interest in the video content. As a consequence,
viewers' attention is focused, reducing exploratory behavior and enabling the
optimization of network resources; in addition, it allows for a precise
selection of events to be shown to viewers, supporting viewers to follow the
storyline. In this work, we investigate the effects of alignment edits on QoE
by conducting two user studies. Specifically, we measured three QoE factors:
presence, comfort, and overall QoE. We introduce a new alignment edit, named
\textit{Fade-rotation}, based on a mechanism to reduce cybersickness in VR
games. In the user studies, we tested four versions of fade-rotation and
compared them with instant alignment. We observed from the results that gradual
alignment achieves good levels of comfort for all contents and rotational speed
tested, showing its validity. We observed a decrease in head motion after both
alignment edits, with the gradual edit reaching a reduction in head speed of
8\% greater than that of instant alignment, confirming the usefulness of these
edits for streaming video on-demand. Finally, parameters to implement
\textit{Fade-rotation} are described.
