360: Hemispherical to Equirectangular Video Filter

Converts a video frame with two hemispherical images to a single equirectangular frame. The plugin assumes that both hemispheres are in the frame. If you have a camera like the Garmin Virb360 that produces two videos, one from each camera, you should start by converting them to a single movie by placing them side by side using, for example, ffmpeg (you can also add parameters to produce lossless, intra-only output here for easier editing):

ffmpeg \
    -i left.mp4 \
    -i right.mp4 \
    -filter_complex hstack \
    output.mp4

Parameters

  • Interpolation: Nearest-neighbor or bilinear. Determines the sampling method.See also “Interpolation” in the Glossary / Terminology
  • Yaw, Pitch and Roll: The two fisheye cameras of a 360 camera are rarely perfectly 180 degrees apart. These parameters adds a rotation to both lenses to correct for this.
  • Projection: The fisheye projection type. Currently only equidistant fisheyes, like the Ricoh Theta and Garmin Virb360 are supported.
  • FOV and Radius: The field of view of a single hemisphere in degrees, and the radius of the image circle, expressed as a fraction of the frame width.
  • X, Y and Up: The image center and image orientation for the front- and back-facing camera. The X parameter is a fraction of the image width, and the Y parameter a fraction of the image height. Up is the “up” direction in the image, in degrees clockwise from a direction towards the frame top edge.
  • Nadir Radius and Nadir Start: 360 cameras like the Theta have a problem with the nadir direction where, no matter what, you will have a little of the camera in the image. This parameter “stretches” the image near nadir to cover up the missing parts.