![]() the reason i am setting -5 (upwards tilt) is to offset the pitch, so that it is level with the imaginary horizon.for this I will set -XMP-GPano:PosePitchDegrees=-5.Pitch = 5 degrees (estimate by eye to be tilting downwards).I will not change in -XMP-GPano:InitialViewHeadingDegrees as the photo is facing the same direction as camera forward already.for this I will set -XMP-GPano:PoseHeadingDegrees=225.In my image, I estimate the heading, pitch and yaw values to be roughly: A negative roll assumes a right tilt.Īdjusting Pose Pose Roll = 90 (roll left)Īnd here is what this photo looks like in a photo viewer: Heading is measured between >= 0 and = -90 and -180 and ![]() ![]() I will use the following photo to demonstrate It is much easier to demonstrate these concepts using examples. For example, if I look up 45 degrees from straight ahead, my InitialViewPitch goes from 0 to 45 degrees (however, my PosePitchDegrees is 0 in both examples as the sky as I look up and the view directly in front of me is always in the center of my view). This is a concept much easier to understand. The InitialView considers the “real world” axis, that is a level imaginary horizon for roll and pitch and magnetic heading in the case of heading. This is where InitialView becomes useful because it is not relative to the center of the photo. For example, if I change pitch to 45 degrees, the viewer will load the image facing up +45 from 0. Therefore if I modify PosePitchDegrees post processing, the value I use to offset of pitch will be relative to this view. Let me artificially modify the pitch of the last image to demonstrate this visually.įfmpeg -i GSAQ3296.jpg -vf v360 =e:e:pitch =45 GSAQ3296-modpitch45.jpgĮxiftool -TagsFromFile GSAQ3296.jpg "-all:all>all:all" GSAQ3296-modpitch45.jpgĪgain, PosePitchDegrees here is still 0, relative to the center of the photo (the red line), even though it is actually different to the first image (before I modified pitch). In this case, the center of the image will show the sky directly ahead of the camera as it is tilting upwards. Lets say I take a photo with a pitch of 45 degrees (pitching the camera 45 degrees above the “real world” horizon). Therefore the PosePitchDegrees = 0 in this image. The red lines in the image above annotate the center of the image – the red x line (from left to right) shows the center of the image for pitch. Pose values are all relative to the center of the image – not the actual “real world” axis. It is first important to understand the difference between Pose and InitialView tags for roll, pitch and heading tags. As roll increases, the horizon rotates counterclockwise in the view. GPano:PoseHeadingDegrees (>= 0 and = -90 and -180 and = 0 and = -90 and -180 and In terms of roll, pitch and yaw the relevant tags are You can see the full Google Photosphere (GPano) specification here: You should keep this in mind based on how you plan to share content. YouTube!) that only have partial support the specification (and crucially not the XMP-GSpherical:InitialViewXXX tags). I will use Facebook for rendering videos, which fully supports the XMP-GSpherical specification. Therefore for all demos of XMP-GPano:InitialViewXXX photos I will use Facebook. Pannellum, like many other photo viewers, does not support the use of XMP-GPano:InitialViewXXX tags (it only supports XMP-GPano:PoseXXX tags). In parts of this post I am going to be using the Facebook photo viewer to display photos. An important note on 360 video/photo viewers However, there are a number of other useful metadata tags in these specifications that can be used to adjust roll, pitch and yaw in the viewer. I have talked previously about the importance of setting GPano:ProjectionType = equirectangular and GSpherical:ProjectionType = equirectangular for photo and video files respectively to ensure 360 viewer controls are shown. Many viewers use GPano (photo) and GSpherical metadata tags to render equirectangular content. As you will see in the demos later in this post, the visual content of the image or video remains unchanged (they all look identical), only the metadata used to render it changes. Sometimes this is overkill as it is possible to achieve the same result using the metadata of a photo or video. Over the last few weeks I have talked about how to adjust for roll, pitch, yaw, and heading by modifying the visual element of video and image files. In this post I will show you how to use these tags to ensure your equirectangular images and videos are loaded correctly in viewers.
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