Autopano Video - Creating and editing the reference panorama
This tutorial will show you how to create and edit a reference panorama of your video stitching. What is a reference panorama ? It's a model of stitching, created at a precise instant of your video, used to stitch an entire state in the timeline. For more information about the timeline see Autopano Video user manual - the timeline. You need to create a first panorama to start editing your project and then you will come back to this step as many times as you add transitions. Here you will a find a video illustration of this step followed by the details of the edition.
AUTOPANO / AUTOPANO VIDEO
During this part of the video stitching process you are going to switch between Autopano and Autopano Video. Here is a quick summary of the steps :
- Creating a reference panorama: Autopano Video
- Editing the reference panorama: Autopano
- Validating the reference panorama: Autopano Video
Note that the preview in Autopano Video is updated when saving the .pano file in Autopano.
Once the videos have been loaded and synchronised (see : Practical synchronization), click the button “Stitch as...” to create a reference panorama using stills from the current moment in the timeline.
Pick a moment in the clip that corresponds the best for the video as a whole. For instance, avoid chosing a moment where you are passing through a door, or approaching a wall.
If you are always filming in the same context (always exterior landscapes for example) you can rename your videos to keep the right order of the cameras, you can use the option “stitch as .pano” which will stich your videos the way it has been defined with a previous project.
This can be useful to save time but also to stitch a video sequence where the overlay zones are difficult to analyse (no details or too similar).
To create a reference panorama and to make it editable via Autopano, Autopano Video generates images corresponding to the moment chosen, as well as taking into account the temporal synchronisation.
The stills are generated as .TIFF and the name is composed of the name of the corresponding video + .tif extension.
When a panorama is loaded or rendered in Autopano Video, an inverted name generation is applied, to be able to find the videos corresponding to the stills and to load them if needed.
For example, the extraction of the first frame of the video called cam1.mp4 will generate a file called cam1.MP4.tif .
In the other way around, if Autopano Video loads a .pano containing an image called cam3.mp4.tif, it will be associated with the video named cam3.mp4 if it exists.
This entails many things:
- you can recreate a panorama from scratch and/or copy then modify the original panorama. Slide the .pano into Autopano Video and it will find the videos.
- If Autopano Video does not find videos associated to the image, it will keep the still and stitch it with the other videos that have been found. This would allow you to replace a video by a better quality photo if you know there won't be any movement in that area of the scene. Or even to patch a stitching to correct a potential failure during the shooting.
EDITING IN AUTOPANO
Once you have created at least one reference panorama you can edit it and switch to Autopano. If the panorama is not good you can create another one any time you want, applying some changes, i.e.: synchronization or using a different instant in the timeline.
By default, the generated panorama is in full 360 spherical mode. The color correction is not activated.
The optimization does not use the multiple view point mode despite the imperfect nodal point.
Use Autopano to adjust certain parameters of the generated panorama: horizon, links, colors, projection, blending presets and patching.
- No hypothesis is applied for the panoramas horizon. It will generally require a manual adjustment:
Links between images
- Check your links between images and adjust them if they are not correct. Most of the equipment used for stitching videos does not allow you to align the cameras perfectly to the nodal point. The regular users know that Autopano allows you to improve this type of stitching with the aid of the multiple viewpoint option. However, this mode may allow you to correct the stitching (and the parallax) for the moment of reference, but it will tend to worsen the problems in the rest of the video. This is why the generated panorama does not use this option. In the cases where the cameras will not move, or with very little movement, this option may prove to be relevant. Some useful links :
- Depending on your cameras you might need to adjust . The remaining differences will be compensated by the multiband render.
- If you do not wish to use a video player made for 360° videos such as KolorEyes (iOS/Desktop), you are free to use any type of projection, namely the “little planet” projection which gives it a very fun end result.
- You can adjust the "Blend settings" in Autopano as well as in Autopano Video :
Apply a patch to your video
Your patch has to be applied in Autopano, see this tutorial: How to patch the Nadir simply.
Save your reference panorama
Do not forget, to save your .pano file. Note that it can be reused as a reference if you film another sequence in similar conditions.
VALIDATION IN AUTOPANO VIDEO
Now you can switch back to Autopano Video in order to validate your reference panorama all along the timeline.
Validate your reference panorama
Navigate through the main timeline to validate your reference panorama at different instants. If it needs some modifications just click on "edit", do your changes and save it.
If you want to edit your reference panorama at another instant browse the timeline, click on "Stitch as pano" and browse your first reference panorama. It will create another panorama which can be edited as shown previously.
Note that editing the panorama may have two different aims:
- Keep the horizon straight accros the time despite a rotation of the rig during shooting.
- Adapt the stitch to the parallax accros the time. The effect of rig's parallax on the stitch depends on the scene whitch is likely to change during the video as soon as the rig is not static. To do so, in spite of simply straightening the horizon of the new panorama, delete the links and run a geometric analysis to detect new points, followed by a quick optimization.
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