Je lis la vidéo dans VLC et faire une capture par son intermédiaire directement.
Je peux essayer autre chose si ce n'est pas le bon outil.
Pardon me for answering in English. My French is not good enough to write an understandable answer. I have been experimenting with Livepano also and experienced the same problems at first. I noticed then that they were caused by wrong optimization settings in Autopano Giga. The instructions are somewhere on the Kolor documentation in a video, but they are easy to overlook. What has to be done in APG under Settings > Optimization > Lens distortion:
Focal calculation: force different
Distortion calculation: force different
Distortion model: 2nd order + optical axis center
And under Optimizer stages: turn off 4) Clean up control points or links.
After having done this for the panorama with VLC, stitching was much better and there were no problems anymore drawing the right size polygon in PtP - Livepano.
Let me know if this helps!