System and method for 3D (three-dimensional) video conversion and method and device for selecting key frame in 3D video conversion

The invention discloses a method for 3D (three-dimensional) video conversion and a method and a device for selecting a key frame in 3D video conversion. The method for selecting the key frame includes: after an i key frame is determined, computing feature matching rate of video frames behind the i key frame in a 2D (two-dimensional) video; selecting the video frames with the feature matching rate ranging from T1 to T2 as candidate video frames; and selecting one video frame from the video frames as a (i+1) key frame according to re-projection errors of the candidate video frames. Selection of the key frame is more reasonable as the candidate video frames are selected according to the feature matching rate of the video frames and the preceding key frame, and the subsequent key frame is selected according to the re-projection errors of the candidate video frames. Moreover, conversion of the 2D video to a 3D video based on the more reasonable key frame can improve the quality of 3D video conversion.