This invention relates to video editing, and more particularly to an operator interface for a video editing system that provides enhanced visualization and interactive control of video sequences during the editing process.
Presently, the video editing equipment that is used tends to interpose a lot of numbers and technical considerations between an artist attempting to create a video program and the video images that must be manipulated in the course of creating that program. Cutting and splicing film on a film editor provided a visual and spatial dimension to the temporal aspect of a film. Thus far, efforts to bring this same sort of interactive convenience and "feel" to the video tape editing process have met with limited success, although considerable progress has been made.
U.S. Pat. No. 4,937,685 to Barker et al for a "Method of Display Presentation for Video Editing" discloses an apparatus and method for video composition that presents an operator with video labels at each end of each video clip. Video labels are low resolution digital representations of a frame of actual video. Because these video labels contain much less total information than the underlying video frame that they represent, they can be more readily stored and retrieved than actual video images can be, and are therefore used as surrogates for the real video images during some parts of the editing process.
In the system described in the Barker et al '685 patent, the operator can view a clip of video or a transition between two clips of video on a main monitor in an "endless loop" repeating display. A set of four label display screens show the above described video labels of the clips currently under active manipulation. A plurality of additional smaller display monitors are provided in vertical pairs for viewing a series of pairs of video labels representing a series of clips currently arranged to be viewed in sequence.
In the Barker et al '685 system, the operator is able to manipulate the video labels instead of the video itself, thereby permitting the re-arrangement of the video clips virtually, even though the actual video is still stored in its original order, thus minimizing the need for fast access to the video itself. When rapid access to the actual video is required, it is achieved by recording multiple copies of the same video clip on multiple video tape recorders (VTRs) and positioning each of the VTRs at different locations on the clip, so that one VTR is always close to any desired point of interest.
While the Barker et al '685 system provides the operator with video labels at the beginning and end of clips, a sequential continuous loop display of the active clip and a readout of the duration of the active clip, it does not provide any graphic display of the clip's length or the rest of its internal contents.
A video editing software system called "Media Maker" is produced by Macromind Inc., 410 Townsend St., Suite 408, San Francisco, Calif. This system displays simple timelines that indicate the length of video sequences as they are being manipulated, but these simple timelines do not provide any visual cues as to the contents of the video sequences.
In connection with another aspect of the prior art, control of the displayed location on a video tape in a video tape recorder has traditionally been accomplished with two rotatable wheels or knobs or a single one which operates in two modes, depending on the position of a mode control switch. In the first mode of operation, rotational motion of the wheel or knob is interpreted as positional distance. In the second mode of operation, the same rotational motion is interpreted as velocity magnitude control. U.S. Pat. No. 4,988,982 to the present inventor for "Touch Pad Machine Control", hereby incorporated by reference, describes this prior art in its "Background of the Invention". The specification of U.S. Pat. No. 4,988,982 describes an alternative approach to VTR control that relies on a touch pad with different regions, one of which is devoted to position control, another of which is devoted to velocity control.