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Understanding Spline markersWith Spline markers you define contemporaneous positions in the video and audio data stream by specifying a correction value for the adjustment of picture and sound in each marker. Hereby, the sound is not cut, but its playback speed is adapted like a rubber band in such a way that the marked positions are played at the same time. The correction values within the regions between the spline markers are calculated by means of a smooth interpolation function (a so-called spline). Such a spline distinguishes itself by the fact that it runs precisely through the defined interpolation points, but has no sharp "corners". Thereby is guaranteed that the playback speed does change suddenly nowhere.
If you use less than three Spline markers, the playback speed remains constantly in the entire project. From this result the following simplified applications for the spline marker kind:
Working with the correction curveThe correction curve is one of the most important assistance elements when you work with Spline markers. Here you have the entire correction process with all markers in the overview, can assess the effect of certain Spline markers, and at first sight recognize critical mistakes.
In the previous projects, the correction offset was always constant in a section. Here, however, it changes gradually what at last causes a change of the sound's playback speed. In our example, the sound speed is regular slowed down, what is to be seen in the fact that the gray line is straight and falling. The project analysis functionBesides the correction curve which gives a qualitative overview about the correction course, AV Adjust provides a quantitative project analysis function. You call this function by means of the menu command :Here you see among other things that the sound was slowed down to almost 95% of its original speed, but also, that the playback speed is really constant (the "Global sound speed difference" amounts to 0%). Besides, it is interesting that at the first frame the correction offset is nearly 0. This means that picture and tone start really in sync. If you had known this before, you could have spared yourselves the trouble to adjust the first marker, and instead of this you would have defined right away at frame no. 0 a Spline marker with a correction value of 0... ;o) |
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