Tutorial 1: Constant offset between picture and sound

5. Parameterizing the marker

The correction value

With Spline markers you change the offset between picture and sound by means of a correction value which you enter into the input field of the marker settings. In this way you shift the sound (more exactly: the audio track) relatively to the picture by the specified amount:

Correction value

With regard to the direction of the sound shift counts for all markers:

  • Increasing the correction value causes that the sound appears earlier.
  • Reducing this value causes that the sound is played accordingly later.

Frames and seconds

The correction value is measured in frames. Therefore it depends on the frame rate of the current video, to which time difference a given correction value corresponds. You find out the frame rate in the Properties dialog.

Choose for this the menu option File | Properties .... The following window appears:

Properties dialog

The information "Frames/sec" indicates how many video frames are played in every second. The video in our tutorial has a frame rate of 25 fps (frames per second), what corresponds to the television standard usual in Central Europe. This means, that if you specify e.g. a correction value of 50 in the above input field, you shift the sound thereby by 2 seconds.

Have once again a look at the video in the preview. The sound comes undoubtedly too late - but how much too late? Which amount do you estimate for the time difference to the picture (in seconds)?