creating timeline-based editing gui in java

Question

I want to create a timeline-based editing GUI in java - in the style of a video-editing software (such as adobe premiere for example). Below is an image, how I have the GUI in mind (sorry for not including it directly - as a new user that feature is disabled):

Whats currently implemented is just the timeline-slider at the top (with JSlider) - all the rest is just made up with Photoshop (also the black-line that goes down from the slider, through the layers).

Now my question is not very specific, I just wanted to get some input how I could implement the rest as nice as possible. To be a little bit more precise, I would appreciate hints to the following topics very much:

1. How to organize the whole gui - concerning the time indicator-line which goes from the top to the bottom through all the layers?
2. How to visualize the waveform, are there good (and free) packages that can be used? (audio files are either MP3 or WAV)
3. Which element to use for the text-segment layers (they should be draggable & droppable somehow) -> JLabels, JButtons, how to best solve the drag-n-drop feature?

You see I have still some work ahead of me, any good advice or point to the right direction would be very kind!

Answer 1

1. For the waveform issue you could take a look to this question and the accepted answer. The class creates a PNG image file, but you should be able, instead of saving the image, just display it in your programm.

2. The drag n' drop thing is well explained in this tutorial by Oracle.