[gst-devel] editing list concept - still not sure

[Christoph Scheurer]

On Fri, May 11, 2001 at 04:33:18PM +0200, Ronald Bultje wrote:
> The whole idea here is that you have your NLE reading an editlist file and
> then the NLE will create the sources, nodes etc, put them in the right
> order. I thought it would be a good idea to have a generic format for these
> editing lists, just to make things easy. So although the nodes, sources etc
> exist in gstreamer, I want to make a generic concept of an editing list
> file format to tell the NLE how to put these individual components together
> to get the output video stream that we wanted.
I see. I think writing the editlist in XML is a good idea. For the NLE you
would then have a single timeline as the document root and then a hierarchical
structure that you can follow recursively, like:

|      *
|      | video
|      | file 1
|      |
|      *
|      *-overlay filter
|          *          *
|          | video    |
|          | file 2   | blank
|          |          *
|          |          *-overlay filter
|          |              *          *
|          |              | file 3   | picture
|          |              |          |
|          |              |          |
|          |          *---*----------*
|          |          *
|          |          | blank
|          |          |
|      *---*----------*
|      *
|      | video
|      | file 3
|      |
V      *
time

You would have to make the filters behave correctly if one (or more) input
stream is blank (e.g. don't do the overlay). If the NLE needs a specific frame
it looks on the main time-line which element is currently active, and then
looks on its inputs and so on recursively until it gets to the correct frame
number relative to the main time-line.

Does that seem reasonable?

Christoph




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