Re: [Mlt-devel] Compositing and MLT

[Dan D. <da...@de...>]

On Mon, Nov 29, 2010 at 6:50 PM, Timothy Braun <bra...@gm...> wrote:
> Hello Everyone,
>   I'm hoping someone can help me with this.  I need to compose a video
> consisting of 4 - 30 second segments.  Each segment needs to be split into a
> 3x2 grid with each grid cell containing a 240x240px video.  So the final
> outcome will be 720x480px.  This would allow for a total of 24 - 30 second
> videos in 2 minutes.  Not only that, it needs to be reproducible and
> configurable.  The final version will be developed in C but I would like to
> get something working initially with xml or some sort of scripting language.
>
>   I've looked at the website, but am having a hard time finding where to
> start.  I've attempted to produce something similar using GStreamer but have
> gotten to a point I have to look at other options.

Here is a simple 2x2 example that you extend. Save the following to a .mlt file.
Then, you can process 4 of them as:
melt 1.mlt 2.mlt. 3.mlt 4.mlt -profile dv_ntsc -consumer avformat:foo.mp4 ...

<?xml version="1.0" encoding="UTF8"?>
<mlt profile="dv_ntsc">
  <multitrack>
    <playlist>
      <producer mlt_service="color" out="897">
        <property name="resource">black</property>
      </producer>
    </playlist>
    <playlist>
      <producer out="897">
        <property name="resource">capture001.dv</property>
      </producer>
    </playlist>
    <playlist>
      <producer out="897">
        <property name="resource">capture002.dv</property>
      </producer>
    </playlist>
    <playlist>
      <producer out="897">
        <property name="resource">capture003.dv</property>
      </producer>
    </playlist>
    <playlist>
      <producer out="897">
        <property name="resource">capture004.dv</property>
      </producer>
    </playlist>
  </multitrack>
  <transition out="897">
    <property name="mlt_service">composite</property>
    <property name="a_track">0</property>
    <property name="b_track">1</property>
    <property name="progressive">1</property>
    <property name="geometry">0=0%,0%:50%x50%</property>
  </transition>
  <transition out="897">
    <property name="mlt_service">composite</property>
    <property name="a_track">0</property>
    <property name="b_track">2</property>
    <property name="progressive">1</property>
    <property name="geometry">0=50%,0%:50%x50%</property>
  </transition>
  <transition out="897">
    <property name="mlt_service">composite</property>
    <property name="a_track">0</property>
    <property name="b_track">3</property>
    <property name="progressive">1</property>
    <property name="geometry">0=0%,50%:50%x50%</property>
  </transition>
  <transition out="897">
    <property name="mlt_service">composite</property>
    <property name="a_track">0</property>
    <property name="b_track">4</property>
    <property name="progressive">1</property>
    <property name="geometry">0=50%,50%:50%x50%</property>
  </transition>
</mlt>