The licence was changed from GPL to LGPL with explicit approval from
the original author.
See thread:
Subject: [FFmpeg-devel] [PATCH] lavfi: add rgbtestsrc source,
ported from MPlayer libmpcodecs
Date: Mon, 11 Jul 2011 16:32:41 +0200
In particular creates a special test_init function, which calls a
common init, and introduces a fill_picture_fn which points to the
filling function.
This is required by the pending patch for adding the rgbtestsrc
source.