The feedback factors for the timefilter are directly computed from
the expected period. This commit changes the init function to accept
the period itself and compute the feedback factors internally,
rather than having all client code duplicate the formulas.
This commit also actually fixes the formulas: the current code had
sqrt(2*o), but the correct formula, both theoretically and according
to experimental testing, is sqrt(2)*o.
Furthermore, it adds an exponential to feedback factors larger than
1 with large periods.
This also lists the objects from those two libraries as internal (by adding
the ff_ prefix) so that they can then be hidden via linker scripts.
(cherry picked from commit c6610a216e)
Patch by Olivier Guilyardi list samalyse com.
See the thread: "[FFmpeg-devel] [PATCH] libavdevice: JACK demuxer".
Originally committed as revision 18322 to svn://svn.ffmpeg.org/ffmpeg/trunk