It currently does the following:
1) get a zeroed audio buffer
2) copy some properties (but not the data) of the input buffer to it
3) pass this buffer to the output filter
This looks useless and is indeed not used by any filters, therefore
delete it.

Make ff_null_filter_samples() (just pass the buffer to the next filter)
the new default.

It will allow adding new fields to it without ABI breaks.

Authors according to blame are:
     16 S.N. Hemanth Meenakshisundaram
      4 Stefano Sabatini
      3 Anton Khirnov
      2 Reimar Döffinger

Initial commit was:
	commit 99046339
	Author: S.N. Hemanth Meenakshisundaram <smeenaks@ucsd.edu>
	Date:   Fri Aug 20 23:16:51 2010 +0000
Signed-off-by: NMichael Niedermayer <michaelni@gmx.at>

Those functions are only useful inside filters. It is better to not
support user filters until the API is more stable.

This breaks audio filtering API and ABI in theory, but since it's
unusable right now this shouldn't be a problem.

GCC 4.6.2 at least still seems to fail to put them in .rodata though,
see also http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37303Signed-off-by: NReimar Döffinger <Reimar.Doeffinger@gmx.de>

Signed-off-by: NMans Rullgard <mans@mansr.com>

Patch by S.N. Hemanth Meenakshisundaram -af smeenaks,ucsd,edu.

Originally committed as revision 24856 to svn://svn.ffmpeg.org/ffmpeg/trunk

Passing an explicit filename to this command is only necessary if the
documentation in the @file block refers to a file different from the
one the block resides in.

Originally committed as revision 22921 to svn://svn.ffmpeg.org/ffmpeg/trunk

is deprecated and will be dropped at the next major bump.

Originally committed as revision 22735 to svn://svn.ffmpeg.org/ffmpeg/trunk

Originally committed as revision 22595 to svn://svn.ffmpeg.org/ffmpeg/trunk

noformat and null filters.

Originally committed as revision 20443 to svn://svn.ffmpeg.org/ffmpeg/trunk

That was never required since avfilter_get_video_buffer() already
calls itself on the next link if get_video_buffer is not defined.

Originally committed as revision 20419 to svn://svn.ffmpeg.org/ffmpeg/trunk

Originally committed as revision 20375 to svn://svn.ffmpeg.org/ffmpeg/trunk

Originally committed as revision 20320 to svn://svn.ffmpeg.org/ffmpeg/trunk

Originally committed as revision 20298 to svn://svn.ffmpeg.org/ffmpeg/trunk

Originally committed as revision 20275 to svn://svn.ffmpeg.org/ffmpeg/trunk