Takes a raw input stream containing frames with correct timestamps but
possibly out of order and inserts additional show-existing-frame
packets to correct the ordering.
It is useful for testing/debugging and will also be used as the default
filter in the following commit adding pre-decode filtering to avoid
having a separate non-filtered codepath.
Based on a patch by Nicolas George
<@var{name}.@var{surname}@@normalesup.@code{org}>.
Originally committed as revision 25709 to svn://svn.ffmpeg.org/ffmpeg/trunk