This way it's easier for the programmer to look-up for a specific
symbols (e.g. for checking if it's unused).

The gradfun filter was already integrated natively in libavfilter.
Both filters issue the same output, and have a comparable performance.

See thread:
Subject: [FFmpeg-devel] [PATCH] lavfi: remove gradfun mp wrapper
Date: Fri,  5 Aug 2011 00:19:04 +0200

blackframe is integrated as a native filter.

The cropdetect filter is natively integrated into libavfilter.

The filter was integrated natively into libavfilter as a source with
name rgbtestsrc.

It is natively included in libavfilter.

This avoid a crash with in avfilter_merge_formats() in case one of the
filter formats list has multiple time the same entry.

Thanks to Mina Nagy Zaki for helping figuring out the issue.

Signed-off-by: NMichael Niedermayer <michaelni@gmx.at>

Fix warning:
vf_mp.c: In function ‘end_frame’:
vf_mp.c:870: warning: unused variable ‘outlink’
Signed-off-by: NStefano Sabatini <stefano.sabatini-lala@poste.it>

Make the mp wrapper accept the syntax mp=filter=params as alternative
to mp=filter:params. The alternative syntax is sligthly more readable
and should simplify copy&paste of MPlayer filter strings to the mp
filter.

Done to keep ABI compatible. Otherwise this is just silly