Based on the work of Mark Himsley <mark@mdsh.com>.

See thread:
Subject: [FFmpeg-devel] libavfilter: extending overlay filter
Date: Sun, 13 Mar 2011 14:18:42 +0000

Add option rgb which forces the RGB path.

Extend syntax, allow to easily add more options later.

Fixes Ticket594

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

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

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

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

Signed-off-by: Stefano Sabatini <stefasab@gmail.com>

Without this patch each displayed second is incremented 1 frame early,
second 0 is only 24 frames long where as every other second is 25 frames
long.

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

Factorize code, extend the functionality of the filter, and make it
return empty buffers. This is useful for filters which ignore the input
frames content.

This is also changing the syntax of the nullsrc source, and dropping the
framerate expression evaluation, which does not look particularly useful.

In particular, fix sliding color bar with padded data, for example with
testsrc,pad=iw+200:ih.

This filter does not support slice-drawing, the whole blurred image needs
to be written in end_frame().

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

Signed-off-by: Anton Khirnov <anton@khirnov.net>

Signed-off-by: Anton Khirnov <anton@khirnov.net>

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

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

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

And simplify the code in the process.

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

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

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

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

Prefer AV_OPT_* over FF_OPT, vertically align fields.

The function strtok_r() is part of the POSIX.1 specification, but is not
available on some platforms. We provide an internal implementation, so we
do not need to rely on a platform implementation.

The ported filter supports named option parsing and more YUV formats.

Signed-off-by: Anton Khirnov <anton@khirnov.net>

With the following additions:
* support to gray format
* support to yuva420p format
* parametric luma/chroma/alpha radius
* consistency check on the radius values, avoid crashes with invalid values

Signed-off-by: Anton Khirnov <anton@khirnov.net>

This filter is a simple wrapper around the LUT filter.

Signed-off-by: Anton Khirnov <anton@khirnov.net>

Signed-off-by: Anton Khirnov <anton@khirnov.net>

+10l.

In particular: set output timebase to 1/output_sample_rate, fix output
PTS computation, and do not forget to copy properties values from the
input buffer.

Fix checksum computation when the used plane size is different from the
allocated plane size, as it was wrongly assumed.

Signed-off-by: Nicolas George <nicolas.george@normalesup.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Nicolas George <nicolas.george@normalesup.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Nicolas George <nicolas.george@normalesup.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Nicolas George <nicolas.george@normalesup.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Nicolas George <nicolas.george@normalesup.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Nicolas George <nicolas.george@normalesup.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Nicolas George <nicolas.george@normalesup.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Signed-off-by: Nicolas George <nicolas.george@normalesup.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>