avconv: add options for reading filtergraphs from a file.
fate: filter: Add dependencies

Signed-off-by: Anton Khirnov <anton@khirnov.net>
lavfi/gradfun: do not increment DC pointer for odd values.

First DC is only used once otherwise. This also makes the code
consistent with ASM versions.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
lavfi/gradfun: fix rounding in MMX code.

Current code divides before increasing precision.

Also reduce upper bound for strength from 255 to 64.  This will prevent
an overflow in the SSSE3 and MMX filter_line code: delta is expressed as
an u16 being shifted by 2 to the left. If it overflows, having a
strength not above 64 will make sure that m is set to 0 (making the
m*m*delta >> 14 expression void).

A value above 64 should not make any sense unless gradfun is used as
a blur filter.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
lavfi/gradfun: fix dithering in MMX code.

Current dithering only uses the first 4 instead of the whole 8 random values.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
lavfi/gradfun: remove rounding to match C and SSE code.

There is no noticable benefit for such precision.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
FATE: add a test for the gradfun filter
FATE: add a test for the boxblur filter
FATE: add a test for the drawbox filter
FATE: add a test for the fade filter
FATE: add a test for the unsharp filter
FATE: add a test for the transpose filter
FATE: add a test for the hqdn3d filter
FATE: add a test for the setpts filter
FATE: add a test for the overlay filter
FATE: add a test for the negate filter
FATE: add a test for the channelmap filter
FATE: add a test for the channelsplit filter
FATE: add a test for the volume filter
FATE: add a test for the join filter