ffmpeg_opt: add OPT_INPUT to -fix_sub_duration and -canvas_size.
Do not (re-)set libx264 parameter b_tff if interlaced encoding was not requested.

Reconfiguring can break x264 lossless encoding.

Fixes ticket #2165.
yadif: x86 assembly for 16-bit samples

This is a fairly dumb copy of the assembly for 8-bit samples but it
works and produces identical output to the C version.  The options have
been tested on an Athlon64 and a Core2Quad.

Athlon64:
1810385 decicycles in C,    32726 runs, 42 skips
1080744 decicycles in mmx,  32744 runs, 24 skips, 1.7x faster
 818315 decicycles in sse2, 32735 runs, 33 skips, 2.2x faster

Core2Quad:
 924025 decicycles in C,     32750 runs, 18 skips
 623995 decicycles in mmx,   32767 runs,  1 skips, 1.5x faster
 406223 decicycles in sse2,  32764 runs,  4 skips, 2.3x faster
 387842 decicycles in ssse3, 32767 runs,  1 skips, 2.4x faster
 307726 decicycles in sse4,  32763 runs,  5 skips, 3.0x faster

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
yadif: x86 assembly for 9 to 14-bit samples

These smaller samples do not need to be unpacked to double words
allowing the code to process more pixels every iteration (still 2 in MMX
but 6 in SSE2).  It also avoids emulating the missing double word
instructions on older instruction sets.

Like with the previous code for 16-bit samples this has been tested on
an Athlon64 and a Core2Quad.

Athlon64:
1809275 decicycles in C,    32718 runs, 50 skips
 911675 decicycles in mmx,  32727 runs, 41 skips, 2.0x faster
 495284 decicycles in sse2, 32747 runs, 21 skips, 3.7x faster

Core2Quad:
 921363 decicycles in C,     32756 runs, 12 skips
 486537 decicycles in mmx,   32764 runs,  4 skips, 1.9x faster
 293296 decicycles in sse2,  32759 runs,  9 skips, 3.1x faster
 284910 decicycles in ssse3, 32759 runs,  9 skips, 3.2x faster

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
yadif: cosmetic indentation from previous commits

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
yadif: remove repeated check on width

The filter already checks that width (and height) are greater than 3.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
yadif: remove an 'm' from the LOAD macro definition

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