This allows the following usages:
FFMPEG_DATADIR=presets ./ffmpeg -f lavfi -i testsrc=d=5 -vcodec libx264 -vpre ipod640 -f null -
FFMPEG_DATADIR=presets ./ffmpeg -f lavfi -i testsrc=d=5 -vpre libx264-ipod640 -f null -

The second example was broken even if documented.

These are available via -preset or -vprofile and the addition of
-qp 0 or -crf 0 if lossless is desired.

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

Signed-off-by: Janne Grunau <janne-libav@jannau.net>

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

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