That's required because -1 is evaluated as NAN, which converted back
to int looks like a random number, this is especially annoying when
debugging sources with undefined pos (as the video4linux2 device).
Signed-off-by: Janne Grunau <janne-ffmpeg@jannau.net>
eval API.
More grep-friendly and more consistent with the rest of the FFmpeg
API.
Originally committed as revision 25708 to svn://svn.ffmpeg.org/ffmpeg/trunk
