Also allow qmin/qmax to go up to 69 (the current max value for libx264). This will have to increase when we add 9/10-bit support.
Originally committed as revision 22671 to svn://svn.ffmpeg.org/ffmpeg/trunk
Not 100% accurate, since not all x264 options have ffmpeg equivalents yet. Patch by Lou Logan. Originally committed as revision 22144 to svn://svn.ffmpeg.org/ffmpeg/trunk