avformat/mxfenc: Accept MXF D-10 with 49.999840 Mbit/sec

This is the maximum rate possible based on the frame size limit of MXF D-10

Previous version reviewed by tim nicholson <nichot20@yahoo.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/mxfenc.c

@@ -2080,9 +2080,10 @@ static int mxf_write_header(AVFormatContext *s)
 
             sc->video_bit_rate = st->codec->bit_rate ? st->codec->bit_rate : st->codec->rc_max_rate;
             if (s->oformat == &ff_mxf_d10_muxer) {
-                if (sc->video_bit_rate == 50000000) {
-                    if (mxf->time_base.den == 25) sc->index = 3;
-                    else                          sc->index = 5;
+                if ((sc->video_bit_rate == 50000000) && (mxf->time_base.den == 25)) {
+                    sc->index = 3;
+                } else if ((sc->video_bit_rate == 49999840 || sc->video_bit_rate == 50000000) && (mxf->time_base.den != 25)) {
+                    sc->index = 5;
                 } else if (sc->video_bit_rate == 40000000) {
                     if (mxf->time_base.den == 25) sc->index = 7;
                     else                          sc->index = 9;