avcodec/libopenh264enc: Do not truncate frame rate

Suggested-by: Gregory J Wolfe <gregory.wolfe@kodakalaris.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/libopenh264enc.c

@@ -92,7 +92,7 @@ static av_cold int svc_encode_init(AVCodecContext *avctx)
 
     (*s->encoder)->GetDefaultParams(s->encoder, &param);
 
-    param.fMaxFrameRate              = avctx->time_base.den / avctx->time_base.num;
+    param.fMaxFrameRate              = 1/av_q2d(avctx->time_base);
     param.iPicWidth                  = avctx->width;
     param.iPicHeight                 = avctx->height;
     param.iTargetBitrate             = avctx->bit_rate;