Fix regression on avdevice.
Fix regression on avdevice.

When using non-integer profile frame rate, supplying frame_rate on URL,
and not supplying frame_rate_base on URL.

ttill/MLT,xzhavilla/mlt,xzhavilla/mlt,mltframework/mlt,xzhavilla/mlt,zzhhui/mlt,mltframework/mlt,wideioltd/mlt,zzhhui/mlt,siddharudh/mlt,siddharudh/mlt,anba8005/mlt,gmarco/mlt-orig,siddharudh/mlt,anba8005/mlt,mltframework/mlt,wideioltd/mlt,j-b-m/mlt,siddharudh/mlt,anba8005/mlt,ttill/MLT,mltframework/mlt,gmarco/mlt-orig,xzhavilla/mlt,ttill/MLT,zzhhui/mlt,j-b-m/mlt,anba8005/mlt,ttill/MLT,wideioltd/mlt,anba8005/mlt,zzhhui/mlt,j-b-m/mlt,zzhhui/mlt,j-b-m/mlt,xzhavilla/mlt,wideioltd/mlt,j-b-m/mlt,siddharudh/mlt,wideioltd/mlt,gmarco/mlt-orig,ttill/MLT,zzhhui/mlt,wideioltd/mlt,j-b-m/mlt,siddharudh/mlt,mltframework/mlt,ttill/MLT,mltframework/mlt,wideioltd/mlt,mltframework/mlt,ttill/MLT,zzhhui/mlt,anba8005/mlt,anba8005/mlt,xzhavilla/mlt,anba8005/mlt,gmarco/mlt-orig,siddharudh/mlt,gmarco/mlt-orig,ttill/MLT,zzhhui/mlt,siddharudh/mlt,j-b-m/mlt,xzhavilla/mlt,anba8005/mlt,gmarco/mlt-orig,siddharudh/mlt,j-b-m/mlt,j-b-m/mlt,zzhhui/mlt,j-b-m/mlt,mltframework/mlt,wideioltd/mlt,wideioltd/mlt,mltframework/mlt,gmarco/mlt-orig,mltframework/mlt,ttill/MLT,gmarco/mlt-orig,xzhavilla/mlt,xzhavilla/mlt,gmarco/mlt-orig