question: public void position ( long pos ) { log . debug ( "Position: {}" , pos ) ; log . debug ( "Current frame: {}" , currentFrame ) ; int len = frames . size ( ) ; MP4Frame frame = null ; for ( int f = 0 ; f < len ; f ++ ) { frame = frames . get ( f ) ; long offset = frame . getOffset ( ) ; if ( pos == offset || ( offset > pos && frame . isKeyFrame ( ) ) ) { if ( ! frame . isKeyFrame ( ) ) { log . debug ( "Frame #{} was not a key frame, so trying again.." , f ) ; continue ; } log . info ( "Frame #{} found for seek: {}" , f , frame ) ; createPreStreamingTags ( ( int ) ( frame . getTime ( ) * 1000 ) , true ) ; currentFrame = f ; break ; } prevVideoTS = ( int ) ( frame . getTime ( ) * 1000 ) ; } log . debug ( "Setting current frame: {}" , currentFrame ) ; }
target:  Put the current position to pos. The caller must ensure the pos is a valid one.