Set the playback rate.
#include <mmplayer/mmplayerclient.h>
int mm_player_set_playback_rate( mmplayer_hdl_t *hdl,
const float rate )
Set the playback rate (speed). The floating-point value in rate is relative to a normal rate of 1.0. A value of 0 pauses playback.
0 on success, -1 on failure