Add multi-instance test case with multi-thread decoding.
This test case is mainly for platform performance evaluation.
Change-Id: I79d86a01778c2e7af00e13d1d3c3d2937bcbbcce
Signed-off-by: sliver.chen <sliver.chen@rock-chips.com>
Signed-off-by: Herman Chen <herman.chen@rock-chips.com>