libmix-videoencode: port the videoencode of libmix from R2 to R3

BZ: 18528

merge/port the changes of R2 to R3

Change-Id: Iea4f47decf70c81598659a0294ac5e0d79f63bcb
Signed-off-by: Ji Guoliang <guoliangx.ji@gmail.com>
Reviewed-on: http://android.intel.com:8080/30075
Reviewed-by: Yuan, Shengquan <shengquan.yuan@intel.com>
Reviewed-by: Chang, Ying <ying.chang@intel.com>
Reviewed-by: Ding, Haitao <haitao.ding@intel.com>
Tested-by: Ding, Haitao <haitao.ding@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>
7 files changed