Enhance mix_encode2 test tool to add VP8 encoder option

BZ: 124301

Add VP8 encode option and IVF writer class into mix_encode2.

Change-Id: I2f8faba86a26af61b845ddd9f342a200f3c020f7
Signed-off-by: Liu Bolun <bolun.liu@intel.com>
Reviewed-on: http://android.intel.com:8080/121789
Reviewed-by: Shi, PingX <pingx.shi@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: Shi, PingX <pingx.shi@intel.com>
Reviewed-by: cactus <cactus@intel.com>
Tested-by: cactus <cactus@intel.com>
1 file changed