hw: add draft rockchip-mpp hw video encoding

stream/video.go

@@ -193,6 +193,6 @@ func WebRTCSettings(c *gin.Context) {
 		ffmpeg.SetFPS(fps)
 	}
 
-	ffmpeg.Stop()
-	ffmpeg.Start()
+	//ffmpeg.Stop()
+	//ffmpeg.Start()
 }