#include <ArduinoJson.h>
const size_t capacity = JSON_ARRAY_SIZE(20) + JSON_OBJECT_SIZE(1) + 20*JSON_OBJECT_SIZE(2) + 460;
DynamicJsonBuffer jsonBuffer(capacity);

const char* json = "{\"dataset\":[{\"btn_no\":162,\"title\":\"POWER\"},{\"btn_no\":226,\"title\":\"MENU\"},{\"btn_no\":34,\"title\":\"TEST\"},{\"btn_no\":2,\"title\":\"PLUS\"},{\"btn_no\":194,\"title\":\"BACK\"},{\"btn_no\":224,\"title\":\"PREVIOUS\"},{\"btn_no\":168,\"title\":\"PLAY\"},{\"btn_no\":144,\"title\":\"NEXT\"},{\"btn_no\":104,\"title\":\"0\"},{\"btn_no\":152,\"title\":\"MINUS\"},{\"btn_no\":176,\"title\":\"C\"},{\"btn_no\":48,\"title\":\"1\"},{\"btn_no\":24,\"title\":\"2\"},{\"btn_no\":122,\"title\":\"3\"},{\"btn_no\":16,\"title\":\"4\"},{\"btn_no\":56,\"title\":\"5\"},{\"btn_no\":90,\"title\":\"6\"},{\"btn_no\":66,\"title\":\"7\"},{\"btn_no\":74,\"title\":\"8\"},{\"btn_no\":82,\"title\":\"9\"}]}";

JsonObject& root = jsonBuffer.parseObject(json);

JsonArray& dataset = root["dataset"];

void setup() {
  // put your setup co  de here, to run once:
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  if(!root.success()) {
  Serial.println("parseObject() failed");
  return false;
  }

}