China's second aircraft carrier, the first domestically built, appears to be preparing for a possible commissioning ceremony since it returned from its eighth sea trial, photos and videos showed.

Troops in white naval uniforms lined the warship's flight deck on the morning of October 24 and practiced an inspection ceremony, Hong Kong-based news website wenweipo.com reported on Tuesday.

A barge loaded with a crane approached the bow of the ship, as workers on the crane painted a huge "1" on the ship's hull, according to photos and videos posted in the wenweipo.com report.

However, the number has since been erased and no further markings were visible as of Tuesday, the report said.

"Painting a hull number is usually a sign that a warship is about to join military service," a military expert who asked not to be named told the Global Times on Wednesday.

The moves mentioned in the report could indicate that the aircraft carrier will be commissioned soon, military enthusiasts said.

China's first aircraft carrier Liaoning was delivered and commissioned to the PLA Navy on September 25, 2012 in Dalian after years of refitting and sea trials. Then president and Central Military Commission chairman Hu Jintao endorsed the naming certificate of Liaoning in a commissioning ceremony, the Xinhua News Agency reported then.

Hu and then premier Wen Jiabao oversaw the ceremony, as Navy honor guards received inspection on board of the ship, according to the Xinhua report.

The Liaoning has the hull number 16, and many military observers expect the yet-to-be-named second carrier will bear the number 17.

The second aircraft carrier is moored at the Dalian Shipyard in Northeast China's Liaoning Province, after it returned from its eighth sea trial held between October 15 and 20, wenweipo.com reported.

Military experts told the Global Times as the carrier first set out on its eighth sea trial the voyage would likely serve as an examination of the warship's readiness for final delivery, and that they expected the ship to be commissioned into the Chinese Navy this year.