Method of synchronization during the processing, by a multimedia player, of an item of multimedia content transmitted by an MBMS service

A multimedia content broadcasting system comprising a multimedia content server configured to send multimedia content in segments, and user devices, a first user device comprising a local proxy server configured to:

• receive segments of an item of multimedia content from the content server, and storing the received segments in a buffer memory of the first user device,
• receive a segment request from a multimedia player of the first user device, and transmit a segment corresponding to the segment request to the multimedia player of the first user device, if the segment is present in the buffer memory of the first user device,
• receive a request for synchronization data from the multimedia player of the first user device, and
• transmit synchronization data corresponding to the request for synchronization data to the multimedia player of the first user device, the synchronization data comprising an identifier of a last received segment, and a time elapsed between the time the last segment is received by the local proxy server and the time the synchronization data is transmitted, the synchronization data being used by the multimedia player to compute a difference between a time base of the multimedia content server and a time base of the user device, on the basis of a time at which a start of the segment identified in the synchronization data is received, determined from a receipt time of the synchronization data by the multimedia player and the elapsed time.

A device comprising a proxy server, a multimedia player and a buffer memory, the proxy server being configured to:

• receive segments of an item of multimedia content, and storing the received segments in the buffer memory,
• receive a segment request from the multimedia player, and transmit a segment corresponding to the segment request to the multimedia player, if the segment is present in the buffer memory,
• receive a request for synchronization data from the multimedia player, and
• transmit synchronization data corresponding to the request for synchronization data to the multimedia player, the synchronization data comprising an identifier of a last received segment, and a time elapsed between the time the last segment is received by the proxy server and the time the synchronization data is transmitted, the multimedia player being configured to:
• save a first time at which the synchronization data is received;
• determine a second time at which a start of the segment identified in the synchronization data is received based on the receipt time of the synchronization data by the multimedia player and on the elapsed time;
• and
• compute a difference between a time base of the user device and a time base of a content server providing the item of multimedia content, on the basis of the first time and the second time.

A method for playing back an item of multimedia content by a user device, the method comprising:

• transmitting, by a multimedia player of the user device to a proxy server of the user device, a segment request,
• receiving, by the multimedia player from the proxy server, a segment corresponding to the segment request, if the segment is present in a buffer memory of the user device,
• transmitting, by the multimedia player to the proxy server, a request for synchronization data,
• receiving, by the multimedia player from the proxy server, synchronization data corresponding to the request for synchronization data, the synchronization data comprising an identifier of a last received segment, and a time elapsed between the time the last segment is received by the proxy server and the time the synchronization data is transmitted,
• saving, by the multimedia player, a time at which the synchronization data is received,
• determining a time at which a start of the segment identified in the synchronization data is received based on the receipt time of the synchronization data by the multimedia player and on the elapsed time, and
• computing, by the multimedia player, a difference between a time base of the user device and a time base of a content server providing the item of multimedia content, on the basis of the receipt time of the start of the segment identified in the synchronization data.