Synchronous playback system and synchronous playback method

A synchronous playback system, comprising:

• M playback devices, wherein each of the M playback devices stores one piece or a plurality of media content, wherein M is a positive integer;
• a control server, connected to the M playback devices through network connection;
• and
• a time server, configured to obtain standard time information through the Network Time Protocol, providing the standard time information to the M playback devices through the Internet,
• wherein each of the M playback devices performs a time-calibrating operation on the time server to obtain a target time error value of each of the M playback devices,
• wherein the control server issues M playback commands to the M playback devices, wherein the M playback commands are configured to instruct the M playback devices to individually play M pieces of target media content stored in the M playback devices at a same target time,
• wherein the M playback devices calculate adjusted target time of each of the M playback devices according to the target time and the target time error value of each of the M playback devices,
• the M playback devices play the M pieces of target media content according to the respective adjusted target time of the M playback devices,
• wherein each of the M playback devices performs the following steps when executing the time-calibrating operation:
• transmitting N time-calibrating packages to the time server to obtain N first time error values corresponding to the N time-calibrating packages;
• sorting the N first time error values according to the values of the N first time error values to obtain a first time error value sequence;
• and
• selecting P second time error values in the sorted N first time error values according to the first time error value sequence to calculate an average value of the P second time error values to be treated as the target time error value, wherein P is less than N, and N and P are both positive integers.