A state estimation method for a terminal comprising a buffer, the method being used for implementing a periodic state estimation of the state of the buffer in an audio-video application implemented based on a transmission control protocol, TCP, the method comprising: receiving at a terminal media data from a media server; obtaining a first continuous play duration representing the size of media data received by the terminal in a period of the present state estimation divided by a current media bit rate or a current media frame rate; characterized by: calculating a second continuous play duration, wherein: if the state before the present state estimation is other than a normal play state of the received media data, the second continuous play duration is the sum of a continuous play duration corresponding to media data in the buffer when a last state estimation ends and the first continuous play duration; or if the state before the present state estimation is the normal play state, the second continuous play duration is obtained by subtracting a continuous play duration corresponding to media data required for a normal play in the period of the present state estimation from the sum of the continuous play duration corresponding to the media data in the buffer when the last state estimation ends and the first continuous play duration; and performing state estimation on the buffer according to the state before the present state estimation, preset buffer configuration parameters and the second continuous play duration, to obtain the present state, start time and duration of the present state, wherein the state comprises at least one of an initial buffering state before the terminal plays the received media data, the normal play state, a rebuffering state for media data stored in the buffer to resume normal play, a play stop state and a play pause state. receiving at a terminal media data from a media server; obtaining a first continuous play duration representing the size of media data received by the terminal in a period of the present state estimation divided by a current media bit rate or a current media frame rate; characterized by: calculating a second continuous play duration, wherein: if the state before the present state estimation is other than a normal play state of the received media data, the second continuous play duration is the sum of a continuous play duration corresponding to media data in the buffer when a last state estimation ends and the first continuous play duration; or if the state before the present state estimation is the normal play state, the second continuous play duration is obtained by subtracting a continuous play duration corresponding to media data required for a normal play in the period of the present state estimation from the sum of the continuous play duration corresponding to the media data in the buffer when the last state estimation ends and the first continuous play duration; and performing state estimation on the buffer according to the state before the present state estimation, preset buffer configuration parameters and the second continuous play duration, to obtain the present state, start time and duration of the present state, wherein the state comprises at least one of an initial buffering state before the terminal plays the received media data, the normal play state, a rebuffering state for media data stored in the buffer to resume normal play, a play stop state and a play pause state. if the state before the present state estimation is other than a normal play state of the received media data, the second continuous play duration is the sum of a continuous play duration corresponding to media data in the buffer when a last state estimation ends and the first continuous play duration; or if the state before the present state estimation is the normal play state, the second continuous play duration is obtained by subtracting a continuous play duration corresponding to media data required for a normal play in the period of the present state estimation from the sum of the continuous play duration corresponding to the media data in the buffer when the last state estimation ends and the first continuous play duration; and performing state estimation on the buffer according to the state before the present state estimation, preset buffer configuration parameters and the second continuous play duration, to obtain the present state, start time and duration of the present state, wherein the state comprises at least one of an initial buffering state before the terminal plays the received media data, the normal play state, a rebuffering state for media data stored in the buffer to resume normal play, a play stop state and a play pause state.