A buffer level for jitter data buffer is determined. A frame payload size difference is determined for a plurality of video frames encoded into data packets sequentially received from a network. The difference is a difference in a payload size of a current frame and a previous frame. A frame network transit delay is determined as a difference in a transport time between the current frame and the previous frame and an expected transport time between the current frame and the previous frame. A slope and a variance of a linear relationship between the frame payload size difference and the frame network transit delay are determined for the plurality of video frames. Finally, a buffer level of a jitter data buffer is determined using a maximum frame payload size, an average frame payload size, the slope and the variance.