Rate control method and device for multi layer coding

Embodiments in the present invention provide a rate control method and device for multi-layer coding, wherein the method includes: allocating a target bit number to an access unit of the current Group Of Pictures (GOP) according to an obtained available bit number (101); allocating a corresponding base layer bit number and a corresponding enhancement layer bit number to the base layer and the enhancement layer of the access unit respectively according to the target bit number (102); performing the base layer encoding according to the base layer bit number, and performing the enhancement layer encoding according to the enhancement layer bit number (103). By using the schemes provided by the embodiments in the present invention, under the condition of satisfying a total bit rate constraint, the proportion of the target bit number occupied by the base layer and the enhancement layer can be adjusted rationally, and the quality of the bit stream outputted by an encoder is improved, thus the decoded image quality is improved.