Aspects of a method and system for signaling and decoding AVS1-P2 bitstreams of different versions are provided. A sequence user data indicating decoding version information such as a decoding version identifier, for example, may inserted into an AVS1-P2 bitstream. The decoding version information may be, for example, AVS1-P2 Rm52j_r1 or AVS1-P2. The AVS1-P2 bitstream may be decoded based on the decoding version information. The sequence user data may be inserted in the AVS1-P2 bitstream during AVS encoding or during AVS1-P2 bitstream transcoding. Upon receiving the AVS1-P2 bitstream, the sequence user data may be detected and extracted to determine the decoding version information. The received encoded AVS1-P2 bitstream may be decoded based on the decoding version information. When no specific decoding version information can be decided, default decoder version information may be used by the video decoder.