The introduction of high resolution 4 k and 8 k Ultra-HD video displays has led to a demand for 4 k and 8 k Ultra-HD content. However, the bit rate of uncompressed 4 k and 8 k Ultra-HD video streams is significantly higher than the bit rate of uncompressed HD video streams, e.g. up to eight times higher, which may render some existing video compression/encoding standards unsuitable for 4 k and 8 k Ultra-HD video streams. As such, additional video compression standards, such as the High Efficiency Video Coding (HEVC) Standard, have been developed for use with high resolution video streams, e.g., 4 k and 8 k Ultra-HD video streams. In the HEVC Standard, an encoded bitstream includes a series of arithmetic-coded symbols that correspond to elements of a compressed image, such as spatial prediction modes, motion vector data, transform coefficients, etc. The elements are combined into coding units (CUs) that correspond to square pixel regions of the coded image.
A video decoder implementing the HEVC Standard, e.g. an HEVC decoder, receives the bitstream that includes HEVC coding units and passes the bitstream through a Context Adaptive Binary Arithmetic Coder (CABAC) block. The CABAC block converts the coding units of the bitstream into a stream of binary symbols (“bins”) and stores the binary symbols in a memory buffer. A symbol decoder of the HEVC decoder retrieves the binary symbols from the memory buffer and decodes the binary symbols into the symbols that correspond to the elements of the compressed image, such as spatial prediction mode symbols, motion vector symbols and/or transform coefficient symbols. The symbols that correspond to the elements of the compressed image are passed to appropriate blocks for generating the corresponding elements, e.g. spatial prediction modes, motion vectors, transform coefficients, etc. However, since the symbols that correspond to the elements may be of varying lengths that are unknown to the symbol decoder, the symbol decoder may need to decode the binary symbols in serial fashion. The serial operation of the symbol decoder may limit the overall decoding performance of the HEVC decoder, which may require that the HEVC decoder operate at a very high frequency to decode high resolution video streams, e.g. 4 k or 8 k Ultra-HD video streams.