1. A method comprising: accessing, without initially decoding, arithmetically encoded data, the arithmetically encoded data comprising data encoded with an arithmetic code, and the encoded data including at least a first coded portion and a second coded portion, wherein the first and second coded portions have been coded with a code having memory, such that decoding the second coded portion relies on an output from decoding the first coded portion; and determining a modified first arithmetically coded portion such that the second coded portion is decodable to produce a common result based on either an output from decoding the first coded portion or an output from decoding the modified first arithmetically coded portion, wherein determining comprises determining a modified first arithmetically coded portion that generates a Context-based Adaptive Binary Arithmetic Coding (CABAC) state value that is the same as a CABAC state value generated by the first coded portion.
1. A method comprising: accessing, without initially decoding, arithmetically encoded data, the arithmetically encoded data comprising data encoded with an arithmetic code, and the encoded data including at least a first coded portion and a second coded portion, wherein the first and second coded portions have been coded with a code having memory, such that decoding the second coded portion relies on an output from decoding the first coded portion; and determining a modified first arithmetically coded portion such that the second coded portion is decodable to produce a common result based on either an output from decoding the first coded portion or an output from decoding the modified first arithmetically coded portion, wherein determining comprises determining a modified first arithmetically coded portion that generates a Context-based Adaptive Binary Arithmetic Coding (CABAC) state value that is the same as a CABAC state value generated by the first coded portion. 13. The method of claim 1 wherein the first coded portion comprises coded syntax elements, and wherein the modified first arithmetically coded portion has a bit length equal to that of the first coded portion, the modified first arithmetically coded portion generating an L value in an CABAC encoder that is equal to the L value that would have been generated by the first coded portion.