Context: Decoding, on the other hand, is carefully defined in the standard. Most decoders are "bitstream compliant", which means that the decompressed output that they produce from a given MP3 file will be the same, within a specified degree of rounding tolerance, as the output specified mathematically in the ISO/IEC high standard document (ISO/IEC 11172-3). Therefore, comparison of decoders is usually based on how computationally efficient they are (i.e., how much memory or CPU time they use in the decoding process).

Question: What is carefully defined in the standard?
Answer: Decoding

Question: What are most decoders?
Answer: bitstream compliant

Question: The ISO/IEC high standard document states that the decompressed output produced from a given MP3 file will be the same within what standards?
Answer: specified degree of rounding tolerance

Question: Decoders are usually compared by examining which factor?
Answer: computationally efficient

Question: The efficiency of decoders is examined by seeing how much memory and what other process they use in the decoding process?
Answer: CPU time