When compressing, for each frame a small section of audio, the encoder first splits the audio into 32 different parts using a filter bank, similar to MP2. The audio is then split further into either 192 or 576 different parts (depending on the complexity of the audio being compressed more complex audio is split into "fewer" parts using the modified discrete cosine transform. The MP3 encoder then removes parts that it thinks the human ear can't hear. The remaining parts are then compressed using Huffman coding. Decompression does these same steps except removal of parts of the audio in reverse.