MAX_LOG2_NFFT      60 libavcodec/fft_table.h #define MAX_FFT_SIZE (1 << MAX_LOG2_NFFT)
MAX_LOG2_NFFT     314 libavcodec/fft_template.c     step = 1 << ((MAX_LOG2_NFFT-4) - 4);
MAX_LOG2_NFFT     200 libavcodec/mips/fft_mips.c     step = 1 << (MAX_LOG2_NFFT - 4);