[CELT-dev] Bitrev for FFT

Riccardo Micci riccardo.micci at cambridgeconsultants.com
Thu Mar 3 03:42:24 PST 2011

Our DSP has a built-in bitrev instruction so we're exploring the 
possibility of calculating the bitrev every time instead of filling the 
table during initialisation, hence saving some memory.

Our frame size is fixed to 320 samples. The two FFTs sizes for normal 
block and short block are 160 and 40 respectively. It's not really clear 
how the function "compute_bitrev_table" calculates the values.
Could you quickly explain the idea behind the function so we can try to 
implement it on the fly?


Riccardo Micci
Senior DSP Engineer, Wireless Group 
Cambridge Consultants
Science Park, Milton Road 
Cambridge, CB4 0DW, England
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riccardo.micci at cambridgeconsultants.com

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