[FFmpeg-devel] Fwd: Fixpoint FFT optimization, with MDCT and IMDCT wrappers for audio optimization

[Justin Ruggles]

Marc Hoffman wrote:
> here are some numbers.
> 	              256	512	1024  2048	4096
> fft32	              46.1	101	205	  494.4	1169.3   fixedpoint 32bit
> simple RAD2 fft
> fftr2	              7.6	16	34.1	  101.3	258.5     simple rad2 first stage rad4.
> fft ffmpeg	7.4	16.4	33.8	  82.4	187.7     current lavc RAD2, first 2
> stages, and middle pulled
> fftr4/2	       6.7	13.6	28.2	  74	       169.8     rad4/2 with last
> stage rad2 if needed.

For everyone like me who couldn't read this table due to the tabs and 
line breaks, here is a cleaned-up version.

	             256    512   1024   2048    4096
-------------------------------------------------------
(1) fft32           46.1   101.0  205.0  494.4  1169.3
(2) fftr2            7.6    16.0   34.1  101.3   258.5
(3) fft ffmpeg       7.4    16.4   33.8   82.4   187.7
(4) fftr4/2          6.7    13.6   28.2   74.0   169.8

(1) fixedpoint 32bit simple RAD2 fft
(2) simple rad2 first stage rad4
(3) current lavc RAD2, first 2 stages, and middle pulled
(4) rad4/2 with last stage rad2 if needed