libavcodec/rdft.c File Reference

(Inverse) Real Discrete Fourier Transforms. More...

#include <math.h>
#include "dsputil.h"

Go to the source code of this file.

Functions
	DECLARE_ALIGNED_16 (FFTSample, ff_sin_16[8])
	DECLARE_ALIGNED_16 (FFTSample, ff_sin_32[16])
	DECLARE_ALIGNED_16 (FFTSample, ff_sin_64[32])
	DECLARE_ALIGNED_16 (FFTSample, ff_sin_128[64])
	DECLARE_ALIGNED_16 (FFTSample, ff_sin_256[128])
	DECLARE_ALIGNED_16 (FFTSample, ff_sin_512[256])
	DECLARE_ALIGNED_16 (FFTSample, ff_sin_1024[512])
	DECLARE_ALIGNED_16 (FFTSample, ff_sin_2048[1024])
	DECLARE_ALIGNED_16 (FFTSample, ff_sin_4096[2048])
	DECLARE_ALIGNED_16 (FFTSample, ff_sin_8192[4096])
	DECLARE_ALIGNED_16 (FFTSample, ff_sin_16384[8192])
	DECLARE_ALIGNED_16 (FFTSample, ff_sin_32768[16384])
	DECLARE_ALIGNED_16 (FFTSample, ff_sin_65536[32768])
av_cold int	ff_rdft_init (RDFTContext *s, int nbits, enum RDFTransformType trans)
	Sets up a real FFT.
void	ff_rdft_calc_c (RDFTContext *s, FFTSample *data)
	Map one real FFT into two parallel real even and odd FFTs.
void	ff_rdft_calc (RDFTContext *s, FFTSample *data)
av_cold void	ff_rdft_end (RDFTContext *s)
Variables
FFTSample *	ff_sin_tabs []

---

Detailed Description

(Inverse) Real Discrete Fourier Transforms.

Definition in file rdft.c.

---

Function Documentation

DECLARE_ALIGNED_16	(	FFTSample	,
		ff_sin_65536	[32768]
	)

DECLARE_ALIGNED_16	(	FFTSample	,
		ff_sin_32768	[16384]
	)

DECLARE_ALIGNED_16	(	FFTSample	,
		ff_sin_16384	[8192]
	)

DECLARE_ALIGNED_16	(	FFTSample	,
		ff_sin_8192	[4096]
	)

DECLARE_ALIGNED_16	(	FFTSample	,
		ff_sin_4096	[2048]
	)

DECLARE_ALIGNED_16	(	FFTSample	,
		ff_sin_2048	[1024]
	)

DECLARE_ALIGNED_16	(	FFTSample	,
		ff_sin_1024	[512]
	)

DECLARE_ALIGNED_16	(	FFTSample	,
		ff_sin_512	[256]
	)

DECLARE_ALIGNED_16	(	FFTSample	,
		ff_sin_256	[128]
	)

DECLARE_ALIGNED_16	(	FFTSample	,
		ff_sin_128	[64]
	)

DECLARE_ALIGNED_16	(	FFTSample	,
		ff_sin_64	[32]
	)

DECLARE_ALIGNED_16	(	FFTSample	,
		ff_sin_32	[16]
	)

DECLARE_ALIGNED_16	(	FFTSample	,
		ff_sin_16	[8]
	)

void ff_rdft_calc	(	RDFTContext *	s,
		FFTSample *	data
	)

Definition at line 119 of file rdft.c.

Referenced by qdm2_calculate_fft().

void ff_rdft_calc_c	(	RDFTContext *	s,
		FFTSample *	data
	)

Map one real FFT into two parallel real even and odd FFTs.

Then interleave the two real FFTs into one complex FFT. Unmangle the results. ref: http://www.engineeringproductivitytools.com/stuff/T0001/PT10.HTM

Definition at line 77 of file rdft.c.

Referenced by ff_rdft_calc().

av_cold void ff_rdft_end

(

RDFTContext *

s

)

Definition at line 124 of file rdft.c.

Referenced by qdm2_decode_close().

av_cold int ff_rdft_init	(	RDFTContext *	s,
		int	nbits,
		enum RDFTransformType	trans
	)

Sets up a real FFT.

Parameters:

	nbits	log2 of the length of the input array
	trans	the type of transform

Definition at line 48 of file rdft.c.

Referenced by qdm2_decode_init().

---

Variable Documentation

FFTSample* ff_sin_tabs[]

Initial value:

 {
    ff_sin_16, ff_sin_32, ff_sin_64, ff_sin_128, ff_sin_256, ff_sin_512, ff_sin_1024,
    ff_sin_2048, ff_sin_4096, ff_sin_8192, ff_sin_16384, ff_sin_32768, ff_sin_65536,
}

Definition at line 43 of file rdft.c.

Referenced by ff_rdft_init().