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author | Alex Converse <alex.converse@gmail.com> | 2009-01-22 22:46:23 +0300 |
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committer | Alex Converse <alex.converse@gmail.com> | 2009-01-22 22:46:23 +0300 |
commit | 8f05c995fd5dac7be01f24382687a944e1105d76 (patch) | |
tree | 7c73bed382937621cf5a849ec1828a3820b2d4dc /libavcodec/dsputil.h | |
parent | 082491c47311619e4b6e1ab5dc0140a3d43769ac (diff) |
Clean up FFT related comments.
Originally committed as revision 16721 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec/dsputil.h')
-rw-r--r-- | libavcodec/dsputil.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/libavcodec/dsputil.h b/libavcodec/dsputil.h index 0fa04e8d14..165aef7a09 100644 --- a/libavcodec/dsputil.h +++ b/libavcodec/dsputil.h @@ -674,6 +674,11 @@ typedef struct FFTContext { void (*imdct_half)(struct MDCTContext *s, FFTSample *output, const FFTSample *input); } FFTContext; +/** + * Sets up a complex FFT. + * @param nbits log2 of the length of the input array + * @param inverse if 0 perform the forward transform, if 1 perform the inverse + */ int ff_fft_init(FFTContext *s, int nbits, int inverse); void ff_fft_permute_c(FFTContext *s, FFTComplex *z); void ff_fft_permute_sse(FFTContext *s, FFTComplex *z); @@ -683,10 +688,17 @@ void ff_fft_calc_3dn(FFTContext *s, FFTComplex *z); void ff_fft_calc_3dn2(FFTContext *s, FFTComplex *z); void ff_fft_calc_altivec(FFTContext *s, FFTComplex *z); +/** + * Do the permutation needed BEFORE calling ff_fft_calc(). + */ static inline void ff_fft_permute(FFTContext *s, FFTComplex *z) { s->fft_permute(s, z); } +/** + * Do a complex FFT with the parameters defined in ff_fft_init(). The + * input data must be permuted before. No 1.0/sqrt(n) normalization is done. + */ static inline void ff_fft_calc(FFTContext *s, FFTComplex *z) { s->fft_calc(s, z); |