[FFmpeg-cvslog] lavu/tx: add a 7-point FFT and (i)MDCT
Lynne
git at videolan.org
Sat Apr 24 18:19:59 EEST 2021
ffmpeg | branch: master | Lynne <dev at lynne.ee> | Sat Apr 10 03:51:59 2021 +0200| [bd9ea917a3eadc97377cffd0bc66c90dcd22a748] | committer: Lynne
lavu/tx: add a 7-point FFT and (i)MDCT
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=bd9ea917a3eadc97377cffd0bc66c90dcd22a748
---
libavutil/tx_template.c | 126 ++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 116 insertions(+), 10 deletions(-)
diff --git a/libavutil/tx_template.c b/libavutil/tx_template.c
index f78e7abfb1..2946c039be 100644
--- a/libavutil/tx_template.c
+++ b/libavutil/tx_template.c
@@ -40,6 +40,7 @@ COSTABLE(32768);
COSTABLE(65536);
COSTABLE(131072);
DECLARE_ALIGNED(32, FFTComplex, TX_NAME(ff_cos_53))[4];
+DECLARE_ALIGNED(32, FFTComplex, TX_NAME(ff_cos_7))[3];
static FFTSample * const cos_tabs[18] = {
NULL,
@@ -103,9 +104,16 @@ static av_cold void ff_init_53_tabs(void)
TX_NAME(ff_cos_53)[3] = (FFTComplex){ RESCALE(cos(2 * M_PI / 10)), RESCALE(sin(2 * M_PI / 10)) };
}
+static av_cold void ff_init_7_tabs(void)
+{
+ TX_NAME(ff_cos_7)[0] = (FFTComplex){ RESCALE(cos(2 * M_PI / 7)), RESCALE(sin(2 * M_PI / 7)) };
+ TX_NAME(ff_cos_7)[1] = (FFTComplex){ RESCALE(sin(2 * M_PI / 28)), RESCALE(cos(2 * M_PI / 28)) };
+ TX_NAME(ff_cos_7)[2] = (FFTComplex){ RESCALE(cos(2 * M_PI / 14)), RESCALE(sin(2 * M_PI / 14)) };
+}
+
static CosTabsInitOnce cos_tabs_init_once[] = {
{ ff_init_53_tabs, AV_ONCE_INIT },
- { NULL },
+ { ff_init_7_tabs, AV_ONCE_INIT },
{ NULL },
{ NULL },
{ init_cos_tabs_16, AV_ONCE_INIT },
@@ -204,6 +212,93 @@ DECL_FFT5(fft5_m1, 0, 6, 12, 3, 9)
DECL_FFT5(fft5_m2, 10, 1, 7, 13, 4)
DECL_FFT5(fft5_m3, 5, 11, 2, 8, 14)
+static av_always_inline void fft7(FFTComplex *out, FFTComplex *in,
+ ptrdiff_t stride)
+{
+ FFTComplex t[6], z[3];
+ const FFTComplex *tab = TX_NAME(ff_cos_7);
+#ifdef TX_INT32
+ int64_t mtmp[12];
+#endif
+
+ BF(t[1].re, t[0].re, in[1].re, in[6].re);
+ BF(t[1].im, t[0].im, in[1].im, in[6].im);
+ BF(t[3].re, t[2].re, in[2].re, in[5].re);
+ BF(t[3].im, t[2].im, in[2].im, in[5].im);
+ BF(t[5].re, t[4].re, in[3].re, in[4].re);
+ BF(t[5].im, t[4].im, in[3].im, in[4].im);
+
+ out[0*stride].re = in[0].re + t[0].re + t[2].re + t[4].re;
+ out[0*stride].im = in[0].im + t[0].im + t[2].im + t[4].im;
+
+#ifdef TX_INT32 /* NOTE: it's possible to do this with 16 mults but 72 adds */
+ mtmp[ 0] = ((int64_t)tab[0].re)*t[0].re - ((int64_t)tab[2].re)*t[4].re;
+ mtmp[ 1] = ((int64_t)tab[0].re)*t[4].re - ((int64_t)tab[1].re)*t[0].re;
+ mtmp[ 2] = ((int64_t)tab[0].re)*t[2].re - ((int64_t)tab[2].re)*t[0].re;
+ mtmp[ 3] = ((int64_t)tab[0].re)*t[0].im - ((int64_t)tab[1].re)*t[2].im;
+ mtmp[ 4] = ((int64_t)tab[0].re)*t[4].im - ((int64_t)tab[1].re)*t[0].im;
+ mtmp[ 5] = ((int64_t)tab[0].re)*t[2].im - ((int64_t)tab[2].re)*t[0].im;
+
+ mtmp[ 6] = ((int64_t)tab[2].im)*t[1].im + ((int64_t)tab[1].im)*t[5].im;
+ mtmp[ 7] = ((int64_t)tab[0].im)*t[5].im + ((int64_t)tab[2].im)*t[3].im;
+ mtmp[ 8] = ((int64_t)tab[2].im)*t[5].im + ((int64_t)tab[1].im)*t[3].im;
+ mtmp[ 9] = ((int64_t)tab[0].im)*t[1].re + ((int64_t)tab[1].im)*t[3].re;
+ mtmp[10] = ((int64_t)tab[2].im)*t[3].re + ((int64_t)tab[0].im)*t[5].re;
+ mtmp[11] = ((int64_t)tab[2].im)*t[1].re + ((int64_t)tab[1].im)*t[5].re;
+
+ z[0].re = (int32_t)(mtmp[ 0] - ((int64_t)tab[1].re)*t[2].re + 0x40000000 >> 31);
+ z[1].re = (int32_t)(mtmp[ 1] - ((int64_t)tab[2].re)*t[2].re + 0x40000000 >> 31);
+ z[2].re = (int32_t)(mtmp[ 2] - ((int64_t)tab[1].re)*t[4].re + 0x40000000 >> 31);
+ z[0].im = (int32_t)(mtmp[ 3] - ((int64_t)tab[2].re)*t[4].im + 0x40000000 >> 31);
+ z[1].im = (int32_t)(mtmp[ 4] - ((int64_t)tab[2].re)*t[2].im + 0x40000000 >> 31);
+ z[2].im = (int32_t)(mtmp[ 5] - ((int64_t)tab[1].re)*t[4].im + 0x40000000 >> 31);
+
+ t[0].re = (int32_t)(mtmp[ 6] - ((int64_t)tab[0].im)*t[3].im + 0x40000000 >> 31);
+ t[2].re = (int32_t)(mtmp[ 7] - ((int64_t)tab[1].im)*t[1].im + 0x40000000 >> 31);
+ t[4].re = (int32_t)(mtmp[ 8] + ((int64_t)tab[0].im)*t[1].im + 0x40000000 >> 31);
+ t[0].im = (int32_t)(mtmp[ 9] + ((int64_t)tab[2].im)*t[5].re + 0x40000000 >> 31);
+ t[2].im = (int32_t)(mtmp[10] - ((int64_t)tab[1].im)*t[1].re + 0x40000000 >> 31);
+ t[4].im = (int32_t)(mtmp[11] - ((int64_t)tab[0].im)*t[3].re + 0x40000000 >> 31);
+#else
+ z[0].re = tab[0].re*t[0].re - tab[2].re*t[4].re - tab[1].re*t[2].re;
+ z[1].re = tab[0].re*t[4].re - tab[1].re*t[0].re - tab[2].re*t[2].re;
+ z[2].re = tab[0].re*t[2].re - tab[2].re*t[0].re - tab[1].re*t[4].re;
+ z[0].im = tab[0].re*t[0].im - tab[1].re*t[2].im - tab[2].re*t[4].im;
+ z[1].im = tab[0].re*t[4].im - tab[1].re*t[0].im - tab[2].re*t[2].im;
+ z[2].im = tab[0].re*t[2].im - tab[2].re*t[0].im - tab[1].re*t[4].im;
+
+ /* It's possible to do t[4].re and t[0].im with 2 multiplies only by
+ * multiplying the sum of all with the average of the twiddles */
+
+ t[0].re = tab[2].im*t[1].im + tab[1].im*t[5].im - tab[0].im*t[3].im;
+ t[2].re = tab[0].im*t[5].im + tab[2].im*t[3].im - tab[1].im*t[1].im;
+ t[4].re = tab[2].im*t[5].im + tab[1].im*t[3].im + tab[0].im*t[1].im;
+ t[0].im = tab[0].im*t[1].re + tab[1].im*t[3].re + tab[2].im*t[5].re;
+ t[2].im = tab[2].im*t[3].re + tab[0].im*t[5].re - tab[1].im*t[1].re;
+ t[4].im = tab[2].im*t[1].re + tab[1].im*t[5].re - tab[0].im*t[3].re;
+#endif
+
+ BF(t[1].re, z[0].re, z[0].re, t[4].re);
+ BF(t[3].re, z[1].re, z[1].re, t[2].re);
+ BF(t[5].re, z[2].re, z[2].re, t[0].re);
+ BF(t[1].im, z[0].im, z[0].im, t[0].im);
+ BF(t[3].im, z[1].im, z[1].im, t[2].im);
+ BF(t[5].im, z[2].im, z[2].im, t[4].im);
+
+ out[1*stride].re = in[0].re + z[0].re;
+ out[1*stride].im = in[0].im + t[1].im;
+ out[2*stride].re = in[0].re + t[3].re;
+ out[2*stride].im = in[0].im + z[1].im;
+ out[3*stride].re = in[0].re + z[2].re;
+ out[3*stride].im = in[0].im + t[5].im;
+ out[4*stride].re = in[0].re + t[5].re;
+ out[4*stride].im = in[0].im + z[2].im;
+ out[5*stride].re = in[0].re + z[1].re;
+ out[5*stride].im = in[0].im + t[3].im;
+ out[6*stride].re = in[0].re + t[1].re;
+ out[6*stride].im = in[0].im + z[0].im;
+}
+
static av_always_inline void fft15(FFTComplex *out, FFTComplex *in,
ptrdiff_t stride)
{
@@ -376,6 +471,7 @@ static void compound_fft_##N##xM(AVTXContext *s, void *_out, \
DECL_COMP_FFT(3)
DECL_COMP_FFT(5)
+DECL_COMP_FFT(7)
DECL_COMP_FFT(15)
static void split_radix_fft(AVTXContext *s, void *_out, void *_in,
@@ -473,6 +569,7 @@ static void compound_imdct_##N##xM(AVTXContext *s, void *_dst, void *_src, \
DECL_COMP_IMDCT(3)
DECL_COMP_IMDCT(5)
+DECL_COMP_IMDCT(7)
DECL_COMP_IMDCT(15)
#define DECL_COMP_MDCT(N) \
@@ -521,6 +618,7 @@ static void compound_mdct_##N##xM(AVTXContext *s, void *_dst, void *_src, \
DECL_COMP_MDCT(3)
DECL_COMP_MDCT(5)
+DECL_COMP_MDCT(7)
DECL_COMP_MDCT(15)
static void monolithic_imdct(AVTXContext *s, void *_dst, void *_src,
@@ -675,6 +773,7 @@ int TX_NAME(ff_tx_init_mdct_fft)(AVTXContext *s, av_tx_fn *tx,
SRC /= FACTOR; \
}
CHECK_FACTOR(n, 15, len)
+ CHECK_FACTOR(n, 7, len)
CHECK_FACTOR(n, 5, len)
CHECK_FACTOR(n, 3, len)
#undef CHECK_FACTOR
@@ -714,22 +813,29 @@ int TX_NAME(ff_tx_init_mdct_fft)(AVTXContext *s, av_tx_fn *tx,
return err;
if (!(s->tmp = av_malloc(n*m*sizeof(*s->tmp))))
return AVERROR(ENOMEM);
- *tx = n == 3 ? compound_fft_3xM :
- n == 5 ? compound_fft_5xM :
- compound_fft_15xM;
- if (is_mdct)
- *tx = n == 3 ? inv ? compound_imdct_3xM : compound_mdct_3xM :
- n == 5 ? inv ? compound_imdct_5xM : compound_mdct_5xM :
- inv ? compound_imdct_15xM : compound_mdct_15xM;
+ if (!(m & (m - 1))) {
+ *tx = n == 3 ? compound_fft_3xM :
+ n == 5 ? compound_fft_5xM :
+ n == 7 ? compound_fft_7xM :
+ compound_fft_15xM;
+ if (is_mdct)
+ *tx = n == 3 ? inv ? compound_imdct_3xM : compound_mdct_3xM :
+ n == 5 ? inv ? compound_imdct_5xM : compound_mdct_5xM :
+ n == 7 ? inv ? compound_imdct_7xM : compound_mdct_7xM :
+ inv ? compound_imdct_15xM : compound_mdct_15xM;
+ }
} else { /* Direct transform case */
*tx = split_radix_fft;
if (is_mdct)
*tx = inv ? monolithic_imdct : monolithic_mdct;
}
- if (n != 1)
+ if (n == 3 || n == 5 || n == 15)
init_cos_tabs(0);
- if (m != 1) {
+ else if (n == 7)
+ init_cos_tabs(1);
+
+ if (m != 1 && !(m & (m - 1))) {
if ((err = ff_tx_gen_ptwo_revtab(s, n == 1 && !is_mdct && !(flags & AV_TX_INPLACE))))
return err;
if (flags & AV_TX_INPLACE) {
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