[FFmpeg-cvslog] avcodec/rdft: remove sintable
Muhammad Faiz
git at videolan.org
Tue Jul 11 09:50:13 EEST 2017
ffmpeg | branch: master | Muhammad Faiz <mfcc64 at gmail.com> | Fri Jul 7 14:43:39 2017 +0700| [0780ad9c688cc8272daa7780d3f112a9f55208ca] | committer: Muhammad Faiz
avcodec/rdft: remove sintable
It is redundant with costable. The first half of sintable is
identical with the second half of costable. The second half
of sintable is negative value of the first half of sintable.
The computation is changed to handle sign of sin values, in
C code and ARM assembly code.
Signed-off-by: Muhammad Faiz <mfcc64 at gmail.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=0780ad9c688cc8272daa7780d3f112a9f55208ca
---
libavcodec/Makefile | 3 +-
libavcodec/arm/rdft_neon.S | 13 ++++++---
libavcodec/rdft.c | 68 ++++++++++++++++------------------------------
libavcodec/rdft.h | 26 ++----------------
4 files changed, 36 insertions(+), 74 deletions(-)
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index b440a00746..59029a853c 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -122,8 +122,7 @@ OBJS-$(CONFIG_QSV) += qsv.o
OBJS-$(CONFIG_QSVDEC) += qsvdec.o
OBJS-$(CONFIG_QSVENC) += qsvenc.o
OBJS-$(CONFIG_RANGECODER) += rangecoder.o
-RDFT-OBJS-$(CONFIG_HARDCODED_TABLES) += sin_tables.o
-OBJS-$(CONFIG_RDFT) += rdft.o $(RDFT-OBJS-yes)
+OBJS-$(CONFIG_RDFT) += rdft.o
OBJS-$(CONFIG_RV34DSP) += rv34dsp.o
OBJS-$(CONFIG_SHARED) += log2_tab.o reverse.o
OBJS-$(CONFIG_SINEWIN) += sinewin.o sinewin_fixed.o
diff --git a/libavcodec/arm/rdft_neon.S b/libavcodec/arm/rdft_neon.S
index 781d976354..eabb92b4bd 100644
--- a/libavcodec/arm/rdft_neon.S
+++ b/libavcodec/arm/rdft_neon.S
@@ -30,18 +30,21 @@ function ff_rdft_calc_neon, export=1
lsls r6, r6, #31
bne 1f
- add r0, r4, #20
+ add r0, r4, #24
bl X(ff_fft_permute_neon)
- add r0, r4, #20
+ add r0, r4, #24
mov r1, r5
bl X(ff_fft_calc_neon)
1:
ldr r12, [r4, #0] @ nbits
mov r2, #1
+ ldr r8, [r4, #20] @ negative_sin
lsl r12, r2, r12
add r0, r5, #8
+ lsl r8, r8, #31
add r1, r5, r12, lsl #2
lsr r12, r12, #2
+ vdup.32 d26, r8
ldr r2, [r4, #12] @ tcos
sub r12, r12, #2
ldr r3, [r4, #16] @ tsin
@@ -55,6 +58,7 @@ function ff_rdft_calc_neon, export=1
vld1.32 {d5}, [r3,:64]! @ tsin[i]
vmov.f32 d18, #0.5 @ k1
vdup.32 d19, r6
+ veor d5, d26, d5
pld [r0, #32]
veor d19, d18, d19 @ k2
vmov.i32 d16, #0
@@ -90,6 +94,7 @@ function ff_rdft_calc_neon, export=1
vld1.32 {d5}, [r3,:64]! @ tsin[i]
veor d24, d22, d17 @ ev.re,-ev.im
vrev64.32 d3, d23 @ od.re, od.im
+ veor d5, d26, d5
pld [r2, #32]
veor d2, d3, d16 @ -od.re, od.im
pld [r3, #32]
@@ -140,10 +145,10 @@ function ff_rdft_calc_neon, export=1
vmul.f32 d22, d22, d18
vst1.32 {d22}, [r5,:64]
- add r0, r4, #20
+ add r0, r4, #24
mov r1, r5
bl X(ff_fft_permute_neon)
- add r0, r4, #20
+ add r0, r4, #24
mov r1, r5
pop {r4-r8,lr}
b X(ff_fft_calc_neon)
diff --git a/libavcodec/rdft.c b/libavcodec/rdft.c
index c318aa8394..194e0bc4ee 100644
--- a/libavcodec/rdft.c
+++ b/libavcodec/rdft.c
@@ -28,28 +28,6 @@
* (Inverse) Real Discrete Fourier Transforms.
*/
-/* sin(2*pi*x/n) for 0<=x<n/4, followed by n/2<=x<3n/4 */
-#if !CONFIG_HARDCODED_TABLES
-SINTABLE(16);
-SINTABLE(32);
-SINTABLE(64);
-SINTABLE(128);
-SINTABLE(256);
-SINTABLE(512);
-SINTABLE(1024);
-SINTABLE(2048);
-SINTABLE(4096);
-SINTABLE(8192);
-SINTABLE(16384);
-SINTABLE(32768);
-SINTABLE(65536);
-#endif
-static SINTABLE_CONST FFTSample * const ff_sin_tabs[] = {
- NULL, NULL, NULL, NULL,
- 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,
-};
-
/** 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
@@ -73,20 +51,29 @@ static void rdft_calc_c(RDFTContext *s, FFTSample *data)
ev.re = data[0];
data[0] = ev.re+data[1];
data[1] = ev.re-data[1];
- for (i = 1; i < (n>>2); i++) {
- i1 = 2*i;
- i2 = n-i1;
- /* Separate even and odd FFTs */
- ev.re = k1*(data[i1 ]+data[i2 ]);
- od.im = -k2*(data[i1 ]-data[i2 ]);
- ev.im = k1*(data[i1+1]-data[i2+1]);
- od.re = k2*(data[i1+1]+data[i2+1]);
- /* Apply twiddle factors to the odd FFT and add to the even FFT */
- data[i1 ] = ev.re + od.re*tcos[i] - od.im*tsin[i];
- data[i1+1] = ev.im + od.im*tcos[i] + od.re*tsin[i];
- data[i2 ] = ev.re - od.re*tcos[i] + od.im*tsin[i];
- data[i2+1] = -ev.im + od.im*tcos[i] + od.re*tsin[i];
+
+#define RDFT_UNMANGLE(sign0, sign1) \
+ for (i = 1; i < (n>>2); i++) { \
+ i1 = 2*i; \
+ i2 = n-i1; \
+ /* Separate even and odd FFTs */ \
+ ev.re = k1*(data[i1 ]+data[i2 ]); \
+ od.im = -k2*(data[i1 ]-data[i2 ]); \
+ ev.im = k1*(data[i1+1]-data[i2+1]); \
+ od.re = k2*(data[i1+1]+data[i2+1]); \
+ /* Apply twiddle factors to the odd FFT and add to the even FFT */ \
+ data[i1 ] = ev.re + od.re*tcos[i] sign0 od.im*tsin[i]; \
+ data[i1+1] = ev.im + od.im*tcos[i] sign1 od.re*tsin[i]; \
+ data[i2 ] = ev.re - od.re*tcos[i] sign1 od.im*tsin[i]; \
+ data[i2+1] = -ev.im + od.im*tcos[i] sign1 od.re*tsin[i]; \
+ }
+
+ if (s->negative_sin) {
+ RDFT_UNMANGLE(+,-)
+ } else {
+ RDFT_UNMANGLE(-,+)
}
+
data[2*i+1]=s->sign_convention*data[2*i+1];
if (s->inverse) {
data[0] *= k1;
@@ -104,6 +91,7 @@ av_cold int ff_rdft_init(RDFTContext *s, int nbits, enum RDFTransformType trans)
s->nbits = nbits;
s->inverse = trans == IDFT_C2R || trans == DFT_C2R;
s->sign_convention = trans == IDFT_R2C || trans == DFT_C2R ? 1 : -1;
+ s->negative_sin = trans == DFT_C2R || trans == DFT_R2C;
if (nbits < 4 || nbits > 16)
return AVERROR(EINVAL);
@@ -113,15 +101,7 @@ av_cold int ff_rdft_init(RDFTContext *s, int nbits, enum RDFTransformType trans)
ff_init_ff_cos_tabs(nbits);
s->tcos = ff_cos_tabs[nbits];
- s->tsin = ff_sin_tabs[nbits]+(trans == DFT_R2C || trans == DFT_C2R)*(n>>2);
-#if !CONFIG_HARDCODED_TABLES
- {
- int i;
- const double theta = (trans == DFT_R2C || trans == DFT_C2R ? -1 : 1) * 2 * M_PI / n;
- for (i = 0; i < (n >> 2); i++)
- s->tsin[i] = sin(i * theta);
- }
-#endif
+ s->tsin = ff_cos_tabs[nbits] + (n >> 2);
s->rdft_calc = rdft_calc_c;
if (ARCH_ARM) ff_rdft_init_arm(s);
diff --git a/libavcodec/rdft.h b/libavcodec/rdft.h
index 37c40e7c80..ffafca7f24 100644
--- a/libavcodec/rdft.h
+++ b/libavcodec/rdft.h
@@ -25,29 +25,6 @@
#include "config.h"
#include "fft.h"
-#if CONFIG_HARDCODED_TABLES
-# define SINTABLE_CONST const
-#else
-# define SINTABLE_CONST
-#endif
-
-#define SINTABLE(size) \
- SINTABLE_CONST DECLARE_ALIGNED(16, FFTSample, ff_sin_##size)[size/2]
-
-extern SINTABLE(16);
-extern SINTABLE(32);
-extern SINTABLE(64);
-extern SINTABLE(128);
-extern SINTABLE(256);
-extern SINTABLE(512);
-extern SINTABLE(1024);
-extern SINTABLE(2048);
-extern SINTABLE(4096);
-extern SINTABLE(8192);
-extern SINTABLE(16384);
-extern SINTABLE(32768);
-extern SINTABLE(65536);
-
struct RDFTContext {
int nbits;
int inverse;
@@ -55,7 +32,8 @@ struct RDFTContext {
/* pre/post rotation tables */
const FFTSample *tcos;
- SINTABLE_CONST FFTSample *tsin;
+ const FFTSample *tsin;
+ int negative_sin;
FFTContext fft;
void (*rdft_calc)(struct RDFTContext *s, FFTSample *z);
};
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