exploit mdct symmetry

2% faster vorbis on conroe, k8. 7% on celeron.

Originally committed as revision 14207 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/dsputil.c

@@ -3931,9 +3931,18 @@ void ff_vector_fmul_add_add_c(float *dst, const float *src0, const float *src1,
 }
 
 void ff_vector_fmul_window_c(float *dst, const float *src0, const float *src1, const float *win, float add_bias, int len){
-    int i;
-    for(i=0; i<len; i++)
-        dst[i] = src0[i]*win[len-i-1] + src1[i]*win[i] + add_bias;
+    int i,j;
+    dst += len;
+    win += len;
+    src0+= len;
+    for(i=-len, j=len-1; i<0; i++, j--) {
+        float s0 = src0[i];
+        float s1 = src1[j];
+        float wi = win[i];
+        float wj = win[j];
+        dst[i] = s0*wj - s1*wi + add_bias;
+        dst[j] = s0*wi + s1*wj + add_bias;
+    }
 }
 
 static av_always_inline int float_to_int16_one(const float *src){

libavcodec/dsputil.h

@@ -641,6 +641,8 @@ typedef struct FFTContext {
     void (*fft_calc)(struct FFTContext *s, FFTComplex *z);
     void (*imdct_calc)(struct MDCTContext *s, FFTSample *output,
                        const FFTSample *input, FFTSample *tmp);
+    void (*imdct_half)(struct MDCTContext *s, FFTSample *output,
+                       const FFTSample *input, FFTSample *tmp);
 } FFTContext;
 
 int ff_fft_init(FFTContext *s, int nbits, int inverse);
@@ -686,10 +688,16 @@ void ff_sine_window_init(float *window, int n);
 int ff_mdct_init(MDCTContext *s, int nbits, int inverse);
 void ff_imdct_calc(MDCTContext *s, FFTSample *output,
                 const FFTSample *input, FFTSample *tmp);
+void ff_imdct_half(MDCTContext *s, FFTSample *output,
+                   const FFTSample *input, FFTSample *tmp);
 void ff_imdct_calc_3dn2(MDCTContext *s, FFTSample *output,
                         const FFTSample *input, FFTSample *tmp);
+void ff_imdct_half_3dn2(MDCTContext *s, FFTSample *output,
+                        const FFTSample *input, FFTSample *tmp);
 void ff_imdct_calc_sse(MDCTContext *s, FFTSample *output,
                        const FFTSample *input, FFTSample *tmp);
+void ff_imdct_half_sse(MDCTContext *s, FFTSample *output,
+                       const FFTSample *input, FFTSample *tmp);
 void ff_mdct_calc(MDCTContext *s, FFTSample *out,
                const FFTSample *input, FFTSample *tmp);
 void ff_mdct_end(MDCTContext *s);

libavcodec/fft.c

@@ -59,6 +59,7 @@ int ff_fft_init(FFTContext *s, int nbits, int inverse)
     }
     s->fft_calc = ff_fft_calc_c;
     s->imdct_calc = ff_imdct_calc;
+    s->imdct_half = ff_imdct_half;
     s->exptab1 = NULL;
 
 #ifdef HAVE_MMX
@@ -67,6 +68,7 @@ int ff_fft_init(FFTContext *s, int nbits, int inverse)
     if (has_vectors & MM_3DNOWEXT) {
         /* 3DNowEx for K7/K8 */
         s->imdct_calc = ff_imdct_calc_3dn2;
+        s->imdct_half = ff_imdct_half_3dn2;
         s->fft_calc = ff_fft_calc_3dn2;
     } else if (has_vectors & MM_3DNOW) {
         /* 3DNow! for K6-2/3 */
@@ -74,6 +76,7 @@ int ff_fft_init(FFTContext *s, int nbits, int inverse)
     } else if (has_vectors & MM_SSE) {
         /* SSE for P3/P4 */
         s->imdct_calc = ff_imdct_calc_sse;
+        s->imdct_half = ff_imdct_half_sse;
         s->fft_calc = ff_fft_calc_sse;
     } else {
         shuffle = 0;

libavcodec/i386/dsputil_mmx.c

@@ -2022,33 +2022,71 @@ static void vector_fmul_add_add_sse(float *dst, const float *src0, const float *
         ff_vector_fmul_add_add_c(dst, src0, src1, src2, src3, len, step);
 }
 
+static void vector_fmul_window_3dnow2(float *dst, const float *src0, const float *src1,
+                                      const float *win, float add_bias, int len){
+#ifdef HAVE_6REGS
+    if(add_bias == 0){
+        x86_reg i = -len*4;
+        x86_reg j = len*4-8;
+        asm volatile(
+            "1: \n"
+            "pswapd  (%5,%1), %%mm1 \n"
+            "movq    (%5,%0), %%mm0 \n"
+            "pswapd  (%4,%1), %%mm5 \n"
+            "movq    (%3,%0), %%mm4 \n"
+            "movq      %%mm0, %%mm2 \n"
+            "movq      %%mm1, %%mm3 \n"
+            "pfmul     %%mm4, %%mm2 \n" // src0[len+i]*win[len+i]
+            "pfmul     %%mm5, %%mm3 \n" // src1[    j]*win[len+j]
+            "pfmul     %%mm4, %%mm1 \n" // src0[len+i]*win[len+j]
+            "pfmul     %%mm5, %%mm0 \n" // src1[    j]*win[len+i]
+            "pfadd     %%mm3, %%mm2 \n"
+            "pfsub     %%mm0, %%mm1 \n"
+            "pswapd    %%mm2, %%mm2 \n"
+            "movq      %%mm1, (%2,%0) \n"
+            "movq      %%mm2, (%2,%1) \n"
+            "sub $8, %1 \n"
+            "add $8, %0 \n"
+            "jl 1b \n"
+            "femms \n"
+            :"+r"(i), "+r"(j)
+            :"r"(dst+len), "r"(src0+len), "r"(src1), "r"(win+len)
+        );
+    }else
+#endif
+        ff_vector_fmul_window_c(dst, src0, src1, win, add_bias, len);
+}
+
 static void vector_fmul_window_sse(float *dst, const float *src0, const float *src1,
                                    const float *win, float add_bias, int len){
 #ifdef HAVE_6REGS
     if(add_bias == 0){
-        x86_reg i = -len*2;
-        x86_reg j = len*2-16;
+        x86_reg i = -len*4;
+        x86_reg j = len*4-16;
         asm volatile(
             "1: \n"
-            "movaps       (%5,%0), %%xmm0 \n"
             "movaps       (%5,%1), %%xmm1 \n"
+            "movaps       (%5,%0), %%xmm0 \n"
+            "movaps       (%4,%1), %%xmm5 \n"
+            "movaps       (%3,%0), %%xmm4 \n"
+            "shufps $0x1b, %%xmm1, %%xmm1 \n"
+            "shufps $0x1b, %%xmm5, %%xmm5 \n"
             "movaps        %%xmm0, %%xmm2 \n"
             "movaps        %%xmm1, %%xmm3 \n"
+            "mulps         %%xmm4, %%xmm2 \n" // src0[len+i]*win[len+i]
+            "mulps         %%xmm5, %%xmm3 \n" // src1[    j]*win[len+j]
+            "mulps         %%xmm4, %%xmm1 \n" // src0[len+i]*win[len+j]
+            "mulps         %%xmm5, %%xmm0 \n" // src1[    j]*win[len+i]
+            "addps         %%xmm3, %%xmm2 \n"
+            "subps         %%xmm0, %%xmm1 \n"
             "shufps $0x1b, %%xmm2, %%xmm2 \n"
-            "shufps $0x1b, %%xmm3, %%xmm3 \n"
-            "mulps        (%4,%0), %%xmm0 \n"
-            "mulps        (%4,%1), %%xmm1 \n"
-            "mulps        (%3,%0), %%xmm3 \n"
-            "mulps        (%3,%1), %%xmm2 \n"
-            "addps         %%xmm3, %%xmm0 \n"
-            "addps         %%xmm2, %%xmm1 \n"
-            "movaps        %%xmm0, (%2,%0) \n"
-            "movaps        %%xmm1, (%2,%1) \n"
+            "movaps        %%xmm1, (%2,%0) \n"
+            "movaps        %%xmm2, (%2,%1) \n"
             "sub $16, %1 \n"
             "add $16, %0 \n"
             "jl 1b \n"
             :"+r"(i), "+r"(j)
-            :"r"(dst+len/2), "r"(src0+len/2), "r"(src1+len/2), "r"(win+len/2)
+            :"r"(dst+len), "r"(src0+len), "r"(src1), "r"(win+len)
         );
     }else
 #endif
@@ -2638,8 +2676,10 @@ void dsputil_init_mmx(DSPContext* c, AVCodecContext *avctx)
                 c->float_to_int16_interleave = float_to_int16_interleave_3dnow;
             }
         }
-        if(mm_flags & MM_3DNOWEXT)
+        if(mm_flags & MM_3DNOWEXT){
             c->vector_fmul_reverse = vector_fmul_reverse_3dnow2;
+            c->vector_fmul_window = vector_fmul_window_3dnow2;
+        }
         if(mm_flags & MM_SSE){
             c->vorbis_inverse_coupling = vorbis_inverse_coupling_sse;
             c->vector_fmul = vector_fmul_sse;

libavcodec/i386/fft_3dn2.c

@@ -124,10 +124,9 @@ void ff_fft_calc_3dn2(FFTContext *s, FFTComplex *z)
     asm volatile("femms");
 }
 
-void ff_imdct_calc_3dn2(MDCTContext *s, FFTSample *output,
-                        const FFTSample *input, FFTSample *tmp)
+static void imdct_3dn2(MDCTContext *s, const FFTSample *input, FFTSample *tmp)
 {
-    long n8, n4, n2, n;
+    long n4, n2, n;
     x86_reg k;
     const uint16_t *revtab = s->fft.revtab;
     const FFTSample *tcos = s->tcos;
@@ -138,7 +137,6 @@ void ff_imdct_calc_3dn2(MDCTContext *s, FFTSample *output,
     n = 1 << s->nbits;
     n2 = n >> 1;
     n4 = n >> 2;
-    n8 = n >> 3;
 
     /* pre rotation */
     in1 = input;
@@ -182,6 +180,20 @@ void ff_imdct_calc_3dn2(MDCTContext *s, FFTSample *output,
             :"m"(tcos[k]), "m"(tsin[k])
         );
     }
+}
+
+void ff_imdct_calc_3dn2(MDCTContext *s, FFTSample *output,
+                        const FFTSample *input, FFTSample *tmp)
+{
+    x86_reg k;
+    long n8, n2, n;
+    FFTComplex *z = (FFTComplex *)tmp;
+
+    n = 1 << s->nbits;
+    n2 = n >> 1;
+    n8 = n >> 3;
+
+    imdct_3dn2(s, input, tmp);
 
     k = n-8;
     asm volatile("movd %0, %%mm7" ::"r"(1<<31));
@@ -212,3 +224,40 @@ void ff_imdct_calc_3dn2(MDCTContext *s, FFTSample *output,
     asm volatile("femms");
 }
 
+void ff_imdct_half_3dn2(MDCTContext *s, FFTSample *output,
+                        const FFTSample *input, FFTSample *tmp)
+{
+    x86_reg j, k;
+    long n8, n4, n;
+    FFTComplex *z = (FFTComplex *)tmp;
+
+    n = 1 << s->nbits;
+    n4 = n >> 2;
+    n8 = n >> 3;
+
+    imdct_3dn2(s, input, tmp);
+
+    j = -n;
+    k = n-8;
+    asm volatile("movd %0, %%mm7" ::"r"(1<<31));
+    asm volatile(
+        "1: \n\t"
+        "movq    (%3,%1), %%mm0 \n\t" // z[n8+k]
+        "pswapd  (%3,%0), %%mm1 \n\t" // z[n8-1-k]
+        "movq      %%mm0, %%mm2 \n\t"
+        "punpckldq %%mm1, %%mm0 \n\t"
+        "punpckhdq %%mm2, %%mm1 \n\t"
+        "pxor      %%mm7, %%mm0 \n\t"
+        "pxor      %%mm7, %%mm1 \n\t"
+        "movq      %%mm0, (%2,%1) \n\t" // output[n4+2*k]   = { -z[n8+k].re, z[n8-1-k].im }
+        "movq      %%mm1, (%2,%0) \n\t" // output[n4-2-2*k] = { -z[n8-1-k].re, z[n8+k].im }
+        "sub $8, %1 \n\t"
+        "add $8, %0 \n\t"
+        "jl 1b \n\t"
+        :"+r"(j), "+r"(k)
+        :"r"(output+n4), "r"(z+n8)
+        :"memory"
+    );
+    asm volatile("femms");
+}
+

libavcodec/i386/fft_sse.c

@@ -142,11 +142,10 @@ void ff_fft_calc_sse(FFTContext *s, FFTComplex *z)
     } while (nblocks != 0);
 }
 
-void ff_imdct_calc_sse(MDCTContext *s, FFTSample *output,
-                       const FFTSample *input, FFTSample *tmp)
+static void imdct_sse(MDCTContext *s, const FFTSample *input, FFTSample *tmp)
 {
     x86_reg k;
-    long n8, n4, n2, n;
+    long n4, n2, n;
     const uint16_t *revtab = s->fft.revtab;
     const FFTSample *tcos = s->tcos;
     const FFTSample *tsin = s->tsin;
@@ -156,7 +155,6 @@ void ff_imdct_calc_sse(MDCTContext *s, FFTSample *output,
     n = 1 << s->nbits;
     n2 = n >> 1;
     n4 = n >> 2;
-    n8 = n >> 3;
 
 #ifdef ARCH_X86_64
     asm volatile ("movaps %0, %%xmm8\n\t"::"m"(*p1m1p1m1));
@@ -260,6 +258,20 @@ void ff_imdct_calc_sse(MDCTContext *s, FFTSample *output,
 #endif
         );
     }
+}
+
+void ff_imdct_calc_sse(MDCTContext *s, FFTSample *output,
+                       const FFTSample *input, FFTSample *tmp)
+{
+    x86_reg k;
+    long n8, n2, n;
+    FFTComplex *z = (FFTComplex *)tmp;
+
+    n = 1 << s->nbits;
+    n2 = n >> 1;
+    n8 = n >> 3;
+
+    imdct_sse(s, input, tmp);
 
     /*
        Mnemonics:
@@ -301,3 +313,41 @@ void ff_imdct_calc_sse(MDCTContext *s, FFTSample *output,
     );
 }
 
+void ff_imdct_half_sse(MDCTContext *s, FFTSample *output,
+                       const FFTSample *input, FFTSample *tmp)
+{
+    x86_reg j, k;
+    long n8, n4, n;
+    FFTComplex *z = (FFTComplex *)tmp;
+
+    n = 1 << s->nbits;
+    n4 = n >> 2;
+    n8 = n >> 3;
+
+    imdct_sse(s, input, tmp);
+
+    j = -n;
+    k = n-16;
+    asm volatile("movaps %0, %%xmm7 \n\t"::"m"(*m1m1m1m1));
+    asm volatile(
+        "1: \n\t"
+        "movaps     (%3,%1), %%xmm0 \n\t"
+        "movaps     (%3,%0), %%xmm1 \n\t"
+        "xorps       %%xmm7, %%xmm0 \n\t"
+        "movaps      %%xmm0, %%xmm2 \n\t"
+        "shufps $141,%%xmm1, %%xmm0 \n\t"
+        "shufps $216,%%xmm1, %%xmm2 \n\t"
+        "shufps $54, %%xmm0, %%xmm0 \n\t"
+        "shufps $156,%%xmm2, %%xmm2 \n\t"
+        "xorps       %%xmm7, %%xmm0 \n\t"
+        "movaps      %%xmm2, (%2,%1) \n\t"
+        "movaps      %%xmm0, (%2,%0) \n\t"
+        "sub $16, %1 \n\t"
+        "add $16, %0 \n\t"
+        "jl 1b \n\t"
+        :"+r"(j), "+r"(k)
+        :"r"(output+n4), "r"(z+n8)
+        :"memory"
+    );
+}
+

libavcodec/mdct.c

@@ -100,16 +100,9 @@ int ff_mdct_init(MDCTContext *s, int nbits, int inverse)
     (pim) = _are * _bim + _aim * _bre;\
 }
 
-/**
- * Compute inverse MDCT of size N = 2^nbits
- * @param output N samples
- * @param input N/2 samples
- * @param tmp N/2 samples
- */
-void ff_imdct_calc(MDCTContext *s, FFTSample *output,
-                   const FFTSample *input, FFTSample *tmp)
+static void imdct_c(MDCTContext *s, const FFTSample *input, FFTSample *tmp)
 {
-    int k, n8, n4, n2, n, j;
+    int k, n4, n2, n, j;
     const uint16_t *revtab = s->fft.revtab;
     const FFTSample *tcos = s->tcos;
     const FFTSample *tsin = s->tsin;
@@ -119,7 +112,6 @@ void ff_imdct_calc(MDCTContext *s, FFTSample *output,
     n = 1 << s->nbits;
     n2 = n >> 1;
     n4 = n >> 2;
-    n8 = n >> 3;
 
     /* pre rotation */
     in1 = input;
@@ -137,6 +129,25 @@ void ff_imdct_calc(MDCTContext *s, FFTSample *output,
     for(k = 0; k < n4; k++) {
         CMUL(z[k].re, z[k].im, z[k].re, z[k].im, tcos[k], tsin[k]);
     }
+}
+
+/**
+ * Compute inverse MDCT of size N = 2^nbits
+ * @param output N samples
+ * @param input N/2 samples
+ * @param tmp N/2 samples
+ */
+void ff_imdct_calc(MDCTContext *s, FFTSample *output,
+                   const FFTSample *input, FFTSample *tmp)
+{
+    int k, n8, n2, n;
+    FFTComplex *z = (FFTComplex *)tmp;
+    n = 1 << s->nbits;
+    n2 = n >> 1;
+    n8 = n >> 3;
+
+    imdct_c(s, input, tmp);
+
     for(k = 0; k < n8; k++) {
         output[2*k] = -z[n8 + k].im;
         output[n2-1-2*k] = z[n8 + k].im;
@@ -152,6 +163,32 @@ void ff_imdct_calc(MDCTContext *s, FFTSample *output,
     }
 }
 
+/**
+ * Compute the middle half of the inverse MDCT of size N = 2^nbits,
+ * thus excluding the parts that can be derived by symmetry
+ * @param output N/2 samples
+ * @param input N/2 samples
+ * @param tmp N/2 samples
+ */
+void ff_imdct_half(MDCTContext *s, FFTSample *output,
+                   const FFTSample *input, FFTSample *tmp)
+{
+    int k, n8, n4, n;
+    FFTComplex *z = (FFTComplex *)tmp;
+    n = 1 << s->nbits;
+    n4 = n >> 2;
+    n8 = n >> 3;
+
+    imdct_c(s, input, tmp);
+
+    for(k = 0; k < n8; k++) {
+        output[n4-1-2*k]   =  z[n8+k].im;
+        output[n4-1-2*k-1] = -z[n8-k-1].re;
+        output[n4 + 2*k]   = -z[n8+k].re;
+        output[n4 + 2*k+1] =  z[n8-k-1].im;
+    }
+}
+
 /**
  * Compute MDCT of size N = 2^nbits
  * @param input N samples

libavcodec/vorbis_dec.c

@@ -899,10 +899,10 @@ static int vorbis_parse_id_hdr(vorbis_context *vc){
 
     vc->channel_residues= av_malloc((vc->blocksize[1]/2)*vc->audio_channels * sizeof(float));
     vc->channel_floors  = av_malloc((vc->blocksize[1]/2)*vc->audio_channels * sizeof(float));
-    vc->saved           = av_mallocz((vc->blocksize[1]/2)*vc->audio_channels * sizeof(float));
+    vc->saved           = av_mallocz((vc->blocksize[1]/4)*vc->audio_channels * sizeof(float));
     vc->ret             = av_malloc((vc->blocksize[1]/2)*vc->audio_channels * sizeof(float));
-    vc->buf             = av_malloc( vc->blocksize[1]                       * sizeof(float));
-    vc->buf_tmp         = av_malloc( vc->blocksize[1]                       * sizeof(float));
+    vc->buf             = av_malloc( vc->blocksize[1]/2                     * sizeof(float));
+    vc->buf_tmp         = av_malloc( vc->blocksize[1]/2                     * sizeof(float));
     vc->previous_window=0;
 
     ff_mdct_init(&vc->mdct[0], bl0, 1);
@@ -1520,23 +1520,23 @@ static int vorbis_parse_audio_packet(vorbis_context *vc) {
     for(j=0;j<vc->audio_channels;++j) {
         uint_fast16_t bs0=vc->blocksize[0];
         uint_fast16_t bs1=vc->blocksize[1];
-        float *saved=vc->saved+j*bs1/2;
+        float *saved=vc->saved+j*bs1/4;
         float *ret=vc->ret+j*retlen;
         float *buf=vc->buf;
         const float *win=vc->win[blockflag&previous_window];
 
-        vc->mdct[0].fft.imdct_calc(&vc->mdct[blockflag], buf, vc->channel_floors+j*blocksize/2, vc->buf_tmp);
+        vc->mdct[0].fft.imdct_half(&vc->mdct[blockflag], buf, vc->channel_floors+j*blocksize/2, vc->buf_tmp);
 
         if(blockflag == previous_window) {
-            vc->dsp.vector_fmul_window(ret, saved, buf, win, fadd_bias, blocksize/2);
+            vc->dsp.vector_fmul_window(ret, saved, buf, win, fadd_bias, blocksize/4);
         } else if(blockflag > previous_window) {
-            vc->dsp.vector_fmul_window(ret, saved, buf+(bs1-bs0)/4, win, fadd_bias, bs0/2);
-            copy_normalize(ret+bs0/2, buf+(bs1+bs0)/4, (bs1-bs0)/4, vc->exp_bias, fadd_bias);
+            vc->dsp.vector_fmul_window(ret, saved, buf, win, fadd_bias, bs0/4);
+            copy_normalize(ret+bs0/2, buf+bs0/4, (bs1-bs0)/4, vc->exp_bias, fadd_bias);
         } else {
             copy_normalize(ret, saved, (bs1-bs0)/4, vc->exp_bias, fadd_bias);
-            vc->dsp.vector_fmul_window(ret+(bs1-bs0)/4, saved+(bs1-bs0)/4, buf, win, fadd_bias, bs0/2);
+            vc->dsp.vector_fmul_window(ret+(bs1-bs0)/4, saved+(bs1-bs0)/4, buf, win, fadd_bias, bs0/4);
         }
-        memcpy(saved, buf+blocksize/2, blocksize/2*sizeof(float));
+        memcpy(saved, buf+blocksize/4, blocksize/4*sizeof(float));
     }
 
     vc->previous_window = blockflag;