diff --git a/libavcodec/mdct15.c b/libavcodec/mdct15.c
index d68372c344..9838082c7e 100644
--- a/libavcodec/mdct15.c
+++ b/libavcodec/mdct15.c
@@ -28,6 +28,7 @@
 #include <math.h>
 #include <stddef.h>
 
+#include "avcodec.h"
 #include "config.h"
 
 #include "libavutil/attributes.h"
@@ -40,6 +41,25 @@
 
 #define CMUL3(c, a, b) CMUL((c).re, (c).im, (a).re, (a).im, (b).re, (b).im)
 
+#define OVERALLOC(val, len, size)                                           \
+    {                                                                       \
+        const int pad = AV_INPUT_BUFFER_PADDING_SIZE/size;                  \
+        (val) = NULL;                                                       \
+        uint8_t *temp = av_mallocz_array(len + pad, size);                  \
+        if (temp)                                                           \
+            (val) = (void *)(temp + AV_INPUT_BUFFER_PADDING_SIZE);          \
+    }
+
+#define OVERFREEP(val)                                                      \
+    {                                                                       \
+        uint8_t *temp = (uint8_t *)(val);                                   \
+        if (temp) {                                                         \
+            temp -= AV_INPUT_BUFFER_PADDING_SIZE;                           \
+            av_free(temp);                                                  \
+        }                                                                   \
+        val = NULL;                                                         \
+    }
+
 av_cold void ff_mdct15_uninit(MDCT15Context **ps)
 {
     MDCT15Context *s = *ps;
@@ -50,9 +70,9 @@ av_cold void ff_mdct15_uninit(MDCT15Context **ps)
     ff_fft_end(&s->ptwo_fft);
 
     av_freep(&s->pfa_prereindex);
-    av_freep(&s->pfa_postreindex);
-    av_freep(&s->twiddle_exptab);
-    av_freep(&s->tmp);
+    OVERFREEP(s->pfa_postreindex);
+    OVERFREEP(s->twiddle_exptab);
+    OVERFREEP(s->tmp);
 
     av_freep(ps);
 }
@@ -65,11 +85,11 @@ static inline int init_pfa_reindex_tabs(MDCT15Context *s)
     const int inv_1 = l_ptwo << ((4 - b_ptwo) & 3); /* (2^b_ptwo)^-1 mod 15 */
     const int inv_2 = 0xeeeeeeef & ((1U << b_ptwo) - 1); /* 15^-1 mod 2^b_ptwo */
 
-    s->pfa_prereindex = av_malloc(15 * l_ptwo * sizeof(*s->pfa_prereindex));
+    s->pfa_prereindex = av_malloc_array(15 * l_ptwo, sizeof(*s->pfa_prereindex));
     if (!s->pfa_prereindex)
         return 1;
 
-    s->pfa_postreindex = av_malloc(15 * l_ptwo * sizeof(*s->pfa_postreindex));
+    OVERALLOC(s->pfa_postreindex, 15 * l_ptwo, sizeof(*s->pfa_postreindex));
     if (!s->pfa_postreindex)
         return 1;
 
@@ -203,6 +223,21 @@ static void mdct15(MDCT15Context *s, float *dst, const float *src, ptrdiff_t str
     }
 }
 
+static void postrotate_c(FFTComplex *out, FFTComplex *in, FFTComplex *exp,
+                         int *lut, ptrdiff_t len8)
+{
+    int i;
+
+    /* Reindex again, apply twiddles and output */
+    for (i = 0; i < len8; i++) {
+        const int i0 = len8 + i, i1 = len8 - i - 1;
+        const int s0 = lut[i0], s1 = lut[i1];
+
+        CMUL(out[i1].re, out[i0].im, in[s1].im, in[s1].re, exp[i1].im, exp[i1].re);
+        CMUL(out[i0].re, out[i1].im, in[s0].im, in[s0].re, exp[i0].im, exp[i0].re);
+    }
+}
+
 static void imdct15_half(MDCT15Context *s, float *dst, const float *src,
                          ptrdiff_t stride)
 {
@@ -226,15 +261,7 @@ static void imdct15_half(MDCT15Context *s, float *dst, const float *src,
         s->ptwo_fft.fft_calc(&s->ptwo_fft, s->tmp + l_ptwo*i);
 
     /* Reindex again, apply twiddles and output */
-    for (i = 0; i < len8; i++) {
-        const int i0 = len8 + i, i1 = len8 - i - 1;
-        const int s0 = s->pfa_postreindex[i0], s1 = s->pfa_postreindex[i1];
-
-        CMUL(z[i1].re, z[i0].im, s->tmp[s1].im, s->tmp[s1].re,
-             s->twiddle_exptab[i1].im, s->twiddle_exptab[i1].re);
-        CMUL(z[i0].re, z[i1].im, s->tmp[s0].im, s->tmp[s0].re,
-             s->twiddle_exptab[i0].im, s->twiddle_exptab[i0].re);
-    }
+    s->postreindex(z, s->tmp, s->twiddle_exptab, s->pfa_postreindex, len8);
 }
 
 av_cold int ff_mdct15_init(MDCT15Context **ps, int inverse, int N, double scale)
@@ -253,13 +280,14 @@ av_cold int ff_mdct15_init(MDCT15Context **ps, int inverse, int N, double scale)
     if (!s)
         return AVERROR(ENOMEM);
 
-    s->fft_n      = N - 1;
-    s->len4       = len2 / 2;
-    s->len2       = len2;
-    s->inverse    = inverse;
-    s->fft15      = fft15_c;
-    s->mdct       = mdct15;
-    s->imdct_half = imdct15_half;
+    s->fft_n       = N - 1;
+    s->len4        = len2 / 2;
+    s->len2        = len2;
+    s->inverse     = inverse;
+    s->fft15       = fft15_c;
+    s->mdct        = mdct15;
+    s->imdct_half  = imdct15_half;
+    s->postreindex = postrotate_c;
 
     if (ff_fft_init(&s->ptwo_fft, N - 1, s->inverse) < 0)
         goto fail;
@@ -267,11 +295,11 @@ av_cold int ff_mdct15_init(MDCT15Context **ps, int inverse, int N, double scale)
     if (init_pfa_reindex_tabs(s))
         goto fail;
 
-    s->tmp  = av_malloc_array(len, 2 * sizeof(*s->tmp));
+    OVERALLOC(s->tmp, 2*len, sizeof(*s->tmp));
     if (!s->tmp)
         goto fail;
 
-    s->twiddle_exptab  = av_malloc_array(s->len4, sizeof(*s->twiddle_exptab));
+    OVERALLOC(s->twiddle_exptab, s->len4, sizeof(*s->twiddle_exptab));
     if (!s->twiddle_exptab)
         goto fail;
 
diff --git a/libavcodec/mdct15.h b/libavcodec/mdct15.h
index 1c2149d436..42e60f3e10 100644
--- a/libavcodec/mdct15.h
+++ b/libavcodec/mdct15.h
@@ -42,6 +42,9 @@ typedef struct MDCT15Context {
     /* 15-point FFT */
     void (*fft15)(FFTComplex *out, FFTComplex *in, FFTComplex *exptab, ptrdiff_t stride);
 
+    /* PFA postrotate and exptab */
+    void (*postreindex)(FFTComplex *out, FFTComplex *in, FFTComplex *exp, int *lut, ptrdiff_t len8);
+
     /* Calculate a full 2N -> N MDCT */
     void (*mdct)(struct MDCT15Context *s, float *dst, const float *src, ptrdiff_t stride);
 
diff --git a/libavcodec/x86/mdct15.asm b/libavcodec/x86/mdct15.asm
index f8b895944d..b42adb4aa9 100644
--- a/libavcodec/x86/mdct15.asm
+++ b/libavcodec/x86/mdct15.asm
@@ -24,7 +24,11 @@
 
 %if ARCH_X86_64
 
-SECTION_RODATA
+SECTION_RODATA 32
+
+perm_neg: dd 2, 5, 3, 4, 6, 1, 7, 0
+perm_pos: dd 0, 7, 1, 6, 4, 3, 5, 2
+sign_adjust_r: times 4 dd 0x80000000, 0x00000000
 
 sign_adjust_5: dd 0x00000000, 0x80000000, 0x80000000, 0x00000000
 
@@ -138,4 +142,91 @@ cglobal fft15, 4, 6, 14, out, in, exptab, stride, stride3, stride5
 
     RET
 
+%macro LUT_LOAD_4D 3
+    mov      r7d, [lutq + %3q*4 +  0]
+    movsd  xmm%1, [inq +  r7q*8]
+    mov      r7d, [lutq + %3q*4 +  4]
+    movhps xmm%1, [inq +  r7q*8]
+%if cpuflag(avx2)
+    mov      r7d, [lutq + %3q*4 +  8]
+    movsd     %2, [inq +  r7q*8]
+    mov      r7d, [lutq + %3q*4 + 12]
+    movhps    %2, [inq +  r7q*8]
+    vinsertf128 %1, %1, %2, 1
+%endif
+%endmacro
+
+%macro POSTROTATE_FN 0
+;**********************************************************************************************************
+;void ff_mdct15_postreindex(FFTComplex *out, FFTComplex *in, FFTComplex *exp, uint32_t *lut, int64_t len8);
+;**********************************************************************************************************
+cglobal mdct15_postreindex, 5, 8, 12, out, in, exp, lut, len8, offset_p, offset_n
+%if cpuflag(avx2)
+    %define INCREMENT 4
+%else
+    %define INCREMENT 2
+%endif
+
+    mova m7, [perm_pos]
+    mova m8, [perm_neg]
+    mova m9, [sign_adjust_r]
+
+    mov offset_pq, len8q
+    lea offset_nq, [len8q - INCREMENT]
+
+    shl len8q, 1
+
+    movups m10, [outq - mmsize]         ; backup from start - mmsize to start
+    movups m11, [outq + len8q*8]        ; backup from end to end + mmsize
+
+.loop:
+    movups m0, [expq + offset_pq*8]     ; exp[p0].re, exp[p0].im, exp[p1].re, exp[p1].im, exp[p2].re, exp[p2].im, exp[p3].re, exp[p3].im
+    movups m1, [expq + offset_nq*8]     ; exp[n3].re, exp[n3].im, exp[n2].re, exp[n2].im, exp[n1].re, exp[n1].im, exp[n0].re, exp[n0].im
+
+    LUT_LOAD_4D m3, xmm4, offset_p      ; in[p0].re, in[p0].im, in[p1].re, in[p1].im, in[p2].re, in[p2].im, in[p3].re, in[p3].im
+    LUT_LOAD_4D m4, xmm5, offset_n      ; in[n3].re, in[n3].im, in[n2].re, in[n2].im, in[n1].re, in[n1].im, in[n0].re, in[n0].im
+
+    mulps m5, m3, m0                    ; in[p].reim * exp[p].reim
+    mulps m6, m4, m1                    ; in[n].reim * exp[n].reim
+
+    xorps m5, m9                        ; in[p].re *= -1, in[p].im *= 1
+    xorps m6, m9                        ; in[n].re *= -1, in[n].im *= 1
+
+    shufps m3, m3, m3, q2301            ; in[p].imre
+    shufps m4, m4, m4, q2301            ; in[n].imre
+
+    mulps m3, m0                        ; in[p].imre * exp[p].reim
+    mulps m4, m1                        ; in[n].imre * exp[n].reim
+
+    haddps m5, m4                       ; out[p0].re, out[p1].re, out[p3].im, out[p2].im, out[p2].re, out[p3].re, out[p1].im, out[p0].im
+    haddps m3, m6                       ; out[n0].im, out[n1].im, out[n3].re, out[n2].re, out[n2].im, out[n3].im, out[n1].re, out[n0].re
+
+%if cpuflag(avx2)
+    vpermps m5, m7, m5                  ; out[p0].re, out[p0].im, out[p1].re, out[p1].im, out[p2].re, out[p2].im, out[p3].re, out[p3].im
+    vpermps m3, m8, m3                  ; out[n3].im, out[n3].re, out[n2].im, out[n2].re, out[n1].im, out[n1].re, out[n0].im, out[n0].re
+%else
+    shufps m5, m5, m5, q2130
+    shufps m3, m3, m3, q0312
+%endif
+
+    movups [outq + offset_pq*8], m5
+    movups [outq + offset_nq*8], m3
+
+    sub offset_nq, INCREMENT
+    add offset_pq, INCREMENT
+
+    cmp offset_pq, len8q
+    jl .loop
+
+    movups [outq - mmsize],  m10
+    movups [outq + len8q*8], m11
+
+    RET
+%endmacro
+
+INIT_XMM sse3
+POSTROTATE_FN
+INIT_YMM avx2
+POSTROTATE_FN
+
 %endif
diff --git a/libavcodec/x86/mdct15_init.c b/libavcodec/x86/mdct15_init.c
index ba3d94c2ec..ec4ff42bb6 100644
--- a/libavcodec/x86/mdct15_init.c
+++ b/libavcodec/x86/mdct15_init.c
@@ -25,6 +25,9 @@
 #include "libavutil/x86/cpu.h"
 #include "libavcodec/mdct15.h"
 
+void ff_mdct15_postreindex_sse3(FFTComplex *out, FFTComplex *in, FFTComplex *exp, int *lut, ptrdiff_t len8);
+void ff_mdct15_postreindex_avx2(FFTComplex *out, FFTComplex *in, FFTComplex *exp, int *lut, ptrdiff_t len8);
+
 void ff_fft15_avx(FFTComplex *out, FFTComplex *in, FFTComplex *exptab, ptrdiff_t stride);
 
 static void perm_twiddles(MDCT15Context *s)
@@ -90,6 +93,12 @@ av_cold void ff_mdct15_init_x86(MDCT15Context *s)
         adjust_twiddles = 1;
     }
 
+    if (ARCH_X86_64 && EXTERNAL_SSE3(cpu_flags))
+        s->postreindex = ff_mdct15_postreindex_sse3;
+
+    if (ARCH_X86_64 && EXTERNAL_AVX2(cpu_flags))
+        s->postreindex = ff_mdct15_postreindex_avx2;
+
     if (adjust_twiddles)
         perm_twiddles(s);
 }
