@@ -68,8 +68,7 @@ typedef struct {

     AVFrame *outpicref;

     FFTContext *fft_context;

     FFTComplex *fft_data;

-    FFTComplex *fft_result_left;

-    FFTComplex *fft_result_right;

+    FFTComplex *fft_result;

     uint8_t *spectogram;

     SparseCoeff *coeff_sort;

     SparseCoeff *coeffs[VIDEO_WIDTH];

@@ -125,8 +124,7 @@ static av_cold void uninit(AVFilterContext *ctx)

     for (k = 0; k < VIDEO_WIDTH; k++)

         av_freep(&s->coeffs[k]);

     av_freep(&s->fft_data);

-    av_freep(&s->fft_result_left);

-    av_freep(&s->fft_result_right);

+    av_freep(&s->fft_result);

     av_freep(&s->coeff_sort);

     av_freep(&s->spectogram);

     av_freep(&s->font_alpha);

@@ -345,11 +343,10 @@ static int config_output(AVFilterLink *outlink)

     s->fft_data         = av_malloc_array(fft_len, sizeof(*s->fft_data));

     s->coeff_sort       = av_malloc_array(fft_len, sizeof(*s->coeff_sort));

-    s->fft_result_left  = av_malloc_array(fft_len, sizeof(*s->fft_result_left));

-    s->fft_result_right = av_malloc_array(fft_len, sizeof(*s->fft_result_right));

+    s->fft_result       = av_malloc_array(fft_len + 1, sizeof(*s->fft_result));

     s->fft_context      = av_fft_init(s->fft_bits, 0);

-    if (!s->fft_data || !s->coeff_sort || !s->fft_result_left || !s->fft_result_right || !s->fft_context)

+    if (!s->fft_data || !s->coeff_sort || !s->fft_result || !s->fft_context)

         return AVERROR(ENOMEM);

 #if CONFIG_LIBFREETYPE

@@ -541,43 +538,32 @@ static int plot_cqt(AVFilterLink *inlink)

     int font_height = (FONT_HEIGHT/2) * video_scale;

     /* real part contains left samples, imaginary part contains right samples */

-    memcpy(s->fft_result_left, s->fft_data, fft_len * sizeof(*s->fft_data));

-    av_fft_permute(s->fft_context, s->fft_result_left);

-    av_fft_calc(s->fft_context, s->fft_result_left);

-

-    /* separate left and right, (and multiply by 2.0) */

-    s->fft_result_right[0].re = 2.0f * s->fft_result_left[0].im;

-    s->fft_result_right[0].im = 0;

-    s->fft_result_left[0].re = 2.0f * s->fft_result_left[0].re;

-    s->fft_result_left[0].im = 0;

-    for (x = 1; x <= fft_len >> 1; x++) {

-        FFTSample tmpy = s->fft_result_left[fft_len-x].im - s->fft_result_left[x].im;

-

-        s->fft_result_right[x].re = s->fft_result_left[x].im + s->fft_result_left[fft_len-x].im;

-        s->fft_result_right[x].im = s->fft_result_left[x].re - s->fft_result_left[fft_len-x].re;

-        s->fft_result_right[fft_len-x].re = s->fft_result_right[x].re;

-        s->fft_result_right[fft_len-x].im = -s->fft_result_right[x].im;

-

-        s->fft_result_left[x].re = s->fft_result_left[x].re + s->fft_result_left[fft_len-x].re;

-        s->fft_result_left[x].im = tmpy;

-        s->fft_result_left[fft_len-x].re = s->fft_result_left[x].re;

-        s->fft_result_left[fft_len-x].im = -s->fft_result_left[x].im;

-    }

+    memcpy(s->fft_result, s->fft_data, fft_len * sizeof(*s->fft_data));

+    av_fft_permute(s->fft_context, s->fft_result);

+    av_fft_calc(s->fft_context, s->fft_result);

+    s->fft_result[fft_len] = s->fft_result[0];

     /* calculating cqt */

     for (x = 0; x < VIDEO_WIDTH; x++) {

         int u;

-        FFTComplex l = {0,0};

-        FFTComplex r = {0,0};

+        FFTComplex v = {0,0};

+        FFTComplex w = {0,0};

+        FFTComplex l, r;

         for (u = 0; u < s->coeffs_len[x]; u++) {

             FFTSample value = s->coeffs[x][u].value;

             int index = s->coeffs[x][u].index;

-            l.re += value * s->fft_result_left[index].re;

-            l.im += value * s->fft_result_left[index].im;

-            r.re += value * s->fft_result_right[index].re;

-            r.im += value * s->fft_result_right[index].im;

+            v.re += value * s->fft_result[index].re;

+            v.im += value * s->fft_result[index].im;

+            w.re += value * s->fft_result[fft_len - index].re;

+            w.im += value * s->fft_result[fft_len - index].im;

         }

+

+        /* separate left and right, (and multiply by 2.0) */

+        l.re = v.re + w.re;

+        l.im = v.im - w.im;

+        r.re = w.im + v.im;

+        r.im = w.re - v.re;

         /* result is power, not amplitude */

         result[x][0] = l.re * l.re + l.im * l.im;

         result[x][2] = r.re * r.re + r.im * r.im;