@@ -64,7 +64,7 @@ typedef struct {

     float rotation;             ///< color rotation

     int data;

     int xpos;                   ///< x position (current column)

-    FFTContext *fft;            ///< Fast Fourier Transform context

+    FFTContext **fft;           ///< Fast Fourier Transform context

     int fft_bits;               ///< number of bits (FFT window size = 1<<fft_bits)

     FFTComplex **fft_data;      ///< bins holder for each (displayed) channels

     float *window_func_lut;     ///< Window function LUT

@@ -225,11 +225,15 @@ static av_cold void uninit(AVFilterContext *ctx)

     int i;

     av_freep(&s->combine_buffer);

-    av_fft_end(s->fft);

+    if (s->fft) {

+        for (i = 0; i < s->nb_display_channels; i++)

+            av_fft_end(s->fft[i]);

+    }

     if (s->fft_data) {

         for (i = 0; i < s->nb_display_channels; i++)

             av_freep(&s->fft_data[i]);

     }

+    av_freep(&s->fft);

     av_freep(&s->fft_data);

     av_freep(&s->window_func_lut);

     if (s->magnitudes) {

@@ -312,26 +316,36 @@ static int config_output(AVFilterLink *outlink)

     }

     s->win_size = 1 << fft_bits;

+    if (!s->fft) {

+        s->fft = av_calloc(inlink->channels, sizeof(*s->fft));

+        if (!s->fft)

+            return AVERROR(ENOMEM);

+    }

+

     /* (re-)configuration if the video output changed (or first init) */

     if (fft_bits != s->fft_bits) {

         AVFrame *outpicref;

-        av_fft_end(s->fft);

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

-        if (!s->fft) {

-            av_log(ctx, AV_LOG_ERROR, "Unable to create FFT context. "

-                   "The window size might be too high.\n");

-            return AVERROR(EINVAL);

-        }

         s->fft_bits = fft_bits;

         /* FFT buffers: x2 for each (display) channel buffer.

          * Note: we use free and malloc instead of a realloc-like function to

          * make sure the buffer is aligned in memory for the FFT functions. */

-        for (i = 0; i < s->nb_display_channels; i++)

+        for (i = 0; i < s->nb_display_channels; i++) {

+            av_fft_end(s->fft[i]);

             av_freep(&s->fft_data[i]);

+        }

         av_freep(&s->fft_data);

+

         s->nb_display_channels = inlink->channels;

+        for (i = 0; i < s->nb_display_channels; i++) {

+            s->fft[i] = av_fft_init(fft_bits, 0);

+            if (!s->fft[i]) {

+                av_log(ctx, AV_LOG_ERROR, "Unable to create FFT context. "

+                       "The window size might be too high.\n");

+                return AVERROR(EINVAL);

+            }

+        }

         s->magnitudes = av_calloc(s->nb_display_channels, sizeof(*s->magnitudes));

         if (!s->magnitudes)

@@ -342,7 +356,7 @@ static int config_output(AVFilterLink *outlink)

                 return AVERROR(ENOMEM);

         }

-        s->phases = av_calloc(s->nb_display_channels, sizeof(*s->magnitudes));

+        s->phases = av_calloc(s->nb_display_channels, sizeof(*s->phases));

         if (!s->phases)

             return AVERROR(ENOMEM);

         for (i = 0; i < s->nb_display_channels; i++) {

@@ -425,25 +439,27 @@ static int config_output(AVFilterLink *outlink)

     return 0;

 }

-static void run_fft(ShowSpectrumContext *s, AVFrame *fin)

+static int run_channel_fft(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)

 {

-    int ch, n;

+    ShowSpectrumContext *s = ctx->priv;

+    const float *window_func_lut = s->window_func_lut;

+    AVFrame *fin = arg;

+    const int ch = jobnr;

+    int n;

     /* fill FFT input with the number of samples available */

-    for (ch = 0; ch < s->nb_display_channels; ch++) {

-        const float *p = (float *)fin->extended_data[ch];

+    const float *p = (float *)fin->extended_data[ch];

-        for (n = 0; n < s->win_size; n++) {

-            s->fft_data[ch][n].re = p[n] * s->window_func_lut[n];

-            s->fft_data[ch][n].im = 0;

-        }

+    for (n = 0; n < s->win_size; n++) {

+        s->fft_data[ch][n].re = p[n] * window_func_lut[n];

+        s->fft_data[ch][n].im = 0;

     }

     /* run FFT on each samples set */

-    for (ch = 0; ch < s->nb_display_channels; ch++) {

-        av_fft_permute(s->fft, s->fft_data[ch]);

-        av_fft_calc(s->fft, s->fft_data[ch]);

-    }

+    av_fft_permute(s->fft[ch], s->fft_data[ch]);

+    av_fft_calc(s->fft[ch], s->fft_data[ch]);

+

+    return 0;

 }

 #define RE(y, ch) s->fft_data[ch][y].re

@@ -451,30 +467,33 @@ static void run_fft(ShowSpectrumContext *s, AVFrame *fin)

 #define MAGNITUDE(y, ch) hypot(RE(y, ch), IM(y, ch))

 #define PHASE(y, ch) atan2(IM(y, ch), RE(y, ch))

-static void calc_magnitudes(ShowSpectrumContext *s)

+static int calc_channel_magnitudes(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)

 {

+    ShowSpectrumContext *s = ctx->priv;

     const double w = s->win_scale * (s->scale == LOG ? s->win_scale : 1);

-    int ch, y, h = s->orientation == VERTICAL ? s->h : s->w;

+    int y, h = s->orientation == VERTICAL ? s->h : s->w;

     const float f = s->gain * w;

+    const int ch = jobnr;

+    float *magnitudes = s->magnitudes[ch];

-    for (ch = 0; ch < s->nb_display_channels; ch++) {

-        float *magnitudes = s->magnitudes[ch];

+    for (y = 0; y < h; y++)

+        magnitudes[y] = MAGNITUDE(y, ch) * f;

-        for (y = 0; y < h; y++)

-            magnitudes[y] = MAGNITUDE(y, ch) * f;

-    }

+    return 0;

 }

-static void calc_phases(ShowSpectrumContext *s)

+static int calc_channel_phases(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)

 {

-    int ch, y, h = s->orientation == VERTICAL ? s->h : s->w;

+    ShowSpectrumContext *s = ctx->priv;

+    const int h = s->orientation == VERTICAL ? s->h : s->w;

+    const int ch = jobnr;

+    float *phases = s->phases[ch];

+    int y;

-    for (ch = 0; ch < s->nb_display_channels; ch++) {

-        float *phases = s->phases[ch];

+    for (y = 0; y < h; y++)

+        phases[y] = (PHASE(y, ch) / M_PI + 1) / 2;

-        for (y = 0; y < h; y++)

-            phases[y] = (PHASE(y, ch) / M_PI + 1) / 2;

-    }

+    return 0;

 }

 static void acalc_magnitudes(ShowSpectrumContext *s)

@@ -614,75 +633,81 @@ static void clear_combine_buffer(ShowSpectrumContext *s, int size)

     }

 }

+static int plot_channel(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)

+{

+    ShowSpectrumContext *s = ctx->priv;

+    const int h = s->orientation == VERTICAL ? s->channel_height : s->channel_width;

+    const int ch = jobnr;

+    float *magnitudes = s->magnitudes[ch];

+    float *phases = s->phases[ch];

+    float yf, uf, vf;

+    int y;

+

+    /* decide color range */

+    color_range(s, ch, &yf, &uf, &vf);

+

+    /* draw the channel */

+    for (y = 0; y < h; y++) {

+        int row = (s->mode == COMBINED) ? y : ch * h + y;

+        float *out = &s->combine_buffer[3 * row];

+        float a;

+

+        switch (s->data) {

+        case D_MAGNITUDE:

+            /* get magnitude */

+            a = magnitudes[y];

+            break;

+        case D_PHASE:

+            /* get phase */

+            a = phases[y];

+            break;

+        default:

+            av_assert0(0);

+        }

+

+        /* apply scale */

+        switch (s->scale) {

+        case LINEAR:

+            a = av_clipf(a, 0, 1);

+            break;

+        case SQRT:

+            a = av_clipf(sqrt(a), 0, 1);

+            break;

+        case CBRT:

+            a = av_clipf(cbrt(a), 0, 1);

+            break;

+        case FOURTHRT:

+            a = av_clipf(sqrt(sqrt(a)), 0, 1);

+            break;

+        case FIFTHRT:

+            a = av_clipf(pow(a, 0.20), 0, 1);

+            break;

+        case LOG:

+            a = 1 + log10(av_clipd(a, 1e-6, 1)) / 6; // zero = -120dBFS

+            break;

+        default:

+            av_assert0(0);

+        }

+

+        pick_color(s, yf, uf, vf, a, out);

+    }

+

+    return 0;

+}

+

 static int plot_spectrum_column(AVFilterLink *inlink, AVFrame *insamples)

 {

-    int ret;

     AVFilterContext *ctx = inlink->dst;

     AVFilterLink *outlink = ctx->outputs[0];

     ShowSpectrumContext *s = ctx->priv;

     AVFrame *outpicref = s->outpicref;

-    int h = s->orientation == VERTICAL ? s->channel_height : s->channel_width;

-

-    int ch, plane, x, y;

+    int ret, plane, x, y;

     /* fill a new spectrum column */

     /* initialize buffer for combining to black */

     clear_combine_buffer(s, s->orientation == VERTICAL ? s->h : s->w);

-    for (ch = 0; ch < s->nb_display_channels; ch++) {

-        float *magnitudes = s->magnitudes[ch];

-        float *phases = s->phases[ch];

-        float yf, uf, vf;

-

-        /* decide color range */

-        color_range(s, ch, &yf, &uf, &vf);

-

-        /* draw the channel */

-        for (y = 0; y < h; y++) {

-            int row = (s->mode == COMBINED) ? y : ch * h + y;

-            float *out = &s->combine_buffer[3 * row];

-            float a;

-

-            switch (s->data) {

-            case D_MAGNITUDE:

-                /* get magnitude */

-                a = magnitudes[y];

-                break;

-            case D_PHASE:

-                /* get phase */

-                a = phases[y];

-                break;

-            default:

-                av_assert0(0);

-            }

-

-            /* apply scale */

-            switch (s->scale) {

-            case LINEAR:

-                a = av_clipf(a, 0, 1);

-                break;

-            case SQRT:

-                a = av_clipf(sqrt(a), 0, 1);

-                break;

-            case CBRT:

-                a = av_clipf(cbrt(a), 0, 1);

-                break;

-            case FOURTHRT:

-                a = av_clipf(sqrt(sqrt(a)), 0, 1);

-                break;

-            case FIFTHRT:

-                a = av_clipf(pow(a, 0.20), 0, 1);

-                break;

-            case LOG:

-                a = 1 + log10(av_clipd(a, 1e-6, 1)) / 6; // zero = -120dBFS

-                break;

-            default:

-                av_assert0(0);

-            }

-

-            pick_color(s, yf, uf, vf, a, out);

-        }

-    }

+    ctx->internal->execute(ctx, plot_channel, NULL, NULL, s->nb_display_channels);

     av_frame_make_writable(s->outpicref);

     /* copy to output */

@@ -821,11 +846,13 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)

         av_assert0(fin->nb_samples == s->win_size);

-        run_fft(s, fin);

+        ctx->internal->execute(ctx, run_channel_fft, fin, NULL, s->nb_display_channels);

+

         if (s->data == D_MAGNITUDE)

-            calc_magnitudes(s);

+            ctx->internal->execute(ctx, calc_channel_magnitudes, NULL, NULL, s->nb_display_channels);

+

         if (s->data == D_PHASE)

-            calc_phases(s);

+            ctx->internal->execute(ctx, calc_channel_phases, NULL, NULL, s->nb_display_channels);

         ret = plot_spectrum_column(inlink, fin);

         av_frame_free(&fin);

@@ -868,6 +895,7 @@ AVFilter ff_avf_showspectrum = {

     .inputs        = showspectrum_inputs,

     .outputs       = showspectrum_outputs,

     .priv_class    = &showspectrum_class,

+    .flags         = AVFILTER_FLAG_SLICE_THREADS,

 };

 #endif // CONFIG_SHOWSPECTRUM_FILTER

@@ -961,8 +989,9 @@ static void drawtext(AVFrame *pic, int x, int y, const char *txt, int o)

 static int showspectrumpic_request_frame(AVFilterLink *outlink)

 {

-    ShowSpectrumContext *s = outlink->src->priv;

-    AVFilterLink *inlink = outlink->src->inputs[0];

+    AVFilterContext *ctx = outlink->src;

+    ShowSpectrumContext *s = ctx->priv;

+    AVFilterLink *inlink = ctx->inputs[0];

     int ret;

     ret = ff_request_frame(inlink);

@@ -996,7 +1025,7 @@ static int showspectrumpic_request_frame(AVFilterLink *outlink)

                 }

             }

-            run_fft(s, fin);

+            ctx->internal->execute(ctx, run_channel_fft, fin, NULL, s->nb_display_channels);

             acalc_magnitudes(s);

             consumed += spf;

@@ -1242,6 +1271,7 @@ AVFilter ff_avf_showspectrumpic = {

     .inputs        = showspectrumpic_inputs,

     .outputs       = showspectrumpic_outputs,

     .priv_class    = &showspectrumpic_class,

+    .flags         = AVFILTER_FLAG_SLICE_THREADS,

 };

 #endif // CONFIG_SHOWSPECTRUMPIC_FILTER