avfilter: new multimedia filter avf_showcqt.c

this filter is the same as showspectrum but with constant Q transform,
so frequency is spaced logarithmically

7 files changed, 660 insertions, 1 deletions

diff --git a/Changelog b/Changelog
index aec10c0ad4..7f3704e621 100644
--- a/Changelog
+++ b/Changelog
@@ -26,6 +26,7 @@ version <next>:
 - native Opus decoder
 - display matrix export and rotation api
 - WebVTT encoder
+- showcqt multimedia filter
 
 
 version 2.2:
diff --git a/MAINTAINERS b/MAINTAINERS
index 29c83969d7..f06c23f92f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -341,6 +341,7 @@ Filters:
   af_ladspa.c                           Paul B Mahol
   af_pan.c                              Nicolas George
   avf_avectorscope.c                    Paul B Mahol
+  avf_showcqt.c                         Muhammad Faiz
   vf_blend.c                            Paul B Mahol
   vf_colorbalance.c                     Paul B Mahol
   vf_dejudder.c                         Nicholas Robbins
diff --git a/doc/filters.texi b/doc/filters.texi
index e004c447f0..9dc97d743d 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -10133,6 +10133,76 @@ settb=AVTB
 @end example
 @end itemize
 
+@section showcqt
+Convert input audio to a video output (at full HD resolution), representing
+frequency spectrum logarithmically (using constant Q transform with
+Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
+
+The filter accepts the following options:
+
+@table @option
+@item volume
+Specify the transform volume (multiplier). Acceptable value is [1.0, 100.0].
+Default value is @code{16.0}.
+
+@item timeclamp
+Specify the transform timeclamp. At low frequency, there is trade-off between
+accuracy in time domain and frequency domain. If timeclamp is lower,
+event in time domain is represented more accurately (such as fast bass drum),
+otherwise event in frequency domain is represented more accurately
+(such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
+
+@item coeffclamp
+Specify the transform coeffclamp. If coeffclamp is lower, transform is
+more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
+Default value is @code{1.0}.
+
+@item gamma
+Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
+makes the spectrum having more range. Acceptable value is [1.0, 7.0].
+Default value is @code{3.0}.
+
+@item fps
+Specify video fps. Default value is @code{25}.
+
+@item count
+Specify number of transform per frame, so there are fps*count transforms
+per second. Note tha audio data rate must be divisible by fps*count.
+Default value is @code{6}.
+
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Playing audio while showing the spectrum:
+@example
+ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
+@end example
+
+@item
+Same as above, but with frame rate 30 fps:
+@example
+ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
+@end example
+
+@item
+A1 and its harmonics: A1, A2, (near)E3, A3:
+@example
+ffplay -f lavfi 'aevalsrc=0.1*sin(2*PI*55*t)+0.1*sin(4*PI*55*t)+0.1*sin(6*PI*55*t)+0.1*sin(8*PI*55*t),
+                 asplit[a][out1]; [a] showcqt [out0]'
+@end example
+
+@item
+Same as above, but with more accuracy in frequency domain (and slower):
+@example
+ffplay -f lavfi 'aevalsrc=0.1*sin(2*PI*55*t)+0.1*sin(4*PI*55*t)+0.1*sin(6*PI*55*t)+0.1*sin(8*PI*55*t),
+                 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
+@end example
+
+@end itemize
+
 @section showspectrum
 
 Convert input audio to a video output, representing the audio frequency
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index f981dfac06..8ba0312b32 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -224,6 +224,7 @@ OBJS-$(CONFIG_MP_FILTER) += libmpcodecs/vf_uspp.o
 # multimedia filters
 OBJS-$(CONFIG_AVECTORSCOPE_FILTER)           += avf_avectorscope.o
 OBJS-$(CONFIG_CONCAT_FILTER)                 += avf_concat.o
+OBJS-$(CONFIG_SHOWCQT_FILTER)                += avf_showcqt.o
 OBJS-$(CONFIG_SHOWSPECTRUM_FILTER)           += avf_showspectrum.o
 OBJS-$(CONFIG_SHOWWAVES_FILTER)              += avf_showwaves.o
 
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 22d643d3e1..55d505adbf 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -231,6 +231,7 @@ void avfilter_register_all(void)
     /* multimedia filters */
     REGISTER_FILTER(AVECTORSCOPE,   avectorscope,   avf);
     REGISTER_FILTER(CONCAT,         concat,         avf);
+    REGISTER_FILTER(SHOWCQT,        showcqt,        avf);
     REGISTER_FILTER(SHOWSPECTRUM,   showspectrum,   avf);
     REGISTER_FILTER(SHOWWAVES,      showwaves,      avf);
 
diff --git a/libavfilter/avf_showcqt.c b/libavfilter/avf_showcqt.c
new file mode 100644
index 0000000000..eaa632d18b
--- /dev/null
+++ b/libavfilter/avf_showcqt.c
@@ -0,0 +1,585 @@
+/*
+ * Copyright (c) 2014 Muhammad Faiz <mfcc64@gmail.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavcodec/avfft.h"
+#include "libavutil/avassert.h"
+#include "libavutil/channel_layout.h"
+#include "libavutil/opt.h"
+#include "libavutil/xga_font_data.h"
+#include "libavutil/qsort.h"
+#include "libavutil/time.h"
+#include "avfilter.h"
+#include "internal.h"
+
+#include <math.h>
+#include <stdlib.h>
+
+/* this filter is designed to do 16 bins/semitones constant Q transform with Brown-Puckette algorithm
+ * start from E0 to D#10 (10 octaves)
+ * so there are 16 bins/semitones * 12 semitones/octaves * 10 octaves = 1920 bins
+ * match with full HD resolution */
+
+#define VIDEO_WIDTH 1920
+#define VIDEO_HEIGHT 1080
+#define FONT_HEIGHT 32
+#define SPECTOGRAM_HEIGHT ((VIDEO_HEIGHT-FONT_HEIGHT)/2)
+#define SPECTOGRAM_START (VIDEO_HEIGHT-SPECTOGRAM_HEIGHT)
+#define BASE_FREQ 20.051392800492
+#define COEFF_CLAMP 1.0e-4
+
+typedef struct {
+    FFTSample value;
+    int index;
+} SparseCoeff;
+
+static inline int qsort_sparsecoeff(const SparseCoeff *a, const SparseCoeff *b)
+{
+    if (fabsf(a->value) >= fabsf(b->value))
+        return 1;
+    else
+        return -1;
+}
+
+typedef struct {
+    const AVClass *class;
+    AVFrame *outpicref;
+    FFTContext *fft_context;
+    FFTComplex *fft_data;
+    FFTComplex *fft_result_left;
+    FFTComplex *fft_result_right;
+    SparseCoeff *coeff_sort;
+    SparseCoeff *coeffs[VIDEO_WIDTH];
+    int coeffs_len[VIDEO_WIDTH];
+    uint8_t font_color[VIDEO_WIDTH];
+    uint8_t spectogram[SPECTOGRAM_HEIGHT][VIDEO_WIDTH][3];
+    int64_t frame_count;
+    int spectogram_count;
+    int spectogram_index;
+    int fft_bits;
+    int req_fullfilled;
+    int remaining_fill;
+    double volume;
+    double timeclamp;   /* lower timeclamp, time-accurate, higher timeclamp, freq-accurate (at low freq)*/
+    float coeffclamp;   /* lower coeffclamp, more precise, higher coeffclamp, faster */
+    float gamma;        /* lower gamma, more contrast, higher gamma, more range */
+    int fps;            /* the required fps is so strict, so it's enough to be int, but 24000/1001 etc cannot be encoded */
+    int count;          /* fps * count = transform rate */
+} ShowCQTContext;
+
+#define OFFSET(x) offsetof(ShowCQTContext, x)
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+
+static const AVOption showcqt_options[] = {
+    { "volume", "set volume", OFFSET(volume), AV_OPT_TYPE_DOUBLE, { .dbl = 16 }, 0.1, 100, FLAGS },
+    { "timeclamp", "set timeclamp", OFFSET(timeclamp), AV_OPT_TYPE_DOUBLE, { .dbl = 0.17 }, 0.1, 1.0, FLAGS },
+    { "coeffclamp", "set coeffclamp", OFFSET(coeffclamp), AV_OPT_TYPE_FLOAT, { .dbl = 1 }, 0.1, 10, FLAGS },
+    { "gamma", "set gamma", OFFSET(gamma), AV_OPT_TYPE_FLOAT, { .dbl = 3 }, 1, 7, FLAGS },
+    { "fps", "set video fps", OFFSET(fps), AV_OPT_TYPE_INT, { .i64 = 25 }, 10, 100, FLAGS },
+    { "count", "set number of transform per frame", OFFSET(count), AV_OPT_TYPE_INT, { .i64 = 6 }, 1, 30, FLAGS },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(showcqt);
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    int k;
+    ShowCQTContext *s = ctx->priv;
+    av_fft_end(s->fft_context);
+    s->fft_context = NULL;
+    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->coeff_sort);
+    av_frame_free(&s->outpicref);
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    AVFilterFormats *formats = NULL;
+    AVFilterChannelLayouts *layouts = NULL;
+    AVFilterLink *inlink = ctx->inputs[0];
+    AVFilterLink *outlink = ctx->outputs[0];
+    static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_NONE };
+    static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_RGB24, AV_PIX_FMT_NONE };
+    static const int64_t channel_layouts[] = { AV_CH_LAYOUT_STEREO, AV_CH_LAYOUT_STEREO_DOWNMIX, -1 };
+    static const int samplerates[] = { 44100, 48000, -1 };
+
+    /* set input audio formats */
+    formats = ff_make_format_list(sample_fmts);
+    if (!formats)
+        return AVERROR(ENOMEM);
+    ff_formats_ref(formats, &inlink->out_formats);
+
+    layouts = avfilter_make_format64_list(channel_layouts);
+    if (!layouts)
+        return AVERROR(ENOMEM);
+    ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts);
+
+    formats = ff_make_format_list(samplerates);
+    if (!formats)
+        return AVERROR(ENOMEM);
+    ff_formats_ref(formats, &inlink->out_samplerates);
+
+    /* set output video format */
+    formats = ff_make_format_list(pix_fmts);
+    if (!formats)
+        return AVERROR(ENOMEM);
+    ff_formats_ref(formats, &outlink->in_formats);
+
+    return 0;
+}
+
+static int config_output(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    AVFilterLink *inlink = ctx->inputs[0];
+    ShowCQTContext *s = ctx->priv;
+    int fft_len, k, x, y;
+    int num_coeffs = 0;
+    int rate = inlink->sample_rate;
+    double max_len = rate * (double) s->timeclamp;
+    int64_t start_time, end_time;
+    s->fft_bits = ceil(log2(max_len));
+    fft_len = 1 << s->fft_bits;
+
+    if (rate % (s->fps * s->count))
+    {
+        av_log(ctx, AV_LOG_ERROR, "Rate (%u) is not divisible by fps*count (%u*%u)\n", rate, s->fps, s->count);
+        return AVERROR(EINVAL);
+    }
+
+    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_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)
+        return AVERROR(ENOMEM);
+
+    /* initializing font */
+    for (x = 0; x < VIDEO_WIDTH; x++)
+    {
+        if (x >= (12*3+8)*16 && x < (12*4+8)*16)
+        {
+            float fx = (x-(12*3+8)*16) * (1.0f/192.0f);
+            float sv = sinf(M_PI*fx);
+            s->font_color[x] = sv*sv*255.0f + 0.5f;
+        }
+        else
+            s->font_color[x] = 0;
+    }
+
+    av_log(ctx, AV_LOG_INFO, "Calculating spectral kernel, please wait\n");
+    start_time = av_gettime_relative();
+    for (k = 0; k < VIDEO_WIDTH; k++)
+    {
+        int hlen = fft_len >> 1;
+        float total = 0;
+        float partial = 0;
+        double freq = BASE_FREQ * exp2(k * (1.0/192.0));
+        double tlen = rate * (24.0 * 16.0) /freq;
+        /* a window function from Albert H. Nuttall,
+         * "Some Windows with Very Good Sidelobe Behavior"
+         * -93.32 dB peak sidelobe and 18 dB/octave asymptotic decay
+         * coefficient normalized to a0 = 1 */
+        double a0 = 0.355768;
+        double a1 = 0.487396/a0;
+        double a2 = 0.144232/a0;
+        double a3 = 0.012604/a0;
+        double sv_step, cv_step, sv, cv;
+        double sw_step, cw_step, sw, cw, w;
+
+        tlen = tlen * max_len / (tlen + max_len);
+        s->fft_data[0].re = 0;
+        s->fft_data[0].im = 0;
+        s->fft_data[hlen].re = (1.0 + a1 + a2 + a3) * (1.0/tlen) * s->volume * (1.0/fft_len);
+        s->fft_data[hlen].im = 0;
+        sv_step = sv = sin(2.0*M_PI*freq*(1.0/rate));
+        cv_step = cv = cos(2.0*M_PI*freq*(1.0/rate));
+        /* also optimizing window func */
+        sw_step = sw = sin(2.0*M_PI*(1.0/tlen));
+        cw_step = cw = cos(2.0*M_PI*(1.0/tlen));
+        for (x = 1; x < 0.5 * tlen; x++)
+        {
+            double cv_tmp, cw_tmp;
+            double cw2, cw3, sw2;
+
+            cw2 = cw * cw - sw * sw;
+            sw2 = cw * sw + sw * cw;
+            cw3 = cw * cw2 - sw * sw2;
+            w = (1.0 + a1 * cw + a2 * cw2 + a3 * cw3) * (1.0/tlen) * s->volume * (1.0/fft_len);
+            s->fft_data[hlen + x].re = w * cv;
+            s->fft_data[hlen + x].im = w * sv;
+            s->fft_data[hlen - x].re = s->fft_data[hlen + x].re;
+            s->fft_data[hlen - x].im = -s->fft_data[hlen + x].im;
+
+            cv_tmp = cv * cv_step - sv * sv_step;
+            sv = sv * cv_step + cv * sv_step;
+            cv = cv_tmp;
+            cw_tmp = cw * cw_step - sw * sw_step;
+            sw = sw * cw_step + cw * sw_step;
+            cw = cw_tmp;
+        }
+        for (; x < hlen; x++)
+        {
+            s->fft_data[hlen + x].re = 0;
+            s->fft_data[hlen + x].im = 0;
+            s->fft_data[hlen - x].re = 0;
+            s->fft_data[hlen - x].im = 0;
+        }
+        av_fft_permute(s->fft_context, s->fft_data);
+        av_fft_calc(s->fft_context, s->fft_data);
+
+        for (x = 0; x < fft_len; x++)
+        {
+            s->coeff_sort[x].index = x;
+            s->coeff_sort[x].value = s->fft_data[x].re;
+        }
+
+        AV_QSORT(s->coeff_sort, fft_len, SparseCoeff, qsort_sparsecoeff);
+        for (x = 0; x < fft_len; x++)
+            total += fabsf(s->coeff_sort[x].value);
+
+        for (x = 0; x < fft_len; x++)
+        {
+            partial += fabsf(s->coeff_sort[x].value);
+            if (partial > (total * s->coeffclamp * COEFF_CLAMP))
+            {
+                s->coeffs_len[k] = fft_len - x;
+                num_coeffs += s->coeffs_len[k];
+                s->coeffs[k] = av_malloc_array(s->coeffs_len[k], sizeof(*s->coeffs[k]));
+                if (!s->coeffs[k])
+                    return AVERROR(ENOMEM);
+                for (y = 0; y < s->coeffs_len[k]; y++)
+                    s->coeffs[k][y] = s->coeff_sort[x+y];
+                break;
+            }
+        }
+    }
+    end_time = av_gettime_relative();
+    av_log(ctx, AV_LOG_INFO, "Elapsed time %.6f s (fft_len=%u, num_coeffs=%u)\n", 1e-6 * (end_time-start_time), fft_len, num_coeffs);
+
+    outlink->w = VIDEO_WIDTH;
+    outlink->h = VIDEO_HEIGHT;
+
+    s->req_fullfilled = 0;
+    s->spectogram_index = 0;
+    s->frame_count = 0;
+    s->spectogram_count = 0;
+    s->remaining_fill = fft_len >> 1;
+    memset(s->spectogram, 0, VIDEO_WIDTH * SPECTOGRAM_HEIGHT * 3);
+    memset(s->fft_data, 0, fft_len * sizeof(*s->fft_data));
+
+    s->outpicref = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+    if (!s->outpicref)
+        return AVERROR(ENOMEM);
+
+    outlink->sample_aspect_ratio = av_make_q(1, 1);
+    outlink->time_base = av_make_q(1, s->fps);
+    outlink->frame_rate = av_make_q(s->fps, 1);
+    return 0;
+}
+
+static int plot_cqt(AVFilterLink *inlink)
+{
+    AVFilterContext *ctx = inlink->dst;
+    ShowCQTContext *s = ctx->priv;
+    AVFilterLink *outlink = ctx->outputs[0];
+    int fft_len = 1 << s->fft_bits;
+    FFTSample result[VIDEO_WIDTH][4];
+    int x, y, ret = 0;
+
+    /* 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;
+    }
+
+    /* calculating cqt */
+    for (x = 0; x < VIDEO_WIDTH; x++)
+    {
+        int u;
+        float g = 1.0f / s->gamma;
+        FFTComplex l = {0,0};
+        FFTComplex r = {0,0};
+
+        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;
+        }
+        /* 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;
+        result[x][1] = 0.5f * (result[x][0] + result[x][2]);
+        result[x][3] = result[x][1];
+        result[x][0] = 255.0f * powf(fminf(1.0f,result[x][0]), g);
+        result[x][1] = 255.0f * powf(fminf(1.0f,result[x][1]), g);
+        result[x][2] = 255.0f * powf(fminf(1.0f,result[x][2]), g);
+    }
+
+    for (x = 0; x < VIDEO_WIDTH; x++)
+    {
+        s->spectogram[s->spectogram_index][x][0] = result[x][0] + 0.5f;
+        s->spectogram[s->spectogram_index][x][1] = result[x][1] + 0.5f;
+        s->spectogram[s->spectogram_index][x][2] = result[x][2] + 0.5f;
+    }
+
+    /* drawing */
+    if (!s->spectogram_count)
+    {
+        uint8_t *data = (uint8_t*) s->outpicref->data[0];
+        int linesize = s->outpicref->linesize[0];
+        float rcp_result[VIDEO_WIDTH];
+
+        for (x = 0; x < VIDEO_WIDTH; x++)
+            rcp_result[x] = 1.0f / (result[x][3]+0.0001f);
+
+        /* drawing bar */
+        for (y = 0; y < SPECTOGRAM_HEIGHT; y++)
+        {
+            float height = (SPECTOGRAM_HEIGHT - y) * (1.0f/SPECTOGRAM_HEIGHT);
+            uint8_t *lineptr = data + y * linesize;
+            for (x = 0; x < VIDEO_WIDTH; x++)
+            {
+                float mul;
+                if (result[x][3] <= height)
+                {
+                    *lineptr++ = 0;
+                    *lineptr++ = 0;
+                    *lineptr++ = 0;
+                }
+                else
+                {
+                    mul = (result[x][3] - height) * rcp_result[x];
+                    *lineptr++ = mul * result[x][0] + 0.5f;
+                    *lineptr++ = mul * result[x][1] + 0.5f;
+                    *lineptr++ = mul * result[x][2] + 0.5f;
+                }
+            }
+
+        }
+
+        /* drawing font */
+        for (y = 0; y < FONT_HEIGHT; y++)
+        {
+            uint8_t *lineptr = data + (SPECTOGRAM_HEIGHT + y) * linesize;
+            memcpy(lineptr, s->spectogram[s->spectogram_index], VIDEO_WIDTH*3);
+        }
+        for (x = 0; x < VIDEO_WIDTH; x += VIDEO_WIDTH/10)
+        {
+            int u;
+            static const char str[] = "EF G A BC D ";
+            uint8_t *startptr = data + SPECTOGRAM_HEIGHT * linesize + x * 3;
+            for (u = 0; str[u]; u++)
+            {
+                int v;
+                for (v = 0; v < 16; v++)
+                {
+                    uint8_t *p = startptr + 2 * v * linesize + 16 * 3 * u;
+                    int ux = x + 16 * u;
+                    int mask;
+                    for (mask = 0x80; mask; mask >>= 1)
+                    {
+                        if (mask & avpriv_vga16_font[str[u] * 16 + v])
+                        {
+                            p[0] = p[linesize] = 255 - s->font_color[ux];
+                            p[1] = p[linesize+1] = 0;
+                            p[2] = p[linesize+2] = s->font_color[ux];
+                            p[3] = p[linesize+3] = 255 - s->font_color[ux+1];
+                            p[4] = p[linesize+4] = 0;
+                            p[5] = p[linesize+5] = s->font_color[ux+1];
+                        }
+                        p += 6;
+                        ux += 2;
+                    }
+                }
+            }
+
+        }
+
+        /* drawing spectogram/sonogram */
+        if (linesize == VIDEO_WIDTH * 3)
+        {
+            int total_length = VIDEO_WIDTH * SPECTOGRAM_HEIGHT * 3;
+            int back_length = VIDEO_WIDTH * s->spectogram_index * 3;
+            data += SPECTOGRAM_START * VIDEO_WIDTH * 3;
+            memcpy(data, s->spectogram[s->spectogram_index], total_length - back_length);
+            data += total_length - back_length;
+            if(back_length)
+                memcpy(data, s->spectogram[0], back_length);
+        }
+        else
+        {
+            for (y = 0; y < SPECTOGRAM_HEIGHT; y++)
+                memcpy(data + (SPECTOGRAM_START + y) * linesize, s->spectogram[(s->spectogram_index + y) % SPECTOGRAM_HEIGHT], VIDEO_WIDTH * 3);
+        }
+
+        s->outpicref->pts = s->frame_count;
+        ret = ff_filter_frame(outlink, av_frame_clone(s->outpicref));
+        s->req_fullfilled = 1;
+        s->frame_count++;
+    }
+    s->spectogram_count = (s->spectogram_count + 1) % s->count;
+    s->spectogram_index = (s->spectogram_index + SPECTOGRAM_HEIGHT - 1) % SPECTOGRAM_HEIGHT;
+    return ret;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
+{
+    AVFilterContext *ctx = inlink->dst;
+    ShowCQTContext *s = ctx->priv;
+    int step = inlink->sample_rate / (s->fps * s->count);
+    int fft_len = 1 << s->fft_bits;
+    int remaining;
+    float *audio_data;
+
+    if (!insamples)
+    {
+        while (s->remaining_fill < (fft_len >> 1))
+        {
+            int ret, x;
+            memset(&s->fft_data[fft_len - s->remaining_fill], 0, sizeof(*s->fft_data) * s->remaining_fill);
+            ret = plot_cqt(inlink);
+            if (ret < 0)
+                return ret;
+            for (x = 0; x < (fft_len-step); x++)
+                s->fft_data[x] = s->fft_data[x+step];
+            s->remaining_fill += step;
+        }
+        return AVERROR(EOF);
+    }
+
+    remaining = insamples->nb_samples;
+    audio_data = (float*) insamples->data[0];
+
+    while (remaining)
+    {
+        if (remaining >= s->remaining_fill)
+        {
+            int i = insamples->nb_samples - remaining;
+            int j = fft_len - s->remaining_fill;
+            int m, ret;
+            for (m = 0; m < s->remaining_fill; m++)
+            {
+                s->fft_data[j+m].re = audio_data[2*(i+m)];
+                s->fft_data[j+m].im = audio_data[2*(i+m)+1];
+            }
+            ret = plot_cqt(inlink);
+            if (ret < 0)
+            {
+                av_frame_free(&insamples);
+                return ret;
+            }
+            remaining -= s->remaining_fill;
+            for (m = 0; m < fft_len-step; m++)
+                s->fft_data[m] = s->fft_data[m+step];
+            s->remaining_fill = step;
+        }
+        else
+        {
+            int i = insamples->nb_samples - remaining;
+            int j = fft_len - s->remaining_fill;
+            int m;
+            for (m = 0; m < remaining; m++)
+            {
+                s->fft_data[m+j].re = audio_data[2*(i+m)];
+                s->fft_data[m+j].im = audio_data[2*(i+m)+1];
+            }
+            s->remaining_fill -= remaining;
+            remaining = 0;
+        }
+    }
+    av_frame_free(&insamples);
+    return 0;
+}
+
+static int request_frame(AVFilterLink *outlink)
+{
+    ShowCQTContext *s = outlink->src->priv;
+    AVFilterLink *inlink = outlink->src->inputs[0];
+    int ret;
+
+    s->req_fullfilled = 0;
+    do {
+        ret = ff_request_frame(inlink);
+    } while (!s->req_fullfilled && ret >= 0);
+
+    if (ret == AVERROR_EOF && s->outpicref)
+        filter_frame(inlink, NULL);
+    return ret;
+}
+
+static const AVFilterPad showcqt_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_AUDIO,
+        .filter_frame = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad showcqt_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .config_props  = config_output,
+        .request_frame = request_frame,
+    },
+    { NULL }
+};
+
+AVFilter ff_avf_showcqt = {
+    .name          = "showcqt",
+    .description   = NULL_IF_CONFIG_SMALL("Convert input audio to a CQT (Constant Q Transform) spectrum video output."),
+    .uninit        = uninit,
+    .query_formats = query_formats,
+    .priv_size     = sizeof(ShowCQTContext),
+    .inputs        = showcqt_inputs,
+    .outputs       = showcqt_outputs,
+    .priv_class    = &showcqt_class,
+};
diff --git a/libavfilter/version.h b/libavfilter/version.h
index 7a6321e53e..d7acf72ff1 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   4
-#define LIBAVFILTER_VERSION_MINOR   5
+#define LIBAVFILTER_VERSION_MINOR   6
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \