libavfilter/avf_showspatial.c - manifest_repos/ffmpeg - Git at Google

 /*
  * Copyright (c) 2019 Paul B Mahol
  *
  * 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 <float.h>
 #include <math.h>

 #include "libavcodec/avfft.h"
 #include "libavutil/audio_fifo.h"
 #include "libavutil/avassert.h"
 #include "libavutil/channel_layout.h"
 #include "libavutil/opt.h"
 #include "libavutil/parseutils.h"
 #include "audio.h"
 #include "video.h"
 #include "avfilter.h"
 #include "filters.h"
 #include "internal.h"
 #include "window_func.h"

 typedef struct ShowSpatialContext {
     const AVClass *class;
     int w, h;
     AVRational frame_rate;
     FFTContext *fft[2];           ///< Fast Fourier Transform context
     FFTContext *ifft[2];          ///< Inverse Fast Fourier Transform context
     int fft_bits;                 ///< number of bits (FFT window size = 1<<fft_bits)
     FFTComplex *fft_data[2];      ///< bins holder for each (displayed) channels
     float *window_func_lut;       ///< Window function LUT
     int win_func;
     int win_size;
     int buf_size;
     float overlap;
     int consumed;
     int hop_size;
     AVAudioFifo *fifo;
     int64_t pts;
 } ShowSpatialContext;

 #define OFFSET(x) offsetof(ShowSpatialContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

 static const AVOption showspatial_options[] = {
     { "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "512x512"}, 0, 0, FLAGS },
     { "s",    "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "512x512"}, 0, 0, FLAGS },
     { "win_size", "set window size", OFFSET(win_size), AV_OPT_TYPE_INT, {.i64 = 4096}, 1024, 65536, FLAGS },
     { "win_func", "set window function", OFFSET(win_func), AV_OPT_TYPE_INT, {.i64 = WFUNC_HANNING}, 0, NB_WFUNC-1, FLAGS, "win_func" },
         { "rect",     "Rectangular",      0, AV_OPT_TYPE_CONST, {.i64=WFUNC_RECT},     0, 0, FLAGS, "win_func" },
         { "bartlett", "Bartlett",         0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BARTLETT}, 0, 0, FLAGS, "win_func" },
         { "hann",     "Hann",             0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HANNING},  0, 0, FLAGS, "win_func" },
         { "hanning",  "Hanning",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HANNING},  0, 0, FLAGS, "win_func" },
         { "hamming",  "Hamming",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HAMMING},  0, 0, FLAGS, "win_func" },
         { "blackman", "Blackman",         0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BLACKMAN}, 0, 0, FLAGS, "win_func" },
         { "welch",    "Welch",            0, AV_OPT_TYPE_CONST, {.i64=WFUNC_WELCH},    0, 0, FLAGS, "win_func" },
         { "flattop",  "Flat-top",         0, AV_OPT_TYPE_CONST, {.i64=WFUNC_FLATTOP},  0, 0, FLAGS, "win_func" },
         { "bharris",  "Blackman-Harris",  0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BHARRIS},  0, 0, FLAGS, "win_func" },
         { "bnuttall", "Blackman-Nuttall", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BNUTTALL}, 0, 0, FLAGS, "win_func" },
         { "bhann",    "Bartlett-Hann",    0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BHANN},    0, 0, FLAGS, "win_func" },
         { "sine",     "Sine",             0, AV_OPT_TYPE_CONST, {.i64=WFUNC_SINE},     0, 0, FLAGS, "win_func" },
         { "nuttall",  "Nuttall",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_NUTTALL},  0, 0, FLAGS, "win_func" },
         { "lanczos",  "Lanczos",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_LANCZOS},  0, 0, FLAGS, "win_func" },
         { "gauss",    "Gauss",            0, AV_OPT_TYPE_CONST, {.i64=WFUNC_GAUSS},    0, 0, FLAGS, "win_func" },
         { "tukey",    "Tukey",            0, AV_OPT_TYPE_CONST, {.i64=WFUNC_TUKEY},    0, 0, FLAGS, "win_func" },
         { "dolph",    "Dolph-Chebyshev",  0, AV_OPT_TYPE_CONST, {.i64=WFUNC_DOLPH},    0, 0, FLAGS, "win_func" },
         { "cauchy",   "Cauchy",           0, AV_OPT_TYPE_CONST, {.i64=WFUNC_CAUCHY},   0, 0, FLAGS, "win_func" },
         { "parzen",   "Parzen",           0, AV_OPT_TYPE_CONST, {.i64=WFUNC_PARZEN},   0, 0, FLAGS, "win_func" },
         { "poisson",  "Poisson",          0, AV_OPT_TYPE_CONST, {.i64=WFUNC_POISSON},  0, 0, FLAGS, "win_func" },
         { "bohman",   "Bohman",           0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BOHMAN},   0, 0, FLAGS, "win_func" },
     { "overlap", "set window overlap", OFFSET(overlap), AV_OPT_TYPE_FLOAT, {.dbl=0.5}, 0, 1, FLAGS },
     { NULL }
 };

 AVFILTER_DEFINE_CLASS(showspatial);

 static av_cold void uninit(AVFilterContext *ctx)
 {
     ShowSpatialContext *s = ctx->priv;
     int i;

     for (i = 0; i < 2; i++)
         av_fft_end(s->fft[i]);
     for (i = 0; i < 2; i++)
         av_fft_end(s->ifft[i]);
     for (i = 0; i < 2; i++)
         av_freep(&s->fft_data[i]);
     av_freep(&s->window_func_lut);
     av_audio_fifo_free(s->fifo);
 }

 static int query_formats(AVFilterContext *ctx)
 {
     AVFilterFormats *formats = NULL;
     AVFilterChannelLayouts *layout = NULL;
     AVFilterLink *inlink = ctx->inputs[0];
     AVFilterLink *outlink = ctx->outputs[0];
     static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_NONE };
     static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_GBRP, AV_PIX_FMT_NONE };
     int ret;

     formats = ff_make_format_list(sample_fmts);
     if ((ret = ff_formats_ref         (formats, &inlink->outcfg.formats        )) < 0 ||
         (ret = ff_add_channel_layout  (&layout, AV_CH_LAYOUT_STEREO         )) < 0 ||
         (ret = ff_channel_layouts_ref (layout , &inlink->outcfg.channel_layouts)) < 0)
         return ret;

     formats = ff_all_samplerates();
     if ((ret = ff_formats_ref(formats, &inlink->outcfg.samplerates)) < 0)
         return ret;

     formats = ff_make_format_list(pix_fmts);
     if ((ret = ff_formats_ref(formats, &outlink->incfg.formats)) < 0)
         return ret;

     return 0;
 }

 static int run_channel_fft(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
 {
     ShowSpatialContext *s = ctx->priv;
     const float *window_func_lut = s->window_func_lut;
     AVFrame *fin = arg;
     const int ch = jobnr;
     const float *p = (float *)fin->extended_data[ch];

     for (int n = 0; n < fin->nb_samples; n++) {
         s->fft_data[ch][n].re = p[n] * window_func_lut[n];
         s->fft_data[ch][n].im = 0;
     }

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

     return 0;
 }

 static int config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     AVFilterLink *inlink = ctx->inputs[0];
     ShowSpatialContext *s = ctx->priv;
     int i, fft_bits;
     float overlap;

     outlink->w = s->w;
     outlink->h = s->h;
     outlink->sample_aspect_ratio = (AVRational){1,1};

     s->buf_size = 1 << av_log2(s->win_size);
     s->win_size = s->buf_size;
     fft_bits = av_log2(s->win_size);

     /* (re-)configuration if the video output changed (or first init) */
     if (fft_bits != s->fft_bits) {
         s->fft_bits = fft_bits;

         /* FFT buffers: x2 for each 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 < 2; i++) {
             av_fft_end(s->fft[i]);
             av_freep(&s->fft_data[i]);
         }
         for (i = 0; i < 2; 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);
             }
         }

         for (i = 0; i < 2; i++) {
             s->fft_data[i] = av_calloc(s->buf_size, sizeof(**s->fft_data));
             if (!s->fft_data[i])
                 return AVERROR(ENOMEM);
         }

         /* pre-calc windowing function */
         s->window_func_lut =
             av_realloc_f(s->window_func_lut, s->win_size,
                          sizeof(*s->window_func_lut));
         if (!s->window_func_lut)
             return AVERROR(ENOMEM);
         generate_window_func(s->window_func_lut, s->win_size, s->win_func, &overlap);
         if (s->overlap == 1)
             s->overlap = overlap;

         s->hop_size = (1.f - s->overlap) * s->win_size;
         if (s->hop_size < 1) {
             av_log(ctx, AV_LOG_ERROR, "overlap %f too big\n", s->overlap);
             return AVERROR(EINVAL);
         }
     }

     outlink->time_base = av_inv_q(outlink->frame_rate);

     av_audio_fifo_free(s->fifo);
     s->fifo = av_audio_fifo_alloc(inlink->format, inlink->channels, s->win_size);
     if (!s->fifo)
         return AVERROR(ENOMEM);
     return 0;
 }

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

 static void draw_dot(uint8_t *dst, int linesize, int value)
 {
     dst[0] = value;
     dst[1] = value;
     dst[-1] = value;
     dst[linesize] = value;
     dst[-linesize] = value;
 }

 static int draw_spatial(AVFilterLink *inlink, AVFrame *insamples)
 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     ShowSpatialContext *s = ctx->priv;
     AVFrame *outpicref;
     int h = s->h - 2;
     int w = s->w - 2;
     int z = s->win_size / 2;

     outpicref = ff_get_video_buffer(outlink, outlink->w, outlink->h);
     if (!outpicref)
         return AVERROR(ENOMEM);

     outpicref->sample_aspect_ratio = (AVRational){1,1};
     for (int i = 0; i < outlink->h; i++) {
         memset(outpicref->data[0] + i * outpicref->linesize[0], 0, outlink->w);
         memset(outpicref->data[1] + i * outpicref->linesize[1], 0, outlink->w);
         memset(outpicref->data[2] + i * outpicref->linesize[2], 0, outlink->w);
     }

     for (int j = 0; j < z; j++) {
         const int idx = z - 1 - j;
         float l = hypotf(RE(idx, 0), IM(idx, 0));
         float r = hypotf(RE(idx, 1), IM(idx, 1));
         float sum = l + r;
         float lp = atan2f(IM(idx, 0), RE(idx, 0));
         float rp = atan2f(IM(idx, 1), RE(idx, 1));
         float diffp = ((rp - lp) / (2.f * M_PI) + 1.f) * 0.5f;
         float diff = (sum < 0.000001f ? 0.f : (r - l) / sum) * 0.5f + 0.5f;
         float cr = av_clipf(cbrtf(l / sum), 0, 1) * 255.f;
         float cb = av_clipf(cbrtf(r / sum), 0, 1) * 255.f;
         float cg;
         int x, y;

         cg = diffp * 255.f;
         x = av_clip(w * diff,  0, w - 2) + 1;
         y = av_clip(h * diffp, 0, h - 2) + 1;

         draw_dot(outpicref->data[0] + outpicref->linesize[0] * y + x, outpicref->linesize[0], cg);
         draw_dot(outpicref->data[1] + outpicref->linesize[1] * y + x, outpicref->linesize[1], cb);
         draw_dot(outpicref->data[2] + outpicref->linesize[2] * y + x, outpicref->linesize[2], cr);
     }

     outpicref->pts = av_rescale_q(insamples->pts, inlink->time_base, outlink->time_base);

     return ff_filter_frame(outlink, outpicref);
 }

 static int spatial_activate(AVFilterContext *ctx)
 {
     AVFilterLink *inlink = ctx->inputs[0];
     AVFilterLink *outlink = ctx->outputs[0];
     ShowSpatialContext *s = ctx->priv;
     int ret;

     FF_FILTER_FORWARD_STATUS_BACK(outlink, inlink);

     if (av_audio_fifo_size(s->fifo) < s->win_size) {
         AVFrame *frame = NULL;

         ret = ff_inlink_consume_frame(inlink, &frame);
         if (ret < 0)
             return ret;
         if (ret > 0) {
             s->pts = frame->pts;
             s->consumed = 0;

             av_audio_fifo_write(s->fifo, (void **)frame->extended_data, frame->nb_samples);
             av_frame_free(&frame);
         }
     }

     if (av_audio_fifo_size(s->fifo) >= s->win_size) {
         AVFrame *fin = ff_get_audio_buffer(inlink, s->win_size);
         if (!fin)
             return AVERROR(ENOMEM);

         fin->pts = s->pts + s->consumed;
         s->consumed += s->hop_size;
         ret = av_audio_fifo_peek(s->fifo, (void **)fin->extended_data,
                                  FFMIN(s->win_size, av_audio_fifo_size(s->fifo)));
         if (ret < 0) {
             av_frame_free(&fin);
             return ret;
         }

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

         ctx->internal->execute(ctx, run_channel_fft, fin, NULL, 2);

         ret = draw_spatial(inlink, fin);

         av_frame_free(&fin);
         av_audio_fifo_drain(s->fifo, s->hop_size);
         if (ret <= 0)
             return ret;
     }

     FF_FILTER_FORWARD_STATUS(inlink, outlink);
     if (ff_outlink_frame_wanted(outlink) && av_audio_fifo_size(s->fifo) < s->win_size) {
         ff_inlink_request_frame(inlink);
         return 0;
     }

     if (av_audio_fifo_size(s->fifo) >= s->win_size) {
         ff_filter_set_ready(ctx, 10);
         return 0;
     }
     return FFERROR_NOT_READY;
 }

 static const AVFilterPad showspatial_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_AUDIO,
     },
     { NULL }
 };

 static const AVFilterPad showspatial_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .config_props  = config_output,
     },
     { NULL }
 };

 AVFilter ff_avf_showspatial = {
     .name          = "showspatial",
     .description   = NULL_IF_CONFIG_SMALL("Convert input audio to a spatial video output."),
     .uninit        = uninit,
     .query_formats = query_formats,
     .priv_size     = sizeof(ShowSpatialContext),
     .inputs        = showspatial_inputs,
     .outputs       = showspatial_outputs,
     .activate      = spatial_activate,
     .priv_class    = &showspatial_class,
     .flags         = AVFILTER_FLAG_SLICE_THREADS,
 };
	/*
	* Copyright (c) 2019 Paul B Mahol
	*
	* 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 <float.h>
	#include <math.h>

	#include "libavcodec/avfft.h"
	#include "libavutil/audio_fifo.h"
	#include "libavutil/avassert.h"
	#include "libavutil/channel_layout.h"
	#include "libavutil/opt.h"
	#include "libavutil/parseutils.h"
	#include "audio.h"
	#include "video.h"
	#include "avfilter.h"
	#include "filters.h"
	#include "internal.h"
	#include "window_func.h"

	typedef struct ShowSpatialContext {
	const AVClass *class;
	int w, h;
	AVRational frame_rate;
	FFTContext *fft[2]; ///< Fast Fourier Transform context
	FFTContext *ifft[2]; ///< Inverse Fast Fourier Transform context
	int fft_bits; ///< number of bits (FFT window size = 1<<fft_bits)
	FFTComplex *fft_data[2]; ///< bins holder for each (displayed) channels
	float *window_func_lut; ///< Window function LUT
	int win_func;
	int win_size;
	int buf_size;
	float overlap;
	int consumed;
	int hop_size;
	AVAudioFifo *fifo;
	int64_t pts;
	} ShowSpatialContext;

	#define OFFSET(x) offsetof(ShowSpatialContext, x)
	#define FLAGS AV_OPT_FLAG_FILTERING_PARAM\|AV_OPT_FLAG_VIDEO_PARAM

	static const AVOption showspatial_options[] = {
	{ "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "512x512"}, 0, 0, FLAGS },
	{ "s", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "512x512"}, 0, 0, FLAGS },
	{ "win_size", "set window size", OFFSET(win_size), AV_OPT_TYPE_INT, {.i64 = 4096}, 1024, 65536, FLAGS },
	{ "win_func", "set window function", OFFSET(win_func), AV_OPT_TYPE_INT, {.i64 = WFUNC_HANNING}, 0, NB_WFUNC-1, FLAGS, "win_func" },
	{ "rect", "Rectangular", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_RECT}, 0, 0, FLAGS, "win_func" },
	{ "bartlett", "Bartlett", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BARTLETT}, 0, 0, FLAGS, "win_func" },
	{ "hann", "Hann", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HANNING}, 0, 0, FLAGS, "win_func" },
	{ "hanning", "Hanning", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HANNING}, 0, 0, FLAGS, "win_func" },
	{ "hamming", "Hamming", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HAMMING}, 0, 0, FLAGS, "win_func" },
	{ "blackman", "Blackman", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BLACKMAN}, 0, 0, FLAGS, "win_func" },
	{ "welch", "Welch", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_WELCH}, 0, 0, FLAGS, "win_func" },
	{ "flattop", "Flat-top", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_FLATTOP}, 0, 0, FLAGS, "win_func" },
	{ "bharris", "Blackman-Harris", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BHARRIS}, 0, 0, FLAGS, "win_func" },
	{ "bnuttall", "Blackman-Nuttall", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BNUTTALL}, 0, 0, FLAGS, "win_func" },
	{ "bhann", "Bartlett-Hann", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BHANN}, 0, 0, FLAGS, "win_func" },
	{ "sine", "Sine", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_SINE}, 0, 0, FLAGS, "win_func" },
	{ "nuttall", "Nuttall", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_NUTTALL}, 0, 0, FLAGS, "win_func" },
	{ "lanczos", "Lanczos", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_LANCZOS}, 0, 0, FLAGS, "win_func" },
	{ "gauss", "Gauss", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_GAUSS}, 0, 0, FLAGS, "win_func" },
	{ "tukey", "Tukey", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_TUKEY}, 0, 0, FLAGS, "win_func" },
	{ "dolph", "Dolph-Chebyshev", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_DOLPH}, 0, 0, FLAGS, "win_func" },
	{ "cauchy", "Cauchy", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_CAUCHY}, 0, 0, FLAGS, "win_func" },
	{ "parzen", "Parzen", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_PARZEN}, 0, 0, FLAGS, "win_func" },
	{ "poisson", "Poisson", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_POISSON}, 0, 0, FLAGS, "win_func" },
	{ "bohman", "Bohman", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BOHMAN}, 0, 0, FLAGS, "win_func" },
	{ "overlap", "set window overlap", OFFSET(overlap), AV_OPT_TYPE_FLOAT, {.dbl=0.5}, 0, 1, FLAGS },
	{ NULL }
	};

	AVFILTER_DEFINE_CLASS(showspatial);

	static av_cold void uninit(AVFilterContext *ctx)
	{
	ShowSpatialContext *s = ctx->priv;
	int i;

	for (i = 0; i < 2; i++)
	av_fft_end(s->fft[i]);
	for (i = 0; i < 2; i++)
	av_fft_end(s->ifft[i]);
	for (i = 0; i < 2; i++)
	av_freep(&s->fft_data[i]);
	av_freep(&s->window_func_lut);
	av_audio_fifo_free(s->fifo);
	}

	static int query_formats(AVFilterContext *ctx)
	{
	AVFilterFormats *formats = NULL;
	AVFilterChannelLayouts *layout = NULL;
	AVFilterLink *inlink = ctx->inputs[0];
	AVFilterLink *outlink = ctx->outputs[0];
	static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_NONE };
	static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_GBRP, AV_PIX_FMT_NONE };
	int ret;

	formats = ff_make_format_list(sample_fmts);
	if ((ret = ff_formats_ref (formats, &inlink->outcfg.formats )) < 0 \|\|
	(ret = ff_add_channel_layout (&layout, AV_CH_LAYOUT_STEREO )) < 0 \|\|
	(ret = ff_channel_layouts_ref (layout , &inlink->outcfg.channel_layouts)) < 0)
	return ret;

	formats = ff_all_samplerates();
	if ((ret = ff_formats_ref(formats, &inlink->outcfg.samplerates)) < 0)
	return ret;

	formats = ff_make_format_list(pix_fmts);
	if ((ret = ff_formats_ref(formats, &outlink->incfg.formats)) < 0)
	return ret;

	return 0;
	}

	static int run_channel_fft(AVFilterContext ctx, void arg, int jobnr, int nb_jobs)
	{
	ShowSpatialContext *s = ctx->priv;
	const float *window_func_lut = s->window_func_lut;
	AVFrame *fin = arg;
	const int ch = jobnr;
	const float p = (float )fin->extended_data[ch];

	for (int n = 0; n < fin->nb_samples; n++) {
	s->fft_data[ch][n].re = p[n] * window_func_lut[n];
	s->fft_data[ch][n].im = 0;
	}

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

	return 0;
	}

	static int config_output(AVFilterLink *outlink)
	{
	AVFilterContext *ctx = outlink->src;
	AVFilterLink *inlink = ctx->inputs[0];
	ShowSpatialContext *s = ctx->priv;
	int i, fft_bits;
	float overlap;

	outlink->w = s->w;
	outlink->h = s->h;
	outlink->sample_aspect_ratio = (AVRational){1,1};

	s->buf_size = 1 << av_log2(s->win_size);
	s->win_size = s->buf_size;
	fft_bits = av_log2(s->win_size);

	/* (re-)configuration if the video output changed (or first init) */
	if (fft_bits != s->fft_bits) {
	s->fft_bits = fft_bits;

	/* FFT buffers: x2 for each 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 < 2; i++) {
	av_fft_end(s->fft[i]);
	av_freep(&s->fft_data[i]);
	}
	for (i = 0; i < 2; 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);
	}
	}

	for (i = 0; i < 2; i++) {
	s->fft_data[i] = av_calloc(s->buf_size, sizeof(**s->fft_data));
	if (!s->fft_data[i])
	return AVERROR(ENOMEM);
	}

	/* pre-calc windowing function */
	s->window_func_lut =
	av_realloc_f(s->window_func_lut, s->win_size,
	sizeof(*s->window_func_lut));
	if (!s->window_func_lut)
	return AVERROR(ENOMEM);
	generate_window_func(s->window_func_lut, s->win_size, s->win_func, &overlap);
	if (s->overlap == 1)
	s->overlap = overlap;

	s->hop_size = (1.f - s->overlap) * s->win_size;
	if (s->hop_size < 1) {
	av_log(ctx, AV_LOG_ERROR, "overlap %f too big\n", s->overlap);
	return AVERROR(EINVAL);
	}
	}

	outlink->time_base = av_inv_q(outlink->frame_rate);

	av_audio_fifo_free(s->fifo);
	s->fifo = av_audio_fifo_alloc(inlink->format, inlink->channels, s->win_size);
	if (!s->fifo)
	return AVERROR(ENOMEM);
	return 0;
	}

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

	static void draw_dot(uint8_t *dst, int linesize, int value)
	{
	dst[0] = value;
	dst[1] = value;
	dst[-1] = value;
	dst[linesize] = value;
	dst[-linesize] = value;
	}

	static int draw_spatial(AVFilterLink inlink, AVFrame insamples)
	{
	AVFilterContext *ctx = inlink->dst;
	AVFilterLink *outlink = ctx->outputs[0];
	ShowSpatialContext *s = ctx->priv;
	AVFrame *outpicref;
	int h = s->h - 2;
	int w = s->w - 2;
	int z = s->win_size / 2;

	outpicref = ff_get_video_buffer(outlink, outlink->w, outlink->h);
	if (!outpicref)
	return AVERROR(ENOMEM);

	outpicref->sample_aspect_ratio = (AVRational){1,1};
	for (int i = 0; i < outlink->h; i++) {
	memset(outpicref->data[0] + i * outpicref->linesize[0], 0, outlink->w);
	memset(outpicref->data[1] + i * outpicref->linesize[1], 0, outlink->w);
	memset(outpicref->data[2] + i * outpicref->linesize[2], 0, outlink->w);
	}

	for (int j = 0; j < z; j++) {
	const int idx = z - 1 - j;
	float l = hypotf(RE(idx, 0), IM(idx, 0));
	float r = hypotf(RE(idx, 1), IM(idx, 1));
	float sum = l + r;
	float lp = atan2f(IM(idx, 0), RE(idx, 0));
	float rp = atan2f(IM(idx, 1), RE(idx, 1));
	float diffp = ((rp - lp) / (2.f * M_PI) + 1.f) * 0.5f;
	float diff = (sum < 0.000001f ? 0.f : (r - l) / sum) * 0.5f + 0.5f;
	float cr = av_clipf(cbrtf(l / sum), 0, 1) * 255.f;
	float cb = av_clipf(cbrtf(r / sum), 0, 1) * 255.f;
	float cg;
	int x, y;

	cg = diffp * 255.f;
	x = av_clip(w * diff, 0, w - 2) + 1;
	y = av_clip(h * diffp, 0, h - 2) + 1;

	draw_dot(outpicref->data[0] + outpicref->linesize[0] * y + x, outpicref->linesize[0], cg);
	draw_dot(outpicref->data[1] + outpicref->linesize[1] * y + x, outpicref->linesize[1], cb);
	draw_dot(outpicref->data[2] + outpicref->linesize[2] * y + x, outpicref->linesize[2], cr);
	}

	outpicref->pts = av_rescale_q(insamples->pts, inlink->time_base, outlink->time_base);

	return ff_filter_frame(outlink, outpicref);
	}

	static int spatial_activate(AVFilterContext *ctx)
	{
	AVFilterLink *inlink = ctx->inputs[0];
	AVFilterLink *outlink = ctx->outputs[0];
	ShowSpatialContext *s = ctx->priv;
	int ret;

	FF_FILTER_FORWARD_STATUS_BACK(outlink, inlink);

	if (av_audio_fifo_size(s->fifo) < s->win_size) {
	AVFrame *frame = NULL;

	ret = ff_inlink_consume_frame(inlink, &frame);
	if (ret < 0)
	return ret;
	if (ret > 0) {
	s->pts = frame->pts;
	s->consumed = 0;

	av_audio_fifo_write(s->fifo, (void **)frame->extended_data, frame->nb_samples);
	av_frame_free(&frame);
	}
	}

	if (av_audio_fifo_size(s->fifo) >= s->win_size) {
	AVFrame *fin = ff_get_audio_buffer(inlink, s->win_size);
	if (!fin)
	return AVERROR(ENOMEM);

	fin->pts = s->pts + s->consumed;
	s->consumed += s->hop_size;
	ret = av_audio_fifo_peek(s->fifo, (void **)fin->extended_data,
	FFMIN(s->win_size, av_audio_fifo_size(s->fifo)));
	if (ret < 0) {
	av_frame_free(&fin);
	return ret;
	}

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

	ctx->internal->execute(ctx, run_channel_fft, fin, NULL, 2);

	ret = draw_spatial(inlink, fin);

	av_frame_free(&fin);
	av_audio_fifo_drain(s->fifo, s->hop_size);
	if (ret <= 0)
	return ret;
	}

	FF_FILTER_FORWARD_STATUS(inlink, outlink);
	if (ff_outlink_frame_wanted(outlink) && av_audio_fifo_size(s->fifo) < s->win_size) {
	ff_inlink_request_frame(inlink);
	return 0;
	}

	if (av_audio_fifo_size(s->fifo) >= s->win_size) {
	ff_filter_set_ready(ctx, 10);
	return 0;
	}
	return FFERROR_NOT_READY;
	}

	static const AVFilterPad showspatial_inputs[] = {
	{
	.name = "default",
	.type = AVMEDIA_TYPE_AUDIO,
	},
	{ NULL }
	};

	static const AVFilterPad showspatial_outputs[] = {
	{
	.name = "default",
	.type = AVMEDIA_TYPE_VIDEO,
	.config_props = config_output,
	},
	{ NULL }
	};

	AVFilter ff_avf_showspatial = {
	.name = "showspatial",
	.description = NULL_IF_CONFIG_SMALL("Convert input audio to a spatial video output."),
	.uninit = uninit,
	.query_formats = query_formats,
	.priv_size = sizeof(ShowSpatialContext),
	.inputs = showspatial_inputs,
	.outputs = showspatial_outputs,
	.activate = spatial_activate,
	.priv_class = &showspatial_class,
	.flags = AVFILTER_FLAG_SLICE_THREADS,
	};