/*
  * Copyright (c) 2012 Clément Bœsch

  * Copyright (c) 2013 Rudolf Polzer <divverent@xonotic.org>

  *
  * 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
  */
 
 /**
  * @file
  * audio to spectrum (video) transmedia filter, based on ffplay rdft showmode
  * (by Michael Niedermayer) and lavfi/avf_showwaves (by Stefano Sabatini).
  */
 
 #include <math.h>
 
 #include "libavcodec/avfft.h"

 #include "libavutil/avassert.h"

 #include "libavutil/channel_layout.h"

 #include "libavutil/opt.h"
 #include "avfilter.h"
 #include "internal.h"
 

 enum DisplayMode  { COMBINED, SEPARATE, NB_MODES };
 enum DisplayScale { LINEAR, SQRT, CBRT, LOG, NB_SCALES };
 enum ColorMode    { CHANNEL, INTENSITY, NB_CLMODES };
 

 typedef struct {
     const AVClass *class;
     int w, h;
     AVFilterBufferRef *outpicref;
     int req_fullfilled;

     int nb_display_channels;
     int channel_height;

     int sliding;                ///< 1 if sliding mode, 0 otherwise

     enum DisplayMode mode;      ///< channel display mode
     enum ColorMode color_mode;  ///< display color scheme
     enum DisplayScale scale;
     float saturation;           ///< color saturation multiplier

     int xpos;                   ///< x position (current column)
     RDFTContext *rdft;          ///< Real Discrete Fourier Transform context
     int rdft_bits;              ///< number of bits (RDFT window size = 1<<rdft_bits)

     FFTSample **rdft_data;      ///< bins holder for each (displayed) channels

     int filled;                 ///< number of samples (per channel) filled in current rdft_buffer
     int consumed;               ///< number of samples (per channel) consumed from the input frame
     float *window_func_lut;     ///< Window function LUT

     float *combine_buffer;      ///< color combining buffer (3 * h items)

 } ShowSpectrumContext;
 
 #define OFFSET(x) offsetof(ShowSpectrumContext, x)

 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

 
 static const AVOption showspectrum_options[] = {

     { "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "640x512"}, 0, 0, FLAGS },
     { "s",    "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "640x512"}, 0, 0, FLAGS },

     { "slide", "set sliding mode", OFFSET(sliding), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, FLAGS },

     { "mode", "set channel display mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=COMBINED}, COMBINED, NB_MODES-1, FLAGS, "mode" },
     { "combined", "combined mode", 0, AV_OPT_TYPE_CONST, {.i64=COMBINED}, 0, 0, FLAGS, "mode" },
     { "separate", "separate mode", 0, AV_OPT_TYPE_CONST, {.i64=SEPARATE}, 0, 0, FLAGS, "mode" },
     { "color", "set channel coloring", OFFSET(color_mode), AV_OPT_TYPE_INT, {.i64=CHANNEL}, CHANNEL, NB_CLMODES-1, FLAGS, "color" },
     { "channel",   "separate color for each channel", 0, AV_OPT_TYPE_CONST, {.i64=CHANNEL},   0, 0, FLAGS, "color" },
     { "intensity", "intensity based coloring",        0, AV_OPT_TYPE_CONST, {.i64=INTENSITY}, 0, 0, FLAGS, "color" },
     { "scale", "set display scale", OFFSET(scale), AV_OPT_TYPE_INT, {.i64=SQRT}, LINEAR, NB_SCALES-1, FLAGS, "scale" },
     { "sqrt", "square root", 0, AV_OPT_TYPE_CONST, {.i64=SQRT},   0, 0, FLAGS, "scale" },
     { "cbrt", "cubic root",  0, AV_OPT_TYPE_CONST, {.i64=CBRT},   0, 0, FLAGS, "scale" },
     { "log",  "logarithmic", 0, AV_OPT_TYPE_CONST, {.i64=LOG},    0, 0, FLAGS, "scale" },
     { "lin",  "linear",      0, AV_OPT_TYPE_CONST, {.i64=LINEAR}, 0, 0, FLAGS, "scale" },
     { "saturation", "color saturation multiplier", OFFSET(saturation), AV_OPT_TYPE_FLOAT, {.dbl = 1}, -10, 10, FLAGS },

     { NULL },
 };
 
 AVFILTER_DEFINE_CLASS(showspectrum);
 

 static const struct {

     float a, y, u, v;

 } intensity_color_table[] = {

     {    0,                  0,                  0,                   0 },
     { 0.13, .03587126228984074,  .1573300977624594, -.02548747583751842 },
     { 0.30, .18572281794568020,  .1772436246393981,  .17475554840414750 },
     { 0.60, .28184980583656130, -.1593064119945782,  .47132074554608920 },
     { 0.73, .65830621175547810, -.3716070802232764,  .24352759331252930 },
     { 0.78, .76318535758242900, -.4307467689263783,  .16866496622310430 },
     { 0.91, .95336363636363640, -.2045454545454546,  .03313636363636363 },
     {    1,                  1,                  0,                   0 }

 };
 

 static av_cold int init(AVFilterContext *ctx, const char *args)
 {
     ShowSpectrumContext *showspectrum = ctx->priv;
     int err;
 
     showspectrum->class = &showspectrum_class;
     av_opt_set_defaults(showspectrum);
 
     if ((err = av_set_options_string(showspectrum, args, "=", ":")) < 0)
         return err;
 
     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     ShowSpectrumContext *showspectrum = ctx->priv;

     int i;

     av_freep(&showspectrum->combine_buffer);

     av_rdft_end(showspectrum->rdft);

     for (i = 0; i < showspectrum->nb_display_channels; i++)
         av_freep(&showspectrum->rdft_data[i]);

     av_freep(&showspectrum->rdft_data);
     av_freep(&showspectrum->window_func_lut);
     avfilter_unref_bufferp(&showspectrum->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_S16P, AV_SAMPLE_FMT_NONE };

     static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_NONE };

 
     /* set input audio formats */
     formats = ff_make_format_list(sample_fmts);
     if (!formats)
         return AVERROR(ENOMEM);
     ff_formats_ref(formats, &inlink->out_formats);
 
     layouts = ff_all_channel_layouts();
     if (!layouts)
         return AVERROR(ENOMEM);
     ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts);
 
     formats = ff_all_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];

     ShowSpectrumContext *showspectrum = ctx->priv;

     int i, rdft_bits, win_size, h;

 
     outlink->w = showspectrum->w;
     outlink->h = showspectrum->h;
 

     h = (showspectrum->mode == COMBINED) ? outlink->h : outlink->h / inlink->channels;
     showspectrum->channel_height = h;
 

     /* RDFT window size (precision) according to the requested output frame height */

     for (rdft_bits = 1; 1 << rdft_bits < 2 * h; rdft_bits++);

     win_size = 1 << rdft_bits;
 
     /* (re-)configuration if the video output changed (or first init) */
     if (rdft_bits != showspectrum->rdft_bits) {

         size_t rdft_size, rdft_listsize;

         AVFilterBufferRef *outpicref;
 
         av_rdft_end(showspectrum->rdft);
         showspectrum->rdft = av_rdft_init(rdft_bits, DFT_R2C);
         showspectrum->rdft_bits = rdft_bits;
 

         /* RDFT 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 < showspectrum->nb_display_channels; i++)
             av_freep(&showspectrum->rdft_data[i]);

         av_freep(&showspectrum->rdft_data);

         showspectrum->nb_display_channels = inlink->channels;
 
         if (av_size_mult(sizeof(*showspectrum->rdft_data),
                          showspectrum->nb_display_channels, &rdft_listsize) < 0)
             return AVERROR(EINVAL);
         if (av_size_mult(sizeof(**showspectrum->rdft_data),
                          win_size, &rdft_size) < 0)

             return AVERROR(EINVAL);

         showspectrum->rdft_data = av_malloc(rdft_listsize);

         if (!showspectrum->rdft_data)
             return AVERROR(ENOMEM);

         for (i = 0; i < showspectrum->nb_display_channels; i++) {
             showspectrum->rdft_data[i] = av_malloc(rdft_size);
             if (!showspectrum->rdft_data[i])
                 return AVERROR(ENOMEM);
         }

         showspectrum->filled = 0;
 
         /* pre-calc windowing function (hann here) */
         showspectrum->window_func_lut =
             av_realloc_f(showspectrum->window_func_lut, win_size,
                          sizeof(*showspectrum->window_func_lut));
         if (!showspectrum->window_func_lut)
             return AVERROR(ENOMEM);
         for (i = 0; i < win_size; i++)
             showspectrum->window_func_lut[i] = .5f * (1 - cos(2*M_PI*i / (win_size-1)));
 
         /* prepare the initial picref buffer (black frame) */
         avfilter_unref_bufferp(&showspectrum->outpicref);
         showspectrum->outpicref = outpicref =
             ff_get_video_buffer(outlink, AV_PERM_WRITE|AV_PERM_PRESERVE|AV_PERM_REUSE2,
                                 outlink->w, outlink->h);
         if (!outpicref)
             return AVERROR(ENOMEM);
         outlink->sample_aspect_ratio = (AVRational){1,1};
         memset(outpicref->data[0], 0, outlink->h * outpicref->linesize[0]);
     }
 
     if (showspectrum->xpos >= outlink->w)
         showspectrum->xpos = 0;
 

     showspectrum->combine_buffer =
         av_realloc_f(showspectrum->combine_buffer, outlink->h * 3,
                      sizeof(*showspectrum->combine_buffer));
 

     av_log(ctx, AV_LOG_VERBOSE, "s:%dx%d RDFT window size:%d\n",
            showspectrum->w, showspectrum->h, win_size);
     return 0;
 }
 
 inline static void push_frame(AVFilterLink *outlink)
 {
     ShowSpectrumContext *showspectrum = outlink->src->priv;
 
     showspectrum->xpos++;
     if (showspectrum->xpos >= outlink->w)
         showspectrum->xpos = 0;
     showspectrum->filled = 0;
     showspectrum->req_fullfilled = 1;
 

     ff_filter_frame(outlink, avfilter_ref_buffer(showspectrum->outpicref, ~AV_PERM_WRITE));

 }
 
 static int request_frame(AVFilterLink *outlink)
 {
     ShowSpectrumContext *showspectrum = outlink->src->priv;
     AVFilterLink *inlink = outlink->src->inputs[0];
     int ret;
 
     showspectrum->req_fullfilled = 0;
     do {
         ret = ff_request_frame(inlink);
     } while (!showspectrum->req_fullfilled && ret >= 0);
 
     if (ret == AVERROR_EOF && showspectrum->outpicref)
         push_frame(outlink);
     return ret;
 }
 
 static int plot_spectrum_column(AVFilterLink *inlink, AVFilterBufferRef *insamples, int nb_samples)
 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     ShowSpectrumContext *showspectrum = ctx->priv;
     AVFilterBufferRef *outpicref = showspectrum->outpicref;
 
     /* nb_freq contains the power of two superior or equal to the output image
      * height (or half the RDFT window size) */
     const int nb_freq = 1 << (showspectrum->rdft_bits - 1);
     const int win_size = nb_freq << 1;

     const double w = 1. / (sqrt(nb_freq) * 32768.);

     int ch, plane, n, y;

     const int start = showspectrum->filled;
     const int add_samples = FFMIN(win_size - start, nb_samples);
 
     /* fill RDFT input with the number of samples available */

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

         const int16_t *p = (int16_t *)insamples->extended_data[ch];
 
         p += showspectrum->consumed;
         for (n = 0; n < add_samples; n++)

             showspectrum->rdft_data[ch][start + n] = p[n] * showspectrum->window_func_lut[start + n];

     }
     showspectrum->filled += add_samples;
 
     /* complete RDFT window size? */
     if (showspectrum->filled == win_size) {
 

         /* channel height */
         int h = showspectrum->channel_height;
 

         /* run RDFT on each samples set */

         for (ch = 0; ch < showspectrum->nb_display_channels; ch++)
             av_rdft_calc(showspectrum->rdft, showspectrum->rdft_data[ch]);

 
         /* fill a new spectrum column */

 #define RE(y, ch) showspectrum->rdft_data[ch][2 * y + 0]
 #define IM(y, ch) showspectrum->rdft_data[ch][2 * y + 1]
 #define MAGNITUDE(y, ch) hypot(RE(y, ch), IM(y, ch))

         /* initialize buffer for combining to black */

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

             showspectrum->combine_buffer[3 * y    ] = 0;
             showspectrum->combine_buffer[3 * y + 1] = 127.5;
             showspectrum->combine_buffer[3 * y + 2] = 127.5;
         }
 
         for (ch = 0; ch < showspectrum->nb_display_channels; ch++) {
             float yf, uf, vf;
 
             /* decide color range */
             switch (showspectrum->mode) {
             case COMBINED:
                 // reduce range by channel count
                 yf = 256.0f / showspectrum->nb_display_channels;
                 switch (showspectrum->color_mode) {
                 case INTENSITY:
                     uf = yf;
                     vf = yf;
                     break;
                 case CHANNEL:
                     /* adjust saturation for mixed UV coloring */
                     /* this factor is correct for infinite channels, an approximation otherwise */
                     uf = yf * M_PI;
                     vf = yf * M_PI;
                     break;
                 default:
                     av_assert0(0);
                 }
                 break;
             case SEPARATE:
                 // full range
                 yf = 256.0f;
                 uf = 256.0f;
                 vf = 256.0f;
                 break;
             default:
                 av_assert0(0);

             }
 

             if (showspectrum->color_mode == CHANNEL) {
                 if (showspectrum->nb_display_channels > 1) {
                     uf *= 0.5 * sin((2 * M_PI * ch) / showspectrum->nb_display_channels);
                     vf *= 0.5 * cos((2 * M_PI * ch) / showspectrum->nb_display_channels);
                 } else {
                     uf = 0.0f;
                     vf = 0.0f;
                 }
             }
             uf *= showspectrum->saturation;
             vf *= showspectrum->saturation;
 
             /* draw the channel */
             for (y = 0; y < h; y++) {
                 int row = (showspectrum->mode == COMBINED) ? y : ch * h + y;
                 float *out = &showspectrum->combine_buffer[3 * row];
 
                 /* get magnitude */
                 float a = w * MAGNITUDE(y, ch);
 
                 /* apply scale */
                 switch (showspectrum->scale) {
                 case LINEAR:
                     break;
                 case SQRT:
                     a = sqrt(a);
                     break;
                 case CBRT:
                     a = cbrt(a);
                     break;
                 case LOG:
                     a = 1 - log(FFMAX(FFMIN(1, a), 1e-6)) / log(1e-6); // zero = -120dBFS
                     break;
                 default:
                     av_assert0(0);
                 }
 
                 if (showspectrum->color_mode == INTENSITY) {
                     float y, u, v;
                     int i;
 
                     for (i = 1; i < sizeof(intensity_color_table) / sizeof(*intensity_color_table) - 1; i++)
                         if (intensity_color_table[i].a >= a)
                             break;
                     // i now is the first item >= the color
                     // now we know to interpolate between item i - 1 and i
                     if (a <= intensity_color_table[i - 1].a) {
                         y = intensity_color_table[i - 1].y;
                         u = intensity_color_table[i - 1].u;
                         v = intensity_color_table[i - 1].v;
                     } else if (a >= intensity_color_table[i].a) {
                         y = intensity_color_table[i].y;
                         u = intensity_color_table[i].u;
                         v = intensity_color_table[i].v;
                     } else {
                         float start = intensity_color_table[i - 1].a;
                         float end = intensity_color_table[i].a;
                         float lerpfrac = (a - start) / (end - start);
                         y = intensity_color_table[i - 1].y * (1.0f - lerpfrac)
                           + intensity_color_table[i].y * lerpfrac;
                         u = intensity_color_table[i - 1].u * (1.0f - lerpfrac)
                           + intensity_color_table[i].u * lerpfrac;
                         v = intensity_color_table[i - 1].v * (1.0f - lerpfrac)
                           + intensity_color_table[i].v * lerpfrac;
                     }
 
                     out[0] += y * yf;
                     out[1] += u * uf;
                     out[2] += v * vf;
                 } else {
                     out[0] += a * yf;
                     out[1] += a * uf;
                     out[2] += a * vf;
                 }
             }

         }

 
         /* copy to output */
         if (showspectrum->sliding) {
             for (plane = 0; plane < 3; plane++) {
                 for (y = 0; y < outlink->h; y++) {
                     uint8_t *p = outpicref->data[plane] +
                                  y * outpicref->linesize[plane];
                     memmove(p, p + 1, outlink->w - 1);
                 }
             }
             showspectrum->xpos = outlink->w - 1;
         }
         for (plane = 0; plane < 3; plane++) {
             uint8_t *p = outpicref->data[plane] +
                          (outlink->h - 1) * outpicref->linesize[plane] +
                          showspectrum->xpos;
             for (y = 0; y < outlink->h; y++) {
                 *p = rint(FFMAX(0, FFMIN(showspectrum->combine_buffer[3 * y + plane], 255)));
                 p -= outpicref->linesize[plane];
             }
         }
 

         outpicref->pts = insamples->pts +
             av_rescale_q(showspectrum->consumed,
                          (AVRational){ 1, inlink->sample_rate },
                          outlink->time_base);
         push_frame(outlink);
     }
 
     return add_samples;
 }
 

 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *insamples)

 {
     AVFilterContext *ctx = inlink->dst;
     ShowSpectrumContext *showspectrum = ctx->priv;
     int left_samples = insamples->audio->nb_samples;
 
     showspectrum->consumed = 0;
     while (left_samples) {
         const int added_samples = plot_spectrum_column(inlink, insamples, left_samples);
         showspectrum->consumed += added_samples;
         left_samples -= added_samples;
     }
 
     avfilter_unref_buffer(insamples);
     return 0;
 }
 

 static const AVFilterPad showspectrum_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_AUDIO,
         .filter_frame = filter_frame,
         .min_perms    = AV_PERM_READ,
     },
     { NULL }
 };
 
 static const AVFilterPad showspectrum_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .config_props  = config_output,
         .request_frame = request_frame,
     },
     { NULL }
 };
 

 AVFilter avfilter_avf_showspectrum = {
     .name           = "showspectrum",
     .description    = NULL_IF_CONFIG_SMALL("Convert input audio to a spectrum video output."),
     .init           = init,
     .uninit         = uninit,
     .query_formats  = query_formats,
     .priv_size      = sizeof(ShowSpectrumContext),

     .inputs         = showspectrum_inputs,
     .outputs        = showspectrum_outputs,
     .priv_class     = &showspectrum_class,

 };