/*

  * Copyright (c) 2012-2013 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 };

 enum WindowFunc   { WFUNC_NONE, WFUNC_HANN, WFUNC_HAMMING, WFUNC_BLACKMAN, NB_WFUNC };

 enum SlideMode    { REPLACE, SCROLL, FULLFRAME, NB_SLIDES };

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

     AVFrame *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

     float *window_func_lut;     ///< Window function LUT

     enum WindowFunc win_func;

     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, NB_SLIDES, FLAGS, "slide" },

         { "replace", "replace old columns with new", 0, AV_OPT_TYPE_CONST, {.i64=REPLACE}, 0, 0, FLAGS, "slide" },

         { "scroll", "scroll from right to left", 0, AV_OPT_TYPE_CONST, {.i64=SCROLL}, 0, 0, FLAGS, "slide" },
         { "fullframe", "return full frames", 0, AV_OPT_TYPE_CONST, {.i64=FULLFRAME}, 0, 0, FLAGS, "slide" },

     { "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 },

     { "win_func", "set window function", OFFSET(win_func), AV_OPT_TYPE_INT, {.i64 = WFUNC_HANN}, 0, NB_WFUNC-1, FLAGS, "win_func" },

         { "hann",     "Hann window",     0, AV_OPT_TYPE_CONST, {.i64 = WFUNC_HANN},     0, 0, FLAGS, "win_func" },
         { "hamming",  "Hamming window",  0, AV_OPT_TYPE_CONST, {.i64 = WFUNC_HAMMING},  0, 0, FLAGS, "win_func" },
         { "blackman", "Blackman window", 0, AV_OPT_TYPE_CONST, {.i64 = WFUNC_BLACKMAN}, 0, 0, FLAGS, "win_func" },

     { 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 void uninit(AVFilterContext *ctx)
 {

     ShowSpectrumContext *s = ctx->priv;

     int i;

     av_freep(&s->combine_buffer);
     av_rdft_end(s->rdft);
     for (i = 0; i < s->nb_display_channels; i++)
         av_freep(&s->rdft_data[i]);
     av_freep(&s->rdft_data);
     av_freep(&s->window_func_lut);
     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_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 *s = ctx->priv;

     int i, rdft_bits, win_size, h;

     outlink->w = s->w;
     outlink->h = s->h;

     h = (s->mode == COMBINED) ? outlink->h : outlink->h / inlink->channels;
     s->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 != s->rdft_bits) {

         size_t rdft_size, rdft_listsize;

         AVFrame *outpicref;

         av_rdft_end(s->rdft);
         s->rdft = av_rdft_init(rdft_bits, DFT_R2C);

         if (!s->rdft) {
             av_log(ctx, AV_LOG_ERROR, "Unable to create RDFT context. "
                    "The window size might be too high.\n");
             return AVERROR(EINVAL);
         }

         s->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 < s->nb_display_channels; i++)
             av_freep(&s->rdft_data[i]);
         av_freep(&s->rdft_data);
         s->nb_display_channels = inlink->channels;

         if (av_size_mult(sizeof(*s->rdft_data),
                          s->nb_display_channels, &rdft_listsize) < 0)

             return AVERROR(EINVAL);

         if (av_size_mult(sizeof(**s->rdft_data),

                          win_size, &rdft_size) < 0)

             return AVERROR(EINVAL);

         s->rdft_data = av_malloc(rdft_listsize);
         if (!s->rdft_data)

             return AVERROR(ENOMEM);

         for (i = 0; i < s->nb_display_channels; i++) {
             s->rdft_data[i] = av_malloc(rdft_size);
             if (!s->rdft_data[i])

                 return AVERROR(ENOMEM);
         }

         /* pre-calc windowing function */

         s->window_func_lut =
             av_realloc_f(s->window_func_lut, win_size,
                          sizeof(*s->window_func_lut));
         if (!s->window_func_lut)

             return AVERROR(ENOMEM);

         switch (s->win_func) {
         case WFUNC_NONE:
             for (i = 0; i < win_size; i++)
                 s->window_func_lut[i] = 1.;
             break;
         case WFUNC_HANN:
             for (i = 0; i < win_size; i++)
                 s->window_func_lut[i] = .5f * (1 - cos(2*M_PI*i / (win_size-1)));
             break;
         case WFUNC_HAMMING:
             for (i = 0; i < win_size; i++)
                 s->window_func_lut[i] = .54f - .46f * cos(2*M_PI*i / (win_size-1));
             break;

         case WFUNC_BLACKMAN: {
             for (i = 0; i < win_size; i++)
                 s->window_func_lut[i] = .42f - .5f*cos(2*M_PI*i / (win_size-1)) + .08f*cos(4*M_PI*i / (win_size-1));
             break;
         }

         default:
             av_assert0(0);
         }

 
         /* prepare the initial picref buffer (black frame) */

         av_frame_free(&s->outpicref);
         s->outpicref = outpicref =

             ff_get_video_buffer(outlink, outlink->w, outlink->h);

         if (!outpicref)
             return AVERROR(ENOMEM);
         outlink->sample_aspect_ratio = (AVRational){1,1};

         for (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], 128, outlink->w);
             memset(outpicref->data[2] + i * outpicref->linesize[2], 128, outlink->w);
         }

     }
 

     if (s->xpos >= outlink->w)
         s->xpos = 0;

     outlink->frame_rate = av_make_q(inlink->sample_rate, win_size);

     if (s->sliding == FULLFRAME)
         outlink->frame_rate.den *= outlink->w;

     inlink->min_samples = inlink->max_samples = inlink->partial_buf_size =
         win_size;
 

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

     av_log(ctx, AV_LOG_VERBOSE, "s:%dx%d RDFT window size:%d\n",

            s->w, s->h, win_size);

     return 0;
 }
 
 static int request_frame(AVFilterLink *outlink)
 {

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

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

     unsigned i;

     int ret;
 

     s->req_fullfilled = 0;

     do {
         ret = ff_request_frame(inlink);

         if (ret == AVERROR_EOF && s->sliding == FULLFRAME && s->xpos > 0 &&
             s->outpicref) {
             for (i = 0; i < outlink->h; i++) {
                 memset(s->outpicref->data[0] + i * s->outpicref->linesize[0] + s->xpos,   0, outlink->w - s->xpos);
                 memset(s->outpicref->data[1] + i * s->outpicref->linesize[1] + s->xpos, 128, outlink->w - s->xpos);
                 memset(s->outpicref->data[2] + i * s->outpicref->linesize[2] + s->xpos, 128, outlink->w - s->xpos);
             }
             ret = ff_filter_frame(outlink, s->outpicref);
             s->outpicref = NULL;
             s->req_fullfilled = 1;
         }

     } while (!s->req_fullfilled && ret >= 0);

 
     return ret;
 }
 

 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;

 
     /* 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 << (s->rdft_bits - 1);

     const int win_size = nb_freq << 1;

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

     int h = s->channel_height;

     int ch, plane, n, y;

 
     av_assert0(insamples->nb_samples == win_size);

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

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

         const int16_t *p = (int16_t *)insamples->extended_data[ch];
 

         for (n = 0; n < win_size; n++)
             s->rdft_data[ch][n] = p[n] * s->window_func_lut[n];

     }
 

     /* TODO reindent */

         /* run RDFT on each samples set */

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

 
         /* fill a new spectrum column */

 #define RE(y, ch) s->rdft_data[ch][2 * (y) + 0]
 #define IM(y, ch) s->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++) {

             s->combine_buffer[3 * y    ] = 0;
             s->combine_buffer[3 * y + 1] = 127.5;
             s->combine_buffer[3 * y + 2] = 127.5;

         }
 

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

             float yf, uf, vf;
 
             /* decide color range */

             switch (s->mode) {

             case COMBINED:
                 // reduce range by channel count

                 yf = 256.0f / s->nb_display_channels;
                 switch (s->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 (s->color_mode == CHANNEL) {
                 if (s->nb_display_channels > 1) {
                     uf *= 0.5 * sin((2 * M_PI * ch) / s->nb_display_channels);
                     vf *= 0.5 * cos((2 * M_PI * ch) / s->nb_display_channels);

                 } else {
                     uf = 0.0f;
                     vf = 0.0f;
                 }
             }

             uf *= s->saturation;
             vf *= s->saturation;

 
             /* 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];

 
                 /* get magnitude */
                 float a = w * MAGNITUDE(y, ch);
 
                 /* apply scale */

                 switch (s->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 (s->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 (s->sliding == SCROLL) {

             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);
                 }
             }

             s->xpos = outlink->w - 1;

         }
         for (plane = 0; plane < 3; plane++) {
             uint8_t *p = outpicref->data[plane] +
                          (outlink->h - 1) * outpicref->linesize[plane] +

                          s->xpos;

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

                 *p = rint(FFMAX(0, FFMIN(s->combine_buffer[3 * y + plane], 255)));

                 p -= outpicref->linesize[plane];
             }
         }
 

         if (s->sliding != FULLFRAME || s->xpos == 0)
             outpicref->pts = insamples->pts;
 
         s->xpos++;
         if (s->xpos >= outlink->w)
             s->xpos = 0;
         if (s->sliding != FULLFRAME || s->xpos == 0) {
             s->req_fullfilled = 1;
             ret = ff_filter_frame(outlink, av_frame_clone(s->outpicref));
             if (ret < 0)
                 return ret;
         }

     return win_size;

 }
 

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

 {
     AVFilterContext *ctx = inlink->dst;

     ShowSpectrumContext *s = ctx->priv;

     unsigned win_size = 1 << s->rdft_bits;
     int ret = 0;

     av_assert0(insamples->nb_samples <= win_size);
     if (insamples->nb_samples == win_size)
         ret = plot_spectrum_column(inlink, insamples);

     av_frame_free(&insamples);

     return ret;

 }
 

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

 AVFilter ff_avf_showspectrum = {

     .name          = "showspectrum",
     .description   = NULL_IF_CONFIG_SMALL("Convert input audio to a spectrum video output."),
     .uninit        = uninit,
     .query_formats = query_formats,
     .priv_size     = sizeof(ShowSpectrumContext),
     .inputs        = showspectrum_inputs,
     .outputs       = showspectrum_outputs,
     .priv_class    = &showspectrum_class,

 };