/*
  * Copyright (c) 2012 Stefano Sabatini
  *
  * 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 video multimedia filter

  */
 

 #include "libavutil/channel_layout.h"

 #include "libavutil/opt.h"
 #include "libavutil/parseutils.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "audio.h"
 #include "video.h"

 #include "internal.h"

 enum ShowWavesMode {
     MODE_POINT,
     MODE_LINE,
     MODE_NB,
 };
 

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

     AVFrame *outpicref;

     int req_fullfilled;
     int n;
     int sample_count_mod;

     enum ShowWavesMode mode;

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

 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

 
 static const AVOption showwaves_options[] = {

     { "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "600x240"}, 0, 0, FLAGS },
     { "s",    "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "600x240"}, 0, 0, FLAGS },

     { "mode", "select display mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=MODE_POINT}, 0, MODE_NB-1, FLAGS, "mode"},
         { "point", "draw a point for each sample", 0, AV_OPT_TYPE_CONST, {.i64=MODE_POINT}, .flags=FLAGS, .unit="mode"},
         { "line",  "draw a line for each sample",  0, AV_OPT_TYPE_CONST, {.i64=MODE_LINE},  .flags=FLAGS, .unit="mode"},

     { "n",    "set how many samples to show in the same point", OFFSET(n), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, FLAGS },

     { "rate", "set video rate", OFFSET(rate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, 0, FLAGS },
     { "r",    "set video rate", OFFSET(rate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, 0, FLAGS },

     { NULL }

 };
 

 AVFILTER_DEFINE_CLASS(showwaves);

 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     ShowWavesContext *showwaves = ctx->priv;
 

     av_frame_free(&showwaves->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_S16, AV_SAMPLE_FMT_NONE };
     static const enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_GRAY8, 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];
     ShowWavesContext *showwaves = ctx->priv;
 

     if (!showwaves->n)

         showwaves->n = FFMAX(1, ((double)inlink->sample_rate / (showwaves->w * av_q2d(showwaves->rate))) + 0.5);
 

     showwaves->buf_idx = 0;

     outlink->w = showwaves->w;
     outlink->h = showwaves->h;
     outlink->sample_aspect_ratio = (AVRational){1,1};
 
     outlink->frame_rate = av_div_q((AVRational){inlink->sample_rate,showwaves->n},
                                    (AVRational){showwaves->w,1});
 

     av_log(ctx, AV_LOG_VERBOSE, "s:%dx%d r:%f n:%d\n",

            showwaves->w, showwaves->h, av_q2d(outlink->frame_rate), showwaves->n);
     return 0;
 }
 

 inline static int push_frame(AVFilterLink *outlink)

 {
     ShowWavesContext *showwaves = outlink->src->priv;

     int ret;

     if ((ret = ff_filter_frame(outlink, showwaves->outpicref)) >= 0)
         showwaves->req_fullfilled = 1;

     showwaves->outpicref = NULL;
     showwaves->buf_idx = 0;

     return ret;

 }
 
 static int request_frame(AVFilterLink *outlink)
 {
     ShowWavesContext *showwaves = outlink->src->priv;
     AVFilterLink *inlink = outlink->src->inputs[0];
     int ret;
 
     showwaves->req_fullfilled = 0;
     do {

         ret = ff_request_frame(inlink);

     } while (!showwaves->req_fullfilled && ret >= 0);
 
     if (ret == AVERROR_EOF && showwaves->outpicref)
         push_frame(outlink);
     return ret;
 }
 
 #define MAX_INT16 ((1<<15) -1)
 

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

 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     ShowWavesContext *showwaves = ctx->priv;

     const int nb_samples = insamples->nb_samples;
     AVFrame *outpicref = showwaves->outpicref;

     int linesize = outpicref ? outpicref->linesize[0] : 0;
     int16_t *p = (int16_t *)insamples->data[0];

     int nb_channels = inlink->channels;

     int i, j, k, h, ret = 0;

     const int n = showwaves->n;
     const int x = 255 / (nb_channels * n); /* multiplication factor, pre-computed to avoid in-loop divisions */
 
     /* draw data in the buffer */
     for (i = 0; i < nb_samples; i++) {

         if (!showwaves->outpicref) {

             showwaves->outpicref = outpicref =

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

             if (!outpicref)
                 return AVERROR(ENOMEM);

             outpicref->width  = outlink->w;
             outpicref->height = outlink->h;

             outpicref->pts = insamples->pts +
                              av_rescale_q((p - (int16_t *)insamples->data[0]) / nb_channels,
                                           (AVRational){ 1, inlink->sample_rate },
                                           outlink->time_base);

             linesize = outpicref->linesize[0];

             for (j = 0; j < outlink->h; j++)
                 memset(outpicref->data[0] + j * linesize, 0, outlink->w);

         }
         for (j = 0; j < nb_channels; j++) {
             h = showwaves->h/2 - av_rescale(*p++, showwaves->h/2, MAX_INT16);

             switch (showwaves->mode) {
             case MODE_POINT:
                 if (h >= 0 && h < outlink->h)
                     *(outpicref->data[0] + showwaves->buf_idx + h * linesize) += x;
                 break;
 
             case MODE_LINE:
             {
                 int start = showwaves->h/2, end = av_clip(h, 0, outlink->h-1);
                 if (start > end) FFSWAP(int16_t, start, end);
                 for (k = start; k < end; k++)
                     *(outpicref->data[0] + showwaves->buf_idx + k * linesize) += x;
                 break;
             }
             }

         }

         showwaves->sample_count_mod++;
         if (showwaves->sample_count_mod == n) {
             showwaves->sample_count_mod = 0;
             showwaves->buf_idx++;
         }
         if (showwaves->buf_idx == showwaves->w)

             if ((ret = push_frame(outlink)) < 0)
                 break;

         outpicref = showwaves->outpicref;

     }
 

     av_frame_free(&insamples);

     return ret;

 }
 

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

 AVFilter ff_avf_showwaves = {

     .name          = "showwaves",
     .description   = NULL_IF_CONFIG_SMALL("Convert input audio to a video output."),
     .uninit        = uninit,
     .query_formats = query_formats,
     .priv_size     = sizeof(ShowWavesContext),
     .inputs        = showwaves_inputs,
     .outputs       = showwaves_outputs,
     .priv_class    = &showwaves_class,

 };