/*
  * Copyright (c) 2017 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 "libavutil/imgutils.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 #include "libavutil/qsort.h"
 #include "avfilter.h"
 
 #define FF_BUFQUEUE_SIZE 129
 #include "bufferqueue.h"
 
 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 
 #define SIZE FF_BUFQUEUE_SIZE
 
 enum smooth_mode {
     ARITHMETIC_MEAN,
     GEOMETRIC_MEAN,
     HARMONIC_MEAN,
     QUADRATIC_MEAN,
     CUBIC_MEAN,
     POWER_MEAN,
     MEDIAN,
     NB_SMOOTH_MODE,
 };
 
 typedef struct DeflickerContext {
     const AVClass *class;
 
     int size;
     int mode;

     int bypass;

 
     int eof;
     int depth;
     int nb_planes;
     int planewidth[4];
     int planeheight[4];
 
     uint64_t *histogram;
     float luminance[SIZE];
     float sorted[SIZE];
 
     struct FFBufQueue q;
     int available;
 
     void (*get_factor)(AVFilterContext *ctx, float *f);
     float (*calc_avgy)(AVFilterContext *ctx, AVFrame *in);
     int (*deflicker)(AVFilterContext *ctx, const uint8_t *src, ptrdiff_t src_linesize,
                      uint8_t *dst, ptrdiff_t dst_linesize, int w, int h, float f);
 } DeflickerContext;
 
 #define OFFSET(x) offsetof(DeflickerContext, x)
 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 
 static const AVOption deflicker_options[] = {
     { "size",  "set how many frames to use",  OFFSET(size), AV_OPT_TYPE_INT, {.i64=5}, 2, SIZE, FLAGS },
     { "s",     "set how many frames to use",  OFFSET(size), AV_OPT_TYPE_INT, {.i64=5}, 2, SIZE, FLAGS },
     { "mode",  "set how to smooth luminance", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=0}, 0, NB_SMOOTH_MODE-1, FLAGS, "mode" },
     { "m",     "set how to smooth luminance", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=0}, 0, NB_SMOOTH_MODE-1, FLAGS, "mode" },
         { "am",      "arithmetic mean", 0, AV_OPT_TYPE_CONST, {.i64=ARITHMETIC_MEAN},  0, 0, FLAGS, "mode" },
         { "gm",      "geometric mean",  0, AV_OPT_TYPE_CONST, {.i64=GEOMETRIC_MEAN},   0, 0, FLAGS, "mode" },
         { "hm",      "harmonic mean",   0, AV_OPT_TYPE_CONST, {.i64=HARMONIC_MEAN},    0, 0, FLAGS, "mode" },
         { "qm",      "quadratic mean",  0, AV_OPT_TYPE_CONST, {.i64=QUADRATIC_MEAN},   0, 0, FLAGS, "mode" },
         { "cm",      "cubic mean",      0, AV_OPT_TYPE_CONST, {.i64=CUBIC_MEAN},       0, 0, FLAGS, "mode" },
         { "pm",      "power mean",      0, AV_OPT_TYPE_CONST, {.i64=POWER_MEAN},       0, 0, FLAGS, "mode" },
         { "median",  "median",          0, AV_OPT_TYPE_CONST, {.i64=MEDIAN},           0, 0, FLAGS, "mode" },

     { "bypass", "leave frames unchanged",  OFFSET(bypass), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, FLAGS },

     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(deflicker);
 
 static int query_formats(AVFilterContext *ctx)
 {
     static const enum AVPixelFormat pixel_fmts[] = {

         AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY9, AV_PIX_FMT_GRAY10,

         AV_PIX_FMT_GRAY12, AV_PIX_FMT_GRAY16,
         AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P,
         AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P,
         AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P,
         AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
         AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ444P,
         AV_PIX_FMT_YUVJ411P,
         AV_PIX_FMT_YUV420P9, AV_PIX_FMT_YUV422P9, AV_PIX_FMT_YUV444P9,
         AV_PIX_FMT_YUV420P10, AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV444P10,
         AV_PIX_FMT_YUV440P10,
         AV_PIX_FMT_YUV444P12, AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV420P12,
         AV_PIX_FMT_YUV440P12,
         AV_PIX_FMT_YUV444P14, AV_PIX_FMT_YUV422P14, AV_PIX_FMT_YUV420P14,
         AV_PIX_FMT_YUV420P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV444P16,
         AV_PIX_FMT_NONE
     };
     AVFilterFormats *formats = ff_make_format_list(pixel_fmts);
     if (!formats)
         return AVERROR(ENOMEM);
     return ff_set_common_formats(ctx, formats);
 }
 
 static int deflicker8(AVFilterContext *ctx,
                       const uint8_t *src, ptrdiff_t src_linesize,
                       uint8_t *dst, ptrdiff_t dst_linesize,
                       int w, int h, float f)
 {
     int x, y;
 
     for (y = 0; y < h; y++) {
         for (x = 0; x < w; x++) {
             dst[x] = av_clip_uint8(src[x] * f);
         }
 
         dst += dst_linesize;
         src += src_linesize;
     }
 
     return 0;
 }
 
 static int deflicker16(AVFilterContext *ctx,
                        const uint8_t *ssrc, ptrdiff_t src_linesize,
                        uint8_t *ddst, ptrdiff_t dst_linesize,
                        int w, int h, float f)
 {
     DeflickerContext *s = ctx->priv;
     const uint16_t *src = (const uint16_t *)ssrc;
     uint16_t *dst = (uint16_t *)ddst;
     const int max = (1 << s->depth) - 1;
     int x, y;
 
     for (y = 0; y < h; y++) {
         for (x = 0; x < w; x++) {
             dst[x] = av_clip(src[x] * f, 0, max);
         }
 
         dst += dst_linesize / 2;
         src += src_linesize / 2;
     }
 
     return 0;
 }
 
 static float calc_avgy8(AVFilterContext *ctx, AVFrame *in)
 {
     DeflickerContext *s = ctx->priv;
     const uint8_t *src = in->data[0];
     int64_t sum = 0;
     int y, x;
 
     memset(s->histogram, 0, (1 << s->depth) * sizeof(*s->histogram));
 
     for (y = 0; y < s->planeheight[0]; y++) {
         for (x = 0; x < s->planewidth[0]; x++) {
             s->histogram[src[x]]++;
         }
         src += in->linesize[0];
     }
 
     for (y = 0; y < 1 << s->depth; y++) {
         sum += s->histogram[y] * y;
     }
 
     return 1.0f * sum / (s->planeheight[0] * s->planewidth[0]);
 }
 
 static float calc_avgy16(AVFilterContext *ctx, AVFrame *in)
 {
     DeflickerContext *s = ctx->priv;
     const uint16_t *src = (const uint16_t *)in->data[0];
     int64_t sum = 0;
     int y, x;
 
     memset(s->histogram, 0, (1 << s->depth) * sizeof(*s->histogram));
 
     for (y = 0; y < s->planeheight[0]; y++) {
         for (x = 0; x < s->planewidth[0]; x++) {
             s->histogram[src[x]]++;
         }
         src += in->linesize[0] / 2;
     }
 
     for (y = 0; y < 1 << s->depth; y++) {
         sum += s->histogram[y] * y;
     }
 
     return 1.0f * sum / (s->planeheight[0] * s->planewidth[0]);
 }
 
 static void get_am_factor(AVFilterContext *ctx, float *f)
 {
     DeflickerContext *s = ctx->priv;
     int y;
 
     *f = 0.0f;
 
     for (y = 0; y < s->size; y++) {
         *f += s->luminance[y];
     }
 
     *f /= s->size;
     *f /= s->luminance[0];
 }
 
 static void get_gm_factor(AVFilterContext *ctx, float *f)
 {
     DeflickerContext *s = ctx->priv;
     int y;
 
     *f = 1;
 
     for (y = 0; y < s->size; y++) {
         *f *= s->luminance[y];
     }
 
     *f = pow(*f, 1.0f / s->size);
     *f /= s->luminance[0];
 }
 
 static void get_hm_factor(AVFilterContext *ctx, float *f)
 {
     DeflickerContext *s = ctx->priv;
     int y;
 
     *f = 0.0f;
 
     for (y = 0; y < s->size; y++) {
         *f += 1.0f / s->luminance[y];
     }
 
     *f = s->size / *f;
     *f /= s->luminance[0];
 }
 
 static void get_qm_factor(AVFilterContext *ctx, float *f)
 {
     DeflickerContext *s = ctx->priv;
     int y;
 
     *f = 0.0f;
 
     for (y = 0; y < s->size; y++) {
         *f += s->luminance[y] * s->luminance[y];
     }
 
     *f /= s->size;
     *f  = sqrtf(*f);
     *f /= s->luminance[0];
 }
 
 static void get_cm_factor(AVFilterContext *ctx, float *f)
 {
     DeflickerContext *s = ctx->priv;
     int y;
 
     *f = 0.0f;
 
     for (y = 0; y < s->size; y++) {
         *f += s->luminance[y] * s->luminance[y] * s->luminance[y];
     }
 
     *f /= s->size;
     *f  = cbrtf(*f);
     *f /= s->luminance[0];
 }
 
 static void get_pm_factor(AVFilterContext *ctx, float *f)
 {
     DeflickerContext *s = ctx->priv;
     int y;
 
     *f = 0.0f;
 
     for (y = 0; y < s->size; y++) {
         *f += powf(s->luminance[y], s->size);
     }
 
     *f /= s->size;
     *f  = powf(*f, 1.0f / s->size);
     *f /= s->luminance[0];
 }
 
 static int comparef(const void *a, const void *b)
 {
     const float *aa = a, *bb = b;
     return round(aa - bb);
 }
 
 static void get_median_factor(AVFilterContext *ctx, float *f)
 {
     DeflickerContext *s = ctx->priv;
 
     memcpy(s->sorted, s->luminance, sizeof(s->sorted));
     AV_QSORT(s->sorted, s->size, float, comparef);
 
     *f = s->sorted[s->size >> 1] / s->luminance[0];
 }
 
 static int config_input(AVFilterLink *inlink)
 {
     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
     AVFilterContext *ctx = inlink->dst;
     DeflickerContext *s = ctx->priv;
 
     s->nb_planes = desc->nb_components;
 
     s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
     s->planeheight[0] = s->planeheight[3] = inlink->h;
     s->planewidth[1]  = s->planewidth[2]  = AV_CEIL_RSHIFT(inlink->w, desc->log2_chroma_w);
     s->planewidth[0]  = s->planewidth[3]  = inlink->w;
 
     s->depth = desc->comp[0].depth;
     if (s->depth == 8) {
         s->deflicker = deflicker8;
         s->calc_avgy = calc_avgy8;
     } else {
         s->deflicker = deflicker16;
         s->calc_avgy = calc_avgy16;
     }
 
     s->histogram = av_calloc(1 << s->depth, sizeof(*s->histogram));
     if (!s->histogram)
         return AVERROR(ENOMEM);
 
     switch (s->mode) {
     case MEDIAN:          s->get_factor = get_median_factor; break;
     case ARITHMETIC_MEAN: s->get_factor = get_am_factor;     break;
     case GEOMETRIC_MEAN:  s->get_factor = get_gm_factor;     break;
     case HARMONIC_MEAN:   s->get_factor = get_hm_factor;     break;
     case QUADRATIC_MEAN:  s->get_factor = get_qm_factor;     break;
     case CUBIC_MEAN:      s->get_factor = get_cm_factor;     break;
     case POWER_MEAN:      s->get_factor = get_pm_factor;     break;
     }
 
     return 0;
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     DeflickerContext *s = ctx->priv;
     AVDictionary **metadata;
     AVFrame *out, *in;
     float f;
     int y;
 
     if (s->q.available < s->size && !s->eof) {
         s->luminance[s->available] = s->calc_avgy(ctx, buf);
         ff_bufqueue_add(ctx, &s->q, buf);
         s->available++;
         return 0;
     }
 
     in = ff_bufqueue_peek(&s->q, 0);
 
     out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
     if (!out) {
         av_frame_free(&buf);
         return AVERROR(ENOMEM);
     }
 
     s->get_factor(ctx, &f);

     if (!s->bypass)
         s->deflicker(ctx, in->data[0], in->linesize[0], out->data[0], out->linesize[0],
                      outlink->w, outlink->h, f);
     for (y = 1 - s->bypass; y < s->nb_planes; y++) {

         av_image_copy_plane(out->data[y], out->linesize[y],
                             in->data[y], in->linesize[y],
                             s->planewidth[y] * (1 + (s->depth > 8)), s->planeheight[y]);
     }
 
     av_frame_copy_props(out, in);

     metadata = &out->metadata;

     if (metadata) {
         uint8_t value[128];
 
         snprintf(value, sizeof(value), "%f", s->luminance[0]);
         av_dict_set(metadata, "lavfi.deflicker.luminance", value, 0);
 
         snprintf(value, sizeof(value), "%f", s->luminance[0] * f);
         av_dict_set(metadata, "lavfi.deflicker.new_luminance", value, 0);
 
         snprintf(value, sizeof(value), "%f", f - 1.0f);
         av_dict_set(metadata, "lavfi.deflicker.relative_change", value, 0);
     }
 
     in = ff_bufqueue_get(&s->q);
     av_frame_free(&in);
     memmove(&s->luminance[0], &s->luminance[1], sizeof(*s->luminance) * (s->size - 1));
     s->luminance[s->available - 1] = s->calc_avgy(ctx, buf);
     ff_bufqueue_add(ctx, &s->q, buf);
 
     return ff_filter_frame(outlink, out);
 }
 
 static int request_frame(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     DeflickerContext *s = ctx->priv;
     int ret;
 
     ret = ff_request_frame(ctx->inputs[0]);
     if (ret == AVERROR_EOF && s->available > 0) {
         AVFrame *buf = av_frame_clone(ff_bufqueue_peek(&s->q, s->size - 1));
         if (!buf)
             return AVERROR(ENOMEM);
 
         s->eof = 1;
         ret = filter_frame(ctx->inputs[0], buf);
         s->available--;
     }
 
     return ret;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     DeflickerContext *s = ctx->priv;
 
     ff_bufqueue_discard_all(&s->q);
     av_freep(&s->histogram);
 }
 
 static const AVFilterPad inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame,
         .config_props = config_input,
     },
     { NULL }
 };
 
 static const AVFilterPad outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .request_frame = request_frame,
     },
     { NULL }
 };
 
 AVFilter ff_vf_deflicker = {
     .name          = "deflicker",
     .description   = NULL_IF_CONFIG_SMALL("Remove temporal frame luminance variations."),
     .priv_size     = sizeof(DeflickerContext),
     .priv_class    = &deflicker_class,
     .uninit        = uninit,
     .query_formats = query_formats,
     .inputs        = inputs,
     .outputs       = outputs,
 };