/*
  * Copyright (c) 2010 Brandon Mintern
  * Copyright (c) 2007 Bobby Bingham
  *

  * 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
  * video fade filter
  * based heavily on vf_negate.c by Bobby Bingham
  */
 

 #include "libavutil/avassert.h"

 #include "libavutil/avstring.h"

 #include "libavutil/common.h"

 #include "libavutil/eval.h"
 #include "libavutil/opt.h"

 #include "libavutil/pixdesc.h"
 #include "avfilter.h"

 #include "drawutils.h"

 #include "formats.h"

 #include "internal.h"

 #include "video.h"

 #define R 0
 #define G 1
 #define B 2
 #define A 3
 
 #define Y 0
 #define U 1
 #define V 2
 

 #define FADE_IN  0
 #define FADE_OUT 1
 

 typedef struct FadeContext {

     const AVClass *class;

     int type;

     int factor, fade_per_frame;

     int start_frame, nb_frames;

     int hsub, vsub, bpp;

     unsigned int black_level, black_level_scaled;

     uint8_t is_packed_rgb;
     uint8_t rgba_map[4];
     int alpha;

     uint64_t start_time, duration;
     enum {VF_FADE_WAITING=0, VF_FADE_FADING, VF_FADE_DONE} fade_state;

     uint8_t color_rgba[4];  ///< fade color
     int black_fade;         ///< if color_rgba is black

 } FadeContext;
 

 static av_cold int init(AVFilterContext *ctx)

 {

     FadeContext *s = ctx->priv;

     s->fade_per_frame = (1 << 16) / s->nb_frames;

     s->fade_state = VF_FADE_WAITING;

     if (s->duration != 0) {

         // If duration (seconds) is non-zero, assume that we are not fading based on frames

         s->nb_frames = 0; // Mostly to clean up logging

     }
 
     // Choose what to log. If both time-based and frame-based options, both lines will be in the log

     if (s->start_frame || s->nb_frames) {

         av_log(ctx, AV_LOG_VERBOSE,
                "type:%s start_frame:%d nb_frames:%d alpha:%d\n",

                s->type == FADE_IN ? "in" : "out", s->start_frame,
                s->nb_frames,s->alpha);

     }

     if (s->start_time || s->duration) {

         av_log(ctx, AV_LOG_VERBOSE,
                "type:%s start_time:%f duration:%f alpha:%d\n",

                s->type == FADE_IN ? "in" : "out", (s->start_time / (double)AV_TIME_BASE),
                (s->duration / (double)AV_TIME_BASE),s->alpha);

     }
 

     s->black_fade = !memcmp(s->color_rgba, "\x00\x00\x00\xff", 4);

     return 0;

 }
 

 static int query_formats(AVFilterContext *ctx)
 {

     const FadeContext *s = ctx->priv;

     static const enum AVPixelFormat pix_fmts[] = {
         AV_PIX_FMT_YUV444P,  AV_PIX_FMT_YUV422P,  AV_PIX_FMT_YUV420P,
         AV_PIX_FMT_YUV411P,  AV_PIX_FMT_YUV410P,
         AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
         AV_PIX_FMT_YUV440P,  AV_PIX_FMT_YUVJ440P,

         AV_PIX_FMT_YUVA420P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA444P,

         AV_PIX_FMT_RGB24,    AV_PIX_FMT_BGR24,

         AV_PIX_FMT_ARGB,     AV_PIX_FMT_ABGR,
         AV_PIX_FMT_RGBA,     AV_PIX_FMT_BGRA,

         AV_PIX_FMT_NONE

     };

     static const enum AVPixelFormat pix_fmts_rgb[] = {
         AV_PIX_FMT_RGB24,    AV_PIX_FMT_BGR24,
         AV_PIX_FMT_ARGB,     AV_PIX_FMT_ABGR,
         AV_PIX_FMT_RGBA,     AV_PIX_FMT_BGRA,
         AV_PIX_FMT_NONE
     };

     static const enum AVPixelFormat pix_fmts_alpha[] = {
         AV_PIX_FMT_YUVA420P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA444P,
         AV_PIX_FMT_ARGB,     AV_PIX_FMT_ABGR,
         AV_PIX_FMT_RGBA,     AV_PIX_FMT_BGRA,
         AV_PIX_FMT_NONE
     };
     static const enum AVPixelFormat pix_fmts_rgba[] = {
         AV_PIX_FMT_ARGB,     AV_PIX_FMT_ABGR,
         AV_PIX_FMT_RGBA,     AV_PIX_FMT_BGRA,
         AV_PIX_FMT_NONE
     };

     AVFilterFormats *fmts_list;

     if (s->alpha) {
         if (s->black_fade)
             fmts_list = ff_make_format_list(pix_fmts_alpha);
         else
             fmts_list = ff_make_format_list(pix_fmts_rgba);
     } else {
         if (s->black_fade)
             fmts_list = ff_make_format_list(pix_fmts);
         else
             fmts_list = ff_make_format_list(pix_fmts_rgb);
     }

     if (!fmts_list)
         return AVERROR(ENOMEM);
     return ff_set_common_formats(ctx, fmts_list);

 }
 

 const static enum AVPixelFormat studio_level_pix_fmts[] = {
     AV_PIX_FMT_YUV444P,  AV_PIX_FMT_YUV422P,  AV_PIX_FMT_YUV420P,
     AV_PIX_FMT_YUV411P,  AV_PIX_FMT_YUV410P,
     AV_PIX_FMT_YUV440P,
     AV_PIX_FMT_NONE

 };
 

 static int config_props(AVFilterLink *inlink)
 {

     FadeContext *s = inlink->dst->priv;

     const AVPixFmtDescriptor *pixdesc = av_pix_fmt_desc_get(inlink->format);

     s->hsub = pixdesc->log2_chroma_w;
     s->vsub = pixdesc->log2_chroma_h;

     s->bpp = pixdesc->flags & AV_PIX_FMT_FLAG_PLANAR ?
              1 :
              av_get_bits_per_pixel(pixdesc) >> 3;

     s->alpha &= !!(pixdesc->flags & AV_PIX_FMT_FLAG_ALPHA);

     s->is_packed_rgb = ff_fill_rgba_map(s->rgba_map, inlink->format) >= 0;

     /* use CCIR601/709 black level for studio-level pixel non-alpha components */

     s->black_level =
             ff_fmt_is_in(inlink->format, studio_level_pix_fmts) && !s->alpha ? 16 : 0;

     /* 32768 = 1 << 15, it is an integer representation
      * of 0.5 and is for rounding. */

     s->black_level_scaled = (s->black_level << 16) + 32768;

     return 0;
 }
 

 static av_always_inline void filter_rgb(FadeContext *s, const AVFrame *frame,
                                         int slice_start, int slice_end,
                                         int do_alpha, int step)
 {
     int i, j;
     const uint8_t r_idx  = s->rgba_map[R];
     const uint8_t g_idx  = s->rgba_map[G];
     const uint8_t b_idx  = s->rgba_map[B];
     const uint8_t a_idx  = s->rgba_map[A];
     const uint8_t *c = s->color_rgba;
 
     for (i = slice_start; i < slice_end; i++) {
         uint8_t *p = frame->data[0] + i * frame->linesize[0];
         for (j = 0; j < frame->width; j++) {
 #define INTERP(c_name, c_idx) av_clip_uint8(((c[c_idx]<<16) + ((int)p[c_name] - (int)c[c_idx]) * s->factor + (1<<15)) >> 16)
             p[r_idx] = INTERP(r_idx, 0);
             p[g_idx] = INTERP(g_idx, 1);
             p[b_idx] = INTERP(b_idx, 2);
             if (do_alpha)
                 p[a_idx] = INTERP(a_idx, 3);
             p += step;
         }
     }
 }
 
 static int filter_slice_rgb(AVFilterContext *ctx, void *arg, int jobnr,
                             int nb_jobs)
 {
     FadeContext *s = ctx->priv;
     AVFrame *frame = arg;
     int slice_start = (frame->height *  jobnr   ) / nb_jobs;
     int slice_end   = (frame->height * (jobnr+1)) / nb_jobs;
 
     if      (s->alpha)    filter_rgb(s, frame, slice_start, slice_end, 1, 4);
     else if (s->bpp == 3) filter_rgb(s, frame, slice_start, slice_end, 0, 3);
     else if (s->bpp == 4) filter_rgb(s, frame, slice_start, slice_end, 0, 4);
     else                  av_assert0(0);
 
     return 0;
 }
 

 static int filter_slice_luma(AVFilterContext *ctx, void *arg, int jobnr,
                              int nb_jobs)

 {

     FadeContext *s = ctx->priv;
     AVFrame *frame = arg;

     int slice_start = (frame->height *  jobnr   ) / nb_jobs;
     int slice_end   = (frame->height * (jobnr+1)) / nb_jobs;

     int i, j;
 
     for (i = slice_start; i < slice_end; i++) {
         uint8_t *p = frame->data[0] + i * frame->linesize[0];
         for (j = 0; j < frame->width * s->bpp; j++) {
             /* s->factor is using 16 lower-order bits for decimal
              * places. 32768 = 1 << 15, it is an integer representation
              * of 0.5 and is for rounding. */

             *p = ((*p - s->black_level) * s->factor + s->black_level_scaled) >> 16;

             p++;
         }
     }
 
     return 0;
 }
 
 static int filter_slice_chroma(AVFilterContext *ctx, void *arg, int jobnr,
                                int nb_jobs)
 {
     FadeContext *s = ctx->priv;
     AVFrame *frame = arg;

     int i, j, plane;

     const int width = AV_CEIL_RSHIFT(frame->width, s->hsub);
     const int height= AV_CEIL_RSHIFT(frame->height, s->vsub);

     int slice_start = (height *  jobnr   ) / nb_jobs;

     int slice_end   = FFMIN(((height * (jobnr+1)) / nb_jobs), frame->height);

     for (plane = 1; plane < 3; plane++) {
         for (i = slice_start; i < slice_end; i++) {

             uint8_t *p = frame->data[plane] + i * frame->linesize[plane];

             for (j = 0; j < width; j++) {

                 /* 8421367 = ((128 << 1) + 1) << 15. It is an integer
                  * representation of 128.5. The .5 is for rounding
                  * purposes. */
                 *p = ((*p - 128) * s->factor + 8421367) >> 16;

                 p++;
             }
         }

     }
 
     return 0;
 }
 

 static int filter_slice_alpha(AVFilterContext *ctx, void *arg, int jobnr,
                               int nb_jobs)
 {
     FadeContext *s = ctx->priv;
     AVFrame *frame = arg;
     int plane = s->is_packed_rgb ? 0 : A;
     int slice_start = (frame->height *  jobnr   ) / nb_jobs;
     int slice_end   = (frame->height * (jobnr+1)) / nb_jobs;
     int i, j;
 
     for (i = slice_start; i < slice_end; i++) {
         uint8_t *p = frame->data[plane] + i * frame->linesize[plane] + s->is_packed_rgb*s->rgba_map[A];
         int step = s->is_packed_rgb ? 4 : 1;
         for (j = 0; j < frame->width; j++) {
             /* s->factor is using 16 lower-order bits for decimal
              * places. 32768 = 1 << 15, it is an integer representation
              * of 0.5 and is for rounding. */
             *p = ((*p - s->black_level) * s->factor + s->black_level_scaled) >> 16;
             p += step;
         }
     }
 
     return 0;
 }
 

 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
 {
     AVFilterContext *ctx = inlink->dst;
     FadeContext *s       = ctx->priv;

     double frame_timestamp = frame->pts == AV_NOPTS_VALUE ? -1 : frame->pts * av_q2d(inlink->time_base);
 
     // Calculate Fade assuming this is a Fade In

     if (s->fade_state == VF_FADE_WAITING) {
         s->factor=0;

         if (frame_timestamp >= s->start_time/(double)AV_TIME_BASE

             && inlink->frame_count_out >= s->start_frame) {

             // Time to start fading

             s->fade_state = VF_FADE_FADING;

 
             // Save start time in case we are starting based on frames and fading based on time

             if (s->start_time == 0 && s->start_frame != 0) {

                 s->start_time = frame_timestamp*(double)AV_TIME_BASE;

             }
 
             // Save start frame in case we are starting based on time and fading based on frames

             if (s->start_time != 0 && s->start_frame == 0) {

                 s->start_frame = inlink->frame_count_out;

             }
         }
     }

     if (s->fade_state == VF_FADE_FADING) {
         if (s->duration == 0) {

             // Fading based on frame count

             s->factor = (inlink->frame_count_out - s->start_frame) * s->fade_per_frame;
             if (inlink->frame_count_out > s->start_frame + s->nb_frames) {

                 s->fade_state = VF_FADE_DONE;

             }
 
         } else {
             // Fading based on duration

             s->factor = (frame_timestamp - s->start_time/(double)AV_TIME_BASE)

                             * (float) UINT16_MAX / (s->duration/(double)AV_TIME_BASE);

             if (frame_timestamp > s->start_time/(double)AV_TIME_BASE
                                   + s->duration/(double)AV_TIME_BASE) {

                 s->fade_state = VF_FADE_DONE;

             }
         }
     }

     if (s->fade_state == VF_FADE_DONE) {
         s->factor=UINT16_MAX;

     }
 

     s->factor = av_clip_uint16(s->factor);

 
     // Invert fade_factor if Fading Out

     if (s->type == FADE_OUT) {

         s->factor=UINT16_MAX-s->factor;

     }

     if (s->factor < UINT16_MAX) {
         if (s->alpha) {

             ctx->internal->execute(ctx, filter_slice_alpha, frame, NULL,

                                 FFMIN(frame->height, ff_filter_get_nb_threads(ctx)));

         } else if (s->is_packed_rgb && !s->black_fade) {
             ctx->internal->execute(ctx, filter_slice_rgb, frame, NULL,

                                    FFMIN(frame->height, ff_filter_get_nb_threads(ctx)));

         } else {

             /* luma, or rgb plane in case of black */

             ctx->internal->execute(ctx, filter_slice_luma, frame, NULL,

                                 FFMIN(frame->height, ff_filter_get_nb_threads(ctx)));

             if (frame->data[1] && frame->data[2]) {

                 /* chroma planes */

                 ctx->internal->execute(ctx, filter_slice_chroma, frame, NULL,

                                     FFMIN(frame->height, ff_filter_get_nb_threads(ctx)));

             }
         }
     }
 

     return ff_filter_frame(inlink->dst->outputs[0], frame);

 }
 

 #define OFFSET(x) offsetof(FadeContext, x)

 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 
 static const AVOption fade_options[] = {

     { "type", "'in' or 'out' for fade-in/fade-out", OFFSET(type), AV_OPT_TYPE_INT, { .i64 = FADE_IN }, FADE_IN, FADE_OUT, FLAGS, "type" },

     { "t",    "'in' or 'out' for fade-in/fade-out", OFFSET(type), AV_OPT_TYPE_INT, { .i64 = FADE_IN }, FADE_IN, FADE_OUT, FLAGS, "type" },

         { "in",  "fade-in",  0, AV_OPT_TYPE_CONST, { .i64 = FADE_IN },  .unit = "type" },
         { "out", "fade-out", 0, AV_OPT_TYPE_CONST, { .i64 = FADE_OUT }, .unit = "type" },
     { "start_frame", "Number of the first frame to which to apply the effect.",
                                                     OFFSET(start_frame), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, FLAGS },

     { "s",           "Number of the first frame to which to apply the effect.",
                                                     OFFSET(start_frame), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, FLAGS },

     { "nb_frames",   "Number of frames to which the effect should be applied.",

                                                     OFFSET(nb_frames),   AV_OPT_TYPE_INT, { .i64 = 25 }, 0, INT_MAX, FLAGS },
     { "n",           "Number of frames to which the effect should be applied.",
                                                     OFFSET(nb_frames),   AV_OPT_TYPE_INT, { .i64 = 25 }, 0, INT_MAX, FLAGS },

     { "alpha",       "fade alpha if it is available on the input", OFFSET(alpha),       AV_OPT_TYPE_BOOL, {.i64 = 0    }, 0,       1, FLAGS },

     { "start_time",  "Number of seconds of the beginning of the effect.",
                                                     OFFSET(start_time),  AV_OPT_TYPE_DURATION, {.i64 = 0. }, 0, INT32_MAX, FLAGS },
     { "st",          "Number of seconds of the beginning of the effect.",
                                                     OFFSET(start_time),  AV_OPT_TYPE_DURATION, {.i64 = 0. }, 0, INT32_MAX, FLAGS },
     { "duration",    "Duration of the effect in seconds.",
                                                     OFFSET(duration),    AV_OPT_TYPE_DURATION, {.i64 = 0. }, 0, INT32_MAX, FLAGS },
     { "d",           "Duration of the effect in seconds.",
                                                     OFFSET(duration),    AV_OPT_TYPE_DURATION, {.i64 = 0. }, 0, INT32_MAX, FLAGS },

     { "color",       "set color",                   OFFSET(color_rgba),  AV_OPT_TYPE_COLOR,    {.str = "black"}, CHAR_MIN, CHAR_MAX, FLAGS },
     { "c",           "set color",                   OFFSET(color_rgba),  AV_OPT_TYPE_COLOR,    {.str = "black"}, CHAR_MIN, CHAR_MAX, FLAGS },

     { NULL }

 };
 

 AVFILTER_DEFINE_CLASS(fade);

 static const AVFilterPad avfilter_vf_fade_inputs[] = {
     {

         .name           = "default",
         .type           = AVMEDIA_TYPE_VIDEO,
         .config_props   = config_props,
         .filter_frame   = filter_frame,
         .needs_writable = 1,

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

 AVFilter ff_vf_fade = {

     .name          = "fade",

     .description   = NULL_IF_CONFIG_SMALL("Fade in/out input video."),

     .init          = init,
     .priv_size     = sizeof(FadeContext),

     .priv_class    = &fade_class,

     .query_formats = query_formats,

     .inputs        = avfilter_vf_fade_inputs,
     .outputs       = avfilter_vf_fade_outputs,
     .flags         = AVFILTER_FLAG_SLICE_THREADS,

 };