/*
  * 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/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 "internal.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
 

 typedef struct {

     const AVClass *class;

     int factor, fade_per_frame;

     unsigned int frame_index, start_frame, stop_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;

 
     char *type;

 } FadeContext;
 

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

 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM

 
 static const AVOption fade_options[] = {

     { "type",        "set the fade direction",                     OFFSET(type),        AV_OPT_TYPE_STRING, {.str = "in" }, CHAR_MIN, CHAR_MAX, FLAGS },
     { "t",           "set the fade direction",                     OFFSET(type),        AV_OPT_TYPE_STRING, {.str = "in" }, CHAR_MIN, CHAR_MAX, FLAGS },

     { "start_frame", "set expression of frame to start fading",    OFFSET(start_frame), AV_OPT_TYPE_INT, {.i64 = 0    }, 0, INT_MAX, FLAGS },
     { "s",           "set expression of frame to start fading",    OFFSET(start_frame), AV_OPT_TYPE_INT, {.i64 = 0    }, 0, INT_MAX, FLAGS },
     { "nb_frames",   "set expression for fade duration in frames", OFFSET(nb_frames),   AV_OPT_TYPE_INT, {.i64 = 25   }, 0, INT_MAX, FLAGS },
     { "n",           "set expression for fade duration in frames", 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_INT, {.i64 = 0    }, 0,       1, FLAGS },

     {NULL},
 };
 

 AVFILTER_DEFINE_CLASS(fade);

 static av_cold int init(AVFilterContext *ctx, const char *args)

 {
     FadeContext *fade = ctx->priv;

     static const char *shorthand[] = { "type", "start_frame", "nb_frames", NULL };
     int ret;

     fade->class = &fade_class;
     av_opt_set_defaults(fade);
 

     if ((ret = av_opt_set_from_string(fade, args, shorthand, "=", ":")) < 0)
         return ret;

     fade->fade_per_frame = (1 << 16) / fade->nb_frames;
     if (!strcmp(fade->type, "in"))

         fade->factor = 0;

     else if (!strcmp(fade->type, "out")) {

         fade->fade_per_frame = -fade->fade_per_frame;
         fade->factor = (1 << 16);
     } else {
         av_log(ctx, AV_LOG_ERROR,

                "Type argument must be 'in' or 'out' but '%s' was specified\n", fade->type);

         return AVERROR(EINVAL);

     }

     fade->stop_frame = fade->start_frame + fade->nb_frames;

     av_log(ctx, AV_LOG_VERBOSE,

            "type:%s start_frame:%d nb_frames:%d alpha:%d\n",
            fade->type, fade->start_frame, fade->nb_frames, fade->alpha);

     return 0;

 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     FadeContext *fade = ctx->priv;
 

     av_opt_free(fade);

 }
 
 static int query_formats(AVFilterContext *ctx)
 {

     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

     };
 

     ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));

     return 0;
 }
 

 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 *fade = inlink->dst->priv;

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

 
     fade->hsub = pixdesc->log2_chroma_w;
     fade->vsub = pixdesc->log2_chroma_h;
 
     fade->bpp = av_get_bits_per_pixel(pixdesc) >> 3;

     fade->alpha &= pixdesc->flags & PIX_FMT_ALPHA;

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

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

     fade->black_level =

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

     /* 32768 = 1 << 15, it is an integer representation
      * of 0.5 and is for rounding. */
     fade->black_level_scaled = (fade->black_level << 16) + 32768;

     return 0;
 }
 

 static void fade_plane(int y, int h, int w,
                        int fade_factor, int black_level, int black_level_scaled,
                        uint8_t offset, uint8_t step, int bytes_per_plane,
                        uint8_t *data, int line_size)
 {
     uint8_t *p;
     int i, j;
 
     /* luma, alpha or rgb plane */
     for (i = 0; i < h; i++) {
         p = data + offset + (y+i) * line_size;
         for (j = 0; j < w * bytes_per_plane; j++) {
             /* fade->factor is using 16 lower-order bits for decimal places. */
             *p = ((*p - black_level) * fade_factor + black_level_scaled) >> 16;
             p+=step;
         }
     }
 }
 

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

 {
     FadeContext *fade = inlink->dst->priv;
     uint8_t *p;
     int i, j, plane;
 

     if (fade->factor < UINT16_MAX) {

         if (fade->alpha) {
             // alpha only
             plane = fade->is_packed_rgb ? 0 : A; // alpha is on plane 0 for packed formats
                                                  // or plane 3 for planar formats

             fade_plane(0, frame->video->h, inlink->w,

                        fade->factor, fade->black_level, fade->black_level_scaled,
                        fade->is_packed_rgb ? fade->rgba_map[A] : 0, // alpha offset for packed formats
                        fade->is_packed_rgb ? 4 : 1,                 // pixstep for 8 bit packed formats

                        1, frame->data[plane], frame->linesize[plane]);

         } else {

             /* luma or rgb plane */

             fade_plane(0, frame->video->h, inlink->w,

                        fade->factor, fade->black_level, fade->black_level_scaled,
                        0, 1, // offset & pixstep for Y plane or RGB packed format

                        fade->bpp, frame->data[0], frame->linesize[0]);
             if (frame->data[1] && frame->data[2]) {

                 /* chroma planes */
                 for (plane = 1; plane < 3; plane++) {

                     for (i = 0; i < frame->video->h; i++) {
                         p = frame->data[plane] + (i >> fade->vsub) * frame->linesize[plane];

                         for (j = 0; j < inlink->w >> fade->hsub; j++) {
                             /* 8421367 = ((128 << 1) + 1) << 15. It is an integer
                              * representation of 128.5. The .5 is for rounding
                              * purposes. */
                             *p = ((*p - 128) * fade->factor + 8421367) >> 16;
                             p++;
                         }

                     }
                 }
             }
         }
     }
 
     if (fade->frame_index >= fade->start_frame &&
         fade->frame_index <= fade->stop_frame)
         fade->factor += fade->fade_per_frame;
     fade->factor = av_clip_uint16(fade->factor);
     fade->frame_index++;

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

 }
 

 static const AVFilterPad avfilter_vf_fade_inputs[] = {
     {
         .name             = "default",
         .type             = AVMEDIA_TYPE_VIDEO,
         .config_props     = config_props,
         .get_video_buffer = ff_null_get_video_buffer,

         .filter_frame     = filter_frame,

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

 AVFilter avfilter_vf_fade = {
     .name          = "fade",

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

     .init          = init,

     .uninit        = uninit,

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

     .inputs    = avfilter_vf_fade_inputs,
     .outputs   = avfilter_vf_fade_outputs,

     .priv_class = &fade_class,

 };