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

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

 #include "drawutils.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)
 
 static const AVOption fade_options[] = {
     { "type",        "set the fade direction",                     OFFSET(type),        AV_OPT_TYPE_STRING, {.str = "in" }, CHAR_MIN, CHAR_MAX },
     { "t",           "set the fade direction",                     OFFSET(type),        AV_OPT_TYPE_STRING, {.str = "in" }, CHAR_MIN, CHAR_MAX },
     { "start_frame", "set expression of frame to start fading",    OFFSET(start_frame), AV_OPT_TYPE_INT, {.dbl = 0    }, 0, INT_MAX },
     { "s",           "set expression of frame to start fading",    OFFSET(start_frame), AV_OPT_TYPE_INT, {.dbl = 0    }, 0, INT_MAX },
     { "nb_frames",   "set expression for fade duration in frames", OFFSET(nb_frames),   AV_OPT_TYPE_INT, {.dbl = 25   }, 0, INT_MAX },
     { "n",           "set expression for fade duration in frames", OFFSET(nb_frames),   AV_OPT_TYPE_INT, {.dbl = 25   }, 0, INT_MAX },

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

     {NULL},
 };
 
 static const char *fade_get_name(void *ctx)
 {
     return "fade";
 }
 
 static const AVClass fade_class = {
     "FadeContext",
     fade_get_name,
     fade_options
 };
 

 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
 {
     FadeContext *fade = ctx->priv;

     int ret = 0;
     char *args1, *expr, *bufptr = NULL;

     fade->class = &fade_class;
     av_opt_set_defaults(fade);
 
     if (!(args1 = av_strdup(args))) {
         ret = AVERROR(ENOMEM);
         goto end;
     }
 
     if (expr = av_strtok(args1, ":", &bufptr)) {

         av_free(fade->type);

         if (!(fade->type = av_strdup(expr))) {
             ret = AVERROR(ENOMEM);
             goto end;
         }
     }
     if (expr = av_strtok(NULL, ":", &bufptr)) {
         if ((ret = av_opt_set(fade, "start_frame", expr, 0)) < 0) {
             av_log(ctx, AV_LOG_ERROR,
                    "Invalid value '%s' for start_frame option\n", expr);
             return ret;
         }

     }

     if (expr = av_strtok(NULL, ":", &bufptr)) {
         if ((ret = av_opt_set(fade, "nb_frames", expr, 0)) < 0) {
             av_log(ctx, AV_LOG_ERROR,
                    "Invalid value '%s' for nb_frames option\n", expr);
             return ret;
         }
     }
 
     if (bufptr && (ret = av_set_options_string(fade, bufptr, "=", ":")) < 0)
         goto end;

     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);
         ret = AVERROR(EINVAL);
         goto end;

     }

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

 
     av_log(ctx, AV_LOG_INFO,

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

 
 end:
     av_free(args1);
     return ret;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     FadeContext *fade = ctx->priv;
 
     av_freep(&fade->type);

 }
 
 static int query_formats(AVFilterContext *ctx)
 {

     static const enum PixelFormat pix_fmts[] = {

         PIX_FMT_YUV444P,  PIX_FMT_YUV422P,  PIX_FMT_YUV420P,
         PIX_FMT_YUV411P,  PIX_FMT_YUV410P,
         PIX_FMT_YUVJ444P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ420P,
         PIX_FMT_YUV440P,  PIX_FMT_YUVJ440P,

         PIX_FMT_YUVA420P,

         PIX_FMT_RGB24,    PIX_FMT_BGR24,

         PIX_FMT_ARGB,     PIX_FMT_ABGR,
         PIX_FMT_RGBA,     PIX_FMT_BGRA,

         PIX_FMT_NONE
     };
 

     avfilter_set_common_pixel_formats(ctx, avfilter_make_format_list(pix_fmts));

     return 0;
 }
 

 const static enum PixelFormat studio_level_pix_fmts[] = {
     PIX_FMT_YUV444P,  PIX_FMT_YUV422P,  PIX_FMT_YUV420P,
     PIX_FMT_YUV411P,  PIX_FMT_YUV410P,
     PIX_FMT_YUV440P,
     PIX_FMT_NONE
 };
 

 static enum PixelFormat alpha_pix_fmts[] = {
     PIX_FMT_YUVA420P,
     PIX_FMT_ARGB, PIX_FMT_ABGR,
     PIX_FMT_RGBA, PIX_FMT_BGRA,
     PIX_FMT_NONE
 };
 

 static int config_props(AVFilterLink *inlink)
 {
     FadeContext *fade = inlink->dst->priv;
     const AVPixFmtDescriptor *pixdesc = &av_pix_fmt_descriptors[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 = fade->alpha ? ff_fmt_is_in(inlink->format, alpha_pix_fmts) : 0;
     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 void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
 {
     FadeContext *fade = inlink->dst->priv;
     AVFilterBufferRef *outpic = inlink->cur_buf;
     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(y, 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, outpic->data[plane], outpic->linesize[plane]);
         } else {

             /* luma or rgb plane */
             fade_plane(y, 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, outpic->data[0], outpic->linesize[0]);
             if (outpic->data[1] && outpic->data[2]) {
                 /* chroma planes */
                 for (plane = 1; plane < 3; plane++) {
                     for (i = 0; i < h; i++) {
                         p = outpic->data[plane] + ((y+i) >> fade->vsub) * outpic->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++;
                         }

                     }
                 }
             }
         }
     }
 
     avfilter_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
 }
 
 static void end_frame(AVFilterLink *inlink)
 {
     FadeContext *fade = inlink->dst->priv;
 
     avfilter_end_frame(inlink->dst->outputs[0]);
 
     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++;
 }
 
 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    = (const AVFilterPad[]) {{ .name      = "default",

                                     .type            = AVMEDIA_TYPE_VIDEO,
                                     .config_props    = config_props,

                                     .get_video_buffer = ff_null_get_video_buffer,
                                     .start_frame      = ff_null_start_frame,

                                     .draw_slice      = draw_slice,
                                     .end_frame       = end_frame,
                                     .min_perms       = AV_PERM_READ | AV_PERM_WRITE,
                                     .rej_perms       = AV_PERM_PRESERVE, },
                                   { .name = NULL}},

     .outputs   = (const AVFilterPad[]) {{ .name      = "default",

                                     .type            = AVMEDIA_TYPE_VIDEO, },
                                   { .name = NULL}},
 };