/*
  * Copyright (C) 2012 Mark Himsley
  *
  * get_scene_score() Copyright (c) 2011 Stefano Sabatini
  * taken from libavfilter/vf_select.c
  *
  * 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
  * filter for upsampling or downsampling a progressive source
  */
 
 #define DEBUG
 
 #include "libavutil/avassert.h"
 #include "libavutil/imgutils.h"
 #include "libavutil/internal.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 #include "libavutil/pixelutils.h"
 
 #include "avfilter.h"
 #include "internal.h"
 #include "video.h"
 
 #define N_SRCE 3
 
 typedef struct FrameRateContext {
     const AVClass *class;
     // parameters
     AVRational dest_frame_rate;         ///< output frames per second
     int flags;                          ///< flags affecting frame rate conversion algorithm
     double scene_score;                 ///< score that denotes a scene change has happened
     int interp_start;                   ///< start of range to apply linear interpolation
     int interp_end;                     ///< end of range to apply linear interpolation
 
     int line_size[4];                   ///< bytes of pixel data per line for each plane
     int vsub;
 
     int frst, next, prev, crnt, last;
     int pending_srce_frames;            ///< how many input frames are still waiting to be processed
     int flush;                          ///< are we flushing final frames
     int pending_end_frame;              ///< flag indicating we are waiting to call filter_frame()
 
     AVRational srce_time_base;          ///< timebase of source
 
     AVRational dest_time_base;          ///< timebase of destination
     int32_t dest_frame_num;
     int64_t last_dest_frame_pts;        ///< pts of the last frame output
     int64_t average_srce_pts_dest_delta;///< average input pts delta converted from input rate to output rate
     int64_t average_dest_pts_delta;     ///< calculated average output pts delta
 
     av_pixelutils_sad_fn sad;           ///< Sum of the absolute difference function (scene detect only)
     double prev_mafd;                   ///< previous MAFD                           (scene detect only)
 
     AVFrame *srce[N_SRCE];              ///< buffered source frames
     int64_t srce_pts_dest[N_SRCE];      ///< pts for source frames scaled to output timebase
     int64_t pts;                        ///< pts of frame we are working on

 
     int (*blend_frames)(AVFilterContext *ctx, float interpolate,
                         AVFrame *copy_src1, AVFrame *copy_src2);
     int max;
     int bitdepth;
     AVFrame *work;

 } FrameRateContext;
 
 #define OFFSET(x) offsetof(FrameRateContext, x)
 #define V AV_OPT_FLAG_VIDEO_PARAM
 #define F AV_OPT_FLAG_FILTERING_PARAM
 #define FRAMERATE_FLAG_SCD 01
 
 static const AVOption framerate_options[] = {
     {"fps",                 "required output frames per second rate", OFFSET(dest_frame_rate), AV_OPT_TYPE_VIDEO_RATE, {.str="50"},             0,       INT_MAX, V|F },
 
     {"interp_start",        "point to start linear interpolation",    OFFSET(interp_start),    AV_OPT_TYPE_INT,      {.i64=15},                 0,       255,     V|F },
     {"interp_end",          "point to end linear interpolation",      OFFSET(interp_end),      AV_OPT_TYPE_INT,      {.i64=240},                0,       255,     V|F },
     {"scene",               "scene change level",                     OFFSET(scene_score),     AV_OPT_TYPE_DOUBLE,   {.dbl=7.0},                0,       INT_MAX, V|F },
 
     {"flags",               "set flags",                              OFFSET(flags),           AV_OPT_TYPE_FLAGS,    {.i64=1},                  0,       INT_MAX, V|F, "flags" },
     {"scene_change_detect", "enable scene change detection",          0,                       AV_OPT_TYPE_CONST,    {.i64=FRAMERATE_FLAG_SCD}, INT_MIN, INT_MAX, V|F, "flags" },
     {"scd",                 "enable scene change detection",          0,                       AV_OPT_TYPE_CONST,    {.i64=FRAMERATE_FLAG_SCD}, INT_MIN, INT_MAX, V|F, "flags" },
 
     {NULL}
 };
 
 AVFILTER_DEFINE_CLASS(framerate);
 
 static void next_source(AVFilterContext *ctx)
 {
     FrameRateContext *s = ctx->priv;
     int i;
 
     ff_dlog(ctx,  "next_source()\n");
 
     if (s->srce[s->last] && s->srce[s->last] != s->srce[s->last-1]) {
         ff_dlog(ctx, "next_source() unlink %d\n", s->last);
         av_frame_free(&s->srce[s->last]);
     }
     for (i = s->last; i > s->frst; i--) {
         ff_dlog(ctx, "next_source() copy %d to %d\n", i - 1, i);
         s->srce[i] = s->srce[i - 1];
     }
     ff_dlog(ctx, "next_source() make %d null\n", s->frst);
     s->srce[s->frst] = NULL;
 }
 

 static av_always_inline int64_t sad_8x8_16(const uint16_t *src1, ptrdiff_t stride1,
                                            const uint16_t *src2, ptrdiff_t stride2)
 {
     int sum = 0;
     int x, y;
 
     for (y = 0; y < 8; y++) {
         for (x = 0; x < 8; x++)
             sum += FFABS(src1[x] - src2[x]);
         src1 += stride1;
         src2 += stride2;
     }
     return sum;
 }
 
 static double get_scene_score16(AVFilterContext *ctx, AVFrame *crnt, AVFrame *next)
 {
     FrameRateContext *s = ctx->priv;
     double ret = 0;
 
     ff_dlog(ctx, "get_scene_score16()\n");
 
     if (crnt &&
         crnt->height == next->height &&
         crnt->width  == next->width) {
         int x, y;
         int64_t sad;
         double mafd, diff;
         const uint16_t *p1 = (const uint16_t *)crnt->data[0];
         const uint16_t *p2 = (const uint16_t *)next->data[0];
         const int p1_linesize = crnt->linesize[0] / 2;
         const int p2_linesize = next->linesize[0] / 2;
 
         ff_dlog(ctx, "get_scene_score16() process\n");
 
         for (sad = y = 0; y < crnt->height; y += 8) {
             for (x = 0; x < p1_linesize; x += 8) {
                 sad += sad_8x8_16(p1 + y * p1_linesize + x,
                                   p1_linesize,
                                   p2 + y * p2_linesize + x,
                                   p2_linesize);
             }
         }
         mafd = sad / (crnt->height * crnt->width * 3);
         diff = fabs(mafd - s->prev_mafd);
         ret  = av_clipf(FFMIN(mafd, diff), 0, 100.0);
         s->prev_mafd = mafd;
     }
     ff_dlog(ctx, "get_scene_score16() result is:%f\n", ret);
     return ret;
 }
 

 static double get_scene_score(AVFilterContext *ctx, AVFrame *crnt, AVFrame *next)
 {
     FrameRateContext *s = ctx->priv;
     double ret = 0;
 
     ff_dlog(ctx, "get_scene_score()\n");
 
     if (crnt &&
         crnt->height == next->height &&
         crnt->width  == next->width) {
         int x, y;
         int64_t sad;
         double mafd, diff;
         uint8_t *p1 = crnt->data[0];
         uint8_t *p2 = next->data[0];
         const int p1_linesize = crnt->linesize[0];
         const int p2_linesize = next->linesize[0];
 
         ff_dlog(ctx, "get_scene_score() process\n");
 
         for (sad = y = 0; y < crnt->height; y += 8) {
             for (x = 0; x < p1_linesize; x += 8) {
                 sad += s->sad(p1 + y * p1_linesize + x,
                               p1_linesize,
                               p2 + y * p2_linesize + x,
                               p2_linesize);
             }
         }
         emms_c();
         mafd = sad / (crnt->height * crnt->width * 3);
         diff = fabs(mafd - s->prev_mafd);
         ret  = av_clipf(FFMIN(mafd, diff), 0, 100.0);
         s->prev_mafd = mafd;
     }
         ff_dlog(ctx, "get_scene_score() result is:%f\n", ret);
     return ret;
 }
 

 static int blend_frames16(AVFilterContext *ctx, float interpolate,
                           AVFrame *copy_src1, AVFrame *copy_src2)
 {
     FrameRateContext *s = ctx->priv;
     AVFilterLink *outlink = ctx->outputs[0];
     double interpolate_scene_score = 0;
 
     if ((s->flags & FRAMERATE_FLAG_SCD) && copy_src2) {
         interpolate_scene_score = get_scene_score16(ctx, copy_src1, copy_src2);
         ff_dlog(ctx, "blend_frames16() interpolate scene score:%f\n", interpolate_scene_score);
     }
     // decide if the shot-change detection allows us to blend two frames
     if (interpolate_scene_score < s->scene_score && copy_src2) {

         uint16_t src2_factor = fabsf(interpolate) * (1 << (s->bitdepth - 8));

         uint16_t src1_factor = s->max - src2_factor;
         const int half = s->max / 2;
         const int uv = (s->max + 1) * half;
         const int shift = s->bitdepth;
         int plane, line, pixel;
 
         // get work-space for output frame
         s->work = ff_get_video_buffer(outlink, outlink->w, outlink->h);
         if (!s->work)
             return AVERROR(ENOMEM);
 
         av_frame_copy_props(s->work, s->srce[s->crnt]);
 
         ff_dlog(ctx, "blend_frames16() INTERPOLATE to create work frame\n");
         for (plane = 0; plane < 4 && copy_src1->data[plane] && copy_src2->data[plane]; plane++) {
             int cpy_line_width = s->line_size[plane];
             const uint16_t *cpy_src1_data = (const uint16_t *)copy_src1->data[plane];
             int cpy_src1_line_size = copy_src1->linesize[plane] / 2;
             const uint16_t *cpy_src2_data = (const uint16_t *)copy_src2->data[plane];
             int cpy_src2_line_size = copy_src2->linesize[plane] / 2;
             int cpy_src_h = (plane > 0 && plane < 3) ? (copy_src1->height >> s->vsub) : (copy_src1->height);
             uint16_t *cpy_dst_data = (uint16_t *)s->work->data[plane];
             int cpy_dst_line_size = s->work->linesize[plane] / 2;
 
             if (plane <1 || plane >2) {
                 // luma or alpha
                 for (line = 0; line < cpy_src_h; line++) {
                     for (pixel = 0; pixel < cpy_line_width; pixel++)
                         cpy_dst_data[pixel] = ((cpy_src1_data[pixel] * src1_factor) + (cpy_src2_data[pixel] * src2_factor) + half) >> shift;
                     cpy_src1_data += cpy_src1_line_size;
                     cpy_src2_data += cpy_src2_line_size;
                     cpy_dst_data += cpy_dst_line_size;
                 }
             } else {
                 // chroma
                 for (line = 0; line < cpy_src_h; line++) {
                     for (pixel = 0; pixel < cpy_line_width; pixel++) {
                         cpy_dst_data[pixel] = (((cpy_src1_data[pixel] - half) * src1_factor) + ((cpy_src2_data[pixel] - half) * src2_factor) + uv) >> shift;
                     }
                     cpy_src1_data += cpy_src1_line_size;
                     cpy_src2_data += cpy_src2_line_size;
                     cpy_dst_data += cpy_dst_line_size;
                 }
             }
         }
         return 1;
     }
     return 0;
 }
 
 static int blend_frames8(AVFilterContext *ctx, float interpolate,
                          AVFrame *copy_src1, AVFrame *copy_src2)

 {
     FrameRateContext *s = ctx->priv;
     AVFilterLink *outlink = ctx->outputs[0];

     double interpolate_scene_score = 0;
 
     if ((s->flags & FRAMERATE_FLAG_SCD) && copy_src2) {
         interpolate_scene_score = get_scene_score(ctx, copy_src1, copy_src2);
         ff_dlog(ctx, "blend_frames8() interpolate scene score:%f\n", interpolate_scene_score);
     }
     // decide if the shot-change detection allows us to blend two frames
     if (interpolate_scene_score < s->scene_score && copy_src2) {

         uint16_t src2_factor = fabsf(interpolate);

         uint16_t src1_factor = 256 - src2_factor;
         int plane, line, pixel;
 
         // get work-space for output frame
         s->work = ff_get_video_buffer(outlink, outlink->w, outlink->h);
         if (!s->work)
             return AVERROR(ENOMEM);
 
         av_frame_copy_props(s->work, s->srce[s->crnt]);
 
         ff_dlog(ctx, "blend_frames8() INTERPOLATE to create work frame\n");
         for (plane = 0; plane < 4 && copy_src1->data[plane] && copy_src2->data[plane]; plane++) {
             int cpy_line_width = s->line_size[plane];
             uint8_t *cpy_src1_data = copy_src1->data[plane];
             int cpy_src1_line_size = copy_src1->linesize[plane];
             uint8_t *cpy_src2_data = copy_src2->data[plane];
             int cpy_src2_line_size = copy_src2->linesize[plane];
             int cpy_src_h = (plane > 0 && plane < 3) ? (copy_src1->height >> s->vsub) : (copy_src1->height);
             uint8_t *cpy_dst_data = s->work->data[plane];
             int cpy_dst_line_size = s->work->linesize[plane];
             if (plane <1 || plane >2) {
                 // luma or alpha
                 for (line = 0; line < cpy_src_h; line++) {
                     for (pixel = 0; pixel < cpy_line_width; pixel++) {
                         // integer version of (src1 * src1_factor) + (src2 + src2_factor) + 0.5
                         // 0.5 is for rounding
                         // 128 is the integer representation of 0.5 << 8
                         cpy_dst_data[pixel] = ((cpy_src1_data[pixel] * src1_factor) + (cpy_src2_data[pixel] * src2_factor) + 128) >> 8;
                     }
                     cpy_src1_data += cpy_src1_line_size;
                     cpy_src2_data += cpy_src2_line_size;
                     cpy_dst_data += cpy_dst_line_size;
                 }
             } else {
                 // chroma
                 for (line = 0; line < cpy_src_h; line++) {
                     for (pixel = 0; pixel < cpy_line_width; pixel++) {
                         // as above
                         // because U and V are based around 128 we have to subtract 128 from the components.
                         // 32896 is the integer representation of 128.5 << 8
                         cpy_dst_data[pixel] = (((cpy_src1_data[pixel] - 128) * src1_factor) + ((cpy_src2_data[pixel] - 128) * src2_factor) + 32896) >> 8;
                     }
                     cpy_src1_data += cpy_src1_line_size;
                     cpy_src2_data += cpy_src2_line_size;
                     cpy_dst_data += cpy_dst_line_size;
                 }
             }
         }
         return 1;
     }
     return 0;
 }
 
 static int process_work_frame(AVFilterContext *ctx, int stop)
 {
     FrameRateContext *s = ctx->priv;

     int64_t work_next_pts;

     AVFrame *copy_src1;
     float interpolate;

 
     ff_dlog(ctx, "process_work_frame()\n");
 
     ff_dlog(ctx, "process_work_frame() pending_input_frames %d\n", s->pending_srce_frames);
 
     if (s->srce[s->prev]) ff_dlog(ctx, "process_work_frame() srce prev pts:%"PRId64"\n", s->srce[s->prev]->pts);
     if (s->srce[s->crnt]) ff_dlog(ctx, "process_work_frame() srce crnt pts:%"PRId64"\n", s->srce[s->crnt]->pts);
     if (s->srce[s->next]) ff_dlog(ctx, "process_work_frame() srce next pts:%"PRId64"\n", s->srce[s->next]->pts);
 
     if (!s->srce[s->crnt]) {
         // the filter cannot do anything
         ff_dlog(ctx, "process_work_frame() no current frame cached: move on to next frame, do not output a frame\n");
         next_source(ctx);
         return 0;
     }
 
     work_next_pts = s->pts + s->average_dest_pts_delta;
 
     ff_dlog(ctx, "process_work_frame() work crnt pts:%"PRId64"\n", s->pts);
     ff_dlog(ctx, "process_work_frame() work next pts:%"PRId64"\n", work_next_pts);
     if (s->srce[s->prev])
         ff_dlog(ctx, "process_work_frame() srce prev pts:%"PRId64" at dest time base:%u/%u\n",
             s->srce_pts_dest[s->prev], s->dest_time_base.num, s->dest_time_base.den);
     if (s->srce[s->crnt])
         ff_dlog(ctx, "process_work_frame() srce crnt pts:%"PRId64" at dest time base:%u/%u\n",
             s->srce_pts_dest[s->crnt], s->dest_time_base.num, s->dest_time_base.den);
     if (s->srce[s->next])
         ff_dlog(ctx, "process_work_frame() srce next pts:%"PRId64" at dest time base:%u/%u\n",
             s->srce_pts_dest[s->next], s->dest_time_base.num, s->dest_time_base.den);
 
     av_assert0(s->srce[s->next]);
 
     // should filter be skipping input frame (output frame rate is lower than input frame rate)
     if (!s->flush && s->pts >= s->srce_pts_dest[s->next]) {
         ff_dlog(ctx, "process_work_frame() work crnt pts >= srce next pts: SKIP FRAME, move on to next frame, do not output a frame\n");
         next_source(ctx);
         s->pending_srce_frames--;
         return 0;
     }
 
     // calculate interpolation

     interpolate = ((s->pts - s->srce_pts_dest[s->crnt]) * 256.0 / s->average_srce_pts_dest_delta);
     ff_dlog(ctx, "process_work_frame() interpolate:%f/256\n", interpolate);

     copy_src1 = s->srce[s->crnt];
     if (interpolate > s->interp_end) {
         ff_dlog(ctx, "process_work_frame() source is:NEXT\n");
         copy_src1 = s->srce[s->next];
     }
     if (s->srce[s->prev] && interpolate < -s->interp_end) {
         ff_dlog(ctx, "process_work_frame() source is:PREV\n");
         copy_src1 = s->srce[s->prev];
     }
 
     // decide whether to blend two frames
     if ((interpolate >= s->interp_start && interpolate <= s->interp_end) || (interpolate <= -s->interp_start && interpolate >= -s->interp_end)) {

         AVFrame *copy_src2;

 
         if (interpolate > 0) {
             ff_dlog(ctx, "process_work_frame() interpolate source is:NEXT\n");
             copy_src2 = s->srce[s->next];
         } else {
             ff_dlog(ctx, "process_work_frame() interpolate source is:PREV\n");
             copy_src2 = s->srce[s->prev];
         }

         if (s->blend_frames(ctx, interpolate, copy_src1, copy_src2))

             goto copy_done;

         else

             ff_dlog(ctx, "process_work_frame() CUT - DON'T INTERPOLATE\n");
     }
 
     ff_dlog(ctx, "process_work_frame() COPY to the work frame\n");
     // copy the frame we decided is our base source

     s->work = av_frame_clone(copy_src1);
     if (!s->work)

         return AVERROR(ENOMEM);
 
 copy_done:

     s->work->pts = s->pts;

 
     // should filter be re-using input frame (output frame rate is higher than input frame rate)
     if (!s->flush && (work_next_pts + s->average_dest_pts_delta) < (s->srce_pts_dest[s->crnt] + s->average_srce_pts_dest_delta)) {
         ff_dlog(ctx, "process_work_frame() REPEAT FRAME\n");
     } else {
         ff_dlog(ctx, "process_work_frame() CONSUME FRAME, move to next frame\n");
         s->pending_srce_frames--;
         next_source(ctx);
     }
     ff_dlog(ctx, "process_work_frame() output a frame\n");
     s->dest_frame_num++;
     if (stop)
         s->pending_end_frame = 0;

     s->last_dest_frame_pts = s->work->pts;

     return 1;

 }
 
 static void set_srce_frame_dest_pts(AVFilterContext *ctx)
 {
     FrameRateContext *s = ctx->priv;
 
     ff_dlog(ctx, "set_srce_frame_output_pts()\n");
 
     // scale the input pts from the timebase difference between input and output
     if (s->srce[s->prev])
         s->srce_pts_dest[s->prev] = av_rescale_q(s->srce[s->prev]->pts, s->srce_time_base, s->dest_time_base);
     if (s->srce[s->crnt])
         s->srce_pts_dest[s->crnt] = av_rescale_q(s->srce[s->crnt]->pts, s->srce_time_base, s->dest_time_base);
     if (s->srce[s->next])
         s->srce_pts_dest[s->next] = av_rescale_q(s->srce[s->next]->pts, s->srce_time_base, s->dest_time_base);
 }
 
 static void set_work_frame_pts(AVFilterContext *ctx)
 {
     FrameRateContext *s = ctx->priv;
     int64_t pts, average_srce_pts_delta = 0;
 
     ff_dlog(ctx, "set_work_frame_pts()\n");
 
     av_assert0(s->srce[s->next]);
     av_assert0(s->srce[s->crnt]);
 
     ff_dlog(ctx, "set_work_frame_pts() srce crnt pts:%"PRId64"\n", s->srce[s->crnt]->pts);
     ff_dlog(ctx, "set_work_frame_pts() srce next pts:%"PRId64"\n", s->srce[s->next]->pts);
     if (s->srce[s->prev])
         ff_dlog(ctx, "set_work_frame_pts() srce prev pts:%"PRId64"\n", s->srce[s->prev]->pts);
 
     average_srce_pts_delta = s->average_srce_pts_dest_delta;
     ff_dlog(ctx, "set_work_frame_pts() initial average srce pts:%"PRId64"\n", average_srce_pts_delta);
 

     set_srce_frame_dest_pts(ctx);
 

     // calculate the PTS delta

     if ((pts = (s->srce_pts_dest[s->next] - s->srce_pts_dest[s->crnt]))) {

         average_srce_pts_delta = average_srce_pts_delta?((average_srce_pts_delta+pts)>>1):pts;

     } else if (s->srce[s->prev] && (pts = (s->srce_pts_dest[s->crnt] - s->srce_pts_dest[s->prev]))) {

         average_srce_pts_delta = average_srce_pts_delta?((average_srce_pts_delta+pts)>>1):pts;
     }
 

     s->average_srce_pts_dest_delta = average_srce_pts_delta;

     ff_dlog(ctx, "set_work_frame_pts() average srce pts:%"PRId64"\n", average_srce_pts_delta);
     ff_dlog(ctx, "set_work_frame_pts() average srce pts:%"PRId64" at dest time base:%u/%u\n",
             s->average_srce_pts_dest_delta, s->dest_time_base.num, s->dest_time_base.den);
 
     if (ctx->inputs[0] && !s->average_dest_pts_delta) {

         int64_t d = av_q2d(av_inv_q(av_mul_q(s->dest_time_base, s->dest_frame_rate)));
         s->average_dest_pts_delta = d;

         ff_dlog(ctx, "set_work_frame_pts() average dest pts delta:%"PRId64"\n", s->average_dest_pts_delta);
     }
 
     if (!s->dest_frame_num) {
         s->pts = s->last_dest_frame_pts = s->srce_pts_dest[s->crnt];
     } else {
         s->pts = s->last_dest_frame_pts + s->average_dest_pts_delta;
     }
 
     ff_dlog(ctx, "set_work_frame_pts() calculated pts:%"PRId64" at dest time base:%u/%u\n",
             s->pts, s->dest_time_base.num, s->dest_time_base.den);
 }
 
 static av_cold int init(AVFilterContext *ctx)
 {
     FrameRateContext *s = ctx->priv;
 
     s->dest_frame_num = 0;
 
     s->crnt = (N_SRCE)>>1;
     s->last = N_SRCE - 1;
 
     s->next = s->crnt - 1;
     s->prev = s->crnt + 1;
 
     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     FrameRateContext *s = ctx->priv;
     int i;
 

     for (i = s->frst; i < s->last; i++) {

         if (s->srce[i] && (s->srce[i] != s->srce[i + 1]))
             av_frame_free(&s->srce[i]);
     }
     av_frame_free(&s->srce[s->last]);
 }
 
 static int query_formats(AVFilterContext *ctx)
 {
     static const enum AVPixelFormat pix_fmts[] = {
         AV_PIX_FMT_YUV410P,
         AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUVJ411P,
         AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUVJ420P,
         AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUVJ422P,
         AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUVJ440P,
         AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUVJ444P,

         AV_PIX_FMT_YUV420P9, AV_PIX_FMT_YUV420P10, AV_PIX_FMT_YUV420P12,
         AV_PIX_FMT_YUV422P9, AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV422P12,
         AV_PIX_FMT_YUV444P9, AV_PIX_FMT_YUV444P10, AV_PIX_FMT_YUV444P12,

         AV_PIX_FMT_NONE
     };
 
     AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
     if (!fmts_list)
         return AVERROR(ENOMEM);
     return ff_set_common_formats(ctx, fmts_list);
 }
 
 static int config_input(AVFilterLink *inlink)
 {
     AVFilterContext *ctx = inlink->dst;
     FrameRateContext *s = ctx->priv;
     const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(inlink->format);
     int plane;
 
     for (plane = 0; plane < 4; plane++) {
         s->line_size[plane] = av_image_get_linesize(inlink->format, inlink->w,
                                                     plane);
     }
 

     s->bitdepth = pix_desc->comp[0].depth;

     s->vsub = pix_desc->log2_chroma_h;
 
     s->sad = av_pixelutils_get_sad_fn(3, 3, 2, s); // 8x8 both sources aligned
     if (!s->sad)
         return AVERROR(EINVAL);
 
     s->srce_time_base = inlink->time_base;
 

     if (s->bitdepth == 8)
         s->blend_frames = blend_frames8;
     else
         s->blend_frames = blend_frames16;
     s->max = 1 << (s->bitdepth);
 

     return 0;
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *inpicref)
 {

     int ret;

     AVFilterContext *ctx = inlink->dst;
     FrameRateContext *s = ctx->priv;
 
     // we have one new frame
     s->pending_srce_frames++;
 
     if (inpicref->interlaced_frame)
         av_log(ctx, AV_LOG_WARNING, "Interlaced frame found - the output will not be correct.\n");
 
     // store the pointer to the new frame
     av_frame_free(&s->srce[s->frst]);
     s->srce[s->frst] = inpicref;
 
     if (!s->pending_end_frame && s->srce[s->crnt]) {
         set_work_frame_pts(ctx);
         s->pending_end_frame = 1;
     } else {
         set_srce_frame_dest_pts(ctx);
     }
 

     ret = process_work_frame(ctx, 1);
     if (ret < 0)
         return ret;
     return ret ? ff_filter_frame(ctx->outputs[0], s->work) : 0;

 }
 
 static int config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     FrameRateContext *s = ctx->priv;
     int exact;
 
     ff_dlog(ctx, "config_output()\n");
 
     ff_dlog(ctx,
            "config_output() input time base:%u/%u (%f)\n",
            ctx->inputs[0]->time_base.num,ctx->inputs[0]->time_base.den,
            av_q2d(ctx->inputs[0]->time_base));
 
     // make sure timebase is small enough to hold the framerate
 
     exact = av_reduce(&s->dest_time_base.num, &s->dest_time_base.den,
                       av_gcd((int64_t)s->srce_time_base.num * s->dest_frame_rate.num,
                              (int64_t)s->srce_time_base.den * s->dest_frame_rate.den ),
                       (int64_t)s->srce_time_base.den * s->dest_frame_rate.num, INT_MAX);
 
     av_log(ctx, AV_LOG_INFO,
            "time base:%u/%u -> %u/%u exact:%d\n",
            s->srce_time_base.num, s->srce_time_base.den,
            s->dest_time_base.num, s->dest_time_base.den, exact);
     if (!exact) {
         av_log(ctx, AV_LOG_WARNING, "Timebase conversion is not exact\n");
     }
 
     outlink->frame_rate = s->dest_frame_rate;
     outlink->time_base = s->dest_time_base;
 
     ff_dlog(ctx,
            "config_output() output time base:%u/%u (%f) w:%d h:%d\n",
            outlink->time_base.num, outlink->time_base.den,
            av_q2d(outlink->time_base),
            outlink->w, outlink->h);
 
 
     av_log(ctx, AV_LOG_INFO, "fps -> fps:%u/%u scene score:%f interpolate start:%d end:%d\n",
             s->dest_frame_rate.num, s->dest_frame_rate.den,
             s->scene_score, s->interp_start, s->interp_end);
 
     return 0;
 }
 
 static int request_frame(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     FrameRateContext *s = ctx->priv;

     int ret, i;

 
     ff_dlog(ctx, "request_frame()\n");
 
     // if there is no "next" frame AND we are not in flush then get one from our input filter

     if (!s->srce[s->frst] && !s->flush)
         goto request;

 
     ff_dlog(ctx, "request_frame() REPEAT or FLUSH\n");
 
     if (s->pending_srce_frames <= 0) {
         ff_dlog(ctx, "request_frame() nothing else to do, return:EOF\n");
         return AVERROR_EOF;
     }
 
     // otherwise, make brand-new frame and pass to our output filter
     ff_dlog(ctx, "request_frame() FLUSH\n");
 
     // back fill at end of file when source has no more frames
     for (i = s->last; i > s->frst; i--) {
         if (!s->srce[i - 1] && s->srce[i]) {
             ff_dlog(ctx, "request_frame() copy:%d to:%d\n", i, i - 1);
             s->srce[i - 1] = s->srce[i];
         }
     }
 
     set_work_frame_pts(ctx);

     ret = process_work_frame(ctx, 0);
     if (ret < 0)
         return ret;
     if (ret)
         return ff_filter_frame(ctx->outputs[0], s->work);
 
 request:
     ff_dlog(ctx, "request_frame() call source's request_frame()\n");
     ret = ff_request_frame(ctx->inputs[0]);
     if (ret < 0 && (ret != AVERROR_EOF)) {
         ff_dlog(ctx, "request_frame() source's request_frame() returned error:%d\n", ret);
         return ret;
     } else if (ret == AVERROR_EOF) {
         s->flush = 1;
     }
     ff_dlog(ctx, "request_frame() source's request_frame() returned:%d\n", ret);
     return 0;

 }
 
 static const AVFilterPad framerate_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .config_props = config_input,
         .filter_frame = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad framerate_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .request_frame = request_frame,
         .config_props  = config_output,
     },
     { NULL }
 };
 
 AVFilter ff_vf_framerate = {
     .name          = "framerate",
     .description   = NULL_IF_CONFIG_SMALL("Upsamples or downsamples progressive source between specified frame rates."),
     .priv_size     = sizeof(FrameRateContext),
     .priv_class    = &framerate_class,
     .init          = init,
     .uninit        = uninit,
     .query_formats = query_formats,
     .inputs        = framerate_inputs,
     .outputs       = framerate_outputs,
 };