/*
  * Copyright (c) 2011 Stefano Sabatini
  * Copyright (c) 2010 Baptiste Coudurier
  * Copyright (c) 2003 Michael Zucchi <notzed@ximian.com>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 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 General Public License for more details.
  *
  * You should have received a copy of the GNU 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
  * temporal field interlace filter, ported from MPlayer/libmpcodecs
  */
 

 #include "libavutil/opt.h"

 #include "libavutil/imgutils.h"

 #include "libavutil/avassert.h"

 #include "avfilter.h"
 #include "internal.h"

 #include "tinterlace.h"

 #define OFFSET(x) offsetof(TInterlaceContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

 #define TINTERLACE_FLAG_VLPF 01

 #define TINTERLACE_FLAG_EXACT_TB 2

 
 static const AVOption tinterlace_options[] = {
     {"mode",              "select interlace mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=MODE_MERGE}, 0, MODE_NB-1, FLAGS, "mode"},
     {"merge",             "merge fields",                                 0, AV_OPT_TYPE_CONST, {.i64=MODE_MERGE},             INT_MIN, INT_MAX, FLAGS, "mode"},
     {"drop_even",         "drop even fields",                             0, AV_OPT_TYPE_CONST, {.i64=MODE_DROP_EVEN},         INT_MIN, INT_MAX, FLAGS, "mode"},
     {"drop_odd",          "drop odd fields",                              0, AV_OPT_TYPE_CONST, {.i64=MODE_DROP_ODD},          INT_MIN, INT_MAX, FLAGS, "mode"},
     {"pad",               "pad alternate lines with black",               0, AV_OPT_TYPE_CONST, {.i64=MODE_PAD},               INT_MIN, INT_MAX, FLAGS, "mode"},
     {"interleave_top",    "interleave top and bottom fields",             0, AV_OPT_TYPE_CONST, {.i64=MODE_INTERLEAVE_TOP},    INT_MIN, INT_MAX, FLAGS, "mode"},
     {"interleave_bottom", "interleave bottom and top fields",             0, AV_OPT_TYPE_CONST, {.i64=MODE_INTERLEAVE_BOTTOM}, INT_MIN, INT_MAX, FLAGS, "mode"},
     {"interlacex2",       "interlace fields from two consecutive frames", 0, AV_OPT_TYPE_CONST, {.i64=MODE_INTERLACEX2},       INT_MIN, INT_MAX, FLAGS, "mode"},

     {"mergex2",           "merge fields keeping same frame rate",         0, AV_OPT_TYPE_CONST, {.i64=MODE_MERGEX2},           INT_MIN, INT_MAX, FLAGS, "mode"},

     {"flags",             "set flags", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = 0}, 0, INT_MAX, 0, "flags" },
     {"low_pass_filter",   "enable vertical low-pass filter",              0, AV_OPT_TYPE_CONST, {.i64 = TINTERLACE_FLAG_VLPF}, INT_MIN, INT_MAX, FLAGS, "flags" },
     {"vlpf",              "enable vertical low-pass filter",              0, AV_OPT_TYPE_CONST, {.i64 = TINTERLACE_FLAG_VLPF}, INT_MIN, INT_MAX, FLAGS, "flags" },

     {"exact_tb",          "force a timebase which can represent timestamps exactly", 0, AV_OPT_TYPE_CONST, {.i64 = TINTERLACE_FLAG_EXACT_TB}, INT_MIN, INT_MAX, FLAGS, "flags" },

     {NULL}
 };
 
 AVFILTER_DEFINE_CLASS(tinterlace);
 

 #define FULL_SCALE_YUVJ_FORMATS \

     AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P

 static const enum AVPixelFormat full_scale_yuvj_pix_fmts[] = {

     FULL_SCALE_YUVJ_FORMATS, AV_PIX_FMT_NONE

 };
 

 static const AVRational standard_tbs[] = {
     {1, 25},
     {1, 30},
     {1001, 30000},
 };
 

 static int query_formats(AVFilterContext *ctx)
 {

     static const enum AVPixelFormat pix_fmts[] = {

         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_YUVA420P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA444P,

         AV_PIX_FMT_GRAY8, FULL_SCALE_YUVJ_FORMATS,
         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 void lowpass_line_c(uint8_t *dstp, ptrdiff_t width, const uint8_t *srcp,
                            const uint8_t *srcp_above, const uint8_t *srcp_below)
 {
     int i;
     for (i = 0; i < width; i++) {
         // this calculation is an integer representation of
         // '0.5 * current + 0.25 * above + 0.25 * below'
         // '1 +' is for rounding.
         dstp[i] = (1 + srcp[i] + srcp[i] + srcp_above[i] + srcp_below[i]) >> 2;
     }
 }
 

 static av_cold void uninit(AVFilterContext *ctx)
 {
     TInterlaceContext *tinterlace = ctx->priv;
 

     av_frame_free(&tinterlace->cur );
     av_frame_free(&tinterlace->next);

     av_freep(&tinterlace->black_data[0]);
 }
 
 static int config_out_props(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     AVFilterLink *inlink = outlink->src->inputs[0];

     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(outlink->format);

     TInterlaceContext *tinterlace = ctx->priv;

     int i;

 
     tinterlace->vsub = desc->log2_chroma_h;
     outlink->w = inlink->w;

     outlink->h = tinterlace->mode == MODE_MERGE || tinterlace->mode == MODE_PAD || tinterlace->mode == MODE_MERGEX2?

         inlink->h*2 : inlink->h;

     if (tinterlace->mode == MODE_MERGE || tinterlace->mode == MODE_PAD || tinterlace->mode == MODE_MERGEX2)

         outlink->sample_aspect_ratio = av_mul_q(inlink->sample_aspect_ratio,
                                                 av_make_q(2, 1));

     if (tinterlace->mode == MODE_PAD) {

         uint8_t black[4] = { 16, 128, 128, 16 };
         int i, ret;
         if (ff_fmt_is_in(outlink->format, full_scale_yuvj_pix_fmts))
             black[0] = black[3] = 0;
         ret = av_image_alloc(tinterlace->black_data, tinterlace->black_linesize,

                              outlink->w, outlink->h, outlink->format, 16);

         if (ret < 0)
             return ret;
 
         /* fill black picture with black */
         for (i = 0; i < 4 && tinterlace->black_data[i]; i++) {

             int h = i == 1 || i == 2 ? AV_CEIL_RSHIFT(outlink->h, desc->log2_chroma_h) : outlink->h;

             memset(tinterlace->black_data[i], black[i],
                    tinterlace->black_linesize[i] * h);
         }
     }

     if ((tinterlace->flags & TINTERLACE_FLAG_VLPF)
             && !(tinterlace->mode == MODE_INTERLEAVE_TOP
               || tinterlace->mode == MODE_INTERLEAVE_BOTTOM)) {
         av_log(ctx, AV_LOG_WARNING, "low_pass_filter flag ignored with mode %d\n",
                 tinterlace->mode);

         tinterlace->flags &= ~TINTERLACE_FLAG_VLPF;

     }

     tinterlace->preout_time_base = inlink->time_base;

     if (tinterlace->mode == MODE_INTERLACEX2) {

         tinterlace->preout_time_base.den *= 2;

         outlink->frame_rate = av_mul_q(inlink->frame_rate, (AVRational){2,1});

         outlink->time_base  = av_mul_q(inlink->time_base , (AVRational){1,2});

     } else if (tinterlace->mode == MODE_MERGEX2) {
         outlink->frame_rate = inlink->frame_rate;
         outlink->time_base  = inlink->time_base;

     } else if (tinterlace->mode != MODE_PAD) {
         outlink->frame_rate = av_mul_q(inlink->frame_rate, (AVRational){1,2});

         outlink->time_base  = av_mul_q(inlink->time_base , (AVRational){2,1});
     }
 
     for (i = 0; i<FF_ARRAY_ELEMS(standard_tbs); i++){
         if (!av_cmp_q(standard_tbs[i], outlink->time_base))
             break;

     }

     if (i == FF_ARRAY_ELEMS(standard_tbs) ||
         (tinterlace->flags & TINTERLACE_FLAG_EXACT_TB))
         outlink->time_base = tinterlace->preout_time_base;

     if (tinterlace->flags & TINTERLACE_FLAG_VLPF) {
         tinterlace->lowpass_line = lowpass_line_c;

         if (ARCH_X86)
             ff_tinterlace_init_x86(tinterlace);

     }
 

     av_log(ctx, AV_LOG_VERBOSE, "mode:%d filter:%s h:%d -> h:%d\n",
            tinterlace->mode, (tinterlace->flags & TINTERLACE_FLAG_VLPF) ? "on" : "off",
            inlink->h, outlink->h);

 
     return 0;
 }
 
 #define FIELD_UPPER           0
 #define FIELD_LOWER           1
 #define FIELD_UPPER_AND_LOWER 2
 
 /**
  * Copy picture field from src to dst.
  *
  * @param src_field copy from upper, lower field or both

  * @param interleave leave a padding line between each copied line

  * @param dst_field copy to upper or lower field,
  *        only meaningful when interleave is selected

  * @param flags context flags

  */
 static inline

 void copy_picture_field(TInterlaceContext *tinterlace,
                         uint8_t *dst[4], int dst_linesize[4],

                         const uint8_t *src[4], int src_linesize[4],

                         enum AVPixelFormat format, int w, int src_h,

                         int src_field, int interleave, int dst_field,
                         int flags)

 {

     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(format);

     int hsub = desc->log2_chroma_w;

     int plane, vsub = desc->log2_chroma_h;
     int k = src_field == FIELD_UPPER_AND_LOWER ? 1 : 2;

     int h;

 
     for (plane = 0; plane < desc->nb_components; plane++) {

         int lines = plane == 1 || plane == 2 ? AV_CEIL_RSHIFT(src_h, vsub) : src_h;
         int cols  = plane == 1 || plane == 2 ? AV_CEIL_RSHIFT(    w, hsub) : w;

         uint8_t *dstp = dst[plane];

         const uint8_t *srcp = src[plane];

         lines = (lines + (src_field == FIELD_UPPER)) / k;

         if (src_field == FIELD_LOWER)
             srcp += src_linesize[plane];
         if (interleave && dst_field == FIELD_LOWER)
             dstp += dst_linesize[plane];

         if (flags & TINTERLACE_FLAG_VLPF) {
             // Low-pass filtering is required when creating an interlaced destination from
             // a progressive source which contains high-frequency vertical detail.
             // Filtering will reduce interlace 'twitter' and Moire patterning.
             int srcp_linesize = src_linesize[plane] * k;
             int dstp_linesize = dst_linesize[plane] * (interleave ? 2 : 1);

             for (h = lines; h > 0; h--) {

                 const uint8_t *srcp_above = srcp - src_linesize[plane];
                 const uint8_t *srcp_below = srcp + src_linesize[plane];
                 if (h == lines) srcp_above = srcp; // there is no line above
                 if (h == 1) srcp_below = srcp;     // there is no line below

 
                 tinterlace->lowpass_line(dstp, cols, srcp, srcp_above, srcp_below);

                 dstp += dstp_linesize;
                 srcp += srcp_linesize;
             }
         } else {
             av_image_copy_plane(dstp, dst_linesize[plane] * (interleave ? 2 : 1),

                                 srcp, src_linesize[plane]*k, cols, lines);

         }

     }
 }
 

 static int filter_frame(AVFilterLink *inlink, AVFrame *picref)

 {
     AVFilterContext *ctx = inlink->dst;

     AVFilterLink *outlink = ctx->outputs[0];

     TInterlaceContext *tinterlace = ctx->priv;

     AVFrame *cur, *next, *out;

     int field, tff, ret;

     av_frame_free(&tinterlace->cur);

     tinterlace->cur  = tinterlace->next;
     tinterlace->next = picref;
 

     cur = tinterlace->cur;
     next = tinterlace->next;

     /* we need at least two frames */
     if (!tinterlace->cur)

         return 0;

 
     switch (tinterlace->mode) {

     case MODE_MERGEX2: /* move the odd frame into the upper field of the new image, even into
                         * the lower field, generating a double-height video at same framerate */

     case MODE_MERGE: /* move the odd frame into the upper field of the new image, even into

              * the lower field, generating a double-height video at half framerate */

         out = ff_get_video_buffer(outlink, outlink->w, outlink->h);

         if (!out)
             return AVERROR(ENOMEM);

         av_frame_copy_props(out, cur);
         out->height = outlink->h;
         out->interlaced_frame = 1;
         out->top_field_first = 1;

         out->sample_aspect_ratio = av_mul_q(cur->sample_aspect_ratio, av_make_q(2, 1));

 
         /* write odd frame lines into the upper field of the new frame */

         copy_picture_field(tinterlace, out->data, out->linesize,

                            (const uint8_t **)cur->data, cur->linesize,

                            inlink->format, inlink->w, inlink->h,

                            FIELD_UPPER_AND_LOWER, 1, tinterlace->mode == MODE_MERGEX2 ? inlink->frame_count & 1 ? FIELD_LOWER : FIELD_UPPER : FIELD_UPPER, tinterlace->flags);

         /* write even frame lines into the lower field of the new frame */

         copy_picture_field(tinterlace, out->data, out->linesize,

                            (const uint8_t **)next->data, next->linesize,

                            inlink->format, inlink->w, inlink->h,

                            FIELD_UPPER_AND_LOWER, 1, tinterlace->mode == MODE_MERGEX2 ? inlink->frame_count & 1 ? FIELD_UPPER : FIELD_LOWER : FIELD_LOWER, tinterlace->flags);
         if (tinterlace->mode != MODE_MERGEX2)
             av_frame_free(&tinterlace->next);

         break;
 

     case MODE_DROP_ODD:  /* only output even frames, odd  frames are dropped; height unchanged, half framerate */
     case MODE_DROP_EVEN: /* only output odd  frames, even frames are dropped; height unchanged, half framerate */

         out = av_frame_clone(tinterlace->mode == MODE_DROP_EVEN ? cur : next);

         if (!out)
             return AVERROR(ENOMEM);

         av_frame_free(&tinterlace->next);

         break;
 

     case MODE_PAD: /* expand each frame to double height, but pad alternate
                     * lines with black; framerate unchanged */

         out = ff_get_video_buffer(outlink, outlink->w, outlink->h);

         if (!out)
             return AVERROR(ENOMEM);

         av_frame_copy_props(out, cur);
         out->height = outlink->h;

         out->sample_aspect_ratio = av_mul_q(cur->sample_aspect_ratio, av_make_q(2, 1));

 
         field = (1 + tinterlace->frame) & 1 ? FIELD_UPPER : FIELD_LOWER;
         /* copy upper and lower fields */

         copy_picture_field(tinterlace, out->data, out->linesize,

                            (const uint8_t **)cur->data, cur->linesize,

                            inlink->format, inlink->w, inlink->h,

                            FIELD_UPPER_AND_LOWER, 1, field, tinterlace->flags);

         /* pad with black the other field */

         copy_picture_field(tinterlace, out->data, out->linesize,

                            (const uint8_t **)tinterlace->black_data, tinterlace->black_linesize,

                            inlink->format, inlink->w, inlink->h,

                            FIELD_UPPER_AND_LOWER, 1, !field, tinterlace->flags);

         break;
 

         /* interleave upper/lower lines from odd frames with lower/upper lines from even frames,
          * halving the frame rate and preserving image height */

     case MODE_INTERLEAVE_TOP:    /* top    field first */
     case MODE_INTERLEAVE_BOTTOM: /* bottom field first */
         tff = tinterlace->mode == MODE_INTERLEAVE_TOP;

         out = ff_get_video_buffer(outlink, outlink->w, outlink->h);

         if (!out)
             return AVERROR(ENOMEM);

         av_frame_copy_props(out, cur);
         out->interlaced_frame = 1;
         out->top_field_first = tff;

         /* copy upper/lower field from cur */

         copy_picture_field(tinterlace, out->data, out->linesize,

                            (const uint8_t **)cur->data, cur->linesize,

                            inlink->format, inlink->w, inlink->h,

                            tff ? FIELD_UPPER : FIELD_LOWER, 1, tff ? FIELD_UPPER : FIELD_LOWER,
                            tinterlace->flags);

         /* copy lower/upper field from next */

         copy_picture_field(tinterlace, out->data, out->linesize,

                            (const uint8_t **)next->data, next->linesize,

                            inlink->format, inlink->w, inlink->h,

                            tff ? FIELD_LOWER : FIELD_UPPER, 1, tff ? FIELD_LOWER : FIELD_UPPER,
                            tinterlace->flags);

         av_frame_free(&tinterlace->next);

         break;

     case MODE_INTERLACEX2: /* re-interlace preserving image height, double frame rate */

         /* output current frame first */

         out = av_frame_clone(cur);

         if (!out)
             return AVERROR(ENOMEM);

         out->interlaced_frame = 1;

         if (cur->pts != AV_NOPTS_VALUE)
             out->pts = cur->pts*2;

         out->pts = av_rescale_q(out->pts, tinterlace->preout_time_base, outlink->time_base);

         if ((ret = ff_filter_frame(outlink, out)) < 0)
             return ret;

 
         /* output mix of current and next frame */

         tff = next->top_field_first;
         out = ff_get_video_buffer(outlink, outlink->w, outlink->h);

         if (!out)
             return AVERROR(ENOMEM);

         av_frame_copy_props(out, next);
         out->interlaced_frame = 1;

         out->top_field_first = !tff;

         if (next->pts != AV_NOPTS_VALUE && cur->pts != AV_NOPTS_VALUE)
             out->pts = cur->pts + next->pts;
         else
             out->pts = AV_NOPTS_VALUE;

         /* write current frame second field lines into the second field of the new frame */

         copy_picture_field(tinterlace, out->data, out->linesize,

                            (const uint8_t **)cur->data, cur->linesize,

                            inlink->format, inlink->w, inlink->h,

                            tff ? FIELD_LOWER : FIELD_UPPER, 1, tff ? FIELD_LOWER : FIELD_UPPER,
                            tinterlace->flags);

         /* write next frame first field lines into the first field of the new frame */

         copy_picture_field(tinterlace, out->data, out->linesize,

                            (const uint8_t **)next->data, next->linesize,

                            inlink->format, inlink->w, inlink->h,

                            tff ? FIELD_UPPER : FIELD_LOWER, 1, tff ? FIELD_UPPER : FIELD_LOWER,
                            tinterlace->flags);

         break;

     default:
         av_assert0(0);

     }
 

     out->pts = av_rescale_q(out->pts, tinterlace->preout_time_base, outlink->time_base);

     ret = ff_filter_frame(outlink, out);

     tinterlace->frame++;

     return ret;

 }
 

 static const AVFilterPad tinterlace_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,

         .filter_frame = filter_frame,

     },
     { NULL }
 };
 
 static const AVFilterPad tinterlace_outputs[] = {
     {

         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .config_props = config_out_props,

     },
     { NULL }
 };
 

 AVFilter ff_vf_tinterlace = {

     .name          = "tinterlace",
     .description   = NULL_IF_CONFIG_SMALL("Perform temporal field interlacing."),
     .priv_size     = sizeof(TInterlaceContext),
     .uninit        = uninit,
     .query_formats = query_formats,

     .inputs        = tinterlace_inputs,
     .outputs       = tinterlace_outputs,

     .priv_class    = &tinterlace_class,

 };