/*

 *  Copyright (c) 2012 The WebM project authors. All Rights Reserved.

 *

 *  Use of this source code is governed by a BSD-style license

 *  that can be found in the LICENSE file in the root of the source

 *  tree. An additional intellectual property rights grant can be found

 *  in the file PATENTS.  All contributing project authors may

 *  be found in the AUTHORS file in the root of the source tree.

 */

/* MFQE: Multiframe Quality Enhancement

 * In rate limited situations keyframes may cause significant visual artifacts

 * commonly referred to as "popping." This file implements a postproccesing

 * algorithm which blends data from the preceeding frame when there is no

 * motion and the q from the previous frame is lower which indicates that it is

 * higher quality.

 */

#include "./vp8_rtcd.h"

#include "./vpx_dsp_rtcd.h"

#include "vp8/common/common.h"

#include "vp8/common/postproc.h"

#include "vpx_dsp/variance.h"

#include "vpx_mem/vpx_mem.h"

#include "vpx_scale/yv12config.h"

#include <limits.h>

#include <stdlib.h>

static void filter_by_weight(unsigned char *src, int src_stride,

                             unsigned char *dst, int dst_stride, int block_size,

                             int src_weight) {

  int dst_weight = (1 << MFQE_PRECISION) - src_weight;

  int rounding_bit = 1 << (MFQE_PRECISION - 1);

  int r, c;

  for (r = 0; r < block_size; ++r) {

    for (c = 0; c < block_size; ++c) {

      dst[c] = (src[c] * src_weight + dst[c] * dst_weight + rounding_bit) >>

               MFQE_PRECISION;

    }

    src += src_stride;

    dst += dst_stride;

  }

}

void vp8_filter_by_weight16x16_c(unsigned char *src, int src_stride,

                                 unsigned char *dst, int dst_stride,

                                 int src_weight) {

  filter_by_weight(src, src_stride, dst, dst_stride, 16, src_weight);

}

void vp8_filter_by_weight8x8_c(unsigned char *src, int src_stride,

                               unsigned char *dst, int dst_stride,

                               int src_weight) {

  filter_by_weight(src, src_stride, dst, dst_stride, 8, src_weight);

}

void vp8_filter_by_weight4x4_c(unsigned char *src, int src_stride,

                               unsigned char *dst, int dst_stride,

                               int src_weight) {

  filter_by_weight(src, src_stride, dst, dst_stride, 4, src_weight);

}

static void apply_ifactor(unsigned char *y_src, int y_src_stride,

                          unsigned char *y_dst, int y_dst_stride,

                          unsigned char *u_src, unsigned char *v_src,

                          int uv_src_stride, unsigned char *u_dst,

                          unsigned char *v_dst, int uv_dst_stride,

                          int block_size, int src_weight) {

  if (block_size == 16) {

    vp8_filter_by_weight16x16(y_src, y_src_stride, y_dst, y_dst_stride,

                              src_weight);

    vp8_filter_by_weight8x8(u_src, uv_src_stride, u_dst, uv_dst_stride,

                            src_weight);

    vp8_filter_by_weight8x8(v_src, uv_src_stride, v_dst, uv_dst_stride,

                            src_weight);

  } else {

    vp8_filter_by_weight8x8(y_src, y_src_stride, y_dst, y_dst_stride,

                            src_weight);

    vp8_filter_by_weight4x4(u_src, uv_src_stride, u_dst, uv_dst_stride,

                            src_weight);

    vp8_filter_by_weight4x4(v_src, uv_src_stride, v_dst, uv_dst_stride,

                            src_weight);

  }

}

static unsigned int int_sqrt(unsigned int x) {

  unsigned int y = x;

  unsigned int guess;

  int p = 1;

  while (y >>= 1) p++;

  p >>= 1;

  guess = 0;

  while (p >= 0) {

    guess |= (1 << p);

    if (x < guess * guess) guess -= (1 << p);

    p--;

  }

  /* choose between guess or guess+1 */

  return guess + (guess * guess + guess + 1 <= x);

}

#define USE_SSD

static void multiframe_quality_enhance_block(

    int blksize, /* Currently only values supported are 16, 8 */

    int qcurr, int qprev, unsigned char *y, unsigned char *u, unsigned char *v,

    int y_stride, int uv_stride, unsigned char *yd, unsigned char *ud,

    unsigned char *vd, int yd_stride, int uvd_stride) {

  static const unsigned char VP8_ZEROS[16] = { 0, 0, 0, 0, 0, 0, 0, 0,

                                               0, 0, 0, 0, 0, 0, 0, 0 };

  int uvblksize = blksize >> 1;

  int qdiff = qcurr - qprev;

  int i;

  unsigned char *up;

  unsigned char *udp;

  unsigned char *vp;

  unsigned char *vdp;

  unsigned int act, actd, sad, usad, vsad, sse, thr, thrsq, actrisk;

  if (blksize == 16) {

    actd = (vpx_variance16x16(yd, yd_stride, VP8_ZEROS, 0, &sse) + 128) >> 8;

    act = (vpx_variance16x16(y, y_stride, VP8_ZEROS, 0, &sse) + 128) >> 8;

#ifdef USE_SSD

    vpx_variance16x16(y, y_stride, yd, yd_stride, &sse);

    sad = (sse + 128) >> 8;

    vpx_variance8x8(u, uv_stride, ud, uvd_stride, &sse);

    usad = (sse + 32) >> 6;

    vpx_variance8x8(v, uv_stride, vd, uvd_stride, &sse);

    vsad = (sse + 32) >> 6;

#else

    sad = (vpx_sad16x16(y, y_stride, yd, yd_stride) + 128) >> 8;

    usad = (vpx_sad8x8(u, uv_stride, ud, uvd_stride) + 32) >> 6;

    vsad = (vpx_sad8x8(v, uv_stride, vd, uvd_stride) + 32) >> 6;

#endif

  } else {

    actd = (vpx_variance8x8(yd, yd_stride, VP8_ZEROS, 0, &sse) + 32) >> 6;

    act = (vpx_variance8x8(y, y_stride, VP8_ZEROS, 0, &sse) + 32) >> 6;

#ifdef USE_SSD

    vpx_variance8x8(y, y_stride, yd, yd_stride, &sse);

    sad = (sse + 32) >> 6;

    vpx_variance4x4(u, uv_stride, ud, uvd_stride, &sse);

    usad = (sse + 8) >> 4;

    vpx_variance4x4(v, uv_stride, vd, uvd_stride, &sse);

    vsad = (sse + 8) >> 4;

#else

    sad = (vpx_sad8x8(y, y_stride, yd, yd_stride) + 32) >> 6;

    usad = (vpx_sad4x4(u, uv_stride, ud, uvd_stride) + 8) >> 4;

    vsad = (vpx_sad4x4(v, uv_stride, vd, uvd_stride) + 8) >> 4;

#endif

  }

  actrisk = (actd > act * 5);

  /* thr = qdiff/16 + log2(act) + log4(qprev) */

  thr = (qdiff >> 4);

  while (actd >>= 1) thr++;

  while (qprev >>= 2) thr++;

#ifdef USE_SSD

  thrsq = thr * thr;

  if (sad < thrsq &&

      /* additional checks for color mismatch and excessive addition of

       * high-frequencies */

      4 * usad < thrsq && 4 * vsad < thrsq && !actrisk)

#else

  if (sad < thr &&

      /* additional checks for color mismatch and excessive addition of

       * high-frequencies */

      2 * usad < thr && 2 * vsad < thr && !actrisk)

#endif

  {

    int ifactor;

#ifdef USE_SSD

    /* TODO: optimize this later to not need sqr root */

    sad = int_sqrt(sad);

#endif

    ifactor = (sad << MFQE_PRECISION) / thr;

    ifactor >>= (qdiff >> 5);

    if (ifactor) {

      apply_ifactor(y, y_stride, yd, yd_stride, u, v, uv_stride, ud, vd,

                    uvd_stride, blksize, ifactor);

    }

  } else { /* else implicitly copy from previous frame */

    if (blksize == 16) {

      vp8_copy_mem16x16(y, y_stride, yd, yd_stride);

      vp8_copy_mem8x8(u, uv_stride, ud, uvd_stride);

      vp8_copy_mem8x8(v, uv_stride, vd, uvd_stride);

    } else {

      vp8_copy_mem8x8(y, y_stride, yd, yd_stride);

      for (up = u, udp = ud, i = 0; i < uvblksize;

           ++i, up += uv_stride, udp += uvd_stride) {

        memcpy(udp, up, uvblksize);

      }

      for (vp = v, vdp = vd, i = 0; i < uvblksize;

           ++i, vp += uv_stride, vdp += uvd_stride) {

        memcpy(vdp, vp, uvblksize);

      }

    }

  }

}

static int qualify_inter_mb(const MODE_INFO *mode_info_context, int *map) {

  if (mode_info_context->mbmi.mb_skip_coeff) {

    map[0] = map[1] = map[2] = map[3] = 1;

  } else if (mode_info_context->mbmi.mode == SPLITMV) {

    static int ndx[4][4] = {

      { 0, 1, 4, 5 }, { 2, 3, 6, 7 }, { 8, 9, 12, 13 }, { 10, 11, 14, 15 }

    };

    int i, j;

    vp8_zero(*map);

    for (i = 0; i < 4; ++i) {

      map[i] = 1;

      for (j = 0; j < 4 && map[j]; ++j) {

        map[i] &= (mode_info_context->bmi[ndx[i][j]].mv.as_mv.row <= 2 &&

                   mode_info_context->bmi[ndx[i][j]].mv.as_mv.col <= 2);

      }

    }

  } else {

    map[0] = map[1] = map[2] = map[3] =

        (mode_info_context->mbmi.mode > B_PRED &&

         abs(mode_info_context->mbmi.mv.as_mv.row) <= 2 &&

         abs(mode_info_context->mbmi.mv.as_mv.col) <= 2);

  }

  return (map[0] + map[1] + map[2] + map[3]);

}

void vp8_multiframe_quality_enhance(VP8_COMMON *cm) {

  YV12_BUFFER_CONFIG *show = cm->frame_to_show;

  YV12_BUFFER_CONFIG *dest = &cm->post_proc_buffer;

  FRAME_TYPE frame_type = cm->frame_type;

  /* Point at base of Mb MODE_INFO list has motion vectors etc */

  const MODE_INFO *mode_info_context = cm->mi;

  int mb_row;

  int mb_col;

  int totmap, map[4];

  int qcurr = cm->base_qindex;

  int qprev = cm->postproc_state.last_base_qindex;

  unsigned char *y_ptr, *u_ptr, *v_ptr;

  unsigned char *yd_ptr, *ud_ptr, *vd_ptr;

  /* Set up the buffer pointers */

  y_ptr = show->y_buffer;

  u_ptr = show->u_buffer;

  v_ptr = show->v_buffer;

  yd_ptr = dest->y_buffer;

  ud_ptr = dest->u_buffer;

  vd_ptr = dest->v_buffer;

  /* postprocess each macro block */

  for (mb_row = 0; mb_row < cm->mb_rows; ++mb_row) {

    for (mb_col = 0; mb_col < cm->mb_cols; ++mb_col) {

      /* if motion is high there will likely be no benefit */

      if (frame_type == INTER_FRAME) {

        totmap = qualify_inter_mb(mode_info_context, map);

      } else {

        totmap = (frame_type == KEY_FRAME ? 4 : 0);

      }

      if (totmap) {

        if (totmap < 4) {

          int i, j;

          for (i = 0; i < 2; ++i) {

            for (j = 0; j < 2; ++j) {

              if (map[i * 2 + j]) {

                multiframe_quality_enhance_block(

                    8, qcurr, qprev, y_ptr + 8 * (i * show->y_stride + j),

                    u_ptr + 4 * (i * show->uv_stride + j),

                    v_ptr + 4 * (i * show->uv_stride + j), show->y_stride,

                    show->uv_stride, yd_ptr + 8 * (i * dest->y_stride + j),

                    ud_ptr + 4 * (i * dest->uv_stride + j),

                    vd_ptr + 4 * (i * dest->uv_stride + j), dest->y_stride,

                    dest->uv_stride);

              } else {

                /* copy a 8x8 block */

                int k;

                unsigned char *up = u_ptr + 4 * (i * show->uv_stride + j);

                unsigned char *udp = ud_ptr + 4 * (i * dest->uv_stride + j);

                unsigned char *vp = v_ptr + 4 * (i * show->uv_stride + j);

                unsigned char *vdp = vd_ptr + 4 * (i * dest->uv_stride + j);

                vp8_copy_mem8x8(

                    y_ptr + 8 * (i * show->y_stride + j), show->y_stride,

                    yd_ptr + 8 * (i * dest->y_stride + j), dest->y_stride);

                for (k = 0; k < 4; ++k, up += show->uv_stride,

                    udp += dest->uv_stride, vp += show->uv_stride,

                    vdp += dest->uv_stride) {

                  memcpy(udp, up, 4);

                  memcpy(vdp, vp, 4);

                }

              }

            }

          }

        } else { /* totmap = 4 */

          multiframe_quality_enhance_block(

              16, qcurr, qprev, y_ptr, u_ptr, v_ptr, show->y_stride,

              show->uv_stride, yd_ptr, ud_ptr, vd_ptr, dest->y_stride,

              dest->uv_stride);

        }

      } else {

        vp8_copy_mem16x16(y_ptr, show->y_stride, yd_ptr, dest->y_stride);

        vp8_copy_mem8x8(u_ptr, show->uv_stride, ud_ptr, dest->uv_stride);

        vp8_copy_mem8x8(v_ptr, show->uv_stride, vd_ptr, dest->uv_stride);

      }

      y_ptr += 16;

      u_ptr += 8;

      v_ptr += 8;

      yd_ptr += 16;

      ud_ptr += 8;

      vd_ptr += 8;

      mode_info_context++; /* step to next MB */

    }

    y_ptr += show->y_stride * 16 - 16 * cm->mb_cols;

    u_ptr += show->uv_stride * 8 - 8 * cm->mb_cols;

    v_ptr += show->uv_stride * 8 - 8 * cm->mb_cols;

    yd_ptr += dest->y_stride * 16 - 16 * cm->mb_cols;

    ud_ptr += dest->uv_stride * 8 - 8 * cm->mb_cols;

    vd_ptr += dest->uv_stride * 8 - 8 * cm->mb_cols;

    mode_info_context++; /* Skip border mb */

  }

}