rav1e/
cdef.rs

1// Copyright (c) 2017-2022, The rav1e contributors. All rights reserved
2//
3// This source code is subject to the terms of the BSD 2 Clause License and
4// the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
5// was not distributed with this source code in the LICENSE file, you can
6// obtain it at www.aomedia.org/license/software. If the Alliance for Open
7// Media Patent License 1.0 was not distributed with this source code in the
8// PATENTS file, you can obtain it at www.aomedia.org/license/patent.
9
10use crate::color::ChromaSampling::Cs400;
11use crate::context::*;
12use crate::encoder::FrameInvariants;
13use crate::frame::*;
14use crate::tiling::*;
15use crate::util::{clamp, msb, CastFromPrimitive, Pixel};
16
17use crate::cpu_features::CpuFeatureLevel;
18use std::cmp;
19
20cfg_if::cfg_if! {
21  if #[cfg(nasm_x86_64)] {
22    pub(crate) use crate::asm::x86::cdef::*;
23  } else if #[cfg(asm_neon)] {
24    pub(crate) use crate::asm::aarch64::cdef::*;
25  } else {
26    pub(crate) use self::rust::*;
27  }
28}
29
30pub const CDEF_VERY_LARGE: u16 = 0x8000;
31// These values match dav1d; flags indicating where padding exists
32pub const CDEF_HAVE_LEFT: u8 = 1 << 0;
33pub const CDEF_HAVE_RIGHT: u8 = 1 << 1;
34pub const CDEF_HAVE_TOP: u8 = 1 << 2;
35pub const CDEF_HAVE_BOTTOM: u8 = 1 << 3;
36pub const CDEF_HAVE_ALL: u8 =
37  CDEF_HAVE_LEFT | CDEF_HAVE_RIGHT | CDEF_HAVE_TOP | CDEF_HAVE_BOTTOM;
38
39pub(crate) const CDEF_SEC_STRENGTHS: u8 = 4;
40
41pub struct CdefDirections {
42  dir: [[u8; 8]; 8],
43  var: [[i32; 8]; 8],
44}
45
46pub(crate) mod rust {
47  use super::*;
48
49  use simd_helpers::cold_for_target_arch;
50
51  // Instead of dividing by n between 2 and 8, we multiply by 3*5*7*8/n.
52  // The output is then 840 times larger, but we don't care for finding
53  // the max.
54  const CDEF_DIV_TABLE: [i32; 9] = [0, 840, 420, 280, 210, 168, 140, 120, 105];
55
56  /// Returns the position and value of the first instance of the max element in
57  /// a slice as a tuple.
58  ///
59  /// # Arguments
60  ///
61  /// * `elems` - A non-empty slice of integers
62  ///
63  /// # Panics
64  ///
65  /// Panics if `elems` is empty
66  #[inline]
67  fn first_max_element(elems: &[i32]) -> (usize, i32) {
68    // In case of a tie, the first element must be selected.
69    let (max_idx, max_value) = elems
70      .iter()
71      .enumerate()
72      .max_by_key(|&(i, v)| (v, -(i as isize)))
73      .unwrap();
74    (max_idx, *max_value)
75  }
76
77  // Detect direction. 0 means 45-degree up-right, 2 is horizontal, and so on.
78  // The search minimizes the weighted variance along all the lines in a
79  // particular direction, i.e. the squared error between the input and a
80  // "predicted" block where each pixel is replaced by the average along a line
81  // in a particular direction. Since each direction have the same sum(x^2) term,
82  // that term is never computed. See Section 2, step 2, of:
83  // http://jmvalin.ca/notes/intra_paint.pdf
84  pub fn cdef_find_dir<T: Pixel>(
85    img: &PlaneSlice<'_, T>, var: &mut u32, coeff_shift: usize,
86    _cpu: CpuFeatureLevel,
87  ) -> i32 {
88    let mut cost: [i32; 8] = [0; 8];
89    let mut partial: [[i32; 15]; 8] = [[0; 15]; 8];
90    for i in 0..8 {
91      for j in 0..8 {
92        let p: i32 = i32::cast_from(img[i][j]);
93        // We subtract 128 here to reduce the maximum range of the squared
94        // partial sums.
95        debug_assert!(p >> coeff_shift <= 255);
96        let x = (p >> coeff_shift) - 128;
97        partial[0][i + j] += x;
98        partial[1][i + j / 2] += x;
99        partial[2][i] += x;
100        partial[3][3 + i - j / 2] += x;
101        partial[4][7 + i - j] += x;
102        partial[5][3 - i / 2 + j] += x;
103        partial[6][j] += x;
104        partial[7][i / 2 + j] += x;
105      }
106    }
107    for i in 0..8 {
108      cost[2] += partial[2][i] * partial[2][i];
109      cost[6] += partial[6][i] * partial[6][i];
110    }
111    cost[2] *= CDEF_DIV_TABLE[8];
112    cost[6] *= CDEF_DIV_TABLE[8];
113    for i in 0..7 {
114      cost[0] += (partial[0][i] * partial[0][i]
115        + partial[0][14 - i] * partial[0][14 - i])
116        * CDEF_DIV_TABLE[i + 1];
117      cost[4] += (partial[4][i] * partial[4][i]
118        + partial[4][14 - i] * partial[4][14 - i])
119        * CDEF_DIV_TABLE[i + 1];
120    }
121    cost[0] += partial[0][7] * partial[0][7] * CDEF_DIV_TABLE[8];
122    cost[4] += partial[4][7] * partial[4][7] * CDEF_DIV_TABLE[8];
123    for i in (1..8).step_by(2) {
124      for j in 0..5 {
125        cost[i] += partial[i][3 + j] * partial[i][3 + j];
126      }
127      cost[i] *= CDEF_DIV_TABLE[8];
128      for j in 0..3 {
129        cost[i] += (partial[i][j] * partial[i][j]
130          + partial[i][10 - j] * partial[i][10 - j])
131          * CDEF_DIV_TABLE[2 * j + 2];
132      }
133    }
134
135    let (best_dir, best_cost) = first_max_element(&cost);
136    // Difference between the optimal variance and the variance along the
137    // orthogonal direction. Again, the sum(x^2) terms cancel out.
138    // We'd normally divide by 840, but dividing by 1024 is close enough
139    // for what we're going to do with this. */
140    *var = ((best_cost - cost[(best_dir + 4) & 7]) >> 10) as u32;
141
142    best_dir as i32
143  }
144
145  #[inline(always)]
146  fn constrain(diff: i32, threshold: i32, damping: i32) -> i32 {
147    if threshold != 0 {
148      let shift = cmp::max(0, damping - msb(threshold));
149      let magnitude = (threshold - (diff.abs() >> shift)).clamp(0, diff.abs());
150
151      if diff < 0 {
152        -magnitude
153      } else {
154        magnitude
155      }
156    } else {
157      0
158    }
159  }
160
161  pub unsafe fn pad_into_tmp16<T: Pixel>(
162    dst: *mut u16, dst_stride: isize, src: *const T, src_stride: isize,
163    block_width: usize, block_height: usize, edges: u8,
164  ) {
165    let mut w = block_width;
166    let mut h = block_height;
167    let (dst_col, src_col) = if (edges & CDEF_HAVE_LEFT) != 0 {
168      w += 2;
169      (dst, src.offset(-2))
170    } else {
171      (dst.offset(2), src)
172    };
173    if (edges & CDEF_HAVE_RIGHT) != 0 {
174      w += 2;
175    };
176
177    let (mut dst_ptr, mut src_ptr) = if (edges & CDEF_HAVE_TOP) != 0 {
178      h += 2;
179      (dst_col, src_col.offset(-2 * src_stride))
180    } else {
181      (dst_col.offset(2 * dst_stride), src_col)
182    };
183    if (edges & CDEF_HAVE_BOTTOM) != 0 {
184      h += 2;
185    };
186
187    for _y in 0..h {
188      for x in 0..w {
189        *dst_ptr.add(x) = u16::cast_from(*src_ptr.add(x));
190      }
191      src_ptr = src_ptr.offset(src_stride);
192      dst_ptr = dst_ptr.offset(dst_stride);
193    }
194  }
195
196  #[cold_for_target_arch("x86_64")]
197  #[allow(clippy::erasing_op, clippy::identity_op, clippy::neg_multiply)]
198  pub(crate) unsafe fn cdef_filter_block<T: Pixel, U: Pixel>(
199    dst: &mut PlaneRegionMut<'_, T>, input: *const U, istride: isize,
200    pri_strength: i32, sec_strength: i32, dir: usize, damping: i32,
201    bit_depth: usize, xdec: usize, ydec: usize, edges: u8,
202    _cpu: CpuFeatureLevel,
203  ) {
204    if edges != CDEF_HAVE_ALL {
205      // slowpath for unpadded border[s]
206      let tmpstride = 2 + (8 >> xdec) + 2;
207      let mut tmp = [CDEF_VERY_LARGE; (2 + 8 + 2) * (2 + 8 + 2)];
208      // copy in what pixels we have/are allowed to use
209      pad_into_tmp16(
210        tmp.as_mut_ptr(), // points to *padding* upper left
211        tmpstride,
212        input, // points to *block* upper left
213        istride,
214        8 >> xdec,
215        8 >> ydec,
216        edges,
217      );
218      cdef_filter_block(
219        dst,
220        tmp.as_ptr().offset(2 * tmpstride + 2),
221        tmpstride,
222        pri_strength,
223        sec_strength,
224        dir,
225        damping,
226        bit_depth,
227        xdec,
228        ydec,
229        CDEF_HAVE_ALL,
230        _cpu,
231      );
232    } else {
233      let xsize = (8 >> xdec) as isize;
234      let ysize = (8 >> ydec) as isize;
235      let coeff_shift = bit_depth - 8;
236      let cdef_pri_taps = [[4, 2], [3, 3]];
237      let cdef_sec_taps = [[2, 1], [2, 1]];
238      let pri_taps =
239        cdef_pri_taps[((pri_strength >> coeff_shift) & 1) as usize];
240      let sec_taps =
241        cdef_sec_taps[((pri_strength >> coeff_shift) & 1) as usize];
242      let cdef_directions = [
243        [-1 * istride + 1, -2 * istride + 2],
244        [0 * istride + 1, -1 * istride + 2],
245        [0 * istride + 1, 0 * istride + 2],
246        [0 * istride + 1, 1 * istride + 2],
247        [1 * istride + 1, 2 * istride + 2],
248        [1 * istride + 0, 2 * istride + 1],
249        [1 * istride + 0, 2 * istride + 0],
250        [1 * istride + 0, 2 * istride - 1],
251      ];
252      for i in 0..ysize {
253        for j in 0..xsize {
254          let ptr_in = input.offset(i * istride + j);
255          let x = i32::cast_from(*ptr_in);
256          let mut sum: i32 = 0;
257          let mut max = x;
258          let mut min = x;
259          for k in 0..2usize {
260            let cdef_dirs = [
261              cdef_directions[dir][k],
262              cdef_directions[(dir + 2) & 7][k],
263              cdef_directions[(dir + 6) & 7][k],
264            ];
265            let pri_tap = pri_taps[k];
266            let p = [
267              i32::cast_from(*ptr_in.offset(cdef_dirs[0])),
268              i32::cast_from(*ptr_in.offset(-cdef_dirs[0])),
269            ];
270            for p_elem in p.iter() {
271              sum += pri_tap * constrain(*p_elem - x, pri_strength, damping);
272              if *p_elem != CDEF_VERY_LARGE as i32 {
273                max = cmp::max(*p_elem, max);
274              }
275              min = cmp::min(*p_elem, min);
276            }
277
278            let s = [
279              i32::cast_from(*ptr_in.offset(cdef_dirs[1])),
280              i32::cast_from(*ptr_in.offset(-cdef_dirs[1])),
281              i32::cast_from(*ptr_in.offset(cdef_dirs[2])),
282              i32::cast_from(*ptr_in.offset(-cdef_dirs[2])),
283            ];
284            let sec_tap = sec_taps[k];
285            for s_elem in s.iter() {
286              if *s_elem != CDEF_VERY_LARGE as i32 {
287                max = cmp::max(*s_elem, max);
288              }
289              min = cmp::min(*s_elem, min);
290              sum += sec_tap * constrain(*s_elem - x, sec_strength, damping);
291            }
292          }
293          let v = x + ((8 + sum - (sum < 0) as i32) >> 4);
294          dst[i as usize][j as usize] = T::cast_from(clamp(v, min, max));
295        }
296      }
297    }
298  }
299
300  #[cfg(test)]
301  mod test {
302    use super::*;
303
304    #[test]
305    fn check_max_element() {
306      assert_eq!(first_max_element(&[-1, -1, 1, 2, 3, 4, 6, 6]), (6, 6));
307      assert_eq!(first_max_element(&[-1, -1, 1, 2, 3, 4, 7, 6]), (6, 7));
308      assert_eq!(first_max_element(&[0, 0]), (0, 0));
309    }
310  }
311}
312
313// We use the variance of an 8x8 block to adjust the effective filter strength.
314#[inline]
315fn adjust_strength(strength: i32, var: i32) -> i32 {
316  let i = if (var >> 6) != 0 { cmp::min(msb(var >> 6), 12) } else { 0 };
317  if var != 0 {
318    (strength * (4 + i) + 8) >> 4
319  } else {
320    0
321  }
322}
323
324#[profiling::function]
325pub fn cdef_analyze_superblock_range<T: Pixel>(
326  fi: &FrameInvariants<T>, in_frame: &Frame<T>, blocks: &TileBlocks<'_>,
327  sb_w: usize, sb_h: usize,
328) -> Vec<CdefDirections> {
329  let mut ret = Vec::<CdefDirections>::with_capacity(sb_h * sb_w);
330  for sby in 0..sb_h {
331    for sbx in 0..sb_w {
332      let sbo = TileSuperBlockOffset(SuperBlockOffset { x: sbx, y: sby });
333      ret.push(cdef_analyze_superblock(fi, in_frame, blocks, sbo));
334    }
335  }
336  ret
337}
338
339#[profiling::function]
340pub fn cdef_analyze_superblock<T: Pixel>(
341  fi: &FrameInvariants<T>, in_frame: &Frame<T>, blocks: &TileBlocks<'_>,
342  sbo: TileSuperBlockOffset,
343) -> CdefDirections {
344  let coeff_shift = fi.sequence.bit_depth - 8;
345  let mut dir: CdefDirections =
346    CdefDirections { dir: [[0; 8]; 8], var: [[0; 8]; 8] };
347  // Each direction block is 8x8 in y, and direction computation only looks at y
348  for by in 0..8 {
349    for bx in 0..8 {
350      let block_offset = sbo.block_offset(bx << 1, by << 1);
351      if block_offset.0.x < blocks.cols() && block_offset.0.y < blocks.rows() {
352        let skip = blocks[block_offset].skip
353          & blocks[sbo.block_offset(2 * bx + 1, 2 * by)].skip
354          & blocks[sbo.block_offset(2 * bx, 2 * by + 1)].skip
355          & blocks[sbo.block_offset(2 * bx + 1, 2 * by + 1)].skip;
356
357        if !skip {
358          let mut var: u32 = 0;
359          let in_plane = &in_frame.planes[0];
360          let in_po = sbo.plane_offset(&in_plane.cfg);
361          let in_slice = in_plane.slice(in_po);
362          dir.dir[bx][by] = cdef_find_dir::<T>(
363            &in_slice.reslice(8 * bx as isize, 8 * by as isize),
364            &mut var,
365            coeff_shift,
366            fi.cpu_feature_level,
367          ) as u8;
368          dir.var[bx][by] = var as i32;
369        }
370      }
371    }
372  }
373  dir
374}
375
376//   input: A Frame of reconstructed/deblocked pixels prepared to
377//   undergo CDEF. Note that the input is a Frame and not a Tile due to
378//   Tiles not allowing [supervised] out-of-rect access for padding
379//   pixels.  This will be corrected at some point in the future.
380
381//   tile_sbo: specifies an offset into the output Tile, not an
382//   absolute offset in the visible frame.  The Tile's own offset is
383//   added to this in order to address into the input Frame.
384
385//   tb: the TileBlocks associated with the filtered region; the
386//   provided blocks co-locate with the output region.  The TileBlocks
387//   provide by-[super]qblock CDEF parameters.
388
389//   output: TileMut destination for filtered pixels.  The output's
390//   rect specifies the region of the input to be processed (x and y
391//   are relative to the input Frame's origin).  Note that an
392//   additional area of 2 pixels of padding is used for CDEF.  When
393//   these pixels are unavailable (beyond the visible frame or at a
394//   tile boundary), the filtering process ignores input pixels that
395//   don't exist.
396
397/// # Panics
398///
399/// - If called with invalid parameters
400#[profiling::function]
401pub fn cdef_filter_superblock<T: Pixel>(
402  fi: &FrameInvariants<T>, input: &Frame<T>, output: &mut TileMut<'_, T>,
403  blocks: &TileBlocks<'_>, tile_sbo: TileSuperBlockOffset, cdef_index: u8,
404  cdef_dirs: &CdefDirections,
405) {
406  let bit_depth = fi.sequence.bit_depth;
407  let coeff_shift = fi.sequence.bit_depth as i32 - 8;
408  let cdef_damping = fi.cdef_damping as i32;
409  let cdef_y_strength = fi.cdef_y_strengths[cdef_index as usize];
410  let cdef_uv_strength = fi.cdef_uv_strengths[cdef_index as usize];
411  let cdef_pri_y_strength = (cdef_y_strength / CDEF_SEC_STRENGTHS) as i32;
412  let mut cdef_sec_y_strength = (cdef_y_strength % CDEF_SEC_STRENGTHS) as i32;
413  let cdef_pri_uv_strength = (cdef_uv_strength / CDEF_SEC_STRENGTHS) as i32;
414  let planes = if fi.sequence.chroma_sampling == Cs400 { 1 } else { 3 };
415  let mut cdef_sec_uv_strength =
416    (cdef_uv_strength % CDEF_SEC_STRENGTHS) as i32;
417  if cdef_sec_y_strength == 3 {
418    cdef_sec_y_strength += 1;
419  }
420  if cdef_sec_uv_strength == 3 {
421    cdef_sec_uv_strength += 1;
422  }
423
424  let tile_rect = *output.planes[0].rect();
425  let input_xoffset =
426    tile_rect.x + tile_sbo.plane_offset(&input.planes[0].cfg).x;
427  let input_yoffset =
428    tile_rect.y + tile_sbo.plane_offset(&input.planes[0].cfg).y;
429  let input_xavail = input.planes[0].cfg.width as isize - input_xoffset;
430  let input_yavail = input.planes[0].cfg.height as isize - input_yoffset;
431
432  /* determine what edge padding we have, and what padding we don't.
433   * We don't pad here, but rather tell the filter_block call what it
434   * needs to do, then let it handle the specifics (following dav1d's
435   * lead).  We make one assumption that's not obvious: Because the
436   * cdef clipping area is rounded up to an even 8x8 luma block, we
437   * don't need to guard against having only one (as opposed to two)
438   * pixels of padding past the current block boundary.  The padding
439   * is all-or-nothing. */
440
441  // Slightly harder than in dav1d; we're not always doing full-frame.
442  let have_top_p =
443    if tile_sbo.0.y as isize + tile_rect.y > 0 { CDEF_HAVE_TOP } else { 0 };
444  let have_left_p =
445    if tile_sbo.0.x as isize + tile_rect.x > 0 { CDEF_HAVE_LEFT } else { 0 };
446  let mut edges = have_top_p | CDEF_HAVE_BOTTOM;
447
448  // Each direction block is 8x8 in y, potentially smaller if subsampled in chroma
449  for by in 0..8usize {
450    if by + 1 >= (input_yavail as usize >> 3) {
451      edges &= !CDEF_HAVE_BOTTOM
452    };
453    edges &= !CDEF_HAVE_LEFT;
454    edges |= have_left_p;
455    edges |= CDEF_HAVE_RIGHT;
456    for bx in 0..8usize {
457      if bx + 1 >= (input_xavail as usize >> 3) {
458        edges &= !CDEF_HAVE_RIGHT
459      };
460      let block_offset = tile_sbo.block_offset(bx << 1, by << 1);
461      if block_offset.0.x < blocks.cols() && block_offset.0.y < blocks.rows() {
462        let skip = blocks[block_offset].skip
463          & blocks[tile_sbo.block_offset(2 * bx + 1, 2 * by)].skip
464          & blocks[tile_sbo.block_offset(2 * bx, 2 * by + 1)].skip
465          & blocks[tile_sbo.block_offset(2 * bx + 1, 2 * by + 1)].skip;
466        let dir = cdef_dirs.dir[bx][by];
467        let var = cdef_dirs.var[bx][by];
468        for p in 0..planes {
469          let out_plane = &mut output.planes[p];
470          let in_plane = &input.planes[p];
471          let xdec = in_plane.cfg.xdec;
472          let ydec = in_plane.cfg.ydec;
473          let xsize = 8 >> xdec;
474          let ysize = 8 >> ydec;
475          let in_po = PlaneOffset {
476            x: (input_xoffset >> xdec) + (bx * xsize) as isize,
477            y: (input_yoffset >> ydec) + (by * ysize) as isize,
478          };
479          let in_stride = in_plane.cfg.stride;
480          let in_slice = &in_plane.slice(in_po);
481
482          let out_block = &mut out_plane.subregion_mut(Area::BlockRect {
483            bo: tile_sbo.block_offset(2 * bx, 2 * by).0,
484            width: xsize,
485            height: ysize,
486          });
487
488          if !skip {
489            let local_pri_strength;
490            let local_sec_strength;
491            let mut local_damping: i32 = cdef_damping + coeff_shift;
492            // See `Cdef_Uv_Dir` constant lookup table in Section 7.15.1
493            // <https://aomediacodec.github.io/av1-spec/#cdef-block-process>
494            let local_dir = if p == 0 {
495              local_pri_strength =
496                adjust_strength(cdef_pri_y_strength << coeff_shift, var);
497              local_sec_strength = cdef_sec_y_strength << coeff_shift;
498              if cdef_pri_y_strength != 0 {
499                dir as usize
500              } else {
501                0
502              }
503            } else {
504              local_pri_strength = cdef_pri_uv_strength << coeff_shift;
505              local_sec_strength = cdef_sec_uv_strength << coeff_shift;
506              local_damping -= 1;
507              if cdef_pri_uv_strength != 0 {
508                if xdec != ydec {
509                  [7, 0, 2, 4, 5, 6, 6, 6][dir as usize]
510                } else {
511                  dir as usize
512                }
513              } else {
514                0
515              }
516            };
517
518            // SAFETY: `cdef_filter_block` may call Assembly code.
519            // The asserts here verify that we are not calling it
520            // with invalid parameters.
521            unsafe {
522              assert!(
523                input.planes[p].cfg.width as isize
524                  >= in_po.x
525                    + xsize as isize
526                    + if edges & CDEF_HAVE_RIGHT > 0 { 2 } else { 0 }
527              );
528              assert!(
529                0 <= in_po.x - if edges & CDEF_HAVE_LEFT > 0 { 2 } else { 0 }
530              );
531              assert!(
532                input.planes[p].cfg.height as isize
533                  >= in_po.y
534                    + ysize as isize
535                    + if edges & CDEF_HAVE_BOTTOM > 0 { 2 } else { 0 }
536              );
537              assert!(
538                0 <= in_po.y - if edges & CDEF_HAVE_TOP > 0 { 2 } else { 0 }
539              );
540
541              cdef_filter_block(
542                out_block,
543                in_slice.as_ptr(),
544                in_stride as isize,
545                local_pri_strength,
546                local_sec_strength,
547                local_dir,
548                local_damping,
549                bit_depth,
550                xdec,
551                ydec,
552                edges,
553                fi.cpu_feature_level,
554              );
555            }
556          } else {
557            // no filtering, but we need to copy input to output
558            for i in 0..ysize {
559              for j in 0..xsize {
560                out_block[i][j] = in_slice[i][j];
561              }
562            }
563          }
564        }
565      }
566      edges |= CDEF_HAVE_LEFT;
567    }
568    edges |= CDEF_HAVE_TOP;
569  }
570}
571
572// The purpose of CDEF is to perform deringing based on the detected
573// direction of blocks.  CDEF parameters are stored for each 64 by 64
574// block of pixels.  The CDEF filter is applied on each 8 by 8 block
575// of pixels.  Reference:
576// http://av1-spec.argondesign.com/av1-spec/av1-spec.html#cdef-process
577
578//   input: A Frame of reconstructed/deblocked pixels prepared to
579//   undergo CDEF.  cdef_filter_tile acts on a subset of these input
580//   pixels, as specified by the PlaneRegion rect of the output. Note
581//   that the input is a Frame and not a Tile due to Tiles not
582//   allowing [supervised] out-of-rect access for padding pixels.
583//   This will be corrected at some point in the future.
584
585//   tb: the TileBlocks associated with the filtered region; the
586//   provided blocks co-locate with the output region.
587
588//   output: TileMut destination for filtered pixels.  The output's
589//   rect specifies the region of the input to be processed (x and y
590//   are relative to the input Frame's origin).  Note that an
591//   additional area of 2 pixels of padding is used for CDEF.  When
592//   these pixels are unavailable (beyond the visible frame or at a
593//   tile boundary), the filtering process ignores input pixels that
594//   don't exist.
595
596#[profiling::function]
597pub fn cdef_filter_tile<T: Pixel>(
598  fi: &FrameInvariants<T>, input: &Frame<T>, tb: &TileBlocks,
599  output: &mut TileMut<'_, T>,
600) {
601  // Each filter block is 64x64, except right and/or bottom for non-multiple-of-64 sizes.
602  // FIXME: 128x128 SB support will break this, we need FilterBlockOffset etc.
603
604  // No need to guard against having fewer actual coded blocks than
605  // the output.rect() area.  Inner code already guards this case.
606  let fb_width = (output.planes[0].rect().width + 63) / 64;
607  let fb_height = (output.planes[0].rect().height + 63) / 64;
608
609  // should parallelize this
610  for fby in 0..fb_height {
611    for fbx in 0..fb_width {
612      // tile_sbo is treated as an offset into the Tiles' plane
613      // regions, not as an absolute offset in the visible frame.  The
614      // Tile's own offset is added to this in order to address into
615      // the input Frame.
616      let tile_sbo = TileSuperBlockOffset(SuperBlockOffset { x: fbx, y: fby });
617      let cdef_index = tb.get_cdef(tile_sbo);
618      let cdef_dirs = cdef_analyze_superblock(fi, input, tb, tile_sbo);
619
620      cdef_filter_superblock(
621        fi, input, output, tb, tile_sbo, cdef_index, &cdef_dirs,
622      );
623    }
624  }
625}