Commit dff901ff authored by David Barker's avatar David Barker Committed by Debargha Mukherjee

[loop-restoration, bugfix] Restrict sampling of deblocked pixels

There is a special case with certain frame heights, where we
end up with a loop restoration stripe which ends 1px above the
crop border.

Previously this case was handled in quite an ugly way, which also
disagrees with the spec (+ isn't great for hardware). This patch
changes things to match the spec.

Specifically, the old method was to sometimes upscale one extra
row of deblocked pixels so that we could always have a 2px
"below" border for each processing stripe. The new method is to
only use rows inside the crop border, and to duplicate them if


Change-Id: Idf8ab510e1091dc3f5b257de60e16bca214d8dc4
parent 47cc2559
......@@ -1729,23 +1729,6 @@ static void extend_lines(uint8_t *buf, int width, int height, int stride,
/* Important: There is a special case in this function which we manage to
deal with easily in this implementation, but which other implementations
should be aware of.
When frame->crop_height[] is either:
* 57 (mod 64) for planes with subsampling_y == 0, or
* 29 (mod 32) for planes with subsampling_y == 1
then we will have a restoration stripe which ends 1px above the crop border
in this particular plane. We want to save 2 rows of deblocked "below"
pixels. We can get away with doing that, even though one of the rows lies
outside of the crop region, because the deblocker always produces output
which is a multiple of 8 luma pixels high.
Note that save_cdef_boundary_lines() doesn't have this issue, because it
always saves CDEF pixels from *inside* the appropriate stripe, rather
than above/below it.
static void save_deblock_boundary_lines(
const YV12_BUFFER_CONFIG *frame, const AV1_COMMON *cm, int plane, int row,
int stripe, int use_highbd, int is_above,
......@@ -1762,31 +1745,46 @@ static void save_deblock_boundary_lines(
uint8_t *bdry_rows = bdry_start + RESTORATION_CTX_VERT * stripe * bdry_stride;
// There is a rare case in which a processing stripe can end 1px above the
// crop border. In this case, we do want to use deblocked pixels from below
// the stripe (hence why we ended up in this function), but instead of
// fetching 2 "below" rows we need to fetch one and duplicate it.
// This is equivalent to clamping the sample locations against the crop border
const int lines_to_save =
AOMMIN(RESTORATION_CTX_VERT, frame->crop_heights[is_uv] - row);
assert(lines_to_save == 1 || lines_to_save == 2);
int upscaled_width;
int line_bytes;
if (!av1_superres_unscaled(cm)) {
const int ss_x = is_uv && cm->subsampling_x;
upscaled_width = (cm->superres_upscaled_width + ss_x) >> ss_x;
line_bytes = upscaled_width << use_highbd;
if (use_highbd)
cm, CONVERT_TO_BYTEPTR(src_rows), frame->strides[is_uv],
CONVERT_TO_BYTEPTR(bdry_rows), boundaries->stripe_boundary_stride,
plane, lines_to_save);
av1_upscale_normative_rows(cm, src_rows, frame->strides[is_uv], bdry_rows,
boundaries->stripe_boundary_stride, plane,
} else {
upscaled_width = frame->crop_widths[is_uv];
const int line_bytes = upscaled_width << use_highbd;
for (int i = 0; i < RESTORATION_CTX_VERT; i++) {
line_bytes = upscaled_width << use_highbd;
for (int i = 0; i < lines_to_save; i++) {
memcpy(bdry_rows + i * bdry_stride, src_rows + i * src_stride,
// If we only saved one line, then copy it into the second line buffer
if (lines_to_save == 1)
memcpy(bdry_rows + bdry_stride, bdry_rows, line_bytes);
extend_lines(bdry_rows, upscaled_width, RESTORATION_CTX_VERT, bdry_stride,
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