This avoids triggering overflows in the filters, and avoids stray
test failures in the approximate functions on x86; due to rounding
differences, one implementation might overflow while another one
doesn't.
Signed-off-by: Martin Storsjö <mar...@martin.st>
---
FWIW, this modification runs successfully with over 1000 different
seeds in checkasm.
---
tests/checkasm/sw_scale.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/tests/checkasm/sw_scale.c b/tests/checkasm/sw_scale.c
index d72506ed86..ec06eafebe 100644
--- a/tests/checkasm/sw_scale.c
+++ b/tests/checkasm/sw_scale.c
@@ -188,7 +188,6 @@ static void check_yuv2yuvX(int accurate)
uint8_t d_val = rnd();
memset(dither, d_val, LARGEST_INPUT_SIZE);
randomize_buffers((uint8_t*)src_pixels, LARGEST_FILTER *
LARGEST_INPUT_SIZE * sizeof(int16_t));
- randomize_buffers((uint8_t*)filter_coeff, LARGEST_FILTER *
sizeof(int16_t));
ctx = sws_alloc_context();
if (accurate)
ctx->flags |= SWS_ACCURATE_RND;
@@ -202,6 +201,21 @@ static void check_yuv2yuvX(int accurate)
if (dstW <= osi)
continue;
for (fsi = 0; fsi < FILTER_SIZES; ++fsi) {
+ // Generate filter coefficients for the given filter size,
+ // with some properties:
+ // - The coefficients add up to the intended sum (4096, 1<<12)
+ // - The coefficients contain negative values
+ // - The filter intermediates don't overflow for worst case
+ // inputs (all positive coefficients are coupled with
+ // input_max and all negative coefficients with input_min,
+ // or vice versa).
+ // Produce a filter with all coefficients set to
+ // -((1<<12)/(filter_size-1)) except for one (randomly chosen)
+ // which is set to ((1<<13)-1).
+ for (i = 0; i < filter_sizes[fsi]; ++i)
+ filter_coeff[i] = -((1 << 12) / (filter_sizes[fsi] - 1));
+ filter_coeff[rnd() % filter_sizes[fsi]] = (1 << 13) - 1;
+
src = av_malloc(sizeof(int16_t*) * filter_sizes[fsi]);
vFilterData = av_malloc((filter_sizes[fsi] + 2) * sizeof(union
VFilterData));
memset(vFilterData, 0, (filter_sizes[fsi] + 2) * sizeof(union
VFilterData));
--
2.25.1
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