diff options
author | Marton Balint <cus@passwd.hu> | 2022-07-07 21:43:20 +0200 |
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committer | Marton Balint <cus@passwd.hu> | 2022-07-10 22:35:20 +0200 |
commit | a6f0e641bcde6d8475c5d5473ac9b4de89618fc5 (patch) | |
tree | 99eb2dfffcab5f6b17bbc8e8242b5aeaf6ff9faa /libavfilter | |
parent | 68fdc9de8462f9661f86d1b2e13c06695247e480 (diff) |
avfilter/vf_zscale: simplify and fix slice_params calculations
Do not insist on a fixed slice height, because that can still cause overflows
in corner cases as described in this comment:
https://github.com/sekrit-twc/zimg/issues/177#issuecomment-1157734233
Signed-off-by: Marton Balint <cus@passwd.hu>
Diffstat (limited to 'libavfilter')
-rw-r--r-- | libavfilter/vf_zscale.c | 18 |
1 files changed, 4 insertions, 14 deletions
diff --git a/libavfilter/vf_zscale.c b/libavfilter/vf_zscale.c index 6861eef278..8e50457c6b 100644 --- a/libavfilter/vf_zscale.c +++ b/libavfilter/vf_zscale.c @@ -227,22 +227,12 @@ static int query_formats(AVFilterContext *ctx) static void slice_params(ZScaleContext *s, int out_h, int in_h) { - int slice_size; - - slice_size = (out_h + (s->nb_threads / 2)) / s->nb_threads; - if (slice_size % 2) - slice_size += 1; s->out_slice_start[0] = 0; - s->out_slice_end[0] = FFMIN(out_h, slice_size); - for (int i = 1; i < s->nb_threads - 1; i++) { - s->out_slice_start[i] = s->out_slice_end[i-1]; - s->out_slice_end[i] = s->out_slice_start[i] + slice_size; - } - - if (s->nb_threads > 1) { - s->out_slice_start[s->nb_threads - 1] = s->out_slice_end[s->nb_threads - 2]; - s->out_slice_end[s->nb_threads - 1] = out_h; + for (int i = 1; i < s->nb_threads; i++) { + int slice_end = out_h * i / s->nb_threads; + s->out_slice_end[i - 1] = s->out_slice_start[i] = FFALIGN(slice_end, 2); } + s->out_slice_end[s->nb_threads - 1] = out_h; for (int i = 0; i < s->nb_threads; i++) { s->in_slice_start[i] = s->out_slice_start[i] * in_h / (double)out_h; |