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mirror of https://github.com/FFmpeg/FFmpeg.git synced 2025-08-10 06:10:52 +02:00

avfilter/vf_libplacebo: set correct alpha mode before blending

&pl_alpha_overlay expects straight alpha, but the alpha output may be
premultiplied as a result of the target alpha mode (or in the absence of an
alpha channel). Fix it by requesting independent alpha explicitly when
blending.
This commit is contained in:
Niklas Haas
2025-02-19 22:08:30 +01:00
parent c85879c601
commit 651bfd0dad

View File

@@ -908,6 +908,9 @@ static int output_frame(AVFilterContext *ctx, int64_t pts)
opts->params.skip_caching_single_frame = high_fps; opts->params.skip_caching_single_frame = high_fps;
update_crops(ctx, in, &target, out->pts * av_q2d(outlink->time_base)); update_crops(ctx, in, &target, out->pts * av_q2d(outlink->time_base));
pl_render_image_mix(in->renderer, &in->mix, &target, &opts->params); pl_render_image_mix(in->renderer, &in->mix, &target, &opts->params);
/* Force straight output and set correct blend mode */
target.repr.alpha = PL_ALPHA_INDEPENDENT;
opts->params.blend_params = &pl_alpha_overlay; opts->params.blend_params = &pl_alpha_overlay;
#if PL_API_VER >= 346 #if PL_API_VER >= 346
opts->params.background = opts->params.border = PL_CLEAR_SKIP; opts->params.background = opts->params.border = PL_CLEAR_SKIP;