PR #21038 opened by Niklas Haas (haasn) URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21038 Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21038.patch
The current logic assumes `s->reset_sar` always resets the SAR, but this is only true if `force_oar` is actually true as well, meaning that in the case of `s->reset_sar && !force_oar`, the SAR is incorrectly set to 1:1. While we could fix this by also forcing `force_oar` for multiple inputs, that would have unintended consequences when the user explicitly sets the desired resolution. Instead, pass-through the SAR in this case; matching the intended behavior of inheriting the SAR from the base layer input. >From 0ab721603cd708327d70ac9721950778fe2d7b5c Mon Sep 17 00:00:00 2001 From: Niklas Haas <[email protected]> Date: Fri, 28 Nov 2025 13:43:27 +0100 Subject: [PATCH] avfilter/vf_libplacebo: always pass through SAR when stretching The current logic assumes `s->reset_sar` always resets the SAR, but this is only true if `force_oar` is actually true as well, meaning that in the case of `s->reset_sar && !force_oar`, the SAR is incorrectly set to 1:1. While we could fix this by also forcing `force_oar` for multiple inputs, that would have unintended consequences when the user explicitly sets the desired resolution. Instead, pass-through the SAR in this case; matching the intended behavior of inheriting the SAR from the base layer input. --- libavfilter/vf_libplacebo.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/libavfilter/vf_libplacebo.c b/libavfilter/vf_libplacebo.c index 42501c51f2..c5085aa7e9 100644 --- a/libavfilter/vf_libplacebo.c +++ b/libavfilter/vf_libplacebo.c @@ -1507,10 +1507,7 @@ static int libplacebo_config_output(AVFilterLink *outlink) } } - if (s->reset_sar) { - /* SAR is normalized, or we have multiple inputs, set out to 1:1 */ - outlink->sample_aspect_ratio = (AVRational){ 1, 1 }; - } else if (inlink->sample_aspect_ratio.num && s->fit_mode == FIT_FILL) { + if (inlink->sample_aspect_ratio.num && s->fit_mode == FIT_FILL) { /* This is consistent with other scale_* filters, which only * set the outlink SAR to be equal to the scale SAR iff the input SAR * was set to something nonzero */ @@ -1518,6 +1515,9 @@ static int libplacebo_config_output(AVFilterLink *outlink) const AVRational ar_out = { outlink->w, outlink->h }; const AVRational stretch = av_div_q(ar_in, ar_out); outlink->sample_aspect_ratio = av_mul_q(inlink->sample_aspect_ratio, stretch); + } else if (s->reset_sar) { + /* SAR is normalized, or we have multiple inputs, set out to 1:1 */ + outlink->sample_aspect_ratio = (AVRational){ 1, 1 }; } else { outlink->sample_aspect_ratio = inlink->sample_aspect_ratio; } -- 2.49.1 _______________________________________________ ffmpeg-devel mailing list -- [email protected] To unsubscribe send an email to [email protected]
