[FFmpeg-cvslog] avfilter/bwdif: account for chroma sub-sampling in min size calculation

[Cosmin Stejerean]

ffmpeg | branch: release/4.3 | Cosmin Stejerean <cosmin at cosmin.at> | Wed Dec  6 18:39:32 2023 +0800| [23afb77b8ed5fd368c26292e927531b6470ff040] | committer: Michael Niedermayer

avfilter/bwdif: account for chroma sub-sampling in min size calculation

The current logic for detecting frames that are too small for the
algorithm does not account for chroma sub-sampling, and so a sample
where the luma plane is large enough, but the chroma planes are not
will not be rejected. In that event, a heap overflow will occur.

This change adjusts the logic to consider the chroma planes and makes
the change to all three bwdif implementations.

Fixes #10688

Signed-off-by: Cosmin Stejerean <cosmin at cosmin.at>
Reviewed-by: Thomas Mundt <tmundt75 at gmail.com>
Signed-off-by: Philip Langdale <philipl at overt.org>
(cherry picked from commit 737ede405b11a37fdd61d19cf25df296a0cb0b75)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=23afb77b8ed5fd368c26292e927531b6470ff040
---

 libavfilter/vf_bwdif.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/libavfilter/vf_bwdif.c b/libavfilter/vf_bwdif.c
index b6aed7a450..e4b4ec79b0 100644
--- a/libavfilter/vf_bwdif.c
+++ b/libavfilter/vf_bwdif.c
@@ -343,13 +343,14 @@ static int config_props(AVFilterLink *link)
     if(yadif->mode&1)
         link->frame_rate = av_mul_q(link->src->inputs[0]->frame_rate, (AVRational){2,1});
 
-    if (link->w < 3 || link->h < 4) {
-        av_log(ctx, AV_LOG_ERROR, "Video of less than 3 columns or 4 lines is not supported\n");
+    yadif->csp = av_pix_fmt_desc_get(link->format);
+    yadif->filter = filter;
+
+    if (AV_CEIL_RSHIFT(link->w, yadif->csp->log2_chroma_w) < 3 || AV_CEIL_RSHIFT(link->h, yadif->csp->log2_chroma_h) < 4) {
+        av_log(ctx, AV_LOG_ERROR, "Video with planes less than 3 columns or 4 lines is not supported\n");
         return AVERROR(EINVAL);
     }
 
-    yadif->csp = av_pix_fmt_desc_get(link->format);
-    yadif->filter = filter;
     if (yadif->csp->comp[0].depth > 8) {
         s->filter_intra = filter_intra_16bit;
         s->filter_line  = filter_line_c_16bit;