[FFmpeg-devel] [PATCH] fix pad artifacting

Ben Lu benlu at x.com
Sat Feb 1 02:18:08 EET 2025


When using pad with eval=frame with variable frame sizes, we get
significant artifacting. This is due to incorrect frame sizes, resulting in
invalid frames. Made changes to use the output width and height for frame
sizes when using eval=frame, with if statement guards to make sure the
normal usage is unaffected

Signed-off-by: Ben Lu <benlu at x.com>
---
 libavfilter/vf_pad.c | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/libavfilter/vf_pad.c b/libavfilter/vf_pad.c
index 49fb272b24..846dd0a9f4 100644
--- a/libavfilter/vf_pad.c
+++ b/libavfilter/vf_pad.c
@@ -237,15 +237,24 @@ static AVFrame *get_video_buffer(AVFilterLink
*inlink, int w, int h)
     if (s->inlink_w <= 0)
         return NULL;

-    frame = ff_get_video_buffer(inlink->dst->outputs[0],
-                                w + (s->w - s->in_w),
-                                h + (s->h - s->in_h) + (s->x > 0));
+    if (s->eval_mode == EVAL_MODE_FRAME) {
+        frame = ff_get_video_buffer(inlink->dst->outputs[0], s->w, s->h);
+    } else {
+        frame = ff_get_video_buffer(inlink->dst->outputs[0],
+                                    w + (s->w - s->in_w),
+                                    h + (s->h - s->in_h) + (s->x > 0));
+    }

     if (!frame)
         return NULL;

-    frame->width  = w;
-    frame->height = h;
+    if (s->eval_mode == EVAL_MODE_FRAME) {
+        frame->width  = s->w;
+        frame->height = s->h;
+    } else {
+        frame->width  = w;
+        frame->height = h;
+    }

     for (plane = 0; plane < 4 && frame->data[plane] &&
frame->linesize[plane]; plane++) {
         int hsub = s->draw.hsub[plane];
@@ -358,9 +367,13 @@ static int filter_frame(AVFilterLink *inlink, AVFrame
*in)

     if (needs_copy) {
         av_log(inlink->dst, AV_LOG_DEBUG, "Direct padding impossible
allocating new frame\n");
-        out = ff_get_video_buffer(outlink,
-                                  FFMAX(inlink->w, s->w),
-                                  FFMAX(inlink->h, s->h));
+        if (s->eval_mode == EVAL_MODE_FRAME) {
+            out = ff_get_video_buffer(outlink, s->w, s->h);
+        } else {
+            out = ff_get_video_buffer(outlink,
+                                      FFMAX(inlink->w, s->w),
+                                      FFMAX(inlink->h, s->h));
+        }
         if (!out) {
             av_frame_free(&in);
             return AVERROR(ENOMEM);
-- 
2.35.1.70.gdb80f58b59-twtrsrc


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