avfilter/buffersrc: stop passing AV_NOPTS_VALUE on EOF

libavfilter/buffersrc.c

@@ -61,6 +61,7 @@ typedef struct BufferSourceContext {
     AVChannelLayout ch_layout;
 
     int eof;
+    int64_t last_pts;
 } BufferSourceContext;
 
 #define CHECK_VIDEO_PARAM_CHANGE(s, c, width, height, format, pts)\
@@ -191,10 +192,12 @@ FF_ENABLE_DEPRECATION_WARNINGS
     s->nb_failed_requests = 0;
 
     if (!frame)
-        return av_buffersrc_close(ctx, AV_NOPTS_VALUE, flags);
+        return av_buffersrc_close(ctx, s->last_pts, flags);
     if (s->eof)
         return AVERROR(EINVAL);
 
+    s->last_pts = frame->pts + frame->duration;
+
     refcounted = !!frame->buf[0];
 
     if (!(flags & AV_BUFFERSRC_FLAG_NO_CHECK_FORMAT)) {