diff --git a/libswscale/filters.c b/libswscale/filters.c
index f9e0f3a1d0..e94b2ea5f6 100644
--- a/libswscale/filters.c
+++ b/libswscale/filters.c
@@ -192,7 +192,11 @@ int ff_sws_filter_generate(void *log, const SwsFilterParams *params,
     if (scaler == SWS_SCALE_AUTO)
         scaler = SWS_SCALE_BICUBIC;
 
-    const double ratio = (double) params->dst_size / params->src_size;
+    double virtual_size = params->virtual_size;
+    if (!virtual_size)
+        virtual_size = params->dst_size;
+
+    const double ratio = virtual_size / params->src_size;
     double stretch = 1.0;
     if (ratio < 1.0 && scaler != SWS_SCALE_POINT) {
         /* Widen filter for downscaling (anti-aliasing) */
@@ -241,6 +245,7 @@ int ff_sws_filter_generate(void *log, const SwsFilterParams *params,
     memcpy(filter->name, fun.name, sizeof(filter->name));
     filter->src_size = params->src_size;
     filter->dst_size = params->dst_size;
+    filter->virtual_size = virtual_size;
     filter->offset = params->offset;
     filter->filter_size = filter_size;
     if (filter->filter_size == 1)
diff --git a/libswscale/filters.h b/libswscale/filters.h
index 9cb467db24..830ee00200 100644
--- a/libswscale/filters.h
+++ b/libswscale/filters.h
@@ -73,6 +73,20 @@ typedef struct SwsFilterParams {
     int src_size;
     int dst_size;
 
+    /**
+     * The virtual output size. If zero, this is assumed to be the same as
+     * `dst_size`. Matters for e.g. chroma subsampling, where the the luma
+     * plane may be smaller than the dst_size. For example, a 99x99 input
+     * image has a chroma size of 50x50, which would be 100x100 after
+     * chroma upscaling; but is sampled only at 99x99 resolution. In this
+     * instance, dst_size is 99x99 and virtual_size is 100x100.
+     *
+     * The upscaling offset from this shift is implicit and does not need
+     * to be accounted for in `offset`. In other words, `offset` is taken
+     * relative to the virtual size, not the sampled size.
+     */
+    double virtual_size;
+
     /**
      * The sample offset, in units of input pixels. This is added onto all
      * sampled coordinates directly, i.e. a value of offset = 1.0 would shift
@@ -111,6 +125,7 @@ typedef struct SwsFilterWeights {
      */
     int src_size;
     int dst_size;
+    double virtual_size;
     double offset;
 
     /**