diff --git a/src/encoderstate.c b/src/encoderstate.c
index 0bf19cd7..d2b0cd49 100644
--- a/src/encoderstate.c
+++ b/src/encoderstate.c
@@ -942,26 +942,10 @@ void encoder_compute_stats(encoder_state_t *state, FILE * const recout, double f
   threadqueue_waitfor(encoder->threadqueue, state->tqj_bitstream_written);
   
   if (recout) {
-    const videoframe_t * const frame = state->tile->frame;
-    // Write reconstructed frame out.
-    // Use conformance-window dimensions instead of internal ones.
-    const int width = frame->width;
-    const int out_width = encoder->in.real_width;
-    const int out_height = encoder->in.real_height;
-    int y;
-    const pixel_t *y_rec = frame->rec->y;
-    const pixel_t *u_rec = frame->rec->u;
-    const pixel_t *v_rec = frame->rec->v;
-
-    for (y = 0; y < out_height; ++y) {
-      fwrite(&y_rec[y * width], sizeof(*y_rec), out_width, recout);
-    }
-    for (y = 0; y < out_height / 2; ++y) {
-      fwrite(&u_rec[y * width / 2], sizeof(*u_rec), out_width / 2, recout);
-    }
-    for (y = 0; y < out_height / 2; ++y) {
-      fwrite(&v_rec[y * width / 2], sizeof(*v_rec), out_width / 2, recout);
-    }
+    yuv_io_write(recout,
+                 state->tile->frame->rec,
+                 encoder->in.real_width,
+                 encoder->in.real_height);
   }
   
   videoframe_compute_psnr(state->tile->frame, frame_psnr);
diff --git a/src/yuv_io.c b/src/yuv_io.c
index a45d0c43..33da011b 100644
--- a/src/yuv_io.c
+++ b/src/yuv_io.c
@@ -148,3 +148,33 @@ int yuv_io_seek(FILE* file, unsigned frames,
 
     return !error || feof(file);
 }
+
+
+/**
+ * \brief Write a single frame to a file.
+ *
+ * \param file           output file
+ * \param img            image to output
+ * \param output_width   width of the output in pixels
+ * \param output_height  height of the output in pixels
+ *
+ * \return              1 on success, 0 on failure
+ */
+int yuv_io_write(FILE* file,
+                image_t const* img,
+                unsigned output_width, unsigned output_height)
+{
+  const int width = img->width;
+  for (int y = 0; y < output_height; ++y) {
+    fwrite(&img->y[y * width], sizeof(*img->y), output_width, file);
+    // TODO: Check that fwrite succeeded.
+  }
+  for (int y = 0; y < output_height / 2; ++y) {
+    fwrite(&img->u[y * width / 2], sizeof(*img->u), output_width / 2, file);
+  }
+  for (int y = 0; y < output_height / 2; ++y) {
+    fwrite(&img->v[y * width / 2], sizeof(*img->v), output_width / 2, file);
+  }
+
+  return 1;
+}
diff --git a/src/yuv_io.h b/src/yuv_io.h
index dca7e574..6fcd2081 100644
--- a/src/yuv_io.h
+++ b/src/yuv_io.h
@@ -35,4 +35,8 @@ int yuv_io_read(FILE* file,
 int yuv_io_seek(FILE* file, unsigned frames,
                 unsigned input_width, unsigned input_height);
 
+int yuv_io_write(FILE* file,
+                image_t const* img,
+                unsigned output_width, unsigned output_height);
+
 #endif // YUV_IO_H_