diff --git a/src/dec/io.c b/src/dec/io.c
index e718acf6..0f2c8d10 100644
--- a/src/dec/io.c
+++ b/src/dec/io.c
@@ -250,7 +250,11 @@ static int EmitAlphaRGBA4444(const VP8Io* const io, WebPDecParams* const p) {
     int num_rows;
     const int start_y = GetAlphaSourceRow(io, &alpha, &num_rows);
     uint8_t* const base_rgba = buf->rgba + start_y * buf->stride;
+#ifdef WEBP_SWAP_16BIT_CSP
+    uint8_t* alpha_dst = base_rgba;
+#else
     uint8_t* alpha_dst = base_rgba + 1;
+#endif
     uint32_t alpha_mask = 0x0f;
     int i, j;
 
@@ -435,7 +439,11 @@ static int ExportAlpha(WebPDecParams* const p, int y_pos) {
 static int ExportAlphaRGBA4444(WebPDecParams* const p, int y_pos) {
   const WebPRGBABuffer* const buf = &p->output->u.RGBA;
   uint8_t* const base_rgba = buf->rgba + (p->last_y + y_pos) * buf->stride;
+#ifdef WEBP_SWAP_16BIT_CSP
+  uint8_t* alpha_dst = base_rgba;
+#else
   uint8_t* alpha_dst = base_rgba + 1;
+#endif
   int num_lines_out = 0;
   const WEBP_CSP_MODE colorspace = p->output->colorspace;
   const int width = p->scaler_a.dst_width;
diff --git a/src/dsp/upsampling.c b/src/dsp/upsampling.c
index e90310e8..5f1c1278 100644
--- a/src/dsp/upsampling.c
+++ b/src/dsp/upsampling.c
@@ -281,6 +281,15 @@ static void ApplyAlphaMultiply4444(uint8_t* rgba4444,
   while (h-- > 0) {
     int i;
     for (i = 0; i < w; ++i) {
+#ifdef WEBP_SWAP_16BIT_CSP
+      const uint8_t a = (rgba4444[2 * i + 0] & 0x0f);
+      const uint32_t mult = MULTIPLIER(a);
+      const uint8_t r = multiply(dither_hi(rgba4444[2 * i + 1]), mult);
+      const uint8_t g = multiply(dither_lo(rgba4444[2 * i + 1]), mult);
+      const uint8_t b = multiply(dither_hi(rgba4444[2 * i + 0]), mult);
+      rgba4444[2 * i + 1] = (r & 0xf0) | ((g >> 4) & 0x0f);
+      rgba4444[2 * i + 0] = (b & 0xf0) | a;
+#else
       const uint8_t a = (rgba4444[2 * i + 1] & 0x0f);
       const uint32_t mult = MULTIPLIER(a);
       const uint8_t r = multiply(dither_hi(rgba4444[2 * i + 0]), mult);
@@ -288,6 +297,7 @@ static void ApplyAlphaMultiply4444(uint8_t* rgba4444,
       const uint8_t b = multiply(dither_hi(rgba4444[2 * i + 1]), mult);
       rgba4444[2 * i + 0] = (r & 0xf0) | ((g >> 4) & 0x0f);
       rgba4444[2 * i + 1] = (b & 0xf0) | a;
+#endif
     }
     rgba4444 += stride;
   }