diff --git a/dlls/windowscodecs/ddsformat.c b/dlls/windowscodecs/ddsformat.c
index 54126c13d70..7a27c48dee0 100644
--- a/dlls/windowscodecs/ddsformat.c
+++ b/dlls/windowscodecs/ddsformat.c
@@ -475,9 +475,47 @@ static HRESULT WINAPI DdsFrameDecode_Dds_CopyBlocks(IWICDdsFrameDecode *iface,
                                                     const WICRect *boundsInBlocks, UINT stride, UINT bufferSize,
                                                     BYTE *buffer)
 {
-    FIXME("(%p,%p,%u,%u,%p): stub.\n", iface, boundsInBlocks, stride, bufferSize, buffer);
+    DdsFrameDecode *This = impl_from_IWICDdsFrameDecode(iface);
+    int x, y, width, height;
+    UINT bytes_per_block, frame_stride, frame_size, i;
+    BYTE *data, *dst_buffer;
 
-    return E_NOTIMPL;
+    TRACE("(%p,%p,%u,%u,%p)\n", iface, boundsInBlocks, stride, bufferSize, buffer);
+
+    if (!buffer) return E_INVALIDARG;
+
+    bytes_per_block = This->info.bytes_per_block;
+    frame_stride = This->info.width_in_blocks * bytes_per_block;
+    frame_size = frame_stride * This->info.height_in_blocks;
+    if (!boundsInBlocks) {
+        if (stride < frame_stride) return E_INVALIDARG;
+        if (bufferSize < frame_size) return E_INVALIDARG;
+        memcpy(buffer, This->data, frame_size);
+        return S_OK;
+    }
+
+    x = boundsInBlocks->X;
+    y = boundsInBlocks->Y;
+    width = boundsInBlocks->Width;
+    height = boundsInBlocks->Height;
+    if (x < 0 || y < 0 || width <= 0 || height <= 0 ||
+        x + width > This->info.width_in_blocks ||
+        y + height > This->info.height_in_blocks) {
+        return E_INVALIDARG;
+    }
+    if (stride < width * bytes_per_block) return E_INVALIDARG;
+    if (bufferSize < stride * height) return E_INVALIDARG;
+
+    data = This->data + (x + y * This->info.width_in_blocks) * bytes_per_block;
+    dst_buffer = buffer;
+    for (i = 0; i < height; i++)
+    {
+        memcpy(dst_buffer, data, (size_t)width * bytes_per_block);
+        data += This->info.width_in_blocks * bytes_per_block;
+        dst_buffer += stride;
+    }
+
+    return S_OK;
 }
 
 static const IWICDdsFrameDecodeVtbl DdsFrameDecode_Dds_Vtbl = {
diff --git a/dlls/windowscodecs/tests/ddsformat.c b/dlls/windowscodecs/tests/ddsformat.c
index d718a07f962..a69ff35dcb9 100644
--- a/dlls/windowscodecs/tests/ddsformat.c
+++ b/dlls/windowscodecs/tests/ddsformat.c
@@ -537,46 +537,46 @@ static void test_dds_decoder_frame_data(IWICDdsFrameDecode *dds_frame, UINT fram
     frame_size = frame_stride * height_in_blocks;
 
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, NULL, 0, 0, NULL);
-    todo_wine ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
 
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, &rect_test_a, stride, sizeof(buffer), buffer);
-    todo_wine ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, &rect_test_b, stride, sizeof(buffer), buffer);
-    todo_wine ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, &rect_test_c, stride, sizeof(buffer), buffer);
-    todo_wine ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, &rect_test_d, stride, sizeof(buffer), buffer);
-    todo_wine ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
 
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, NULL, frame_stride - 1, sizeof(buffer), buffer);
-    todo_wine ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, NULL, frame_stride * 2, sizeof(buffer), buffer);
-    todo_wine ok (hr == S_OK, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == S_OK, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, NULL, frame_stride, sizeof(buffer), buffer);
-    todo_wine ok (hr == S_OK, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == S_OK, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, NULL, frame_stride, frame_stride * height_in_blocks - 1, buffer);
-    todo_wine ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, NULL, frame_stride, frame_stride * height_in_blocks, buffer);
-    todo_wine ok (hr == S_OK, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == S_OK, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
 
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, &rect, 0, sizeof(buffer), buffer);
-    todo_wine ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, &rect, stride - 1, sizeof(buffer), buffer);
-    todo_wine ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, &rect, stride * 2, sizeof(buffer), buffer);
-    todo_wine ok (hr == S_OK, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == S_OK, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
 
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, &rect, stride, 0, buffer);
-    todo_wine ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, &rect, stride, 1, buffer);
-    todo_wine ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, &rect, stride, stride * rect.Height - 1, buffer);
-    todo_wine ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, &rect, stride, stride * rect.Height, buffer);
-    todo_wine ok (hr == S_OK, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == S_OK, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
 
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, &rect, stride, sizeof(buffer), NULL);
-    todo_wine ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
+    ok (hr == E_INVALIDARG, "%d: [frame %d] Got unexpected hr %x\n", i, frame_index, hr);
 
     block_offset = 128; /* DDS magic and header */
     if (has_extended_header(test_data[i].data)) block_offset += 20; /* DDS extended header */
@@ -600,19 +600,19 @@ static void test_dds_decoder_frame_data(IWICDdsFrameDecode *dds_frame, UINT fram
     }
 
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, &rect, stride, sizeof(buffer), buffer);
-    todo_wine ok (hr == S_OK, "%d: [frame %d] CopyBlocks failed, hr=%x\n", i, frame_index, hr);
+    ok (hr == S_OK, "%d: [frame %d] CopyBlocks failed, hr=%x\n", i, frame_index, hr);
     if (hr != S_OK) return;
     ok (!strncmp((const char *)test_data[i].data + block_offset, (const char *)buffer, format_info.BytesPerBlock),
         "%d: [frame %d] Block data mismatch\n", i, frame_index);
 
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, NULL, frame_stride, sizeof(buffer), buffer);
-    todo_wine ok (hr == S_OK, "%d: [frame %d] CopyBlocks failed, hr=%x\n", i, frame_index, hr);
+    ok (hr == S_OK, "%d: [frame %d] CopyBlocks failed, hr=%x\n", i, frame_index, hr);
     if (hr != S_OK) return;
     ok (!strncmp((const char *)test_data[i].data + block_offset, (const char *)buffer, frame_size),
         "%d: [frame %d] Block data mismatch\n", i, frame_index);
 
     hr = IWICDdsFrameDecode_CopyBlocks(dds_frame, NULL, frame_stride * 2, sizeof(buffer), buffer);
-    todo_wine ok (hr == S_OK, "%d: [frame %d] CopyBlocks failed, hr=%x\n", i, frame_index, hr);
+    ok (hr == S_OK, "%d: [frame %d] CopyBlocks failed, hr=%x\n", i, frame_index, hr);
     if (hr != S_OK) return;
     ok (!strncmp((const char *)test_data[i].data + block_offset, (const char *)buffer, frame_size),
         "%d: [frame %d] Block data mismatch\n", i, frame_index);