diff --git a/src/gallium/drivers/d3d12/d3d12_video_dec_av1.cpp b/src/gallium/drivers/d3d12/d3d12_video_dec_av1.cpp
index 7c0b57a7d4e..3998b4c0b47 100644
--- a/src/gallium/drivers/d3d12/d3d12_video_dec_av1.cpp
+++ b/src/gallium/drivers/d3d12/d3d12_video_dec_av1.cpp
@@ -332,7 +332,7 @@ d3d12_video_decoder_prepare_dxva_slices_control_av1(struct d3d12_video_decoder *
    debug_printf("[d3d12_video_decoder_av1] Upper layer reported %d tiles for this frame, parsing them below...\n",
                   tileCount);
 
-   uint64_t totalSlicesDXVAArrayByteSize = tileCount * sizeof(DXVA_Tile_AV1);
+   size_t totalSlicesDXVAArrayByteSize = tileCount * sizeof(DXVA_Tile_AV1);
    vecOutSliceControlBuffers.resize(totalSlicesDXVAArrayByteSize);
 
    uint8_t* pData = vecOutSliceControlBuffers.data();
diff --git a/src/gallium/drivers/d3d12/d3d12_video_dec_h264.cpp b/src/gallium/drivers/d3d12/d3d12_video_dec_h264.cpp
index ded46644622..680ca4e765d 100644
--- a/src/gallium/drivers/d3d12/d3d12_video_dec_h264.cpp
+++ b/src/gallium/drivers/d3d12/d3d12_video_dec_h264.cpp
@@ -135,7 +135,7 @@ d3d12_video_decoder_prepare_dxva_slices_control_h264(struct d3d12_video_decoder
                                                      std::vector<uint8_t> &vecOutSliceControlBuffers,
                                                      struct pipe_h264_picture_desc *picture_h264)
 {
-   uint64_t TotalSlicesDXVAArrayByteSize = picture_h264->slice_count * sizeof(DXVA_Slice_H264_Short);
+   size_t TotalSlicesDXVAArrayByteSize = picture_h264->slice_count * sizeof(DXVA_Slice_H264_Short);
    vecOutSliceControlBuffers.resize(TotalSlicesDXVAArrayByteSize);
    uint8_t* pData = vecOutSliceControlBuffers.data();
    assert(picture_h264->slice_parameter.slice_info_present);