diff --git a/std-det-writer/include/JFH5Writer.hpp b/std-det-writer/include/JFH5Writer.hpp
index 95e05ee..2702f4e 100644
--- a/std-det-writer/include/JFH5Writer.hpp
+++ b/std-det-writer/include/JFH5Writer.hpp
@@ -38,11 +38,11 @@ public:
     ~JFH5Writer();
 
     void open_run(const std::string& output_file,
-                  const int64_t run_id,
-                  const uint32_t n_images,
-                  const uint32_t image_y_size,
-                  const uint32_t image_x_size,
-                  const uint32_t bits_per_pixel);
+                  const int run_id,
+                  const int n_images,
+                  const int image_y_size,
+                  const int image_x_size,
+                  const int bits_per_pixel);
     void close_run();
 
     void write_data(const int64_t run_id,
@@ -51,7 +51,7 @@ public:
 
     void write_meta(const int64_t run_id,
                     const uint32_t index,
-                    const ImageMetadata& meta);
+                    const ImageMetadata* meta);
 };
 
 #endif //JF_LIVE_WRITER_HPP
diff --git a/std-det-writer/src/JFH5Writer.cpp b/std-det-writer/src/JFH5Writer.cpp
index 2af43ad..21879bd 100644
--- a/std-det-writer/src/JFH5Writer.cpp
+++ b/std-det-writer/src/JFH5Writer.cpp
@@ -42,11 +42,11 @@ hid_t JFH5Writer::get_datatype(const int bits_per_pixel)
 }
 
 void JFH5Writer::open_run(const string& output_file,
-                          const int64_t run_id,
-                          const uint32_t n_images,
-                          const uint32_t image_y_size,
-                          const uint32_t image_x_size,
-                          const uint32_t bits_per_pixel)
+                          const int run_id,
+                          const int n_images,
+                          const int image_y_size,
+                          const int image_x_size,
+                          const int dtype)
 {
     close_run();
 
@@ -233,7 +233,7 @@ void JFH5Writer::write_data(
 }
 
 void JFH5Writer::write_meta(
-        const int64_t run_id, const uint32_t index, const ImageMetadata& meta)
+        const int64_t run_id, const uint32_t index, const ImageMetadata* meta)
 {
     if (run_id != current_run_id_) {
         throw runtime_error("Invalid run_id.");
@@ -260,12 +260,12 @@ void JFH5Writer::write_meta(
     }
 
     if (H5Dwrite(image_id_dataset_, H5T_NATIVE_UINT64,
-                 ram_ds, file_ds, H5P_DEFAULT, &(meta.id)) < 0) {
+                 ram_ds, file_ds, H5P_DEFAULT, &(meta->id)) < 0) {
         throw runtime_error("Cannot write data to pulse_id dataset.");
     }
 
     if (H5Dwrite(status_dataset_, H5T_NATIVE_UINT64,
-                 ram_ds, file_ds, H5P_DEFAULT, &(meta.status)) < 0) {
+                 ram_ds, file_ds, H5P_DEFAULT, &(meta->status)) < 0) {
         throw runtime_error("Cannot write data to is_good_image dataset.");
     }
 
diff --git a/std-det-writer/src/main.cpp b/std-det-writer/src/main.cpp
index d77e64e..b9a39e9 100644
--- a/std-det-writer/src/main.cpp
+++ b/std-det-writer/src/main.cpp
@@ -54,11 +54,15 @@ int main (int argc, char *argv[])
 
         // i_image == 0 -> we have a new run.
         if (meta.i_image == 0) {
-            writer.open_run(meta.run_id,
+            auto image_meta = (ImageMetadata*)
+                    image_buffer.get_slot_meta(meta.image_id);
+
+            writer.open_run(meta.output_file,
+                            meta.run_id,
                             meta.n_images,
-                            meta.image_y_size,
-                            meta.image_x_size,
-                            meta.bits_per_pixel);
+                            image_meta->height,
+                            image_meta->width,
+                            image_meta->dtype);
 
             stats.start_run(meta);
         }
@@ -73,7 +77,7 @@ int main (int argc, char *argv[])
 
         // Fair distribution of images among writers.
         if (meta.i_image % n_writers == i_writer) {
-            char* data = image_buffer.get_slot_data(meta.image_metadata.id);
+            char* data = image_buffer.get_slot_data(meta.image_id);
 
             stats.start_image_write();
             writer.write_data(meta.run_id, meta.i_image, data);
@@ -82,7 +86,9 @@ int main (int argc, char *argv[])
 
         // Only the first instance writes metadata.
         if (i_writer == 0) {
-            writer.write_meta(meta.run_id, meta.i_image, meta.image_metadata);
+            auto image_meta = (ImageMetadata*)
+                    image_buffer.get_slot_meta(meta.image_id);
+            writer.write_meta(meta.run_id, meta.i_image, image_meta);
         }
 
     }