diff --git a/Project.toml b/Project.toml
index 9aed8765c10b4294ca1a1116cbfd049f7a703d0f..5dbf3b2616df7ea4b67921f501acf9722250d0a6 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "TaggingBackends"
 uuid = "e551f703-3b82-4335-b341-d497b48d519b"
 authors = ["François Laurent", "Institut Pasteur"]
-version = "0.7"
+version = "0.7.1"
 
 [deps]
 Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
diff --git a/pyproject.toml b/pyproject.toml
index 446468d8a8ece05e1aa0b195634b8e8f83346387..5cab35d6fc8a3a3d121ac999bb46f879935af816 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "TaggingBackends"
-version = "0.7"
+version = "0.7.1"
 description = "Backbone for LarvaTagger.jl tagging backends"
 authors = ["François Laurent"]
 
diff --git a/src/LarvaDatasets.jl b/src/LarvaDatasets.jl
index 4ddeb45eeb427874dd7ea9f7f1d58db83fa382fc..3e89f955b78e957450bf24264f20e5bbbbab3223 100644
--- a/src/LarvaDatasets.jl
+++ b/src/LarvaDatasets.jl
@@ -271,17 +271,18 @@ function write_larva_dataset_hdf5(path, counts, files, refs, nsteps_before, nste
         end
     end
     h5open(path, "w") do h5
+        g = create_group(h5, "samples")
         Threads.foreach(ch) do (file, refs, sampleid)
             @info "Sampling series of spines in run: $(runid(file))"
-            processfile(h5, file, refs, sampleid, nsteps_before, nsteps_after;
+            processfile(g, file, refs, sampleid, nsteps_before, nsteps_after;
                         fixmwt=fixmwt, frameinterval=frameinterval)
         end
-        attributes(h5["samples"])["n_samples"] = sampleid
+        attributes(g)["n_samples"] = sampleid
         # extension
         h5["labels"] = collect(keys(counts))
         #h5["files"] = [f.source for f in files]
         if !isnothing(frameinterval)
-            attributes(h5["samples"])["frame_interval"] = frameinterval
+            attributes(g)["frame_interval"] = frameinterval
         end
     end
 end
@@ -363,7 +364,7 @@ function processfile(h5, file, refs, sampleid, nsteps_before, nsteps_after;
             sample[:,8] = lengths
             sample[:,9:end] = spines
             #
-            name = "samples/sample_$sampleid"
+            name = "sample_$sampleid"
             # transpose for compatibility with h5py
             # see issue https://github.com/JuliaIO/HDF5.jl/issues/785
             h5[name] = permutedims(sample, reverse(1:ndims(sample)))
@@ -517,9 +518,6 @@ function write_larva_dataset_hdf5(output_dir::String,
     h5open(output_file, "cw") do h5
         attributes(h5["samples"])["len_traj"] = window_length
         attributes(h5["samples"])["len_pred"] = window_length
-        if !isnothing(frameinterval)
-            attributes(h5["samples"])["frame_interval"] = frameinterval
-        end
     end
     return output_file
 end