diff --git a/app/codec/samplebuffer.cpp b/app/codec/samplebuffer.cpp
index 45b410535..fdd25b825 100644
--- a/app/codec/samplebuffer.cpp
+++ b/app/codec/samplebuffer.cpp
@@ -173,15 +173,15 @@ void SampleBuffer::speed(double speed)
     return;
   }
 
-  int max_adjusted_nb_samples = qRound(static_cast<double>(sample_count_per_channel_) * speed);
+  sample_count_per_channel_ = qRound(static_cast<double>(sample_count_per_channel_) / speed);
 
   float** input_data = data_;
   float** output_data;
 
-  allocate_sample_buffer(&output_data, audio_params_.channel_count(), max_adjusted_nb_samples);
+  allocate_sample_buffer(&output_data, audio_params_.channel_count(), sample_count_per_channel_);
 
-  for (int i=0;i<max_adjusted_nb_samples;i++) {
-    int input_index = qRound(static_cast<double>(i) * speed);
+  for (int i=0;i<sample_count_per_channel_;i++) {
+    int input_index = qFloor(static_cast<double>(i) * speed);
 
     for (int j=0;j<audio_params_.channel_count();j++) {
       output_data[j][i] = input_data[j][input_index];
diff --git a/app/render/backend/renderworker.cpp b/app/render/backend/renderworker.cpp
index 4fa7b5852..6cb628551 100644
--- a/app/render/backend/renderworker.cpp
+++ b/app/render/backend/renderworker.cpp
@@ -110,11 +110,9 @@ NodeValueTable RenderWorker::GenerateBlockTable(const TrackOutput *track, const
 
       // Destination buffer
       NodeValueTable table = GenerateTable(b, range_for_block);
-      QVariant sample_val = table.Take(NodeParam::kSamples);
-      SampleBufferPtr samples_from_this_block;
+      SampleBufferPtr samples_from_this_block = table.Take(NodeParam::kSamples).value<SampleBufferPtr>();
 
-      if (sample_val.isNull()
-          || !(samples_from_this_block = sample_val.value<SampleBufferPtr>())) {
+      if (!samples_from_this_block) {
         // If we retrieved no samples from this block, do nothing
         continue;
       }