diff --git a/libs/audio/include/psemek/audio/combine/mixer.hpp b/libs/audio/include/psemek/audio/combine/mixer.hpp
index baf9407b..1796978a 100644
--- a/libs/audio/include/psemek/audio/combine/mixer.hpp
+++ b/libs/audio/include/psemek/audio/combine/mixer.hpp
@@ -13,6 +13,8 @@ namespace psemek::audio
 		: stream
 	{
 		virtual channel_ptr add(stream_ptr stream) = 0;
+
+		virtual std::size_t stream_count() const = 0;
 	};
 
 	using mixer_ptr = std::shared_ptr<mixer>;
diff --git a/libs/audio/source/combine/mixer.cpp b/libs/audio/source/combine/mixer.cpp
index ff7f2677..98c5e69c 100644
--- a/libs/audio/source/combine/mixer.cpp
+++ b/libs/audio/source/combine/mixer.cpp
@@ -17,6 +17,11 @@ namespace psemek::audio
 		{
 			channel_ptr add(stream_ptr stream) override;
 
+			std::size_t stream_count() const override
+			{
+				return stream_count_.load();
+			}
+
 			std::size_t read(util::span<float> samples) override;
 
 			std::optional<std::size_t> length() const override
@@ -39,6 +44,7 @@ namespace psemek::audio
 			std::vector<channel_ptr> new_channels_;
 
 			std::atomic<std::size_t> played_{0};
+			std::atomic<std::size_t> stream_count_{0};
 		};
 
 		channel_ptr mixer_impl::add(stream_ptr stream)
@@ -89,6 +95,8 @@ namespace psemek::audio
 				alive_channels_.push_back(std::move(ch));
 			}
 
+			stream_count_ = alive_channels_.size();
+
 			std::swap(channels_, alive_channels_);
 			alive_channels_.clear();