diff --git a/src/app.zig b/src/app.zig
index c84752c..6fd5409 100644
--- a/src/app.zig
+++ b/src/app.zig
@@ -187,6 +187,23 @@ pub const SampleList = struct {
             return self.buffer[0..self.len];
         }
 
+        pub fn recomputeMinMax(self: *Block) void {
+            if (self.len == 0) {
+                self.min = null;
+                self.max = 0;
+            }
+
+            var min = self.buffer[0];
+            var max = self.buffer[0];
+            for (self.samplesSlice()[1..]) |sample| {
+                min = @min(min, sample);
+                max = @max(max, sample);
+            }
+
+            self.min = min;
+            self.max = max;
+        }
+
         pub fn append(self: *Block, samples: []const f64) usize {
             const unused_slice = self.buffer[self.len..];
 
@@ -285,6 +302,18 @@ pub const SampleList = struct {
         self.* = SampleList.init(allocator);
     }
 
+    fn appendEmptyBlock(self: *SampleList) !void {
+        const allocator = self.arena.child_allocator;
+        const buffer_allocator = self.arena.allocator();
+
+        const block_buffer = try buffer_allocator.create(Block.Buffer);
+        errdefer buffer_allocator.destroy(block_buffer);
+
+        try self.blocks.append(allocator, Block{
+            .buffer = block_buffer
+        });
+    }
+
     fn getBlockAtSample(self: *SampleList, sample_index: usize) ?*Block {
         return self.getBlock(@divFloor(sample_index, Block.capacity));
     }
@@ -297,21 +326,35 @@ pub const SampleList = struct {
         return null;
     }
 
+    pub fn getSample(self: *SampleList, sample_index: usize) ?*f64 {
+        const block_id = @divFloor(sample_index, Block.capacity);
+        if (self.getBlock(block_id)) |block| {
+            const i = @mod(sample_index, Block.capacity);
+            if (i <= block.len) {
+                return &block.buffer[i];
+            }
+        }
+
+        return null;
+    }
+
+    pub fn reserveEmptyBlocks(self: *SampleList, total_block_count: usize) !void {
+        for (self.blocks.items) |*block| {
+            block.clear();
+        }
+
+        while (self.blocks.items.len < total_block_count) {
+            try self.appendEmptyBlock();
+        }
+    }
+
     pub fn append(self: *SampleList, samples: []const f64) !void {
         if (samples.len == 0) return;
 
         var appended_count: usize = 0;
         while (appended_count < samples.len) {
             if (self.blocks.items.len == 0 or self.blocks.getLast().len == Block.capacity) {
-                const allocator = self.arena.child_allocator;
-                const buffer_allocator = self.arena.allocator();
-
-                const block_buffer = try buffer_allocator.create(Block.Buffer);
-                errdefer buffer_allocator.destroy(block_buffer);
-
-                try self.blocks.append(allocator, Block{
-                    .buffer = block_buffer
-                });
+                try self.appendEmptyBlock();
             }
 
             const last_block = &self.blocks.items[self.blocks.items.len - 1];
@@ -756,6 +799,7 @@ pub const Project = struct {
     }
 
     pub fn appendSamples(self: *Project, allocator: Allocator, sample_list_id: Id, samples: []const f64) !void {
+        _ = allocator;
         if (samples.len == 0) return;
 
         const sample_list = self.sample_lists.get(sample_list_id).?;
@@ -767,7 +811,6 @@ pub const Project = struct {
 
         try sample_list.append(samples);
 
-        try self.refreshTransformedSamplesBySampleList(allocator, sample_list_id);
         self.refreshMarkedRanges(sample_list_id, affected_range);
     }
 
@@ -781,7 +824,6 @@ pub const Project = struct {
 
         sample_list.clear(allocator);
 
-        try self.refreshTransformedSamplesBySampleList(allocator, sample_list_id);
         self.refreshMarkedRanges(sample_list_id, affected_range);
     }
 
@@ -821,38 +863,6 @@ pub const Project = struct {
         // }
     }
 
-    fn refreshTransformedSamplesBySampleList(self: *Project, allocator: Allocator, sample_list_id: Id) !void {
-        var view_iter = self.views.idIterator();
-        while (view_iter.next()) |view_id| {
-            const view_sample_list_id = self.getViewSampleListId(view_id);
-            if (view_sample_list_id.eql(sample_list_id)) {
-                try self.refreshTransformedSamplesByView(allocator, view_id);
-            }
-        }
-    }
-
-    fn refreshTransformedSamplesByView(self: *Project, allocator: Allocator, view_id: Id) !void {
-        const view = self.views.get(view_id).?;
-
-        if (view.sliding_window) |sliding_window| {
-            if (view.transformed_samples == null) {
-                view.transformed_samples = try self.addSampleList(allocator);
-            }
-            // var transformed_sample_list = self.sample_lists.get(view.transformed_samples.?).?;
-
-            // const samples = self.getViewSamples(view_id);
-
-            // try transformed_sample_list.append(samples);
-
-            _ = sliding_window;
-        } else {
-            if (view.transformed_samples) |sample_list_id| {
-                self.removeSampleList(sample_list_id);
-                view.transformed_samples = null;
-            }
-        }
-    }
-
     pub fn readSamplesFromFile(self: *Project, allocator: Allocator, sample_list_id: Id, file: std.fs.File, sample_count: usize) !void {
         var bytes_left: usize = sample_count * 8;
         var buffer: [SampleList.Block.capacity * 8]u8 = undefined;
@@ -867,17 +877,6 @@ pub const Project = struct {
         }
     }
 
-    pub fn updateSlidingWindow(self: *Project, view_id: Id, allocator: Allocator, sliding_window: ?f64) !void {
-        const view = self.views.get(view_id).?;
-        if (view.sliding_window == sliding_window) {
-            return;
-        }
-
-        view.sliding_window = sliding_window;
-
-        try self.refreshTransformedSamplesByView(allocator, view_id);
-    }
-
     pub fn appendMarkedRange(self: *Project, view_id: Id, axis: UI.Axis, range: RangeF64) ?*View.MarkedRange {
         const view = self.views.get(view_id) orelse return null;
 
@@ -1223,6 +1222,10 @@ pub const Command = union(enum) {
     start_output: Id, // Channel id
     add_file_from_picker,
     reload_file: Id, // File id
+    update_sliding_window: struct {
+        view_id: Id,
+        sliding_window: ?f64
+    }
 };
 
 pub const CollectionTask = struct {
@@ -1237,6 +1240,105 @@ pub const CollectionTask = struct {
     }
 };
 
+const WorkJob = struct {
+    const Stage = enum {
+        init,
+        calculate_blocks
+    };
+
+    view_id: Id,
+    stage: Stage = .init,
+    sliding_window: ?f64 = null,
+
+    mutex: std.Thread.Mutex = .{},
+    running_thread_jobs: std.ArrayListUnmanaged(SampleList.Block.Id) = .{},
+
+    processed_up_to: u32 = 0,
+
+    pub fn appendRunningThread(self: *WorkJob, allocator: Allocator, block_id: SampleList.Block.Id) !void {
+        self.mutex.lock();
+        defer self.mutex.unlock();
+
+        try self.running_thread_jobs.append(allocator, block_id);
+    }
+
+    pub fn removeRunningThread(self: *WorkJob, block_id: SampleList.Block.Id) void {
+        self.mutex.lock();
+        defer self.mutex.unlock();
+
+        if (std.mem.indexOfScalar(SampleList.Block.Id, self.running_thread_jobs.items, block_id)) |index| {
+            _ = self.running_thread_jobs.swapRemove(index);
+        }
+    }
+
+    pub fn getRunningThreadCount(self: *WorkJob) usize {
+        self.mutex.lock();
+        defer self.mutex.unlock();
+
+        return self.running_thread_jobs.items.len;
+    }
+
+    pub fn containsRunningThread(self: *WorkJob, block_id: SampleList.Block.Id) bool {
+        self.mutex.lock();
+        defer self.mutex.unlock();
+
+        return std.mem.indexOfScalar(SampleList.Block.Id, self.running_thread_jobs.items, block_id) != null;
+    }
+
+    pub fn deinit(self: *WorkJob, allocator: Allocator) void {
+        self.running_thread_jobs.deinit(allocator);
+    }
+
+    pub fn update(self: *WorkJob, id: Id, app: *App) !bool {
+        const project = &app.project;
+        const view = project.views.get(self.view_id) orelse return true;
+
+        const sample_list_id = project.getViewSampleListId(self.view_id);
+        const sample_list = project.sample_lists.get(sample_list_id).?;
+
+        if (view.sliding_window != self.sliding_window) return true;
+
+        switch (self.stage) {
+            .init => {
+                if (self.sliding_window == null) {
+                    if (view.transformed_samples) |transformed_samples_id| {
+                        project.removeSampleList(transformed_samples_id);
+                    }
+                    view.transformed_samples = null;
+
+                    return true;
+                } else {
+                    if (view.transformed_samples == null) {
+                        view.transformed_samples = try project.addSampleList(app.allocator);
+                    }
+                    const transformed_samples = project.sample_lists.get(view.transformed_samples.?).?;
+                    try transformed_samples.reserveEmptyBlocks(sample_list.blocks.items.len);
+
+                    self.stage = .calculate_blocks;
+                }
+            },
+            .calculate_blocks => {
+                const max_block_to_process = 32;
+
+                while (self.getRunningThreadCount() < app.work_thread_pool.threads.len and self.processed_up_to < sample_list.blocks.items.len) {
+                    const block_id = self.processed_up_to;
+                    const block_count = @min(sample_list.blocks.items.len - self.processed_up_to, max_block_to_process);
+                    self.processed_up_to += block_count;
+
+                    try app.work_thread_pool.spawn(transformedSamplesWorker, .{ app, id, block_id, block_count });
+                    try self.appendRunningThread(app.allocator, block_id);
+                }
+
+                if (self.processed_up_to == sample_list.blocks.items.len and self.getRunningThreadCount() == 0) {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+};
+
 allocator: Allocator,
 ui: UI,
 double_pass_ui: bool = true,
@@ -1261,15 +1363,22 @@ command_queue: std.BoundedArray(Command, 16) = .{},
 
 file_picker_id: ?Platform.FilePickerId = null,
 
+work_jobs: GenerationalArray(WorkJob) = .{},
+work_thread_pool: std.Thread.Pool,
+
 pub fn init(self: *App, allocator: Allocator) !void {
     self.* = App{
         .allocator = allocator,
         .ui = UI.init(allocator),
         .main_screen = undefined,
         .collection_thread = undefined,
-        .channel_from_device = undefined
+        .channel_from_device = undefined,
+        .work_thread_pool = undefined
     };
     try self.initUI();
+    try self.work_thread_pool.init(.{
+        .allocator = allocator
+    });
 
     if (NIDaq.Api.init()) |ni_daq_api| {
         self.ni_daq_api = ni_daq_api;
@@ -1301,6 +1410,7 @@ pub fn init(self: *App, allocator: Allocator) !void {
 }
 
 pub fn deinit(self: *App) void {
+    self.work_thread_pool.deinit();
     self.deinitProject();
 
     self.should_close = true;
@@ -1316,6 +1426,13 @@ pub fn deinit(self: *App) void {
     if (self.ni_daq_api) |*ni_daq_api| {
         ni_daq_api.deinit();
     }
+
+    {
+        var iter = self.work_jobs.iterator();
+        while (iter.next()) |work_job| {
+            work_job.deinit(self.allocator);
+        }
+    }
 }
 
 fn deinitProject(self: *App) void {
@@ -1357,7 +1474,9 @@ fn loadProject(self: *App) !void {
     errdefer loaded.deinit(self.allocator);
     try loaded.initFromFile(self.allocator, save_location);
 
+    self.deinitUI();
     self.deinitProject();
+
     self.project = loaded.*;
 
     var file_iter = self.project.files.idIterator();
@@ -1381,7 +1500,6 @@ fn loadProject(self: *App) !void {
         };
     }
 
-    self.deinitUI();
     self.initUI() catch @panic("Failed to initialize UI, can't recover");
 }
 
@@ -1525,9 +1643,125 @@ pub fn tick(self: *App) !void {
                 self.loadFile(file_id) catch |e| {
                     log.err("Failed to load file: {}", .{ e });
                 };
+            },
+            .update_sliding_window => |args| {
+                const view = self.project.views.get(args.view_id) orelse continue;
+                view.sliding_window = args.sliding_window;
+
+                _ = self.work_jobs.insert(WorkJob{
+                    .view_id = args.view_id,
+                    .sliding_window = args.sliding_window
+                }) catch |e| {
+                    log.err("Failed to create a work job: {}", .{ e });
+                    continue;
+                };
             }
         }
     }
+
+    {
+        var work_job_iter = self.work_jobs.idIterator();
+        while (work_job_iter.next()) |work_job_id| {
+            const work_job = self.work_jobs.get(work_job_id).?;
+            const job_done = try work_job.update(work_job_id, self);
+
+            if (job_done) {
+                if (work_job.getRunningThreadCount() == 0) {
+                    // std.debug.print("job done {}\n", .{work_job_id});
+                    work_job.deinit(self.allocator);
+                    self.work_jobs.remove(work_job_id);
+                }
+            }
+        }
+    }
+}
+
+fn transformedSamplesWorker(self: *App, work_job_id: Id, starting_block_id: SampleList.Block.Id, block_count: usize) void {
+    const work_job = self.work_jobs.get(work_job_id) orelse return;
+    defer work_job.removeRunningThread(starting_block_id);
+
+    const allocator = self.allocator;
+    var timer = std.time.Timer.start() catch unreachable;
+
+    const view = self.project.views.get(work_job.view_id) orelse return;
+    const transformed_samples_id = view.transformed_samples orelse return;
+    const transformed_samples = self.project.sample_lists.get(transformed_samples_id) orelse return;
+    const sliding_window_f64: f64 = @ceil(view.sliding_window.?);
+    const sliding_window: usize = @intFromFloat(sliding_window_f64);
+
+    const sample_list_id = self.project.getViewSampleListId(work_job.view_id);
+    const sample_list = self.project.sample_lists.get(sample_list_id) orelse return;
+
+    var running_sum: f64 = 0;
+    var last_samples = std.ArrayList(f64).init(allocator);
+    defer last_samples.deinit();
+    last_samples.ensureTotalCapacityPrecise(sliding_window) catch return;
+
+    for (0..@intFromFloat(@ceil(sliding_window_f64/SampleList.Block.capacity))) |block_offset| {
+        if (block_offset >= starting_block_id) {
+            break;
+        }
+
+        const source_block = sample_list.getBlock(starting_block_id - (block_offset + 1)).?;
+        for (0..source_block.len) |i| {
+            const sample = source_block.buffer[source_block.len - (i + 1)];
+
+            if (last_samples.items.len == last_samples.capacity) {
+                _ = last_samples.orderedRemove(0);
+            }
+            last_samples.appendAssumeCapacity(sample);
+        }
+    }
+
+    for (0..block_count) |i| {
+        const block_id = starting_block_id + i;
+
+        const source_block = sample_list.getBlock(block_id).?;
+        const transformed_block = transformed_samples.getBlock(block_id).?;
+
+        for (0..source_block.len) |j| {
+            const sample = source_block.buffer[j];
+            transformed_block.buffer[j] = sample * 0.1;
+
+            if (last_samples.items.len == last_samples.capacity) {
+                running_sum -= last_samples.orderedRemove(0);
+            }
+            last_samples.appendAssumeCapacity(sample);
+            running_sum += sample;
+
+            transformed_block.buffer[j] = running_sum / @as(f64, @floatFromInt(last_samples.items.len));
+        }
+        transformed_block.len = source_block.len;
+        transformed_block.recomputeMinMax();
+    }
+
+    // for (0..(SampleList.Block.capacity * block_count)) |offset| {
+    //     const i = starting_block_id * SampleList.Block.capacity + offset;
+
+    //     const transformed_sample = &transformed_samples.getBlock(@divFloor(i, SampleList.Block.capacity)).?.buffer[@mod(i, SampleList.Block.capacity)];
+
+    //     if (i >= 3) {
+    //         const zero: f64 = 0;
+    //         const sample1 = (sample_list.getSample(i) orelse &zero).*;
+    //         const sample2 = (sample_list.getSample(i-1) orelse &zero).*;
+    //         const sample3 = (sample_list.getSample(i-2) orelse &zero).*;
+    //         const sample4 = (sample_list.getSample(i-3) orelse &zero).*;
+
+    //         // if (sample_list.getSample(i)) |sample| {
+    //         // }
+    //         transformed_sample.* = @tan(sample1 + sample2 + sample3 + sample4);
+    //     } else {
+    //         transformed_sample.* = 0;
+    //     }
+    // }
+
+    // for (0..block_count) |i| {
+    //     transformed_samples.getBlock(starting_block_id + i).?.len = sample_list.getBlock(starting_block_id + i).?.len;
+    // }
+
+    const duration = timer.read();
+    _ = duration;
+    // std.debug.print("finished {d:.5}ms\n", .{ @as(f64, @floatFromInt(duration)) / std.time.ns_per_ms });
 }
 
 pub fn pushCommand(self: *App, command: Command) void {
@@ -1893,6 +2127,9 @@ fn loadSavedSamples(self: *App, channel_id: Id) !void {
         return error.NotMultipleOf8;
     }
 
+    const sample_list = self.project.sample_lists.get(channel.collected_samples_id).?;
+    sample_list.clear(self.allocator);
+
     try self.project.readSamplesFromFile(self.allocator, channel.collected_samples_id, samples_file, @divExact(byte_count, 8));
 
     const stat = try dir.statFile(saved_samples_location);
diff --git a/src/components/view.zig b/src/components/view.zig
index 40ce18d..1ea64d0 100644
--- a/src/components/view.zig
+++ b/src/components/view.zig
@@ -109,7 +109,11 @@ fn showGraph(ctx: Context, view_id: Id) *UI.Box {
 
 
     { // Render graph
-        const sample_list_id = app.project.getViewSampleListId(view_id);
+        var sample_list_id = app.project.getViewSampleListId(view_id);
+        if (view.transformed_samples) |transformed_samples_id| {
+            sample_list_id = transformed_samples_id;
+        }
+
         const sample_list = app.project.sample_lists.get(sample_list_id).?;
         Graph.drawCached(&view.graph_cache, graph_box.persistent.size, view_opts.*, sample_list);
         if (view.graph_cache.texture) |texture| {
diff --git a/src/main.zig b/src/main.zig
index d3099e1..471a268 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -78,8 +78,6 @@ pub fn main() !void {
     raylib_h.SetTraceLogCallback(raylibTraceLogCallback);
     rl.setTraceLogLevel(toRaylibLogLevel(std.options.log_level));
 
-    // std.debug.print("{any}\n", .{ std.mem.bytesAsSlice(f64, std.mem.sliceAsBytes(&[_]f64{ 1, 2, 3}) ) });
-
     const icon_png = @embedFile("./assets/icon.png");
     var icon_image = rl.loadImageFromMemory(".png", icon_png);
     defer icon_image.unload();
diff --git a/src/screens/main_screen.zig b/src/screens/main_screen.zig
index 5b31403..1956ba4 100644
--- a/src/screens/main_screen.zig
+++ b/src/screens/main_screen.zig
@@ -388,10 +388,21 @@ fn showViewSettings(self: *MainScreen, view_id: Id) !void {
     }
     _ = ui.label("Duration: {s}", .{ duration_str });
 
-    try project.updateSlidingWindow(view_id, self.app.allocator, try ui.numberInput(f64, .{
+    const new_sliding_window = try ui.numberInput(f64, .{
         .key = ui.keyFromString("Sliding window"),
         .storage = &self.sliding_window_input
-    }));
+    });
+
+    if (new_sliding_window != view.sliding_window) {
+        if (new_sliding_window == null or new_sliding_window.? > 0) {
+            self.app.pushCommand(.{
+                .update_sliding_window = .{
+                    .view_id = view_id,
+                    .sliding_window = new_sliding_window
+                }
+            });
+        }
+    }
 }
 
 fn showMarkedRange(self: *MainScreen, view_id: Id, index: usize) void {