diff --git a/app/models/asciicast.rb b/app/models/asciicast.rb
index c30a0a2..c0f0cce 100644
--- a/app/models/asciicast.rb
+++ b/app/models/asciicast.rb
@@ -56,17 +56,7 @@ class Asciicast < ActiveRecord::Base
   end
 
   def stdout
-    @stdout ||= Stdout.new(read_stdout_data, read_stdout_timing)
-  end
-
-  private
-
-  def read_stdout_data
-    stdout_data.decompressed
-  end
-
-  def read_stdout_timing
-    TimingParser.parse(stdout_timing.decompressed)
+    @stdout ||= Stdout.new(stdout_data, stdout_timing)
   end
 
 end
diff --git a/app/models/stdout.rb b/app/models/stdout.rb
index 482d16e..2e76703 100644
--- a/app/models/stdout.rb
+++ b/app/models/stdout.rb
@@ -1,40 +1,30 @@
 class Stdout
   include Enumerable
 
-  attr_reader :data, :timing
+  attr_reader :data_file, :timing_file
 
-  def initialize(data, timing)
-    @data = data
-    @timing = timing
+  def initialize(data_file, timing_file)
+    @data_file = data_file
+    @timing_file = timing_file
   end
 
   def each
-    offset = 0
-
-    timing.each do |line|
-      delay, size = line
-      yield(delay, bytes[offset...offset+size])
-      offset += size
+    File.open(data_file.decompressed_path, 'rb') do |file|
+      File.foreach(timing_file.decompressed_path) do |line|
+        delay, size = TimingParser.parse_line(line)
+        yield(delay, file.read(size).force_encoding('utf-8'))
+      end
     end
   end
 
-  def bytes_until(seconds)
-    bytes = []
+  def each_until(seconds)
     time = 0
 
-    each do |delay, frame_bytes|
+    each do |delay, frame_data|
       time += delay
       break if time > seconds
-      bytes.concat(frame_bytes)
+      yield(delay, frame_data)
     end
-
-    bytes
-  end
-
-  private
-
-  def bytes
-    @bytes ||= data.bytes
   end
 
 end
diff --git a/spec/fixtures/stdout.decompressed b/spec/fixtures/stdout.decompressed
new file mode 100644
index 0000000..b134021
--- /dev/null
+++ b/spec/fixtures/stdout.decompressed
@@ -0,0 +1 @@
+foobarbazquxżółć
diff --git a/spec/fixtures/stdout.time.decompressed b/spec/fixtures/stdout.time.decompressed
new file mode 100644
index 0000000..ff76756
--- /dev/null
+++ b/spec/fixtures/stdout.time.decompressed
@@ -0,0 +1,3 @@
+0.5 6
+1.0 7
+2.0 7
diff --git a/spec/models/asciicast_spec.rb b/spec/models/asciicast_spec.rb
index d89dd0e..793d6cd 100644
--- a/spec/models/asciicast_spec.rb
+++ b/spec/models/asciicast_spec.rb
@@ -84,17 +84,21 @@ describe Asciicast do
   end
 
   describe '#stdout' do
+    let(:asciicast) { stub_model(Asciicast) }
+    let(:data_file) { double('data_file') }
+    let(:timing_file) { double('timing_file') }
     let(:stdout) { double('stdout') }
 
     before do
-      allow(asciicast.stdout_data).to receive(:decompressed) { 'foo' }
-      allow(asciicast.stdout_timing).to receive(:decompressed) { '123.0 45' }
+      allow(asciicast).to receive(:stdout_data) { data_file }
+      allow(asciicast).to receive(:stdout_timing) { timing_file }
       allow(Stdout).to receive(:new) { stdout }
     end
 
     it 'creates a new Stdout instance' do
       asciicast.stdout
-      expect(Stdout).to have_received(:new).with('foo', [[123.0, 45]])
+
+      expect(Stdout).to have_received(:new).with(data_file, timing_file)
     end
 
     it 'returns created Stdout instance' do
diff --git a/spec/models/stdout_spec.rb b/spec/models/stdout_spec.rb
index 84e3a2b..be22d1e 100644
--- a/spec/models/stdout_spec.rb
+++ b/spec/models/stdout_spec.rb
@@ -3,31 +3,24 @@
 require 'spec_helper'
 
 describe Stdout do
-  let(:stdout) { Stdout.new(data, timing) }
-  let(:data) { 'foobarbazquxżółć' }
-  let(:timing) { [[0.5, 6], [1.0, 7], [2.0, 7]] }
-
-  describe '#bytes_until' do
-    subject { stdout.bytes_until(1.7) }
-
-    it { should eq([102, 111, 111, 98, 97, 114, 98, 97, 122, 113, 117, 120, 197]) }
-  end
+  let(:stdout) { Stdout.new(data_file, timing_file) }
+  let(:data_file) { double('data_file', :decompressed_path => 'spec/fixtures/stdout.decompressed') }
+  let(:timing_file) { double('timing_file', :decompressed_path => 'spec/fixtures/stdout.time.decompressed') }
 
   describe '#each' do
-    it 'yields for each frame with delay and frame bytes' do
-      frames = []
-      stdout.each do |delay, bytes|
-        frames << [delay, bytes]
-      end
-
-      expect(frames[0][0]).to eq(0.5)
-      expect(frames[0][1]).to eq([102, 111, 111, 98, 97, 114])
-
-      expect(frames[1][0]).to eq(1.0)
-      expect(frames[1][1]).to eq([98, 97, 122, 113, 117, 120, 197])
-
-      expect(frames[2][0]).to eq(2.0)
-      expect(frames[2][1]).to eq([188, 195, 179, 197, 130, 196, 135])
+    it 'yields for each frame with delay and data' do
+      expect { |b| stdout.each(&b) }.
+        to yield_successive_args([0.5, 'foobar'],
+                                 [1.0, "bazqux\xC5"],
+                                 [2.0, "\xBCółć"])
     end
   end
+
+  describe '#each_until' do
+    it 'yields for each frame with delay and data until given time (in seconds)' do
+      expect { |b| stdout.each_until(1.7, &b) }.
+        to yield_successive_args([0.5, 'foobar'], [1.0, "bazqux\xC5"])
+    end
+  end
+
 end