diff --git a/.gitignore b/.gitignore
index 9b4d159..86c0e1f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,3 @@
 artifacts/
 stage/
-
+references/
diff --git a/README.md b/README.md
index b71717f..7fb67c1 100644
--- a/README.md
+++ b/README.md
@@ -26,13 +26,38 @@ It'll build both:
 4. Install development tools.
   * Execute `pacman -S mingw-w64-i686-gcc autoconf automake-wrapper make` if you wanna 32bit binary.
   * Execute `pacman -S mingw-w64-x86_64-gcc autoconf automake-wrapper make` if you wanna 64bit binary.
-5. Execute `./download.sh`, it'll download fdk-aac archive from [official opencore-amr project](https://sourceforge.net/projects/opencore-amr/) mirror.
-6. Execute `./build.sh`.
+5. Execute `./setup.sh`, it'll download fdk-aac archive from [official opencore-amr project](https://sourceforge.net/projects/opencore-amr/) mirror, and extract reference files for testing purpose.
+6. You can choose GCC's optimization option. See `CFLAGS` symbols in the head of `build.sh` file.
+7. Execute `./build.sh`.
 
 Finally, stored binaries into artifacts directory.
   * `artifacts/i686-w64-mingw32/` (32bit)
   * `artifacts/x86_64-w64-mingw32/` (64bit)
 
+If you have to get results for PCM bits equality, you can execute `./test.sh` after building was successful. It'll use `cmp` command, so will show nothing output if these PCM files are verified. For example:
+
+```sh
+$ ./test.sh
+[100%] 01:35.852/01:35.852 (87x), ETA 00:00.000
+4227066/4227066 samples processed in 00:01.106
+[100%] 01:35.852/01:35.852 (71x), ETA 00:00.000
+4227066/4227066 samples processed in 00:01.352
+[100%] 01:35.852/01:35.852 (68x), ETA 00:00.000
+4227066/4227066 samples processed in 00:01.403
+[100%] 01:35.852/01:35.852 (113x), ETA 00:00.000
+4227066/4227066 samples processed in 00:00.848
+[100%] 01:35.852/01:35.852 (69x), ETA 00:00.000
+4227066/4227066 samples processed in 00:01.384
+[100%] 01:35.852/01:35.852 (82x), ETA 00:00.000
+4227066/4227066 samples processed in 00:01.176
+[100%] 01:35.852/01:35.852 (101x), ETA 00:00.000
+4227066/4227066 samples processed in 00:00.950
+[100%] 01:35.852/01:35.852 (80x), ETA 00:00.000
+4227066/4227066 samples processed in 00:01.203
+
+$
+```
+
 # Limitation
 
 Unfortunately, 32bit binaries referenced MinGW32 gcc depending library named `libgcc_s_dw2-1.dll` and `libwinpthread-1.dll`. Because fdk-aac use dividing operator, it requires implicitly asynchronous exception handler contains into it.
diff --git a/build.sh b/build.sh
index 55d5940..11f3860 100644
--- a/build.sh
+++ b/build.sh
@@ -1,5 +1,19 @@
 #! /bin/sh
 
+###################################
+# Compiler optimization flags:
+
+# Platform native (not include AVX-512, it's standard options)
+CFLAGS="-O3 -flto -march=native"
+
+# AVX-512
+#CFLAGS="-O3 -flto -march=native -mavx512f -mavx512dq -mavx512er -mavx512cd -mavx512bw -mavx512pf -mavx512vl -mavx512ifma -mavx512vbmi"
+
+# For debugging/reference usage
+#CFLAGS="-O0"
+
+###################################
+
 cd stage
 
 rm -rf $MINGW_CHOST
@@ -11,20 +25,20 @@ tar -zxvf ../../artifacts/fdk-aac-2.0.1.tar.gz
 tar -zxvf ../../artifacts/fdkaac-1.0.0.tar.gz
 
 cd fdk-aac-0.1.6
-./configure --prefix=$MINGW_PREFIX/$MINGW_CHOST/
+./configure --prefix=$MINGW_PREFIX/$MINGW_CHOST/ CFLAGS="${CFLAGS}"
 make -j40
 make install
 cd ..
 
 cd fdk-aac-2.0.1
-./configure --prefix=$MINGW_PREFIX/$MINGW_CHOST/
+./configure --prefix=$MINGW_PREFIX/$MINGW_CHOST/ CFLAGS="${CFLAGS}"
 make -j40
 make install
 cd ..
 
 cd fdkaac-1.0.0
 autoreconf -i
-./configure --prefix=$MINGW_PREFIX/$MINGW_CHOST/
+./configure --prefix=$MINGW_PREFIX/$MINGW_CHOST/ CFLAGS="${CFLAGS}"
 make -j40
 make install
 cd ..
diff --git a/download.sh b/download.sh
deleted file mode 100644
index 6e1016d..0000000
--- a/download.sh
+++ /dev/null
@@ -1,15 +0,0 @@
-#! /bin/sh
-
-rm -rf artifacts
-rm -rf stage
-
-mkdir artifacts
-mkdir stage
-
-cd artifacts
-
-wget https://jaist.dl.sourceforge.net/project/opencore-amr/fdk-aac/fdk-aac-0.1.6.tar.gz
-wget https://jaist.dl.sourceforge.net/project/opencore-amr/fdk-aac/fdk-aac-2.0.1.tar.gz
-wget https://github.com/nu774/fdkaac/archive/1.0.0.tar.gz
-
-mv 1.0.0.tar.gz fdkaac-1.0.0.tar.gz
diff --git a/setup.sh b/setup.sh
new file mode 100644
index 0000000..4c08593
--- /dev/null
+++ b/setup.sh
@@ -0,0 +1,31 @@
+#! /bin/sh
+
+rm -rf artifacts
+rm -rf stage
+
+mkdir artifacts
+mkdir stage
+
+cd artifacts
+
+wget https://jaist.dl.sourceforge.net/project/opencore-amr/fdk-aac/fdk-aac-0.1.6.tar.gz
+wget https://jaist.dl.sourceforge.net/project/opencore-amr/fdk-aac/fdk-aac-2.0.1.tar.gz
+wget https://github.com/nu774/fdkaac/archive/1.0.0.tar.gz
+
+mv 1.0.0.tar.gz fdkaac-1.0.0.tar.gz
+
+cd ..
+
+rm -rf references
+mkdir references
+
+test-materials/ffmpeg.exe -i test-materials/battleThemeA.mp3 references/BattleThemeA.wav > /dev/null 2>&1
+
+test-materials/ffmpeg.exe -i test-materials/BattleThemeA_p2_44_128.aac -f s16le references/battleThemeA_p2_44_128.pcm > /dev/null 2>&1
+test-materials/ffmpeg.exe -i test-materials/BattleThemeA_p5_44_128.aac -f s16le references/battleThemeA_p5_44_128.pcm > /dev/null 2>&1
+test-materials/ffmpeg.exe -i test-materials/BattleThemeA_p23_44_128.aac -f s16le references/battleThemeA_p23_44_128.pcm > /dev/null 2>&1
+test-materials/ffmpeg.exe -i test-materials/BattleThemeA_p29_44_128.aac -f s16le references/battleThemeA_p29_44_128.pcm > /dev/null 2>&1
+test-materials/ffmpeg.exe -i test-materials/BattleThemeA_p39_44_128.aac -f s16le references/battleThemeA_p39_44_128.pcm > /dev/null 2>&1
+test-materials/ffmpeg.exe -i test-materials/BattleThemeA_p2_44_256.aac -f s16le references/battleThemeA_p2_44_256.pcm > /dev/null 2>&1
+test-materials/ffmpeg.exe -i test-materials/BattleThemeA_p2_44_m1.aac -f s16le references/battleThemeA_p2_44_m1.pcm > /dev/null 2>&1
+test-materials/ffmpeg.exe -i test-materials/BattleThemeA_p2_44_m5.aac -f s16le references/battleThemeA_p2_44_m5.pcm > /dev/null 2>&1
diff --git a/test-materials/BattleThemeA.mp3 b/test-materials/BattleThemeA.mp3
new file mode 100644
index 0000000..d22aa61
Binary files /dev/null and b/test-materials/BattleThemeA.mp3 differ
diff --git a/test-materials/BattleThemeA_p23_44_128.aac b/test-materials/BattleThemeA_p23_44_128.aac
new file mode 100644
index 0000000..e006950
Binary files /dev/null and b/test-materials/BattleThemeA_p23_44_128.aac differ
diff --git a/test-materials/BattleThemeA_p29_44_128.aac b/test-materials/BattleThemeA_p29_44_128.aac
new file mode 100644
index 0000000..fbd1a87
Binary files /dev/null and b/test-materials/BattleThemeA_p29_44_128.aac differ
diff --git a/test-materials/BattleThemeA_p2_44_128.aac b/test-materials/BattleThemeA_p2_44_128.aac
new file mode 100644
index 0000000..f4040ae
Binary files /dev/null and b/test-materials/BattleThemeA_p2_44_128.aac differ
diff --git a/test-materials/BattleThemeA_p2_44_256.aac b/test-materials/BattleThemeA_p2_44_256.aac
new file mode 100644
index 0000000..a8cc854
Binary files /dev/null and b/test-materials/BattleThemeA_p2_44_256.aac differ
diff --git a/test-materials/BattleThemeA_p2_44_m1.aac b/test-materials/BattleThemeA_p2_44_m1.aac
new file mode 100644
index 0000000..efb2905
Binary files /dev/null and b/test-materials/BattleThemeA_p2_44_m1.aac differ
diff --git a/test-materials/BattleThemeA_p2_44_m5.aac b/test-materials/BattleThemeA_p2_44_m5.aac
new file mode 100644
index 0000000..9007bef
Binary files /dev/null and b/test-materials/BattleThemeA_p2_44_m5.aac differ
diff --git a/test-materials/BattleThemeA_p39_44_128.aac b/test-materials/BattleThemeA_p39_44_128.aac
new file mode 100644
index 0000000..949fdac
Binary files /dev/null and b/test-materials/BattleThemeA_p39_44_128.aac differ
diff --git a/test-materials/BattleThemeA_p5_44_128.aac b/test-materials/BattleThemeA_p5_44_128.aac
new file mode 100644
index 0000000..b972658
Binary files /dev/null and b/test-materials/BattleThemeA_p5_44_128.aac differ
diff --git a/test-materials/README.md b/test-materials/README.md
new file mode 100644
index 0000000..b770efa
--- /dev/null
+++ b/test-materials/README.md
@@ -0,0 +1,7 @@
+BattleThemeA.wav imported from:
+
+* [opengameart.org](https://opengameart.org/content/battle-theme-a)
+* License: CC0
+
+It was converted from mp3 format to wav format.
+And spreaded mp4 formats by optimization disabled (64bit, -O0) fdkaac.exe.
diff --git a/test-materials/ffmpeg.exe b/test-materials/ffmpeg.exe
new file mode 100644
index 0000000..2351e76
Binary files /dev/null and b/test-materials/ffmpeg.exe differ
diff --git a/test-materials/make.sh b/test-materials/make.sh
new file mode 100644
index 0000000..c39d166
--- /dev/null
+++ b/test-materials/make.sh
@@ -0,0 +1,14 @@
+#! /bin/sh
+
+./ffmpeg.exe -i BattleThemeA.mp3 BattleThemeA.wav > /dev/null 2>&1
+
+../artifacts/x86_64-w64-mingw32/fdkaac.exe -p 2 -b 128 -o BattleThemeA_p2_44_128.aac BattleThemeA.wav
+../artifacts/x86_64-w64-mingw32/fdkaac.exe -p 5 -b 128 -o BattleThemeA_p5_44_128.aac BattleThemeA.wav
+../artifacts/x86_64-w64-mingw32/fdkaac.exe -p 23 -b 128 -o BattleThemeA_p23_44_128.aac BattleThemeA.wav
+../artifacts/x86_64-w64-mingw32/fdkaac.exe -p 29 -b 128 -o BattleThemeA_p29_44_128.aac BattleThemeA.wav
+../artifacts/x86_64-w64-mingw32/fdkaac.exe -p 39 -b 128 -o BattleThemeA_p39_44_128.aac BattleThemeA.wav
+../artifacts/x86_64-w64-mingw32/fdkaac.exe -p 2 -b 256 -o BattleThemeA_p2_44_256.aac BattleThemeA.wav
+../artifacts/x86_64-w64-mingw32/fdkaac.exe -p 2 -m 1 -o BattleThemeA_p2_44_m1.aac BattleThemeA.wav
+../artifacts/x86_64-w64-mingw32/fdkaac.exe -p 2 -m 5 -o BattleThemeA_p2_44_m5.aac BattleThemeA.wav
+
+rm BattleThemeA.wav
diff --git a/test.sh b/test.sh
new file mode 100644
index 0000000..51f3221
--- /dev/null
+++ b/test.sh
@@ -0,0 +1,39 @@
+#! /bin/sh
+
+DEST=artifacts/$MINGW_CHOST"_test"
+
+rm -rf $DEST
+mkdir $DEST
+
+# Execute using built binary.
+
+artifacts/$MINGW_CHOST/fdkaac.exe -p 2 -b 128 -o $DEST/BattleThemeA_p2_44_128.aac references/BattleThemeA.wav
+artifacts/$MINGW_CHOST/fdkaac.exe -p 5 -b 128 -o $DEST/BattleThemeA_p5_44_128.aac references/BattleThemeA.wav
+artifacts/$MINGW_CHOST/fdkaac.exe -p 23 -b 128 -o $DEST/BattleThemeA_p23_44_128.aac references/BattleThemeA.wav
+artifacts/$MINGW_CHOST/fdkaac.exe -p 29 -b 128 -o $DEST/BattleThemeA_p29_44_128.aac references/BattleThemeA.wav
+artifacts/$MINGW_CHOST/fdkaac.exe -p 39 -b 128 -o $DEST/BattleThemeA_p39_44_128.aac references/BattleThemeA.wav
+artifacts/$MINGW_CHOST/fdkaac.exe -p 2 -b 256 -o $DEST/BattleThemeA_p2_44_256.aac references/BattleThemeA.wav
+artifacts/$MINGW_CHOST/fdkaac.exe -p 2 -m 1 -o $DEST/BattleThemeA_p2_44_m1.aac references/BattleThemeA.wav
+artifacts/$MINGW_CHOST/fdkaac.exe -p 2 -m 5 -o $DEST/BattleThemeA_p2_44_m5.aac references/BattleThemeA.wav
+
+# Make raw pcm from encoded files.
+
+test-materials/ffmpeg.exe -i $DEST/BattleThemeA_p2_44_128.aac -f s16le $DEST/battleThemeA_p2_44_128.pcm > /dev/null 2>&1
+test-materials/ffmpeg.exe -i $DEST/BattleThemeA_p5_44_128.aac -f s16le $DEST/BattleThemeA_p5_44_128.pcm > /dev/null 2>&1
+test-materials/ffmpeg.exe -i $DEST/BattleThemeA_p23_44_128.aac -f s16le $DEST/BattleThemeA_p23_44_128.pcm > /dev/null 2>&1
+test-materials/ffmpeg.exe -i $DEST/BattleThemeA_p29_44_128.aac -f s16le $DEST/BattleThemeA_p29_44_128.pcm > /dev/null 2>&1
+test-materials/ffmpeg.exe -i $DEST/BattleThemeA_p39_44_128.aac -f s16le $DEST/BattleThemeA_p39_44_128.pcm > /dev/null 2>&1
+test-materials/ffmpeg.exe -i $DEST/BattleThemeA_p2_44_256.aac -f s16le $DEST/BattleThemeA_p2_44_256.pcm > /dev/null 2>&1
+test-materials/ffmpeg.exe -i $DEST/BattleThemeA_p2_44_m1.aac -f s16le $DEST/BattleThemeA_p2_44_m1.pcm > /dev/null 2>&1
+test-materials/ffmpeg.exe -i $DEST/BattleThemeA_p2_44_m5.aac -f s16le $DEST/BattleThemeA_p2_44_m5.pcm > /dev/null 2>&1
+
+# Compare raw pcm files.
+
+cmp references/battleThemeA_p2_44_128.pcm $DEST/battleThemeA_p2_44_128.pcm
+cmp references/BattleThemeA_p5_44_128.pcm $DEST/BattleThemeA_p5_44_128.pcm
+cmp references/BattleThemeA_p23_44_128.pcm $DEST/BattleThemeA_p23_44_128.pcm
+cmp references/BattleThemeA_p29_44_128.pcm $DEST/BattleThemeA_p29_44_128.pcm
+cmp references/BattleThemeA_p39_44_128.pcm $DEST/BattleThemeA_p39_44_128.pcm
+cmp references/BattleThemeA_p2_44_256.pcm $DEST/BattleThemeA_p2_44_256.pcm
+cmp references/BattleThemeA_p2_44_m1.pcm $DEST/BattleThemeA_p2_44_m1.pcm
+cmp references/BattleThemeA_p2_44_m5.pcm $DEST/BattleThemeA_p2_44_m5.pcm