diff --git a/.gitignore b/.gitignore
index 6c38d55..b244040 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
 node_modules/
 *.log
 *.brstm
+*.bfstm
 node_modules
 .DS_Store
 dist
diff --git a/app/package.json b/app/package.json
index 3f911f7..ac38e72 100644
--- a/app/package.json
+++ b/app/package.json
@@ -29,6 +29,7 @@
     "build-gh-pages": "vite build --base \"/nikku/\""
   },
   "dependencies": {
+    "bfstm": "^1.0.0",
     "brstm": "^1.6.1",
     "comlink": "^4.3.1",
     "lit": "^2.4.0"
diff --git a/app/src/audio-decoder/worker.ts b/app/src/audio-decoder/worker.ts
index 470b1da..2188b96 100644
--- a/app/src/audio-decoder/worker.ts
+++ b/app/src/audio-decoder/worker.ts
@@ -1,41 +1,41 @@
-import { Brstm, Metadata } from 'brstm';
-import { transfer } from 'comlink';
+import { Bfstm, Metadata } from 'bfstm';
+// import { transfer } from 'comlink';
 
-let brstm: Brstm | null = null;
+let instance: Bfstm | null = null;
 export function init(receivedBuffer: ArrayBuffer) {
-  brstm = new Brstm(receivedBuffer);
+  instance = new Bfstm(receivedBuffer);
 }
 export function destroy() {
-  brstm = null;
+  instance = null;
 }
 export function getMetadata(): Metadata | undefined {
-  if (!brstm) {
+  if (!instance) {
     return;
   }
-  return brstm.metadata;
+  return instance.metadata;
 }
 
-export function getAllSamples() {
-  if (!brstm) {
-    return;
-  }
-  const allSamples = brstm.getAllSamples();
-  return transfer(
-    allSamples,
-    allSamples.map((allSamplesPerChannel) => allSamplesPerChannel.buffer)
-  );
-}
+// export function getAllSamples() {
+//   if (!brstm) {
+//     return;
+//   }
+//   const allSamples = brstm.getAllSamples();
+//   return transfer(
+//     allSamples,
+//     allSamples.map((allSamplesPerChannel) => allSamplesPerChannel.buffer)
+//   );
+// }
 
-export function getSamples(offset: number, size: number) {
-  if (!brstm) {
-    return;
-  }
-  const allSamples = brstm.getSamples(offset, size).map(convertToFloat32);
-  return transfer(
-    allSamples,
-    allSamples.map((allSamplesPerChannel) => allSamplesPerChannel.buffer)
-  );
-}
+// export function getSamples(offset: number, size: number) {
+//   if (!brstm) {
+//     return;
+//   }
+//   const allSamples = brstm.getSamples(offset, size).map(convertToFloat32);
+//   return transfer(
+//     allSamples,
+//     allSamples.map((allSamplesPerChannel) => allSamplesPerChannel.buffer)
+//   );
+// }
 
 
 function convertToFloat32(pcmSamples: Int16Array): Float32Array {
diff --git a/app/src/elements/nikku-main.ts b/app/src/elements/nikku-main.ts
index 0b511bd..89cbd48 100644
--- a/app/src/elements/nikku-main.ts
+++ b/app/src/elements/nikku-main.ts
@@ -95,7 +95,7 @@ export class NikkuMain extends LitElement {
           <input
             type="file"
             id="controls-select-file"
-            accept=".brstm"
+            accept=".brstm,.bfstm"
             @change=${this.#handleFileInputChange}
           />
           <span id="controls-select-file-custom"></span>
@@ -210,6 +210,8 @@ export class NikkuMain extends LitElement {
     try {
       await this.workerInstance.init(transfer(buffer, [buffer]));
       const metadata = await this.workerInstance.getMetadata();
+      console.log('metadata', metadata);
+      return;
 
       if (this.audioPlayer) {
         await this.audioPlayer.destroy();
diff --git a/packages/bfstm/README.md b/packages/bfstm/README.md
new file mode 100644
index 0000000..e3d0eb1
--- /dev/null
+++ b/packages/bfstm/README.md
@@ -0,0 +1,3 @@
+# BFSTM
+
+https://mk8.tockdom.com/wiki/BFSTM_(File_Format)
diff --git a/packages/bfstm/package.json b/packages/bfstm/package.json
new file mode 100644
index 0000000..f578a58
--- /dev/null
+++ b/packages/bfstm/package.json
@@ -0,0 +1,55 @@
+{
+  "name": "bfstm",
+  "version": "1.0.0",
+  "description": "BFSTM Decoder",
+  "keywords": [
+    "bfstm"
+  ],
+  "sideEffects": false,
+  "source": "src/index.ts",
+  "main": "./dist/bfstm.js",
+  "module": "./dist/bfstm.mjs",
+  "umd:main": "./dist/bfstm.umd.js",
+  "unpkg": "./dist/bfstm.umd.js",
+  "exports": {
+    ".": {
+      "import": {
+        "nikku:source": "./src/index.ts",
+        "default": "./dist/bfstm.mjs"
+      },
+      "require": "./dist/bfstm.js"
+    }
+  },
+  "types": "./types/index.d.ts",
+  "files": [
+    "dist/",
+    "types/",
+    "src/"
+  ],
+  "author": {
+    "name": "Kenrick",
+    "email": "kenrick95@gmail.com"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/kenrick95/nikku.git",
+    "directory": "packages/bfstm"
+  },
+  "homepage": "https://github.com/kenrick95/nikku",
+  "bugs": {
+    "url": "https://github.com/kenrick95/nikku/issues"
+  },
+  "license": "MIT",
+  "scripts": {
+    "prepublishOnly": "pnpm run build",
+    "typecheck": "tsc --noEmit --emitDeclarationOnly false",
+    "build": "pnpm run build-declaration && pnpm build-lib",
+    "build-declaration": "tsc",
+    "build-lib": "vite build"
+  },
+  "devDependencies": {
+    "@nikku/utils": "workspace:*",
+    "typescript": "^4.8.4",
+    "vite": "^3.1.8"
+  }
+}
diff --git a/packages/bfstm/src/index.ts b/packages/bfstm/src/index.ts
new file mode 100644
index 0000000..26d457c
--- /dev/null
+++ b/packages/bfstm/src/index.ts
@@ -0,0 +1,193 @@
+import {
+  getSliceAsString,
+  getSliceAsNumber,
+  getInt16,
+  clamp,
+  getEndianness,
+} from '@nikku/utils';
+import type { Endianness } from '@nikku/utils';
+import type {
+  ChannelInfo,
+  CodecType,
+  Metadata,
+  TrackDescription,
+} from './types';
+
+export * from './types';
+
+declare var console: any;
+
+/**
+ * @class
+ */
+export class Bfstm {
+  rawData: Uint8Array;
+  endianness: Endianness;
+  versionNumber: number;
+  metadata: Metadata;
+
+  #offsetToInfo: number;
+  #offsetToSeek: number;
+  #offsetToData: number;
+
+  constructor(arrayBuffer: ArrayBuffer) {
+    /**
+     * @type {Uint8Array} rawData
+     */
+    this.rawData = new Uint8Array(arrayBuffer);
+
+    if (getSliceAsString(this.rawData, 0, 4) !== 'FSTM') {
+      throw new Error('Not a valid BFSTM file');
+    }
+
+    this.endianness = getEndianness(this.rawData);
+    this.versionNumber = getSliceAsNumber(
+      this.rawData,
+      0x08,
+      4,
+      this.endianness
+    );
+    this.#offsetToInfo = getSliceAsNumber(
+      this.rawData,
+      0x18,
+      4,
+      this.endianness
+    );
+    this.#offsetToSeek = getSliceAsNumber(
+      this.rawData,
+      0x24,
+      4,
+      this.endianness
+    );
+    this.#offsetToData = getSliceAsNumber(
+      this.rawData,
+      0x30,
+      4,
+      this.endianness
+    );
+
+    this.metadata = this.#getMetadata();
+  }
+
+  #getMetadata() {
+    const offsetToStreamInfo =
+      this.#offsetToInfo +
+      getSliceAsNumber(
+        this.rawData,
+        this.#offsetToInfo + 0x0c,
+        4,
+        this.endianness
+      ) +
+      0x08;
+    const offsetToTrackInfo =
+      this.#offsetToInfo +
+      getSliceAsNumber(
+        this.rawData,
+        this.#offsetToInfo + 0x14,
+        4,
+        this.endianness
+      ) +
+      0x08;
+    const offsetToChannelInfo =
+      this.#offsetToInfo +
+      getSliceAsNumber(
+        this.rawData,
+        this.#offsetToInfo + 0x1c,
+        4,
+        this.endianness
+      ) +
+      0x08;
+
+    /**
+     * @type {Metadata}
+     */
+    const metadata: Metadata = {
+
+      offsetToTrackInfo,
+      offsetToChannelInfo,
+
+      fileSize: getSliceAsNumber(this.rawData, 0x0c, 4, this.endianness),
+      endianness: this.endianness,
+      codec: getSliceAsNumber(
+        this.rawData,
+        offsetToStreamInfo,
+        1,
+        this.endianness
+      ) as CodecType,
+      loopFlag: getSliceAsNumber(
+        this.rawData,
+        offsetToStreamInfo + 0x01,
+        1,
+        this.endianness
+      ),
+      numberChannels: getSliceAsNumber(
+        this.rawData,
+        offsetToStreamInfo + 0x02,
+        1,
+        this.endianness
+      ),
+      numberRegions: getSliceAsNumber(
+        this.rawData,
+        offsetToStreamInfo + 0x03,
+        1,
+        this.endianness
+      ),
+      sampleRate: getSliceAsNumber(
+        this.rawData,
+        offsetToStreamInfo + 0x04,
+        4,
+        this.endianness
+      ),
+      loopStartSample: getSliceAsNumber(
+        this.rawData,
+        offsetToStreamInfo + 0x08,
+        4,
+        this.endianness
+      ),
+      totalSamples: getSliceAsNumber(
+        this.rawData,
+        offsetToStreamInfo + 0x0c,
+        4,
+        this.endianness
+      ),
+      totalBlocks: getSliceAsNumber(
+        this.rawData,
+        offsetToStreamInfo + 0x10,
+        4,
+        this.endianness
+      ),
+      blockSize: getSliceAsNumber(
+        this.rawData,
+        offsetToStreamInfo + 0x14,
+        4,
+        this.endianness
+      ),
+      samplesPerBlock: getSliceAsNumber(
+        this.rawData,
+        offsetToStreamInfo + 0x18,
+        4,
+        this.endianness
+      ),
+      finalBlockSize: getSliceAsNumber(
+        this.rawData,
+        offsetToStreamInfo + 0x1c,
+        4,
+        this.endianness
+      ),
+      totalSamplesInFinalBlock: getSliceAsNumber(
+        this.rawData,
+        offsetToStreamInfo + 0x20,
+        4,
+        this.endianness
+      ),
+      finalBlockSizeWithPadding: getSliceAsNumber(
+        this.rawData,
+        offsetToStreamInfo + 0x24,
+        4,
+        this.endianness
+      ),
+    };
+
+    return metadata;
+  }
+}
diff --git a/packages/bfstm/src/types.ts b/packages/bfstm/src/types.ts
new file mode 100644
index 0000000..52fb081
--- /dev/null
+++ b/packages/bfstm/src/types.ts
@@ -0,0 +1,53 @@
+import type { Endianness } from '@nikku/utils';
+export type ChannelInfo = {
+  adpcmCoefficients: number[];
+  gain: number;
+  initialPredictorScale: number;
+  historySample1: number;
+  historySample2: number;
+  loopPredictorScale: number;
+  loopHistorySample1: number;
+  loopHistorySample2: number;
+};
+export type TrackDescription = {
+  numberChannels: number;
+  type: number;
+};
+/**
+ * - 0 = PCM8
+ * - 1 = PCM16
+ * - 2 = DSP ADPCM
+ * - 3 = IMA ADPCM.
+ */
+export type CodecType = 0 | 1 | 2 | 3;
+export type Metadata = {
+  fileSize: number;
+  endianness: Endianness;
+  codec: CodecType;
+  loopFlag: number;
+  numberChannels: number;
+  numberRegions: number;
+  sampleRate: number;
+  /** loop start, in terms of sample # */
+  loopStartSample: number;
+  totalSamples: number;
+  /** total number of blocks, per channel, including final block */
+  totalBlocks: number;
+  blockSize: number;
+  samplesPerBlock: number;
+  /** Final block size, without padding, in bytes */
+  finalBlockSize: number;
+  /** Final block size, **with** padding, in bytes */
+  finalBlockSizeWithPadding: number;
+  /** Total samples in final block */
+  totalSamplesInFinalBlock: number;
+
+  /** Samples per entry in ADPC table */
+  adpcTableSamplesPerEntry: number;
+  /** Bytes per entry in ADPC table */
+  adpcTableBytesPerEntry: number;
+  /** Number of tracks */
+  numberTracks: number;
+  trackDescriptionType: number;
+  trackDescriptions: TrackDescription[];
+};
diff --git a/packages/bfstm/tsconfig.json b/packages/bfstm/tsconfig.json
new file mode 100644
index 0000000..9cd71ad
--- /dev/null
+++ b/packages/bfstm/tsconfig.json
@@ -0,0 +1,25 @@
+{
+  "compilerOptions": {
+    "module": "esnext",
+    "lib": ["es2017"],
+    "outDir": "./types",
+    "rootDir": "./src",
+    "strict": true,
+    "declaration": true,
+    "emitDeclarationOnly": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
+    "moduleResolution": "node",
+    "allowSyntheticDefaultImports": true,
+    "experimentalDecorators": true,
+    "forceConsistentCasingInFileNames": true,
+    "useDefineForClassFields": false,
+    "target": "ESNext",
+    "skipLibCheck": true,
+    "typeRoots": []
+  },
+  "include": ["src/"],
+  "exclude": ["node_modules/", "tests/"]
+}
diff --git a/packages/brstm/package.json b/packages/brstm/package.json
index 96efbe7..407a496 100644
--- a/packages/brstm/package.json
+++ b/packages/brstm/package.json
@@ -49,6 +49,7 @@
     "test": "pnpm run build-lib && node tests/index.test.js"
   },
   "devDependencies": {
+    "@nikku/utils": "workspace:*",
     "typescript": "^4.8.4",
     "vite": "^3.1.8"
   }
diff --git a/packages/brstm/src/index.ts b/packages/brstm/src/index.ts
index 9e5d7a8..d28512e 100644
--- a/packages/brstm/src/index.ts
+++ b/packages/brstm/src/index.ts
@@ -4,8 +4,8 @@ import {
   getInt16,
   clamp,
   getEndianness,
-} from './utils';
-import type { Endianness } from './utils';
+} from '@nikku/utils';
+import type { Endianness } from '@nikku/utils';
 import type {
   ChannelInfo,
   CodecType,
diff --git a/packages/brstm/src/types.ts b/packages/brstm/src/types.ts
index c5a8bfa..09903d6 100644
--- a/packages/brstm/src/types.ts
+++ b/packages/brstm/src/types.ts
@@ -1,4 +1,4 @@
-import type { Endianness } from './utils';
+import type { Endianness } from '@nikku/utils';
 export type ChannelInfo = {
   adpcmCoefficients: number[];
   gain: number;
diff --git a/packages/dsp-adpcm/package.json b/packages/dsp-adpcm/package.json
new file mode 100644
index 0000000..26358d3
--- /dev/null
+++ b/packages/dsp-adpcm/package.json
@@ -0,0 +1,9 @@
+{
+  "name": "@nikku/dsp-adpcm",
+  "private": true,
+  "main": "src/index.ts",
+  "sideEffects": false,
+  "dependencies": {
+    "@nikku/utils": "workspace:^"
+  }
+}
diff --git a/packages/dsp-adpcm/src/index.ts b/packages/dsp-adpcm/src/index.ts
new file mode 100644
index 0000000..b2456b3
--- /dev/null
+++ b/packages/dsp-adpcm/src/index.ts
@@ -0,0 +1,89 @@
+import { clamp } from '@nikku/utils';
+
+export class DspAdpcm {
+  samplesInFinalBlock: number;
+  samplesPerBlock: number;
+  totalBlocks: number;
+  totalChannels: number;
+
+  constructor({
+    samplesInFinalBlock,
+    samplesPerBlock,
+    totalBlocks,
+    totalChannels,
+  }: {
+    samplesInFinalBlock: number;
+    samplesPerBlock: number;
+    totalBlocks: number;
+    totalChannels: number;
+  }) {
+    this.samplesInFinalBlock = samplesInFinalBlock;
+    this.samplesPerBlock = samplesPerBlock;
+    this.totalBlocks = totalBlocks;
+    this.totalChannels = totalChannels;
+  }
+  #getSamplesAtBlock(b: number): Array<Int16Array> {
+    const result: Array<Int16Array> = [];
+    const totalSamplesInBlock =
+      b === totalBlocks - 1 ? samplesInFinalBlock : samplesPerBlock;
+
+    for (let c = 0; c < numberChannels; c++) {
+      result.push(new Int16Array(totalSamplesInBlock));
+    }
+
+    for (let c = 0; c < numberChannels; c++) {
+      const { adpcmCoefficients } = channelInfo[c];
+      const blockData = allChannelsBlockData[c];
+
+      const sampleResult: Array<number> = [];
+      const ps = blockData[0];
+      const { yn1, yn2 } = adpcChunkData[c][b];
+
+      // #region Magic adapted from brawllib's ADPCMState.cs
+      let cps = ps,
+        cyn1 = yn1,
+        cyn2 = yn2,
+        dataIndex = 0;
+
+      for (let sampleIndex = 0; sampleIndex < totalSamplesInBlock; ) {
+        let outSample = 0;
+        if (sampleIndex % 14 === 0) {
+          cps = blockData[dataIndex++];
+        }
+        if ((sampleIndex++ & 1) === 0) {
+          outSample = blockData[dataIndex] >> 4;
+        } else {
+          outSample = blockData[dataIndex++] & 0x0f;
+        }
+        if (outSample >= 8) {
+          outSample -= 16;
+        }
+        const scale = 1 << (cps & 0x0f);
+        const cIndex = (cps >> 4) << 1;
+
+        outSample =
+          (0x400 +
+            ((scale * outSample) << 11) +
+            adpcmCoefficients[clamp(cIndex, 0, 15)] * cyn1 +
+            adpcmCoefficients[clamp(cIndex + 1, 0, 15)] * cyn2) >>
+          11;
+
+        cyn2 = cyn1;
+        cyn1 = clamp(outSample, -32768, 32767);
+
+        sampleResult.push(cyn1);
+      }
+
+      // Overwrite history samples for the next block with decoded samples
+      if (b < totalBlocks - 1) {
+        adpcChunkData[c][b + 1].yn1 = sampleResult[totalSamplesInBlock - 1];
+        adpcChunkData[c][b + 1].yn2 = sampleResult[totalSamplesInBlock - 2];
+      }
+
+      // #endregion
+
+      result[c].set(sampleResult);
+    }
+    return result;
+  }
+}
diff --git a/packages/dsp-adpcm/tsconfig.json b/packages/dsp-adpcm/tsconfig.json
new file mode 100644
index 0000000..9cd71ad
--- /dev/null
+++ b/packages/dsp-adpcm/tsconfig.json
@@ -0,0 +1,25 @@
+{
+  "compilerOptions": {
+    "module": "esnext",
+    "lib": ["es2017"],
+    "outDir": "./types",
+    "rootDir": "./src",
+    "strict": true,
+    "declaration": true,
+    "emitDeclarationOnly": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
+    "moduleResolution": "node",
+    "allowSyntheticDefaultImports": true,
+    "experimentalDecorators": true,
+    "forceConsistentCasingInFileNames": true,
+    "useDefineForClassFields": false,
+    "target": "ESNext",
+    "skipLibCheck": true,
+    "typeRoots": []
+  },
+  "include": ["src/"],
+  "exclude": ["node_modules/", "tests/"]
+}
diff --git a/packages/utils/package.json b/packages/utils/package.json
new file mode 100644
index 0000000..9d58811
--- /dev/null
+++ b/packages/utils/package.json
@@ -0,0 +1,6 @@
+{
+  "name": "@nikku/utils",
+  "private": true,
+  "main": "src/index.ts",
+  "sideEffects": false
+}
diff --git a/packages/brstm/src/utils.ts b/packages/utils/src/index.ts
similarity index 91%
rename from packages/brstm/src/utils.ts
rename to packages/utils/src/index.ts
index a0cb432..ecfac86 100644
--- a/packages/brstm/src/utils.ts
+++ b/packages/utils/src/index.ts
@@ -5,7 +5,6 @@ export function getSlice(
 ): number[] {
   const result = [];
   for (let i = start; i < start + length; i++) {
-    // Apparently unsigned
     result.push(uint8Array[i]);
   }
   return result;
@@ -77,7 +76,8 @@ export function getSliceAsNumber(
   if (endianness === ENDIAN.LITTLE) {
     resArr.reverse();
   }
-  return resArr.reduce((acc, curr) => acc * 256 + curr, 0);
+  const res = resArr.reduce((acc, curr) => acc * 256 + curr, 0);
+  return res;
 }
 
 /**
diff --git a/packages/utils/tsconfig.json b/packages/utils/tsconfig.json
new file mode 100644
index 0000000..9cd71ad
--- /dev/null
+++ b/packages/utils/tsconfig.json
@@ -0,0 +1,25 @@
+{
+  "compilerOptions": {
+    "module": "esnext",
+    "lib": ["es2017"],
+    "outDir": "./types",
+    "rootDir": "./src",
+    "strict": true,
+    "declaration": true,
+    "emitDeclarationOnly": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
+    "moduleResolution": "node",
+    "allowSyntheticDefaultImports": true,
+    "experimentalDecorators": true,
+    "forceConsistentCasingInFileNames": true,
+    "useDefineForClassFields": false,
+    "target": "ESNext",
+    "skipLibCheck": true,
+    "typeRoots": []
+  },
+  "include": ["src/"],
+  "exclude": ["node_modules/", "tests/"]
+}
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index bed2dee..87c83f9 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -8,6 +8,7 @@ importers:
   app:
     specifiers:
       '@types/audioworklet': ^0.0.33
+      bfstm: ^1.0.0
       brstm: ^1.6.1
       comlink: ^4.3.1
       lit: ^2.4.0
@@ -17,6 +18,7 @@ importers:
       vite-plugin-comlink: ^3.0.4
       vite-plugin-pwa: ^0.13.1
     dependencies:
+      bfstm: link:../packages/bfstm
       brstm: link:../packages/brstm
       comlink: 4.3.1
       lit: 2.4.0
@@ -28,14 +30,35 @@ importers:
       vite-plugin-comlink: 3.0.4_comlink@4.3.1+vite@3.1.8
       vite-plugin-pwa: 0.13.1_vite@3.1.8
 
+  packages/bfstm:
+    specifiers:
+      '@nikku/utils': workspace:*
+      typescript: ^4.8.4
+      vite: ^3.1.8
+    devDependencies:
+      '@nikku/utils': link:../utils
+      typescript: 4.8.4
+      vite: 3.1.8
+
   packages/brstm:
     specifiers:
+      '@nikku/utils': workspace:*
       typescript: ^4.8.4
       vite: ^3.1.8
     devDependencies:
+      '@nikku/utils': link:../utils
       typescript: 4.8.4
       vite: 3.1.8
 
+  packages/dsp-adpcm:
+    specifiers:
+      '@nikku/utils': workspace:^
+    dependencies:
+      '@nikku/utils': link:../utils
+
+  packages/utils:
+    specifiers: {}
+
 packages:
 
   /@ampproject/remapping/2.2.0: