diff --git a/frontend/pnpm-lock.yaml b/frontend/pnpm-lock.yaml
index 629d82ac98..442ca53cb9 100644
--- a/frontend/pnpm-lock.yaml
+++ b/frontend/pnpm-lock.yaml
@@ -327,6 +327,15 @@ importers:
 
   viewer:
     dependencies:
+      '@ffmpeg/core':
+        specifier: 0.12.10
+        version: 0.12.10
+      '@ffmpeg/ffmpeg':
+        specifier: 0.12.15
+        version: 0.12.15
+      '@ffmpeg/util':
+        specifier: 0.12.2
+        version: 0.12.2
       '@formatjs/intl-durationformat':
         specifier: ^0.7.4
         version: 0.7.4
@@ -1106,6 +1115,22 @@ packages:
   '@fastify/busboy@3.1.1':
     resolution: {integrity: sha512-5DGmA8FTdB2XbDeEwc/5ZXBl6UbBAyBOOLlPuBnZ/N1SwdH9Ii+cOX3tBROlDgcTXxjOYnLMVoKk9+FXAw0CJw==}
 
+  '@ffmpeg/core@0.12.10':
+    resolution: {integrity: sha512-dzNplnn2Nxle2c2i2rrDhqcB19q9cglCkWnoMTDN9Q9l3PvdjZWd1HfSPjCNWc/p8Q3CT+Es9fWOR0UhAeYQZA==}
+    engines: {node: '>=16.x'}
+
+  '@ffmpeg/ffmpeg@0.12.15':
+    resolution: {integrity: sha512-1C8Obr4GsN3xw+/1Ww6PFM84wSQAGsdoTuTWPOj2OizsRDLT4CXTaVjPhkw6ARyDus1B9X/L2LiXHqYYsGnRFw==}
+    engines: {node: '>=18.x'}
+
+  '@ffmpeg/types@0.12.4':
+    resolution: {integrity: sha512-k9vJQNBGTxE5AhYDtOYR5rO5fKsspbg51gbcwtbkw2lCdoIILzklulcjJfIDwrtn7XhDeF2M+THwJ2FGrLeV6A==}
+    engines: {node: '>=16.x'}
+
+  '@ffmpeg/util@0.12.2':
+    resolution: {integrity: sha512-ouyoW+4JB7WxjeZ2y6KpRvB+dLp7Cp4ro8z0HIVpZVCM7AwFlHa0c4R8Y/a4M3wMqATpYKhC7lSFHQ0T11MEDw==}
+    engines: {node: '>=18.x'}
+
   '@floating-ui/core@1.7.2':
     resolution: {integrity: sha512-wNB5ooIKHQc+Kui96jE/n69rHFWAVoxn5CAzL1Xdd8FG03cgY3MLO+GF9U3W737fYDSgPWA6MReKhBQBop6Pcw==}
 
@@ -7143,6 +7168,16 @@ snapshots:
 
   '@fastify/busboy@3.1.1': {}
 
+  '@ffmpeg/core@0.12.10': {}
+
+  '@ffmpeg/ffmpeg@0.12.15':
+    dependencies:
+      '@ffmpeg/types': 0.12.4
+
+  '@ffmpeg/types@0.12.4': {}
+
+  '@ffmpeg/util@0.12.2': {}
+
   '@floating-ui/core@1.7.2':
     dependencies:
       '@floating-ui/utils': 0.2.10
diff --git a/frontend/viewer/package.json b/frontend/viewer/package.json
index 8a0f778660..5a300c5e0f 100644
--- a/frontend/viewer/package.json
+++ b/frontend/viewer/package.json
@@ -11,6 +11,7 @@
   "scripts": {
     "dev": "vite",
     "build": "vite build",
+    "build-ffmpeg-worker": "vite build --config vite.config.ffmpeg-worker.ts",
     "preview": "vite preview",
     "pretest:playwright": "playwright install",
     "test:playwright": "playwright test",
@@ -89,6 +90,9 @@
     "@microsoft/signalr": "^8.0.7",
     "autoprefixer": "^10.4.21",
     "fast-json-patch": "^3.1.1",
+    "@ffmpeg/ffmpeg": "0.12.15",
+    "@ffmpeg/util": "0.12.2",
+    "@ffmpeg/core": "0.12.10",
     "jsdom": "^26.1.0",
     "just-throttle": "^4.2.0",
     "postcss": "catalog:",
diff --git a/frontend/viewer/src/lib/components/audio/AudioDialog.svelte b/frontend/viewer/src/lib/components/audio/AudioDialog.svelte
index 9b5b0a394e..a847847523 100644
--- a/frontend/viewer/src/lib/components/audio/AudioDialog.svelte
+++ b/frontend/viewer/src/lib/components/audio/AudioDialog.svelte
@@ -5,10 +5,8 @@
   import {useDialogsService} from '$lib/services/dialogs-service.js';
   import {useBackHandler} from '$lib/utils/back-handler.svelte';
   import {watch} from 'runed';
-  import {delay} from '$lib/utils/time';
   import AudioProvider from './audio-provider.svelte';
   import AudioEditor from './audio-editor.svelte';
-  import Loading from '$lib/components/Loading.svelte';
   import {useLexboxApi} from '$lib/services/service-provider';
   import {UploadFileResult} from '$lib/dotnet-types/generated-types/MiniLcm/Media/UploadFileResult';
   import {AppNotification} from '$lib/notifications/notifications';
@@ -21,8 +19,8 @@
 
   let submitting = $state(false);
   let selectedFile = $state<File>();
-  let audio = $state<Blob>();
-  const tooBig = $derived((audio?.size ?? 0) > 10 * 1024 * 1024);
+  let finalAudio = $state<File>();
+  const tooBig = $derived((finalAudio?.size ?? 0) > 10 * 1024 * 1024);
 
   let requester: {
     resolve: (mediaUri: string | undefined) => void
@@ -41,6 +39,10 @@
     if (!open) reset();
   });
 
+  watch(() => selectedFile, () => {
+    if (!selectedFile) finalAudio = undefined;
+  })
+
   function close() {
     open = false;
     reset();
@@ -53,12 +55,12 @@
   }
 
   function clearAudio() {
-    audio = selectedFile = undefined;
+    selectedFile = undefined;
     submitting = false;
   }
 
   async function submitAudio() {
-    if (!audio) throw new Error('No audio to upload');
+    if (!selectedFile) throw new Error('No audio to upload');
     if (!requester) throw new Error('No requester');
 
     submitting = true;
@@ -72,8 +74,8 @@
   }
 
   async function uploadAudio() {
-    if (!audio || !selectedFile) throw new Error($t`No file selected`);
-    const response = await lexboxApi.saveFile(audio, {filename: selectedFile.name, mimeType: audio.type});
+    if (!finalAudio) throw new Error($t`No file to upload`);
+    const response = await lexboxApi.saveFile(finalAudio, {filename: finalAudio.name, mimeType: finalAudio.type});
     switch (response.result) {
       case UploadFileResult.SavedLocally:
         AppNotification.display($t`Audio saved locally`, 'success');
@@ -94,16 +96,13 @@
     return response.mediaUri;
   }
 
-  async function onFileSelected(file: File) {
+  function onFileSelected(file: File) {
     selectedFile = file;
-    audio = await processAudio(file);
   }
 
-  async function onRecordingComplete(blob: Blob) {
+  function onRecordingComplete(blob: Blob) {
     let fileExt = mimeTypeToFileExtension(blob.type);
     selectedFile = new File([blob], `recording-${Date.now()}.${fileExt}`, {type: blob.type});
-    if (!open) return;
-    audio = await processAudio(blob);
   }
 
   function mimeTypeToFileExtension(mimeType: string) {
@@ -133,17 +132,8 @@
   }
 
   function onDiscard() {
-    audio = undefined;
     selectedFile = undefined;
   }
-
-  let loading = $state(false);
-  async function processAudio(blob: Blob): Promise<Blob> {
-    loading = true;
-    await delay(1000); // Simulate processing delay
-    loading = false;
-    return blob;
-  }
 </script>
 
 
@@ -152,20 +142,16 @@
     <Dialog.DialogHeader>
       <Dialog.DialogTitle>{$t`Add audio`}</Dialog.DialogTitle>
     </Dialog.DialogHeader>
-    {#if !audio || !selectedFile}
-      {#if loading}
-        <Loading class="self-center justify-self-center size-16"/>
-      {:else}
-        <AudioProvider {onFileSelected} {onRecordingComplete}/>
-      {/if}
+    {#if !selectedFile}
+      <AudioProvider {onFileSelected} {onRecordingComplete}/>
     {:else}
-      <AudioEditor {audio} name={selectedFile.name} onDiscard={onDiscard}/>
+      <AudioEditor audio={selectedFile} bind:finalAudio onDiscard={onDiscard}/>
       {#if tooBig}
         <p class="text-destructive text-lg text-end">{$t`File too big`}</p>
       {/if}
       <Dialog.DialogFooter>
         <Button onclick={() => open = false} variant="secondary">{$t`Cancel`}</Button>
-        <Button onclick={() => submitAudio()} disabled={tooBig} loading={submitting}>
+        <Button onclick={() => submitAudio()} disabled={tooBig || !finalAudio} loading={submitting}>
           {$t`Save audio`}
         </Button>
       </Dialog.DialogFooter>
diff --git a/frontend/viewer/src/lib/components/audio/audio-editor.svelte b/frontend/viewer/src/lib/components/audio/audio-editor.svelte
index 7979859aa8..5f3288f1e5 100644
--- a/frontend/viewer/src/lib/components/audio/audio-editor.svelte
+++ b/frontend/viewer/src/lib/components/audio/audio-editor.svelte
@@ -1,54 +1,119 @@
 <script lang="ts">
-  import { t } from 'svelte-i18n-lingui';
+  import {t} from 'svelte-i18n-lingui';
   import Button from '../ui/button/button.svelte';
   import Waveform from './wavesurfer/waveform.svelte';
   import type WaveSurfer from 'wavesurfer.js';
   import {formatDigitalDuration} from '../ui/format/format-duration';
   import DevContent from '$lib/layout/DevContent.svelte';
   import {Label} from '../ui/label';
+  import {FFmpegApi} from './ffmpeg';
+  import Loading from '$lib/components/Loading.svelte';
+  import {resource, watch} from 'runed';
+  import {onDestroy} from 'svelte';
 
   type Props = {
-    audio: Blob;
-    name: string
+    audio: File;
+    finalAudio: File | undefined;
     onDiscard: () => void;
   };
 
-  let { audio, name, onDiscard }: Props = $props();
+  let {
+    audio,
+    finalAudio = $bindable(undefined),
+    onDiscard
+  }: Props = $props();
 
   let audioApi = $state<WaveSurfer>();
   let playing = $state(false);
   let duration = $state<number | null>(null);
-  const mb = $derived((audio.size / 1024 / 1024).toFixed(2));
-  const formatedDuration = $derived(duration ? formatDigitalDuration({ seconds: duration }) : 'unknown');
+  const mb = $derived(!finalAudio ? '0' : (finalAudio.size / 1024 / 1024).toFixed(2));
+  const formattedDuration = $derived(duration ? formatDigitalDuration({seconds: duration}) : 'unknown');
+  let ffmpegApi: FFmpegApi | undefined;
 
+  let ffmpegFile = resource(() => audio, async (audio, _, {signal}) => {
+    ffmpegApi ??= await FFmpegApi.create();
+    return await ffmpegApi.toFFmpegFile(audio, AbortSignal.any([signal, abortController.signal]));
+  });
+
+  let flacFile = resource(() => [ffmpegFile.current], async ([file], _, {signal}) => {
+    if (!file) return;
+    ffmpegApi ??= await FFmpegApi.create();
+    return await ffmpegApi.convertToFlac(file, AbortSignal.any([signal, abortController.signal]));
+  });
+
+  let readFile = resource(() => [flacFile.current], async ([file], _, {signal}) => {
+    if (!file) return;
+    ffmpegApi ??= await FFmpegApi.create();
+    return await ffmpegApi.readFile(file, AbortSignal.any([signal, abortController.signal]));
+  });
+
+  watch(() => [readFile.current, readFile.loading] as const, ([file, loading]) => {
+    if (loading || !file) {
+      finalAudio = undefined;
+    } else {
+      finalAudio = file;
+    }
+  });
+
+  const loading = $derived(ffmpegFile.loading || flacFile.loading || readFile.loading);
+  const error   = $derived((ffmpegFile.error || flacFile.error || readFile.error)?.toString());
+
+  const abortController = new AbortController();
+  onDestroy(() => {
+    abortController.abort();
+    ffmpegApi?.terminate();
+  });
+
+  function downloadAudio() {
+    if (!finalAudio) throw new Error('No audio to download');
+    const url = URL.createObjectURL(finalAudio);
+    try {
+      const a = document.createElement('a');
+      a.href = url;
+      a.download = `${finalAudio.name}`;
+      a.click();
+    } finally {
+      URL.revokeObjectURL(url);
+    }
+  }
 </script>
 
 <div class="flex flex-col gap-4 items-center justify-center">
+  {#if loading || !finalAudio}
+    <Loading class="self-center justify-self-center size-16"/>
+  {:else}
   <span class="inline-grid grid-cols-[auto_auto_1rem_auto_auto] gap-2 items-baseline">
-    <Label class="justify-self-end">{$t`Length:`}</Label> <span>{$t`${formatedDuration}`}</span>
+    <Label class="justify-self-end">{$t`Length:`}</Label> <span>{$t`${formattedDuration}`}</span>
     <span></span>
     <Label class="justify-self-end">{$t`Size:`}</Label> <span>{$t`${mb} MB`}</span>
-    {#if name}
+    {#if finalAudio.name}
       <Label class="justify-self-end">{$t`File name:`}</Label>
-      <span class="col-span-4">{$t`${name}`}</span>
+      <span class="col-span-4">{$t`${finalAudio.name}`}</span>
     {/if}
     <DevContent>
       <Label class="justify-self-end">{$t`Type:`}</Label>
-      <span class="col-span-4">{$t`${audio.type}`}</span>
+      <span class="col-span-4">{$t`${finalAudio.type}`}</span>
     </DevContent>
   </span>
-  <!-- contain-inline-size prevents wavesurfer from freaking out inside a grid -->
-  <!-- pb-8 ensures the timeline is in the bounds of the container -->
-  <div class="w-full grow max-h-32 pb-3 contain-inline-size border-y">
-    <Waveform {audio} bind:playing bind:audioApi bind:duration showTimeline autoplay class="size-full" />
-  </div>
-  <div class="flex gap-2">
-    <Button variant="secondary" icon="i-mdi-close" onclick={onDiscard} disabled={!audio}>{$t`Discard`}</Button>
-    <Button
-      icon={playing ? 'i-mdi-pause' : 'i-mdi-play'}
-      onclick={() => (playing ? audioApi?.pause() : audioApi?.play())}
-      disabled={!audioApi}
-      size="icon"
-    />
-  </div>
+    <!-- contain-size prevents wavesurfer from freaking out inside a grid
+    contain-inline-size would improve the height reactivity of the waveform, but
+    results in the waveform sometimes change its height unexpectedly -->
+    <!-- pb-8 ensures the timeline is in the bounds of the container -->
+    <div class="w-full grow max-h-32 pb-3 contain-size border-y">
+      <Waveform audio={finalAudio} bind:playing bind:audioApi bind:duration showTimeline autoplay class="size-full"/>
+    </div>
+    <div class="flex gap-2">
+      <Button onclick={() => downloadAudio()} disabled={!finalAudio} variant="secondary" icon="i-mdi-download">{$t`Download`}</Button>
+      <Button variant="secondary" icon="i-mdi-close" onclick={onDiscard} disabled={!audio}>{$t`Discard`}</Button>
+      <Button
+        icon={playing ? 'i-mdi-pause' : 'i-mdi-play'}
+        onclick={() => (playing ? audioApi?.pause() : audioApi?.play())}
+        disabled={!audioApi}
+        size="icon"
+      />
+    </div>
+  {/if}
+  {#if error}
+    <p class="text-destructive">{error}</p>
+  {/if}
 </div>
diff --git a/frontend/viewer/src/lib/components/audio/ffmpeg/bundled-ffmpeg-worker.js b/frontend/viewer/src/lib/components/audio/ffmpeg/bundled-ffmpeg-worker.js
new file mode 100644
index 0000000000..8da5125f02
--- /dev/null
+++ b/frontend/viewer/src/lib/components/audio/ffmpeg/bundled-ffmpeg-worker.js
@@ -0,0 +1,104 @@
+/* This file generated by Vite / pnpm build-ffmpeg-worker. */
+// @ts-nocheck
+const f = "0.12.9", R = `https://unpkg.com/@ffmpeg/core@${f}/dist/umd/ffmpeg-core.js`;
+var E;
+(function(t) {
+  t.LOAD = "LOAD", t.EXEC = "EXEC", t.FFPROBE = "FFPROBE", t.WRITE_FILE = "WRITE_FILE", t.READ_FILE = "READ_FILE", t.DELETE_FILE = "DELETE_FILE", t.RENAME = "RENAME", t.CREATE_DIR = "CREATE_DIR", t.LIST_DIR = "LIST_DIR", t.DELETE_DIR = "DELETE_DIR", t.ERROR = "ERROR", t.DOWNLOAD = "DOWNLOAD", t.PROGRESS = "PROGRESS", t.LOG = "LOG", t.MOUNT = "MOUNT", t.UNMOUNT = "UNMOUNT";
+})(E || (E = {}));
+const u = new Error("unknown message type"), O = new Error("ffmpeg is not loaded, call `await ffmpeg.load()` first"), m = new Error("failed to import ffmpeg-core.js");
+let r;
+const l = async ({ coreURL: t, wasmURL: n, workerURL: e }) => {
+  const o = !r;
+  try {
+    t || (t = R), importScripts(t);
+  } catch {
+    if ((!t || t === R) && (t = R.replace("/umd/", "/esm/")), self.createFFmpegCore = (await import(
+      /* @vite-ignore */
+      t
+    )).default, !self.createFFmpegCore)
+      throw m;
+  }
+  const s = t, c = n || t.replace(/.js$/g, ".wasm"), a = e || t.replace(/.js$/g, ".worker.js");
+  return r = await self.createFFmpegCore({
+    // Fix `Overload resolution failed.` when using multi-threaded ffmpeg-core.
+    // Encoded wasmURL and workerURL in the URL as a hack to fix locateFile issue.
+    mainScriptUrlOrBlob: `${s}#${btoa(JSON.stringify({ wasmURL: c, workerURL: a }))}`
+  }), r.setLogger((i) => self.postMessage({ type: E.LOG, data: i })), r.setProgress((i) => self.postMessage({
+    type: E.PROGRESS,
+    data: i
+  })), o;
+}, D = ({ args: t, timeout: n = -1 }) => {
+  r.setTimeout(n), r.exec(...t);
+  const e = r.ret;
+  return r.reset(), e;
+}, S = ({ args: t, timeout: n = -1 }) => {
+  r.setTimeout(n), r.ffprobe(...t);
+  const e = r.ret;
+  return r.reset(), e;
+}, I = ({ path: t, data: n }) => (r.FS.writeFile(t, n), !0), L = ({ path: t, encoding: n }) => r.FS.readFile(t, { encoding: n }), N = ({ path: t }) => (r.FS.unlink(t), !0), A = ({ oldPath: t, newPath: n }) => (r.FS.rename(t, n), !0), k = ({ path: t }) => (r.FS.mkdir(t), !0), w = ({ path: t }) => {
+  const n = r.FS.readdir(t), e = [];
+  for (const o of n) {
+    const s = r.FS.stat(`${t}/${o}`), c = r.FS.isDir(s.mode);
+    e.push({ name: o, isDir: c });
+  }
+  return e;
+}, b = ({ path: t }) => (r.FS.rmdir(t), !0), p = ({ fsType: t, options: n, mountPoint: e }) => {
+  const o = t, s = r.FS.filesystems[o];
+  return s ? (r.FS.mount(s, n, e), !0) : !1;
+}, d = ({ mountPoint: t }) => (r.FS.unmount(t), !0);
+self.onmessage = async ({ data: { id: t, type: n, data: e } }) => {
+  const o = [];
+  let s;
+  try {
+    if (n !== E.LOAD && !r)
+      throw O;
+    switch (n) {
+      case E.LOAD:
+        s = await l(e);
+        break;
+      case E.EXEC:
+        s = D(e);
+        break;
+      case E.FFPROBE:
+        s = S(e);
+        break;
+      case E.WRITE_FILE:
+        s = I(e);
+        break;
+      case E.READ_FILE:
+        s = L(e);
+        break;
+      case E.DELETE_FILE:
+        s = N(e);
+        break;
+      case E.RENAME:
+        s = A(e);
+        break;
+      case E.CREATE_DIR:
+        s = k(e);
+        break;
+      case E.LIST_DIR:
+        s = w(e);
+        break;
+      case E.DELETE_DIR:
+        s = b(e);
+        break;
+      case E.MOUNT:
+        s = p(e);
+        break;
+      case E.UNMOUNT:
+        s = d(e);
+        break;
+      default:
+        throw u;
+    }
+  } catch (c) {
+    self.postMessage({
+      id: t,
+      type: E.ERROR,
+      data: c.toString()
+    });
+    return;
+  }
+  s instanceof Uint8Array && o.push(s.buffer), self.postMessage({ id: t, type: n, data: s }, o);
+};
diff --git a/frontend/viewer/src/lib/components/audio/ffmpeg/ffmpeg-api.ts b/frontend/viewer/src/lib/components/audio/ffmpeg/ffmpeg-api.ts
new file mode 100644
index 0000000000..9157932b4f
--- /dev/null
+++ b/frontend/viewer/src/lib/components/audio/ffmpeg/ffmpeg-api.ts
@@ -0,0 +1,136 @@
+import {FFmpeg} from '@ffmpeg/ffmpeg';
+import coreURL from '@ffmpeg/core?url';
+import {fetchFile} from '@ffmpeg/util';
+import inlineDataUrlWorker from './bundled-ffmpeg-worker.js?url&inline';
+import wasmUrl from '@ffmpeg/core/wasm?url';
+import {randomId} from '$lib/utils';
+
+
+async function ensureLoaded(ffmpeg: FFmpeg) {
+  if (ffmpeg.loaded) return;
+  await ffmpeg.load({
+    coreURL: coreURL,
+    wasmURL: wasmUrl,
+    classWorkerURL: import.meta.env.DEV ? inlineDataUrlWorker : undefined,
+  });
+}
+
+async function loadFFmpegInternal(): Promise<FFmpeg> {
+  const ffmpeg = new FFmpeg();
+  ffmpeg.on('log', (msg) => {
+    console.log('FFmpeg log:', msg);
+  });
+  await ensureLoaded(ffmpeg);
+
+  return ffmpeg;
+}
+
+export class FFmpegFile {
+  readonly filename: string;
+  private id: string = randomId();
+  private prefix: string;
+
+  constructor(mimeType: string, filename: string, prefix: string) {
+    this.mimeType = mimeType;
+    this.filename = filename;
+    this.prefix = prefix;
+  }
+
+  get internalFilePath() {
+    return `${this.internalFileDir}/${this.filename}`;
+  }
+  get internalFileDir() {
+    return `/${this.prefix}/${this.id}`;
+  }
+  readonly mimeType: string;
+
+  changeExtension(newExtension: string, mimeType?: string, prefix?: string): FFmpegFile {
+    return new FFmpegFile(mimeType ?? this.mimeType, this.filename.replace(/\.[^.]+$/, `.${newExtension}`), prefix ?? this.prefix);
+  }
+}
+
+export class FFmpegApi {
+  private static loadingPromise: Promise<FFmpeg> | null = null;
+
+  public static async create(): Promise<FFmpegApi> {
+    console.log('Loading FFmpeg...');
+    FFmpegApi.loadingPromise ??= loadFFmpegInternal();
+    const ffmpeg = await FFmpegApi.loadingPromise;
+    await ensureLoaded(ffmpeg);
+    console.log('FFmpeg loaded:', ffmpeg);
+    return new FFmpegApi(ffmpeg);
+  }
+
+  private constructor(private ffmpeg: FFmpeg) {
+  }
+
+  public terminate() {
+    this.ffmpeg.terminate();
+  }
+
+  private async createDir(path: string, signal: AbortSignal) {
+    console.log('Creating dir:', path);
+    const paths = path.split('/').filter(v => !!v);
+    let newDir = '';
+    for (const dir of paths) {
+      console.log('Checking dir:', newDir, dir);
+      const dirExists = (await this.ffmpeg.listDir(newDir || '/', {signal})).some(f => f.name === dir);
+      newDir += `/${dir}`;
+      if (dirExists) {
+        continue;
+      }
+      console.log('Creating dir:', newDir);
+      //create dir never returns if the dir already exists or if you're trying to create a sub directory of a directory which doesn't exist
+      await this.ffmpeg.createDir(newDir, {signal});
+    }
+  }
+  async toFFmpegFile(file: File, signal: AbortSignal): Promise<FFmpegFile> {
+    console.log('Writing file to ffmpeg FS:', file.name);
+    const ffmpegFile = new FFmpegFile(file.type, file.name, 'input');
+    await this.createDir(ffmpegFile.internalFileDir, signal);
+    await this.ffmpeg.writeFile(ffmpegFile.internalFilePath, await fetchFile(file), {signal});
+    return ffmpegFile;
+  }
+
+  async readFile(file: FFmpegFile, signal: AbortSignal): Promise<File> {
+    console.log('Reading file from ffmpeg FS:', file.filename);
+    const data = await this.ffmpeg.readFile(file.internalFilePath, undefined, {signal}) as Uint8Array;
+    return new File([data], file.filename, {type: file.mimeType});
+  }
+
+  async convertToWav(file: FFmpegFile, signal: AbortSignal): Promise<FFmpegFile> {
+    const convertedFile = file.changeExtension('wav', 'audio/wav', 'convert');
+    await this.createDir(convertedFile.internalFileDir, signal);
+    await this.ffmpeg.exec(
+      [
+        '-i', file.internalFilePath,
+        '-af', 'loudnorm',
+        '-ar', '44100',
+        '-ac', '2',
+        '-codec:a', 'pcm_s16le',
+        convertedFile.internalFilePath
+      ],
+      undefined,
+      {signal}
+    );
+    return convertedFile;
+  }
+
+  async convertToFlac(file: FFmpegFile,  signal: AbortSignal): Promise<FFmpegFile> {
+    console.log('Converting to FLAC:', file.filename);
+    const convertedFile = file.changeExtension('flac', 'audio/flac', 'convert');
+    await this.createDir(convertedFile.internalFileDir, signal);
+    await this.ffmpeg.exec(
+      [
+        '-i', file.internalFilePath,
+        '-af', 'loudnorm',
+        '-ar', '44100',
+        '-codec:a', 'flac',
+        convertedFile.internalFilePath
+      ],
+      undefined,
+      {signal}
+    );
+    return convertedFile;
+  }
+}
diff --git a/frontend/viewer/src/lib/components/audio/ffmpeg/index.ts b/frontend/viewer/src/lib/components/audio/ffmpeg/index.ts
new file mode 100644
index 0000000000..d3662d20fa
--- /dev/null
+++ b/frontend/viewer/src/lib/components/audio/ffmpeg/index.ts
@@ -0,0 +1 @@
+export * from './ffmpeg-api';
diff --git a/frontend/viewer/src/lib/components/field-editors/audio-input.svelte b/frontend/viewer/src/lib/components/field-editors/audio-input.svelte
index 1d9fe3e440..46b437a11a 100644
--- a/frontend/viewer/src/lib/components/field-editors/audio-input.svelte
+++ b/frontend/viewer/src/lib/components/field-editors/audio-input.svelte
@@ -51,7 +51,6 @@
   import {t} from 'svelte-i18n-lingui';
   import {ReadFileResult} from '$lib/dotnet-types/generated-types/MiniLcm/Media/ReadFileResult';
   import {useDialogsService} from '$lib/services/dialogs-service';
-  import {isDev} from '$lib/layout/DevContent.svelte';
   import * as ResponsiveMenu from '$lib/components/responsive-menu';
 
   const handled = Symbol();
@@ -208,15 +207,9 @@
 </script>
 {#if supportsAudio}
   {#if !audioId}
-    {#if $isDev}
-      <Button variant="secondary" icon="i-mdi-microphone-plus" size="sm" iconProps={{class: 'size-5'}} onclick={onGetAudioClick}>
-        {$t`Add audio`}
-      </Button>
-    {:else}
-      <div class="text-muted-foreground p-1">
-        {$t`No audio`}
-      </div>
-    {/if}
+    <Button variant="secondary" icon="i-mdi-microphone-plus" size="sm" iconProps={{class: 'size-5'}} onclick={onGetAudioClick}>
+      {$t`Add audio`}
+    </Button>
   {:else if isNotFoundAudioId(audioId)}
     <div class="text-muted-foreground p-1">
       {$t`Audio file not included in Send & Receive`}
diff --git a/frontend/viewer/src/lib/sandbox/Sandbox.svelte b/frontend/viewer/src/lib/sandbox/Sandbox.svelte
index 86912fb249..addd451639 100644
--- a/frontend/viewer/src/lib/sandbox/Sandbox.svelte
+++ b/frontend/viewer/src/lib/sandbox/Sandbox.svelte
@@ -33,7 +33,7 @@
   import {formatDate, FormatDate, formatNumber} from '$lib/components/ui/format';
   import {SvelteDate} from 'svelte/reactivity';
   import {RichTextToggle} from '$lib/dotnet-types/generated-types/MiniLcm/Models/RichTextToggle';
-
+  import {FFmpegApi} from '$lib/components/audio/ffmpeg';
 
   const testingService = tryUseService(DotnetService.TestingService);
 
@@ -125,6 +125,12 @@
   let reseter = $state(0);
 
   let currentDate = new SvelteDate();
+
+  async function preloadFFmpeg() {
+    console.log('Loading FFmpeg...');
+    let ffmpeg = await FFmpegApi.create();
+    console.log('FFmpeg loaded:', ffmpeg);
+  }
 </script>
 <DialogsProvider/>
 <div class="p-6 shadcn-root">
@@ -136,6 +142,7 @@
       {/snippet}
     </T>
   </h2>
+  <Button onclick={preloadFFmpeg}>Load FFmpeg</Button>
   <div class="grid grid-cols-3 gap-6">
     <div class="flex flex-col gap-2 border p-4 justify-between">
       <Button onclick={incrementAsync} {loading} icon="i-mdi-ab-testing">Shadcn FTW {count}</Button>
diff --git a/frontend/viewer/src/locales/en.po b/frontend/viewer/src/locales/en.po
index 37306d18e9..60a998b6b4 100644
--- a/frontend/viewer/src/locales/en.po
+++ b/frontend/viewer/src/locales/en.po
@@ -17,9 +17,9 @@ msgstr ""
 msgid "– ({0} changes)"
 msgstr "– ({0} changes)"
 
-#: src/lib/components/audio/audio-editor.svelte:28
-#: src/lib/components/audio/audio-editor.svelte:33
-#: src/lib/components/audio/audio-editor.svelte:37
+#: src/lib/components/audio/audio-editor.svelte:86
+#: src/lib/components/audio/audio-editor.svelte:91
+#: src/lib/components/audio/audio-editor.svelte:95
 msgid "{0}"
 msgstr "{0}"
 
@@ -39,7 +39,7 @@ msgstr "{0} (FieldWorks Lite)"
 msgid "{0} (FieldWorks)"
 msgstr "{0} (FieldWorks)"
 
-#: src/lib/components/audio/audio-editor.svelte:30
+#: src/lib/components/audio/audio-editor.svelte:88
 msgid "{0} MB"
 msgstr "{0} MB"
 
@@ -76,8 +76,8 @@ msgstr "Account"
 msgid "Activity"
 msgstr "Activity"
 
-#: src/lib/components/field-editors/audio-input.svelte:213
-#: src/lib/components/audio/AudioDialog.svelte:153
+#: src/lib/components/field-editors/audio-input.svelte:211
+#: src/lib/components/audio/AudioDialog.svelte:143
 msgid "Add audio"
 msgstr "Add audio"
 
@@ -126,15 +126,15 @@ msgstr "Application version"
 msgid "Are you sure you want to delete {0}?"
 msgstr "Are you sure you want to delete {0}?"
 
-#: src/lib/components/field-editors/audio-input.svelte:222
+#: src/lib/components/field-editors/audio-input.svelte:215
 msgid "Audio file not included in Send & Receive"
 msgstr "Audio file not included in Send & Receive"
 
-#: src/lib/components/audio/AudioDialog.svelte:82
+#: src/lib/components/audio/AudioDialog.svelte:84
 msgid "Audio saved and uploaded to Lexbox"
 msgstr "Audio saved and uploaded to Lexbox"
 
-#: src/lib/components/audio/AudioDialog.svelte:79
+#: src/lib/components/audio/AudioDialog.svelte:81
 msgid "Audio saved locally"
 msgstr "Audio saved locally"
 
@@ -168,7 +168,7 @@ msgstr "Browse"
 #: src/lib/entry-editor/EntryOrSensePicker.svelte:245
 #: src/lib/components/field-editors/select.svelte:166
 #: src/lib/components/field-editors/multi-select.svelte:280
-#: src/lib/components/audio/AudioDialog.svelte:167
+#: src/lib/components/audio/AudioDialog.svelte:153
 msgid "Cancel"
 msgstr "Cancel"
 
@@ -300,7 +300,7 @@ msgstr "Dictionary"
 msgid "Dictionary Preview"
 msgstr "Dictionary Preview"
 
-#: src/lib/components/audio/audio-editor.svelte:46
+#: src/lib/components/audio/audio-editor.svelte:107
 msgid "Discard"
 msgstr "Discard"
 
@@ -314,6 +314,7 @@ msgid "Don't delete"
 msgstr "Don't delete"
 
 #: src/lib/notifications/NotificationOutlet.svelte:26
+#: src/lib/components/audio/audio-editor.svelte:106
 #: src/home/Server.svelte:128
 msgid "Download"
 msgstr "Download"
@@ -407,24 +408,24 @@ msgstr "Field Labels"
 msgid "FieldWorks logo"
 msgstr "FieldWorks logo"
 
-#: src/lib/components/audio/AudioDialog.svelte:89
+#: src/lib/components/audio/AudioDialog.svelte:91
 msgid "File already exists"
 msgstr "File already exists"
 
-#: src/lib/components/audio/audio-editor.svelte:32
+#: src/lib/components/audio/audio-editor.svelte:90
 msgid "File name:"
 msgstr "File name:"
 
-#: src/lib/components/field-editors/audio-input.svelte:79
+#: src/lib/components/field-editors/audio-input.svelte:78
 msgid "File not found"
 msgstr "File not found"
 
-#: src/lib/components/audio/AudioDialog.svelte:87
+#: src/lib/components/audio/AudioDialog.svelte:89
 msgid "File saving not supported"
 msgstr "File saving not supported"
 
-#: src/lib/components/audio/AudioDialog.svelte:164
-#: src/lib/components/audio/AudioDialog.svelte:85
+#: src/lib/components/audio/AudioDialog.svelte:150
+#: src/lib/components/audio/AudioDialog.svelte:87
 msgid "File too big"
 msgstr "File too big"
 
@@ -504,7 +505,7 @@ msgstr "Import"
 msgid "Last change: {0}"
 msgstr "Last change: {0}"
 
-#: src/lib/components/audio/audio-editor.svelte:28
+#: src/lib/components/audio/audio-editor.svelte:86
 msgid "Length:"
 msgstr "Length:"
 
@@ -608,10 +609,6 @@ msgstr "New Entry"
 msgid "No activity found"
 msgstr "No activity found"
 
-#: src/lib/components/field-editors/audio-input.svelte:217
-msgid "No audio"
-msgstr "No audio"
-
 #: src/lib/history/HistoryView.svelte:78
 msgid "No change name"
 msgstr "No change name"
@@ -625,9 +622,9 @@ msgstr "No Dictionaries found"
 msgid "No entries found"
 msgstr "No entries found"
 
-#: src/lib/components/audio/AudioDialog.svelte:75
-msgid "No file selected"
-msgstr "No file selected"
+#: src/lib/components/audio/AudioDialog.svelte:77
+msgid "No file to upload"
+msgstr "No file to upload"
 
 #: src/lib/history/HistoryView.svelte:68
 msgid "No history found"
@@ -670,7 +667,7 @@ msgstr "Note"
 msgid "Offline"
 msgstr "Offline"
 
-#: src/lib/components/field-editors/audio-input.svelte:82
+#: src/lib/components/field-editors/audio-input.svelte:81
 msgid "Offline, unable to download"
 msgstr "Offline, unable to download"
 
@@ -737,7 +734,7 @@ msgstr "Refresh Projects"
 msgid "Remove"
 msgstr "Remove"
 
-#: src/lib/components/field-editors/audio-input.svelte:268
+#: src/lib/components/field-editors/audio-input.svelte:261
 msgid "Remove audio"
 msgstr "Remove audio"
 
@@ -745,11 +742,11 @@ msgstr "Remove audio"
 msgid "Reopen"
 msgstr "Reopen"
 
-#: src/lib/components/field-editors/audio-input.svelte:265
+#: src/lib/components/field-editors/audio-input.svelte:258
 msgid "Replace audio"
 msgstr "Replace audio"
 
-#: src/lib/components/audio/AudioDialog.svelte:169
+#: src/lib/components/audio/AudioDialog.svelte:155
 msgid "Save audio"
 msgstr "Save audio"
 
@@ -813,7 +810,7 @@ msgstr "Show {0} more..."
 msgid "Simple"
 msgstr "Simple"
 
-#: src/lib/components/audio/audio-editor.svelte:30
+#: src/lib/components/audio/audio-editor.svelte:88
 msgid "Size:"
 msgstr "Size:"
 
@@ -886,7 +883,7 @@ msgstr "Translation"
 msgid "Troubleshoot"
 msgstr "Troubleshoot"
 
-#: src/lib/components/audio/audio-editor.svelte:36
+#: src/lib/components/audio/audio-editor.svelte:94
 msgid "Type:"
 msgstr "Type:"
 
@@ -902,11 +899,11 @@ msgid "Unknown"
 msgstr "Unknown"
 
 #: src/project/ProjectSidebar.svelte:115
-#: src/lib/components/audio/AudioDialog.svelte:91
+#: src/lib/components/audio/AudioDialog.svelte:93
 msgid "Unknown error"
 msgstr "Unknown error"
 
-#: src/lib/components/field-editors/audio-input.svelte:85
+#: src/lib/components/field-editors/audio-input.svelte:84
 msgid "Unknown error {0}"
 msgstr "Unknown error {0}"
 
diff --git a/frontend/viewer/src/locales/es.po b/frontend/viewer/src/locales/es.po
index 660ff8b3df..b5d115efe0 100644
--- a/frontend/viewer/src/locales/es.po
+++ b/frontend/viewer/src/locales/es.po
@@ -22,9 +22,9 @@ msgstr ""
 msgid "– ({0} changes)"
 msgstr "- ({0} changes)"
 
-#: src/lib/components/audio/audio-editor.svelte:28
-#: src/lib/components/audio/audio-editor.svelte:33
-#: src/lib/components/audio/audio-editor.svelte:37
+#: src/lib/components/audio/audio-editor.svelte:86
+#: src/lib/components/audio/audio-editor.svelte:91
+#: src/lib/components/audio/audio-editor.svelte:95
 msgid "{0}"
 msgstr "{0}"
 
@@ -44,7 +44,7 @@ msgstr "{0} (FieldWorks Lite)"
 msgid "{0} (FieldWorks)"
 msgstr "{0} (FieldWorks)"
 
-#: src/lib/components/audio/audio-editor.svelte:30
+#: src/lib/components/audio/audio-editor.svelte:88
 msgid "{0} MB"
 msgstr "{0} MB"
 
@@ -81,8 +81,8 @@ msgstr "Cuenta"
 msgid "Activity"
 msgstr "Actividad"
 
-#: src/lib/components/field-editors/audio-input.svelte:213
-#: src/lib/components/audio/AudioDialog.svelte:153
+#: src/lib/components/field-editors/audio-input.svelte:211
+#: src/lib/components/audio/AudioDialog.svelte:143
 msgid "Add audio"
 msgstr "Añadir audio"
 
@@ -131,15 +131,15 @@ msgstr "Versión de la aplicación"
 msgid "Are you sure you want to delete {0}?"
 msgstr "¿Estás seguro de que quieres borrar {0}?"
 
-#: src/lib/components/field-editors/audio-input.svelte:222
+#: src/lib/components/field-editors/audio-input.svelte:215
 msgid "Audio file not included in Send & Receive"
 msgstr "Archivo de audio no incluido en Enviar y Recibir"
 
-#: src/lib/components/audio/AudioDialog.svelte:82
+#: src/lib/components/audio/AudioDialog.svelte:84
 msgid "Audio saved and uploaded to Lexbox"
 msgstr ""
 
-#: src/lib/components/audio/AudioDialog.svelte:79
+#: src/lib/components/audio/AudioDialog.svelte:81
 msgid "Audio saved locally"
 msgstr ""
 
@@ -173,7 +173,7 @@ msgstr "Visite"
 #: src/lib/entry-editor/EntryOrSensePicker.svelte:245
 #: src/lib/components/field-editors/select.svelte:166
 #: src/lib/components/field-editors/multi-select.svelte:280
-#: src/lib/components/audio/AudioDialog.svelte:167
+#: src/lib/components/audio/AudioDialog.svelte:153
 msgid "Cancel"
 msgstr "Cancelar"
 
@@ -305,7 +305,7 @@ msgstr "Diccionario"
 msgid "Dictionary Preview"
 msgstr "Vista previa del diccionario"
 
-#: src/lib/components/audio/audio-editor.svelte:46
+#: src/lib/components/audio/audio-editor.svelte:107
 msgid "Discard"
 msgstr "Descartar"
 
@@ -319,6 +319,7 @@ msgid "Don't delete"
 msgstr "No borrar"
 
 #: src/lib/notifications/NotificationOutlet.svelte:26
+#: src/lib/components/audio/audio-editor.svelte:106
 #: src/home/Server.svelte:128
 msgid "Download"
 msgstr "Descargar"
@@ -412,24 +413,24 @@ msgstr "Etiquetas de campo"
 msgid "FieldWorks logo"
 msgstr "Logotipo de FieldWorks"
 
-#: src/lib/components/audio/AudioDialog.svelte:89
+#: src/lib/components/audio/AudioDialog.svelte:91
 msgid "File already exists"
 msgstr ""
 
-#: src/lib/components/audio/audio-editor.svelte:32
+#: src/lib/components/audio/audio-editor.svelte:90
 msgid "File name:"
 msgstr "Nombre del fichero:"
 
-#: src/lib/components/field-editors/audio-input.svelte:79
+#: src/lib/components/field-editors/audio-input.svelte:78
 msgid "File not found"
 msgstr "Archivo no encontrado"
 
-#: src/lib/components/audio/AudioDialog.svelte:87
+#: src/lib/components/audio/AudioDialog.svelte:89
 msgid "File saving not supported"
 msgstr ""
 
-#: src/lib/components/audio/AudioDialog.svelte:164
-#: src/lib/components/audio/AudioDialog.svelte:85
+#: src/lib/components/audio/AudioDialog.svelte:150
+#: src/lib/components/audio/AudioDialog.svelte:87
 msgid "File too big"
 msgstr ""
 
@@ -509,7 +510,7 @@ msgstr "Importar"
 msgid "Last change: {0}"
 msgstr "Última modificación: {0}"
 
-#: src/lib/components/audio/audio-editor.svelte:28
+#: src/lib/components/audio/audio-editor.svelte:86
 msgid "Length:"
 msgstr "Longitud:"
 
@@ -613,10 +614,6 @@ msgstr "Nueva entrada"
 msgid "No activity found"
 msgstr "No se ha encontrado actividad"
 
-#: src/lib/components/field-editors/audio-input.svelte:217
-msgid "No audio"
-msgstr "Sin audio"
-
 #: src/lib/history/HistoryView.svelte:78
 msgid "No change name"
 msgstr "Sin cambio de nombre"
@@ -630,8 +627,8 @@ msgstr "No se han encontrado diccionarios"
 msgid "No entries found"
 msgstr "No se han encontrado entradas"
 
-#: src/lib/components/audio/AudioDialog.svelte:75
-msgid "No file selected"
+#: src/lib/components/audio/AudioDialog.svelte:77
+msgid "No file to upload"
 msgstr ""
 
 #: src/lib/history/HistoryView.svelte:68
@@ -675,7 +672,7 @@ msgstr "Nota"
 msgid "Offline"
 msgstr "Fuera de línea"
 
-#: src/lib/components/field-editors/audio-input.svelte:82
+#: src/lib/components/field-editors/audio-input.svelte:81
 msgid "Offline, unable to download"
 msgstr "Desconectado, no se puede descargar"
 
@@ -742,7 +739,7 @@ msgstr "Actualizar proyectos"
 msgid "Remove"
 msgstr "Eliminar"
 
-#: src/lib/components/field-editors/audio-input.svelte:268
+#: src/lib/components/field-editors/audio-input.svelte:261
 msgid "Remove audio"
 msgstr "Eliminar audio"
 
@@ -750,11 +747,11 @@ msgstr "Eliminar audio"
 msgid "Reopen"
 msgstr "Vuelva a abrir"
 
-#: src/lib/components/field-editors/audio-input.svelte:265
+#: src/lib/components/field-editors/audio-input.svelte:258
 msgid "Replace audio"
 msgstr "Sustituir audio"
 
-#: src/lib/components/audio/AudioDialog.svelte:169
+#: src/lib/components/audio/AudioDialog.svelte:155
 msgid "Save audio"
 msgstr "Guardar audio"
 
@@ -818,7 +815,7 @@ msgstr "Mostrar {0} más..."
 msgid "Simple"
 msgstr "Simple"
 
-#: src/lib/components/audio/audio-editor.svelte:30
+#: src/lib/components/audio/audio-editor.svelte:88
 msgid "Size:"
 msgstr "Tamaño:"
 
@@ -891,7 +888,7 @@ msgstr "Traducción"
 msgid "Troubleshoot"
 msgstr "Solución de problemas"
 
-#: src/lib/components/audio/audio-editor.svelte:36
+#: src/lib/components/audio/audio-editor.svelte:94
 msgid "Type:"
 msgstr "Tipo:"
 
@@ -907,11 +904,11 @@ msgid "Unknown"
 msgstr "Desconocido"
 
 #: src/project/ProjectSidebar.svelte:115
-#: src/lib/components/audio/AudioDialog.svelte:91
+#: src/lib/components/audio/AudioDialog.svelte:93
 msgid "Unknown error"
 msgstr "Error desconocido"
 
-#: src/lib/components/field-editors/audio-input.svelte:85
+#: src/lib/components/field-editors/audio-input.svelte:84
 msgid "Unknown error {0}"
 msgstr "Error desconocido {0}"
 
diff --git a/frontend/viewer/src/locales/fr.po b/frontend/viewer/src/locales/fr.po
index c22076b387..63d91f7380 100644
--- a/frontend/viewer/src/locales/fr.po
+++ b/frontend/viewer/src/locales/fr.po
@@ -22,9 +22,9 @@ msgstr ""
 msgid "– ({0} changes)"
 msgstr "- ({0} changes)"
 
-#: src/lib/components/audio/audio-editor.svelte:28
-#: src/lib/components/audio/audio-editor.svelte:33
-#: src/lib/components/audio/audio-editor.svelte:37
+#: src/lib/components/audio/audio-editor.svelte:86
+#: src/lib/components/audio/audio-editor.svelte:91
+#: src/lib/components/audio/audio-editor.svelte:95
 msgid "{0}"
 msgstr "{0}"
 
@@ -44,7 +44,7 @@ msgstr "{0} (FieldWorks Lite)"
 msgid "{0} (FieldWorks)"
 msgstr "{0} (FieldWorks)"
 
-#: src/lib/components/audio/audio-editor.svelte:30
+#: src/lib/components/audio/audio-editor.svelte:88
 msgid "{0} MB"
 msgstr "{0} MB"
 
@@ -81,8 +81,8 @@ msgstr "Compte"
 msgid "Activity"
 msgstr "Activité"
 
-#: src/lib/components/field-editors/audio-input.svelte:213
-#: src/lib/components/audio/AudioDialog.svelte:153
+#: src/lib/components/field-editors/audio-input.svelte:211
+#: src/lib/components/audio/AudioDialog.svelte:143
 msgid "Add audio"
 msgstr "Ajouter de l'audio"
 
@@ -131,15 +131,15 @@ msgstr "Version de l'application"
 msgid "Are you sure you want to delete {0}?"
 msgstr "Êtes-vous sûr de vouloir supprimer {0}?"
 
-#: src/lib/components/field-editors/audio-input.svelte:222
+#: src/lib/components/field-editors/audio-input.svelte:215
 msgid "Audio file not included in Send & Receive"
 msgstr "Le fichier audio n'est pas inclus dans l'envoi et la réception"
 
-#: src/lib/components/audio/AudioDialog.svelte:82
+#: src/lib/components/audio/AudioDialog.svelte:84
 msgid "Audio saved and uploaded to Lexbox"
 msgstr ""
 
-#: src/lib/components/audio/AudioDialog.svelte:79
+#: src/lib/components/audio/AudioDialog.svelte:81
 msgid "Audio saved locally"
 msgstr ""
 
@@ -173,7 +173,7 @@ msgstr "Parcourir"
 #: src/lib/entry-editor/EntryOrSensePicker.svelte:245
 #: src/lib/components/field-editors/select.svelte:166
 #: src/lib/components/field-editors/multi-select.svelte:280
-#: src/lib/components/audio/AudioDialog.svelte:167
+#: src/lib/components/audio/AudioDialog.svelte:153
 msgid "Cancel"
 msgstr "Annuler"
 
@@ -305,7 +305,7 @@ msgstr "Dictionnaire"
 msgid "Dictionary Preview"
 msgstr "Aperçu du dictionnaire"
 
-#: src/lib/components/audio/audio-editor.svelte:46
+#: src/lib/components/audio/audio-editor.svelte:107
 msgid "Discard"
 msgstr "Rejeter"
 
@@ -319,6 +319,7 @@ msgid "Don't delete"
 msgstr "Ne pas supprimer"
 
 #: src/lib/notifications/NotificationOutlet.svelte:26
+#: src/lib/components/audio/audio-editor.svelte:106
 #: src/home/Server.svelte:128
 msgid "Download"
 msgstr "Télécharger"
@@ -412,24 +413,24 @@ msgstr "Étiquettes de champ"
 msgid "FieldWorks logo"
 msgstr "Logo FieldWorks"
 
-#: src/lib/components/audio/AudioDialog.svelte:89
+#: src/lib/components/audio/AudioDialog.svelte:91
 msgid "File already exists"
 msgstr ""
 
-#: src/lib/components/audio/audio-editor.svelte:32
+#: src/lib/components/audio/audio-editor.svelte:90
 msgid "File name:"
 msgstr "Nom du fichier :"
 
-#: src/lib/components/field-editors/audio-input.svelte:79
+#: src/lib/components/field-editors/audio-input.svelte:78
 msgid "File not found"
 msgstr "Fichier non trouvé"
 
-#: src/lib/components/audio/AudioDialog.svelte:87
+#: src/lib/components/audio/AudioDialog.svelte:89
 msgid "File saving not supported"
 msgstr ""
 
-#: src/lib/components/audio/AudioDialog.svelte:164
-#: src/lib/components/audio/AudioDialog.svelte:85
+#: src/lib/components/audio/AudioDialog.svelte:150
+#: src/lib/components/audio/AudioDialog.svelte:87
 msgid "File too big"
 msgstr ""
 
@@ -509,7 +510,7 @@ msgstr "Importation"
 msgid "Last change: {0}"
 msgstr "Dernière modification : {0}"
 
-#: src/lib/components/audio/audio-editor.svelte:28
+#: src/lib/components/audio/audio-editor.svelte:86
 msgid "Length:"
 msgstr "Longueur :"
 
@@ -613,10 +614,6 @@ msgstr "Nouvelle entrée"
 msgid "No activity found"
 msgstr "Aucune activité trouvée"
 
-#: src/lib/components/field-editors/audio-input.svelte:217
-msgid "No audio"
-msgstr "Pas d'audio"
-
 #: src/lib/history/HistoryView.svelte:78
 msgid "No change name"
 msgstr "Pas de changement de nom"
@@ -630,8 +627,8 @@ msgstr "Aucun dictionnaire trouvé"
 msgid "No entries found"
 msgstr "Aucune entrée trouvée"
 
-#: src/lib/components/audio/AudioDialog.svelte:75
-msgid "No file selected"
+#: src/lib/components/audio/AudioDialog.svelte:77
+msgid "No file to upload"
 msgstr ""
 
 #: src/lib/history/HistoryView.svelte:68
@@ -675,7 +672,7 @@ msgstr "Note"
 msgid "Offline"
 msgstr "Hors ligne"
 
-#: src/lib/components/field-editors/audio-input.svelte:82
+#: src/lib/components/field-editors/audio-input.svelte:81
 msgid "Offline, unable to download"
 msgstr "Hors ligne, impossible de télécharger"
 
@@ -742,7 +739,7 @@ msgstr "Projets de rafraîchissement"
 msgid "Remove"
 msgstr "Retirer"
 
-#: src/lib/components/field-editors/audio-input.svelte:268
+#: src/lib/components/field-editors/audio-input.svelte:261
 msgid "Remove audio"
 msgstr "Supprimer l'audio"
 
@@ -750,11 +747,11 @@ msgstr "Supprimer l'audio"
 msgid "Reopen"
 msgstr "Réouverture"
 
-#: src/lib/components/field-editors/audio-input.svelte:265
+#: src/lib/components/field-editors/audio-input.svelte:258
 msgid "Replace audio"
 msgstr "Remplacer l'audio"
 
-#: src/lib/components/audio/AudioDialog.svelte:169
+#: src/lib/components/audio/AudioDialog.svelte:155
 msgid "Save audio"
 msgstr "Sauvegarder l'audio"
 
@@ -818,7 +815,7 @@ msgstr "Afficher {0} plus..."
 msgid "Simple"
 msgstr "Simple"
 
-#: src/lib/components/audio/audio-editor.svelte:30
+#: src/lib/components/audio/audio-editor.svelte:88
 msgid "Size:"
 msgstr "Taille :"
 
@@ -891,7 +888,7 @@ msgstr "Traduction"
 msgid "Troubleshoot"
 msgstr "Dépannage"
 
-#: src/lib/components/audio/audio-editor.svelte:36
+#: src/lib/components/audio/audio-editor.svelte:94
 msgid "Type:"
 msgstr "Type :"
 
@@ -907,11 +904,11 @@ msgid "Unknown"
 msgstr "Inconnu"
 
 #: src/project/ProjectSidebar.svelte:115
-#: src/lib/components/audio/AudioDialog.svelte:91
+#: src/lib/components/audio/AudioDialog.svelte:93
 msgid "Unknown error"
 msgstr "Erreur inconnue"
 
-#: src/lib/components/field-editors/audio-input.svelte:85
+#: src/lib/components/field-editors/audio-input.svelte:84
 msgid "Unknown error {0}"
 msgstr "Erreur inconnue {0}"
 
diff --git a/frontend/viewer/src/locales/id.po b/frontend/viewer/src/locales/id.po
index 265c74eb11..11226e7853 100644
--- a/frontend/viewer/src/locales/id.po
+++ b/frontend/viewer/src/locales/id.po
@@ -22,9 +22,9 @@ msgstr ""
 msgid "– ({0} changes)"
 msgstr "- ({0} perubahan)"
 
-#: src/lib/components/audio/audio-editor.svelte:28
-#: src/lib/components/audio/audio-editor.svelte:33
-#: src/lib/components/audio/audio-editor.svelte:37
+#: src/lib/components/audio/audio-editor.svelte:86
+#: src/lib/components/audio/audio-editor.svelte:91
+#: src/lib/components/audio/audio-editor.svelte:95
 msgid "{0}"
 msgstr "{0}"
 
@@ -44,7 +44,7 @@ msgstr "{0} (FieldWorks Lite)"
 msgid "{0} (FieldWorks)"
 msgstr "{0} (Pekerjaan Lapangan)"
 
-#: src/lib/components/audio/audio-editor.svelte:30
+#: src/lib/components/audio/audio-editor.svelte:88
 msgid "{0} MB"
 msgstr "{0} MB"
 
@@ -81,8 +81,8 @@ msgstr "Akun"
 msgid "Activity"
 msgstr "Aktivitas"
 
-#: src/lib/components/field-editors/audio-input.svelte:213
-#: src/lib/components/audio/AudioDialog.svelte:153
+#: src/lib/components/field-editors/audio-input.svelte:211
+#: src/lib/components/audio/AudioDialog.svelte:143
 msgid "Add audio"
 msgstr "Menambahkan audio"
 
@@ -131,15 +131,15 @@ msgstr "Versi aplikasi"
 msgid "Are you sure you want to delete {0}?"
 msgstr "Apakah Anda yakin ingin menghapus {0}?"
 
-#: src/lib/components/field-editors/audio-input.svelte:222
+#: src/lib/components/field-editors/audio-input.svelte:215
 msgid "Audio file not included in Send & Receive"
 msgstr "File audio tidak disertakan dalam Kirim & Terima"
 
-#: src/lib/components/audio/AudioDialog.svelte:82
+#: src/lib/components/audio/AudioDialog.svelte:84
 msgid "Audio saved and uploaded to Lexbox"
 msgstr ""
 
-#: src/lib/components/audio/AudioDialog.svelte:79
+#: src/lib/components/audio/AudioDialog.svelte:81
 msgid "Audio saved locally"
 msgstr ""
 
@@ -173,7 +173,7 @@ msgstr "Jelajahi"
 #: src/lib/entry-editor/EntryOrSensePicker.svelte:245
 #: src/lib/components/field-editors/select.svelte:166
 #: src/lib/components/field-editors/multi-select.svelte:280
-#: src/lib/components/audio/AudioDialog.svelte:167
+#: src/lib/components/audio/AudioDialog.svelte:153
 msgid "Cancel"
 msgstr "Batal"
 
@@ -305,7 +305,7 @@ msgstr "Kamus"
 msgid "Dictionary Preview"
 msgstr "Pratinjau Kamus"
 
-#: src/lib/components/audio/audio-editor.svelte:46
+#: src/lib/components/audio/audio-editor.svelte:107
 msgid "Discard"
 msgstr "Buang"
 
@@ -319,6 +319,7 @@ msgid "Don't delete"
 msgstr "Jangan hapus"
 
 #: src/lib/notifications/NotificationOutlet.svelte:26
+#: src/lib/components/audio/audio-editor.svelte:106
 #: src/home/Server.svelte:128
 msgid "Download"
 msgstr "Unduh"
@@ -412,24 +413,24 @@ msgstr "Label Bidang"
 msgid "FieldWorks logo"
 msgstr "Logo FieldWorks"
 
-#: src/lib/components/audio/AudioDialog.svelte:89
+#: src/lib/components/audio/AudioDialog.svelte:91
 msgid "File already exists"
 msgstr ""
 
-#: src/lib/components/audio/audio-editor.svelte:32
+#: src/lib/components/audio/audio-editor.svelte:90
 msgid "File name:"
 msgstr "Nama file:"
 
-#: src/lib/components/field-editors/audio-input.svelte:79
+#: src/lib/components/field-editors/audio-input.svelte:78
 msgid "File not found"
 msgstr "File tidak ditemukan"
 
-#: src/lib/components/audio/AudioDialog.svelte:87
+#: src/lib/components/audio/AudioDialog.svelte:89
 msgid "File saving not supported"
 msgstr ""
 
-#: src/lib/components/audio/AudioDialog.svelte:164
-#: src/lib/components/audio/AudioDialog.svelte:85
+#: src/lib/components/audio/AudioDialog.svelte:150
+#: src/lib/components/audio/AudioDialog.svelte:87
 msgid "File too big"
 msgstr ""
 
@@ -509,7 +510,7 @@ msgstr "Impor"
 msgid "Last change: {0}"
 msgstr "Perubahan terakhir: {0}"
 
-#: src/lib/components/audio/audio-editor.svelte:28
+#: src/lib/components/audio/audio-editor.svelte:86
 msgid "Length:"
 msgstr "Panjang:"
 
@@ -613,10 +614,6 @@ msgstr "Entri Baru"
 msgid "No activity found"
 msgstr "Tidak ada aktivitas yang ditemukan"
 
-#: src/lib/components/field-editors/audio-input.svelte:217
-msgid "No audio"
-msgstr "Tidak ada audio"
-
 #: src/lib/history/HistoryView.svelte:78
 msgid "No change name"
 msgstr "Tidak ada perubahan nama"
@@ -630,8 +627,8 @@ msgstr "Tidak ditemukan Kamus"
 msgid "No entries found"
 msgstr "Tidak ada entri yang ditemukan"
 
-#: src/lib/components/audio/AudioDialog.svelte:75
-msgid "No file selected"
+#: src/lib/components/audio/AudioDialog.svelte:77
+msgid "No file to upload"
 msgstr ""
 
 #: src/lib/history/HistoryView.svelte:68
@@ -675,7 +672,7 @@ msgstr "Catatan"
 msgid "Offline"
 msgstr "Offline"
 
-#: src/lib/components/field-editors/audio-input.svelte:82
+#: src/lib/components/field-editors/audio-input.svelte:81
 msgid "Offline, unable to download"
 msgstr "Offline, tidak dapat mengunduh"
 
@@ -742,7 +739,7 @@ msgstr "Menyegarkan Proyek"
 msgid "Remove"
 msgstr "Menghapus"
 
-#: src/lib/components/field-editors/audio-input.svelte:268
+#: src/lib/components/field-editors/audio-input.svelte:261
 msgid "Remove audio"
 msgstr "Menghapus audio"
 
@@ -750,11 +747,11 @@ msgstr "Menghapus audio"
 msgid "Reopen"
 msgstr "Buka kembali"
 
-#: src/lib/components/field-editors/audio-input.svelte:265
+#: src/lib/components/field-editors/audio-input.svelte:258
 msgid "Replace audio"
 msgstr "Mengganti audio"
 
-#: src/lib/components/audio/AudioDialog.svelte:169
+#: src/lib/components/audio/AudioDialog.svelte:155
 msgid "Save audio"
 msgstr "Menyimpan audio"
 
@@ -818,7 +815,7 @@ msgstr "Tampilkan {0} selengkapnya..."
 msgid "Simple"
 msgstr "Sederhana"
 
-#: src/lib/components/audio/audio-editor.svelte:30
+#: src/lib/components/audio/audio-editor.svelte:88
 msgid "Size:"
 msgstr "Ukuran:"
 
@@ -891,7 +888,7 @@ msgstr "Terjemahan"
 msgid "Troubleshoot"
 msgstr "Memecahkan masalah"
 
-#: src/lib/components/audio/audio-editor.svelte:36
+#: src/lib/components/audio/audio-editor.svelte:94
 msgid "Type:"
 msgstr "Ketik:"
 
@@ -907,11 +904,11 @@ msgid "Unknown"
 msgstr "Tidak diketahui"
 
 #: src/project/ProjectSidebar.svelte:115
-#: src/lib/components/audio/AudioDialog.svelte:91
+#: src/lib/components/audio/AudioDialog.svelte:93
 msgid "Unknown error"
 msgstr "Kesalahan yang tidak diketahui"
 
-#: src/lib/components/field-editors/audio-input.svelte:85
+#: src/lib/components/field-editors/audio-input.svelte:84
 msgid "Unknown error {0}"
 msgstr "Kesalahan tidak dikenal {0}"
 
diff --git a/frontend/viewer/src/locales/ko.po b/frontend/viewer/src/locales/ko.po
index f3549fa9c0..bc88c54170 100644
--- a/frontend/viewer/src/locales/ko.po
+++ b/frontend/viewer/src/locales/ko.po
@@ -22,9 +22,9 @@ msgstr ""
 msgid "– ({0} changes)"
 msgstr "- ({0} 변경)"
 
-#: src/lib/components/audio/audio-editor.svelte:28
-#: src/lib/components/audio/audio-editor.svelte:33
-#: src/lib/components/audio/audio-editor.svelte:37
+#: src/lib/components/audio/audio-editor.svelte:86
+#: src/lib/components/audio/audio-editor.svelte:91
+#: src/lib/components/audio/audio-editor.svelte:95
 msgid "{0}"
 msgstr "{0}"
 
@@ -44,7 +44,7 @@ msgstr "{0} (필드웍스 라이트)"
 msgid "{0} (FieldWorks)"
 msgstr "{0} (필드웍스)"
 
-#: src/lib/components/audio/audio-editor.svelte:30
+#: src/lib/components/audio/audio-editor.svelte:88
 msgid "{0} MB"
 msgstr "{0} MB"
 
@@ -81,8 +81,8 @@ msgstr "계정"
 msgid "Activity"
 msgstr "활동"
 
-#: src/lib/components/field-editors/audio-input.svelte:213
-#: src/lib/components/audio/AudioDialog.svelte:153
+#: src/lib/components/field-editors/audio-input.svelte:211
+#: src/lib/components/audio/AudioDialog.svelte:143
 msgid "Add audio"
 msgstr "오디오 추가"
 
@@ -131,15 +131,15 @@ msgstr "애플리케이션 버전"
 msgid "Are you sure you want to delete {0}?"
 msgstr "{0}을 삭제하시겠습니까?"
 
-#: src/lib/components/field-editors/audio-input.svelte:222
+#: src/lib/components/field-editors/audio-input.svelte:215
 msgid "Audio file not included in Send & Receive"
 msgstr "보내기 및 받기에 포함되지 않은 오디오 파일"
 
-#: src/lib/components/audio/AudioDialog.svelte:82
+#: src/lib/components/audio/AudioDialog.svelte:84
 msgid "Audio saved and uploaded to Lexbox"
 msgstr ""
 
-#: src/lib/components/audio/AudioDialog.svelte:79
+#: src/lib/components/audio/AudioDialog.svelte:81
 msgid "Audio saved locally"
 msgstr ""
 
@@ -173,7 +173,7 @@ msgstr "찾아보기"
 #: src/lib/entry-editor/EntryOrSensePicker.svelte:245
 #: src/lib/components/field-editors/select.svelte:166
 #: src/lib/components/field-editors/multi-select.svelte:280
-#: src/lib/components/audio/AudioDialog.svelte:167
+#: src/lib/components/audio/AudioDialog.svelte:153
 msgid "Cancel"
 msgstr "취소"
 
@@ -305,7 +305,7 @@ msgstr "사전"
 msgid "Dictionary Preview"
 msgstr "사전 미리보기"
 
-#: src/lib/components/audio/audio-editor.svelte:46
+#: src/lib/components/audio/audio-editor.svelte:107
 msgid "Discard"
 msgstr "폐기"
 
@@ -319,6 +319,7 @@ msgid "Don't delete"
 msgstr "삭제하지 마세요."
 
 #: src/lib/notifications/NotificationOutlet.svelte:26
+#: src/lib/components/audio/audio-editor.svelte:106
 #: src/home/Server.svelte:128
 msgid "Download"
 msgstr "다운로드"
@@ -412,24 +413,24 @@ msgstr "필드 레이블"
 msgid "FieldWorks logo"
 msgstr "FieldWorks 로고"
 
-#: src/lib/components/audio/AudioDialog.svelte:89
+#: src/lib/components/audio/AudioDialog.svelte:91
 msgid "File already exists"
 msgstr ""
 
-#: src/lib/components/audio/audio-editor.svelte:32
+#: src/lib/components/audio/audio-editor.svelte:90
 msgid "File name:"
 msgstr "파일 이름:"
 
-#: src/lib/components/field-editors/audio-input.svelte:79
+#: src/lib/components/field-editors/audio-input.svelte:78
 msgid "File not found"
 msgstr "파일을 찾을 수 없음"
 
-#: src/lib/components/audio/AudioDialog.svelte:87
+#: src/lib/components/audio/AudioDialog.svelte:89
 msgid "File saving not supported"
 msgstr ""
 
-#: src/lib/components/audio/AudioDialog.svelte:164
-#: src/lib/components/audio/AudioDialog.svelte:85
+#: src/lib/components/audio/AudioDialog.svelte:150
+#: src/lib/components/audio/AudioDialog.svelte:87
 msgid "File too big"
 msgstr ""
 
@@ -509,7 +510,7 @@ msgstr "가져오기"
 msgid "Last change: {0}"
 msgstr "마지막 변경 사항: {0}"
 
-#: src/lib/components/audio/audio-editor.svelte:28
+#: src/lib/components/audio/audio-editor.svelte:86
 msgid "Length:"
 msgstr "길이:"
 
@@ -613,10 +614,6 @@ msgstr "새 항목"
 msgid "No activity found"
 msgstr "활동을 찾을 수 없습니다."
 
-#: src/lib/components/field-editors/audio-input.svelte:217
-msgid "No audio"
-msgstr "오디오 없음"
-
 #: src/lib/history/HistoryView.svelte:78
 msgid "No change name"
 msgstr "이름 변경 안 함"
@@ -630,8 +627,8 @@ msgstr "사전을 찾을 수 없습니다."
 msgid "No entries found"
 msgstr "항목을 찾을 수 없습니다."
 
-#: src/lib/components/audio/AudioDialog.svelte:75
-msgid "No file selected"
+#: src/lib/components/audio/AudioDialog.svelte:77
+msgid "No file to upload"
 msgstr ""
 
 #: src/lib/history/HistoryView.svelte:68
@@ -675,7 +672,7 @@ msgstr "참고"
 msgid "Offline"
 msgstr "오프라인"
 
-#: src/lib/components/field-editors/audio-input.svelte:82
+#: src/lib/components/field-editors/audio-input.svelte:81
 msgid "Offline, unable to download"
 msgstr "오프라인 상태, 다운로드할 수 없음"
 
@@ -742,7 +739,7 @@ msgstr "프로젝트 새로 고침"
 msgid "Remove"
 msgstr "제거"
 
-#: src/lib/components/field-editors/audio-input.svelte:268
+#: src/lib/components/field-editors/audio-input.svelte:261
 msgid "Remove audio"
 msgstr "오디오 제거"
 
@@ -750,11 +747,11 @@ msgstr "오디오 제거"
 msgid "Reopen"
 msgstr "다시 열기"
 
-#: src/lib/components/field-editors/audio-input.svelte:265
+#: src/lib/components/field-editors/audio-input.svelte:258
 msgid "Replace audio"
 msgstr "오디오 교체"
 
-#: src/lib/components/audio/AudioDialog.svelte:169
+#: src/lib/components/audio/AudioDialog.svelte:155
 msgid "Save audio"
 msgstr "오디오 저장"
 
@@ -818,7 +815,7 @@ msgstr "보기 {0} 더보기..."
 msgid "Simple"
 msgstr "Simple"
 
-#: src/lib/components/audio/audio-editor.svelte:30
+#: src/lib/components/audio/audio-editor.svelte:88
 msgid "Size:"
 msgstr "크기:"
 
@@ -891,7 +888,7 @@ msgstr "번역"
 msgid "Troubleshoot"
 msgstr "문제 해결"
 
-#: src/lib/components/audio/audio-editor.svelte:36
+#: src/lib/components/audio/audio-editor.svelte:94
 msgid "Type:"
 msgstr "유형:"
 
@@ -907,11 +904,11 @@ msgid "Unknown"
 msgstr "알 수 없음"
 
 #: src/project/ProjectSidebar.svelte:115
-#: src/lib/components/audio/AudioDialog.svelte:91
+#: src/lib/components/audio/AudioDialog.svelte:93
 msgid "Unknown error"
 msgstr "알 수 없는 오류"
 
-#: src/lib/components/field-editors/audio-input.svelte:85
+#: src/lib/components/field-editors/audio-input.svelte:84
 msgid "Unknown error {0}"
 msgstr "알 수 없는 오류 {0}"
 
diff --git a/frontend/viewer/vite.config.ffmpeg-worker.ts b/frontend/viewer/vite.config.ffmpeg-worker.ts
new file mode 100644
index 0000000000..530253dd46
--- /dev/null
+++ b/frontend/viewer/vite.config.ffmpeg-worker.ts
@@ -0,0 +1,22 @@
+import {createRequire} from 'module';
+import {defineConfig} from 'vite';
+
+const require = createRequire(import.meta.url);
+const ffmpegWorkerPath = require.resolve('@ffmpeg/ffmpeg/worker');
+
+export default defineConfig({
+  esbuild: {
+    banner: `/* This file generated by Vite / pnpm build-ffmpeg-worker. */\n// @ts-nocheck`,
+    include: [ffmpegWorkerPath],
+  },
+  build: {
+    emptyOutDir: false,
+    lib: {
+      entry: ffmpegWorkerPath,
+      formats: ['es'],
+      fileName: () => 'bundled-ffmpeg-worker.js',
+    },
+    outDir: 'src/lib/components/audio/ffmpeg',
+    copyPublicDir: false,
+  },
+});