Tool limits and edge cases: encrypted PDFs, large media, and browsers

Why are encrypted or copy-restricted PDFs rejected?

Merge PDF and Split PDF rely on client-side libraries that do not implement password prompts or DRM bypass. Encrypted files fail with an explicit rejection so the product never pretends to unlock content it cannot open here. Remove protection using software you are authorised to use, then retry with the unencrypted copy. Copy-restriction flags are not treated as optional decorations.

If a PDF opens in a viewer but still fails here, it may use permissions encryption rather than a password prompt you noticed. Export a flattened, unencrypted copy from a tool you are allowed to use. Do not paste passwords into random websites promising unlocks.

Why does video conversion feel heavy the first time?

Tools that depend on ffmpeg.wasm download a large engine on first use—commonly on the order of tens of megabytes (roughly a ~31 MB class build, exact size depending on the packaged core). After the browser caches the assets, later visits are quicker. Clearing site data or using a fresh profile repeats the download. Watch the Network panel for the engine files if a spinner seems stuck; a failed fetch looks different from active transcoding progress.

Phones on cellular data may time out mid-download of the media engine. Prefer Wi-Fi for first use. After caching, short clips convert more smoothly than hour-long files; extremely long media can still exhaust memory even with a warm cache.

Which browsers are supported?

Use a current Chromium-based browser, up-to-date Firefox, or a recent Safari. Internet Explorer is unsupported. AVIF decoding, some HEIC variants and certain media paths depend on browser codecs. If a format fails only in one browser, try another modern browser or export from a native app first. Mobile browsers work for many image tasks but hit memory limits sooner on large batches.

Corporate lockdowns that disable WebAssembly or workers can break PDF and media tools even in a “supported” browser brand. If nothing runs, check with IT whether Wasm is blocked before assuming the site is down.

How can I tell files are not uploaded for conversion?

Open DevTools → Network, clear the log, and run a small non-sensitive conversion. You should see site and library assets—not a multipart POST of your document bodies to a conversion API. Page views, Cloudflare Web Analytics and advertising tags are separate requests described in Privacy. Local processing is a claim about tool inputs, not a claim that visiting the website creates zero network metadata.

Repeat the Network check after extensions or corporate proxies change—some environments inject scanners that upload copies outside this app’s control. That is an environment issue, not a feature of the converter code. Report unexpected hosts with screenshots redacting secrets.

Ads, analytics and what this FAQ does not claim

The live site can show ad slots and loads a Google AdSense tag. Those systems may use cookies or identifiers depending on configuration and consent rules. Reading this FAQ is not consent. Privacy links Google Ads Settings and AboutAds opt-out information. This page does not assert that a consent-management platform is complete or that every advertising edge case is closed.

Ad slots may be empty while the tag still loads—empty creative is not proof the tag is absent. For file-privacy questions, focus on whether document bytes leave the tab during conversion; for advertising questions, read Privacy and your browser’s site settings.

Languages versus original guides

The chrome and many tool strings exist in multiple languages. In-depth how-to guides are authored in English first. A translated button label does not automatically create an equally detailed local-language article. When you need worked examples and failure edges, use the English guides and the tool pages linked from them.

Related tools

• Merge PDF

  Combine documents in your preferred order.

• Split PDF

  Extract the pages you need.

• HEIC → JPG

  Make iPhone photos easy to open anywhere.

• MP4 → MP3

  Extract audio from a video.