Known Limitations & Caveats

These limits apply to the browser workflow in use. A successful small sample does not guarantee that every file, codec, source server, or device is supported.

DRM protected content

FlowPick does not bypass DRM, paywalls, authentication, or other source access controls. Widevine, PlayReady, and FairPlay protected media cannot be treated as ordinary downloadable clear tracks. Supported AES-128 HLS handling is separate from DRM and requires valid key material and authorized source access.

CORS cross-origin restrictions

Online tools request URLs under the browser's origin rules. A source that plays on its own site may deny requests from FlowPick. An extension's permitted request context can differ, but does not grant access to content you are not authorized to save. Refreshing, retrying, or increasing concurrency does not remove access restrictions.

Signed URLs can expire, and source servers can apply request headers, cookies, rate limits, or hotlink protection. Do not post private links or credentials in public bug reports.

Container and codec support

Changing an extension does not convert media. A remuxed MP4 can keep a codec that the target player cannot decode. Dedicated converters may re-encode supported inputs, but depend on available browser decoders and encoders. Missing initialization segments, incomplete downloads, or track changes can also prevent successful output.

Use the media info analyzer and format conversion guide to distinguish container, codec, and source problems.

Memory and storage

Streaming writes and OPFS staging reduce some memory pressure but do not make processing unlimited. Browser quota, free disk space, buffers, indexes, decoded frames, and encoding can all affect a task. Blob-based results may remain in memory until the download is confirmed and the workflow releases them.

Do not rely on a universal 2 GB or 4 GB cutoff. Test a smaller sample, avoid concurrent large tasks, and inspect the actual failure stage. Keep the tab open while processing or exporting.

Saving files

File System Access requires a supported browser, permission, and an appropriate user action. StreamSaver depends on its service-worker/iframe environment. When these paths are unavailable, the workflow may use a browser download instead. A prepared output, a save prompt, and a file confirmed on disk are different states.

Browser security and workers

Some browser capabilities require HTTPS, permissions, or cross-origin isolation. Check requirements for the specific tool. Missing isolation headers do not imply that a nonexistent FFmpeg runtime has switched to a slower mode: the current website does not use FFmpeg WASM for its merge pipeline.

Recording and extension lifecycle

The recording page is a workflow entry point, not an automatic recorder for every visited URL. A session depends on the selected capture mode, extension connection where required, source playback, and browser permissions. Keep the relevant source and recording pages open. Extension lifecycle events or a closed tab can interrupt a session.

Startup time and performance

The first use of a tool can load JavaScript, workers, codecs, or a model for an AI feature. A slow first run does not mean that an FFmpeg core is being downloaded. Network conditions, browser caching, media format, hardware, and the selected operation affect startup and processing time; there is no fixed speed guarantee.

Reporting a problem

Include the tool, browser/version, device type, source container and codec, expected result, and failing stage. If permitted, attach a small non-sensitive sample you are entitled to share. Remove credentials, private filenames, signed query parameters, and account data from logs and screenshots.

See Common issues, Download engine, Browser compatibility, and Privacy policy.