CrystalEngine

CrystalEngine

CrystalEngine is an Android on-device search and viewer app developed by BS Planet. It searches device storage by the content of files rather than their names and opens the results directly in the app. Indexing and search happen entirely on the device; there is no account and no upload.

Content search

The app indexes the text of HWP, Office, PDF and plain-text documents and returns results at the level of the matching sentence. It supports Korean initial-consonant (chosung) search, typo correction, search operators (type:hwp, before:, size:>10mb and others) and voice search. The index is built on SQLite FTS5, and search speed is held by automated tests: the baseline is at most 58.4 ms on an index of 100,000 rows, and a build that exceeds 0.1 s fails the test and is not released. Result lists can be exported or shared as text. The calendar can also be enabled as a search source; because it is sensitive, it is off by default and indexed only when switched on. Contacts are not a search source (they were removed in v3.47).

Speech and text in photos

Call recordings and voice memos are transcribed to text on the device and indexed, and playback can jump straight to the matched segment. Text captured in photos (receipts, whiteboards, document photos) is read by OCR and indexed. The Korean text recognition model is built into the app and needs no download. The transcription model and the similar-image model are downloaded once and then run only on the device, and each download is checked against a file fingerprint (sha256) to reject corrupted or tampered copies. Recordings and photos never leave the device.

Document viewer

One viewer opens HWP and HWPX as well as Word, Excel, PowerPoint, PDF, RTF, Markdown, CSV and plain-text documents. Formats confirmed to open on a real device are docx, xlsx, pptx, pdf, rtf, md, csv, txt and hwpx; hwp, hml, doc, xls, ppt, docm, xlsm, pptm, Visio files, mht, tsv, log and others open but have not yet been confirmed on a real device. It supports in-document search, bookmarks, outline jumps, PDF highlighting, text copy and share, dark inversion, pinch zoom and resuming at the last position, and is built to keep the app running when a damaged file is opened.

Media playback

The music player has a rotating disc screen, jog-wheel seeking, crossfade, silence skipping, gapless playback, ReplayGain loudness normalization, a sleep timer, lyrics and lock-screen control. Sound is shaped with a 10-band parametric equalizer (PEQ-10) and seven sound rack modules (tube preamp, tape saturation, vinyl deck, space reverb and others) and can be compared A/B against the original. The video player supports playback speed, SRT and SMI subtitles, brightness and volume gestures, PIP, resume and A-B repeat. Similar photos are found from a photo picked in the gallery or taken with the camera, or from a region of it; a first pass over 20,000 photos took 1.18 ms. Viewing history is collected day by day on a "Footprints" screen.

Chromecast and DLNA devices appear in one list, each row labelled by protocol, so the same television found over both remains distinguishable. While casting, the device screen stays dim and a single tap brings it back.

File management

Documents, music, photos, videos and recordings as well as every other file type, including zip and apk, are handled on one screen (hidden files and folders are not shown). Multiple files can be selected for ZIP compression, sharing, renaming, moving, copying or deletion, and ZIP files are extracted in the app. Copying and moving show progress and can be cancelled, there is a trash, and renaming a file carries its search index along. Folder browsing shows the current path, supports folder favorites, and allows renaming, moving and deleting folders; standard folders are protected from deletion, and the app reports what a folder contains before deleting it. There are finders for duplicate files (shortlisted by size and confirmed by SHA-256 hash), large files and temporary files, storage statistics by type, and collections for grouping frequently used files.

Indexing behavior

Photo indexing runs as a staged pipeline; heavy text recognition is deferred and finishes in the background during use. If indexing is interrupted by a screen change or app exit, the next launch continues from where it stopped. During scanning the current stage (for example, recording scan or speech transcription) is displayed. When the search sources are changed in settings, only the changed sources are scanned again.

Data handling

On first run the app explains what it reads and how it handles it and asks for permission; indexing does not begin before that consent is given.

Document contents, the index and search terms are not sent to any server; there is no account and no tracking. The network is used only for update checks, downloading recognition models and online features such as maps. It is on by default and can be switched off entirely in settings, and search, viewing and lyrics display keep working while it is off. Turning photo coordinates into an address goes through the device's system service when that feature is switched on, and voice search uses the on-device recognizer first; on a device without one it falls back to the system recognizer, and the speech then leaves the device. In the Google Play build, the ad consent check and ad requests sit outside that network switch. They go out only after the terms are accepted and only while no purchase is recognised; at that point the advertising ID, IP address and device information are sent to Google. There are no persistent banners, no interstitials and nothing that plays on launch — a rewarded ad runs only when the user chooses it. The app's privacy policy sets this out in detail.

Pricing

The app runs free for five launches after installation, and if one hour of cumulative use is reached first, the free period ends there. After that the choice is between a 24-hour pass, opened by watching one ad through to the end, and a lifetime purchase, with which the app keeps running without ads. The entitlement is attached to the Google Play account used for the purchase, so it follows its owner to another device, and no separate account or sign-in is needed. A promo code received from Google Play is redeemed on Google Play's code redemption screen, which the app opens; the app does not take the code itself. Documents, search, music, video and photos have no separate usage limit.