Plumemu
Point Plumemu at your ROMs folder. It works out what each game is, picks an emulator for it, and puts everything in one list you can use with buttons or touch. You don't need an account, and it works offline.
This is a working copy of the main screen. Hover over a system, or click the screen and use the arrow keys.
Features
You pick your ROMs folder in Android's own folder picker. Plumemu never asks for access to all your files.
It checks which emulators you have installed and picks one for each system. You can change it for a whole system or for one game.
It reads each game's header or disc serial to find its real name. If a name is wrong, fix it from the game menu and the fix stays.
Systems, games and details sit side by side and slide along as you move. Laid out for 16:9 and 4:3 screens.
Sign in with your own free ScreenScraper account and covers download over Wi-Fi. Show a system as a list or as a grid of covers.
On a dual-screen handheld like the AYN Thor, the bottom screen shows the selected game. While you play it shows a clock, or goes black.
Save your settings, or everything including box art and play time, to one file. Restore it on the same device or a new one.
Pick a background, light or dark text and an accent. The app comes with eight backgrounds and five accents.
Screens
Under the hood
Plumemu is written in Kotlin with Jetpack Compose. This is how 0.0.2-alpha handles your files, your games and the network.
Setup opens Android's folder picker (ACTION_OPEN_DOCUMENT_TREE) and keeps access to that one folder. The manifest has no storage permission.
The scan walks the folder with DocumentsContract queries. A rescan only lists folders whose modified time changed, so when nothing is new it takes about 10 ms. A first scan of 10,000 files took 2.3 s on the test emulator.
The app carries a table of 161 systems and 356 emulator setups, 198 of them RetroArch cores. It is built from the data of Daijishō and ES-DE, both MIT licensed.
After the first frame is drawn, Plumemu asks Android's PackageManager which of those emulators are installed. A game starts with an Android intent built from that table.
Plumemu reads a few kilobytes of each file, never the whole game. Zip files are read from their central directory. CHD disc images are opened with a small LZMA decoder written for Plumemu.
The name lists ship inside the APK as 85 compressed packs, 4.4 MB in total. When nothing matches, it cleans up the file name instead. A game split over several discs or files shows up once.
Every game remembers where its name came from, and the game info screen tells you.
| System | What Plumemu reads |
|---|---|
| PlayStation, PS2 | The boot serial in SYSTEM.CNF |
| PSP | UMD_DATA.BIN and PARAM.SFO |
| SNES | The internal header, LoROM or HiROM, with or without a copier header |
| Game Boy, GBC | The logo bytes and the header checksum |
| Game Boy Advance | The header and its complement check |
| Nintendo DS | The header CRC and the banner |
| NES | The iNES header |
| Nintendo 3DS | NCCH, NCSD and CIA headers. Nothing is decrypted. |
| Switch | The title id, matched against 24,194 ids from titledb |
| Arcade | The short set name, matched against MAME's list of about 42,000 sets |
Box art comes from the ScreenScraper API and needs your own account. Plumemu looks a game up by checksum or serial first, then by name.
Requests are spaced 1.2 s apart and use as many threads as your account allows, up to four. When the daily limit runs out it waits for ScreenScraper's reset at midnight in Paris. Downloads only run on Wi-Fi, and answers are cached for 30 days.
Your ScreenScraper password is encrypted with AES-256-GCM, using a key kept in the Android Keystore.
The bottom screen is an android.app.Presentation on the display that DisplayManager lists as a presentation display. Nothing else in the app depends on it.
A backup is one zip, saved through Android's save dialog. It holds a manifest, your settings as JSON and the library database. A full backup adds the box art.
Only the box art module declares the INTERNET permission. There are no ads and no Plumemu account, and this version sends no usage statistics.
Scroll sideways to see the whole drawing.
Kotlin 2.4 and Jetpack Compose, with Room, DataStore, OkHttp, Coil and WorkManager. minSdk 23, targetSdk 37. Release builds use R8 with resource shrinking and a baseline profile. The code has about 3,800 unit tests, and Macrobenchmark tests measure cold start and scrolling.
Performance
A lot of retro handhelds have weak chips and old Android, so I measure every release.
Measured on 0.0.2-alpha in an Android 6.0 emulator with 2 GB of memory and 10,000 games. Start time is the median of 11 cold starts. Memory is PSS. The clock listens for Android's once-a-minute time tick instead of running its own timer, so an idle home screen does no work. Nothing runs in the background except box art downloads you asked for.
Install
plumemu-0.0.2-alpha.apk on the handheld, or copy it over.I've only tested it on the AYN Thor, because it's the one device I have.
It is laid out for 4.5 to 6 inch screens in 16:9 and 4:3, like the Retroid Pocket 5, 4 Pro, Mini and Nova or the AYN Odin, but I haven't tried those. If you run it on one, a short report helps a lot.
| A | Open, play |
|---|---|
| B | Back |
| X | Search |
| Y | Add to or remove from Favorites |
| START | Game menu, or Settings from the system column |
| SELECT | Switch between list and cover grid |
| L1R1 | Previous or next system. In a grid, smaller or larger covers |
| HOME | Back to the game you played last |
On pads where the confirm button is at the bottom, Settings › Advanced can swap A and B.
Plumemu is free. It doesn't come with games, BIOS files, keys or emulators, so use your own.
SHA-256 2fde7f5e95970ec4b490bd960dbae85460840b8c545d36acc475f8aab1962eee