JMR-devandClaude Opus 5
775a44753b
R16 / #25 -- the branch put API 37 into the default APIS list, where it is permanently two
failures short of green, so a bare `run-e2e.sh` exits 1 by design and nothing said so.
Somebody running it from habit, a wrapper or a hook gets a red exit forever and either
stops reading exit codes or debugs a normal state.
Documented rather than suppressed. The script's own comment already argued that an
expected-red level belongs in the exit code -- reversing that is the branch owner's call,
not a correction -- and the review's alternative needs an exact-set comparison of the
failing test names before it can subtract 37's contribution, which is a new mechanism that
cannot be validated without a device. So:
- the header now states the exit code (0 all green / 1 any level red / 2 refused to
start), says a bare run is 1 by design and why, and gives `run-e2e.sh 33 34 35 36` as
the sweep that can be green;
- a red sweep prints one note after the summary saying the same thing, because the exit
code is read in the terminal and not in the docs -- but ONLY when 37.x is the only level
that went red. `overall` is set by any red level, so a note keyed on "37 was in the
list" would have called a genuine API 34 failure "by design", which is the defect this
is meant to prevent, one layer up. mark_red records which level it was, where the loop
already knows;
- docs/local-emulator.md says it where the default is documented.
R27 / #36 -- 792286a appended the caveat that the harness path reproduces a rate collapse
rather than a clean zero, but left "that is the confirmation that region sampling is the
sole trigger" standing three lines above it, which the caveat contradicts. Now "the
strongest evidence that region sampling is the dominant trigger", with the residue named:
no measurement here separates a second caller of the readback path from a disable that did
not fully take, and the file says so rather than picking one.
R28 / #37 -- "the capability is negotiated regardless of renderer" leaned on the string
search, which shows only that `ANDROID_EMU_read_color_buffer_dma` is implemented in one
shared component, not that it is negotiated on every path. The aborts are the actual
evidence -- the assertion that fires is `!hasReadColorBufferDma` and it fires under ANGLE
too -- and they suffice alone; the string search is demoted to a supporting note. Worth
getting right because the doc says the upstream report should lead with this model.
Two follow-ons that belong with R17 / #26 and land here rather than in their own commit:
bash runs a trap only between commands, so the handler starts when the foreground command
returns -- immediate under Ctrl-C, which reaches that command too, but not under a `kill
-INT` aimed at the script alone; that is now written next to the handler. And
delete_created_avds no longer discards avdmanager's status: an emulator that was SIGKILLed
did not get to remove its own lock files, avdmanager can refuse over them, and silence
there would leak exactly what the trap exists to clean up.
`bash -n` clean; the stub smoke harness (real script, fake SDK binaries, boot-failure path,
no Gradle and no emulator) now also checks that a 37-only red prints the note after the
summary, that a red API 34 alongside it suppresses the note, that a 34-only sweep says
nothing, and that a refused AVD deletion is reported. shellcheck is not installed here.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
LibreMediaConverter
A free and open-source media converter for Android — batch video transcoding and compression, audio extraction and conversion, GIF and frame export, and file merging.
Android 13+ (API 33). Built with Jetpack Compose and Material 3.
Status: working, unreleased. Both conversion engines, the router, the background job queue and the join flow are implemented and building. The FFmpeg format tests have been written but not yet executed on a device.
Licensing at a glance
- Source code: MIT
- Distributed APK: GPL-3.0 — because it bundles FFmpeg built with x264/x265
That split is deliberate, not an oversight. See LICENSES/README.md
for the reasoning and the corresponding-source obligations.
Architecture
Two conversion engines behind an explicit router, because neither one covers the job alone.
AndroidX Media3 Transformer — the hardware path
Handles the common cases: H.264/HEVC, resolution and frame-rate changes, rotation, overlays, and audio to AAC. Fully hardware accelerated end to end — MediaCodec decodes to a GL surface and MediaCodec re-encodes, so frames never round-trip through the CPU. Roughly 7–8× realtime on 720p.
It writes MP4 and nothing else. media3-muxer ships WebM, Ogg, WAV and AAC muxers too,
but none can be driven by Transformer — they throw from addMetadataEntry, which the muxer
wrapper calls for every metadata entry a real recording carries. It reads far more than it
writes, Matroska included, which is what makes MKV → MP4 a hardware remux.
FFmpeg — the long tail
Everything Media3 structurally cannot do:
- Containers outside MP4/WebM/Ogg/WAV/AAC — MKV, MOV, AVI, FLV, MPEG-TS, WMV/ASF
- MP3 output — Android has no MP3 encoder at any version; this is a platform gap
- GIF and image sequences
- Input codecs with no platform decoder on the device
- CRF and 2-pass rate control, for the quality tier
- Codecs Media3's muxers decline even on a stream copy — its MP4 muxer carries AAC, Opus, Vorbis and PCM, but neither MP3 nor FLAC
Quality tiers
The router is surfaced to users as a quality choice rather than hidden:
| Tier | Engine | Rate control | Trade-off |
|---|---|---|---|
| Fast (default) | Media3 / MediaCodec | bitrate-targeted | ~7–8× realtime, low battery cost |
| Best quality | FFmpeg + x264/x265 | CRF or 2-pass | ~realtime or slower, better quality per byte |
A note on "GPU acceleration"
Android has no GPU video codec path. There are three distinct tiers, and conflating them causes a lot of confusion:
- Fixed-function video codec silicon — reached through
MediaCodec. This is what "hardware accelerated" means for encode and decode. It is not the GPU. - GPU shader cores — genuinely used, but only for filters, scaling, and color effects on already-decoded frames, via OpenGL ES. Never for entropy coding.
- CPU — x264, x265, and software decoders.
FFmpeg's -hwaccel is meaningful on Android only as mediacodec, and even then it
targets direct-to-Surface playback rather than file-to-file transcoding. Vulkan Video
exists in FFmpeg 8.0+ but no shipping Android GPU driver exposes it — no VK_KHR_video_*
extension appears in any Android Vulkan Profile tier.
So this app is hardware accelerated via MediaCodec, and GPU accelerated for effects via GL shaders. Both are real; neither is "the GPU decoding video."
Remuxing
Changing the container without touching the streams. Copying an H.264 track from MKV into MP4 moves the same samples into a different wrapper: it finishes in seconds instead of minutes, costs no quality, and needs no encoder — which is why it stays on the hardware path even on a device that cannot encode the codec in question.
Copy is a codec choice like any other, so it can be mixed: copy the video and re-encode
only the audio, or the reverse. Picking a codec the source already uses is upgraded to a
copy automatically when the container is changing — if container and codec both already
match, the only reason to run the job is to re-encode it, so it does.
A copy is never attempted on a stream whose codec could not be identified. A needless re-encode costs time; a wrong stream copy costs a file that will not play.
Features
| Formats | |
|---|---|
| Video out | MP4, MOV, MKV, WebM, MPEG-TS, AVI, FLV, WMV/ASF |
| Video codecs | H.264, H.265, VP9, or copy the source stream |
| Audio out | MP3, AAC/M4A, FLAC, Opus, WAV, MKA |
| Audio codecs | AAC, Opus, MP3, FLAC, PCM, or copy the source stream |
| Images | GIF, PNG frame sequences |
| Other | Remux without re-encoding; join several files into one |
Presets cover the common combinations in one tap. The Advanced picker exposes the full container × codec matrix — including combinations that cannot work, which it explains and offers alternatives for rather than hiding.
Conversions run as durable background work, so they survive leaving the app and are restored after a restart.
Building
Requires JDK 17+ (AGP 9 will not run on older) and the Android SDK with API 37.
FFmpeg is committed as a prebuilt archive under bin/, so a clone
builds without a cross-compile. That is deliberate: rebuilding it per CI run made test
results ambiguous, because a red build could mean broken code or a build that hiccuped.
See bin/README.md for its provenance and how to regenerate it.
./gradlew :app:assembleDebug # debug APK
./gradlew :app:testDebugUnitTest # JVM tests
./gradlew :app:connectedDebugAndroidTest # device tests, needs a running device
./gradlew :app:assembleRelease # R8-minified release
See tools/ffmpeg/README.md for why the build is
containerised and which flags matter. That recipe remains the authority — the committed
archive is its output, and is also what satisfies the GPL corresponding-source
obligation.
Testing
Unit tests cover the parts that decide correctness without needing hardware: the routing matrix, the container × codec capability matrix, the FFmpeg argument builder, and both stream-copy-versus-re-encode planners. They run against fabricated device profiles, so branches like "this device cannot encode HEVC" are reachable regardless of what the test machine is.
Instrumented tests cover the parts that only a device can prove: real hardware
transcoding, the foreground service type, and each FFmpeg output format asserted against
the produced file rather than the exit code. The remux tests additionally assert which
engine ran — a stream copy produces an identical file either way, so an output-only
assertion cannot tell a hardware transmux from FFmpeg's -c copy.
Privacy
The app has no INTERNET permission, so it cannot open a network connection at all.
Nothing is uploaded, and there is no analytics or advertising. See PRIVACY.md,
which also explains the permissions WorkManager adds automatically.
Contributing
Contributions are welcome. Note that contributions to the source are under MIT, while
the distributed binary remains GPL-3.0 for the reasons described in LICENSES/README.md.