A small Windows x86-64 and Apple Silicon macOS media player with assembly decoders and native assembly interfaces. Audio comes first. The long-term goal is to support the relevant formats and playback features people use in mpv, with a small runtime and low CPU use.
Current source: 0.4.0-dev, an early audio prototype. WAV, AIFF/AIFC, native FLAC, MP3, Ogg/Vorbis and Ogg/Opus play in source builds. Opus supports family 0 mono/stereo and family 1 layouts with 1–8 speaker channels, downmixed to stereo. Its elementary decoders include RFC 8251 updates and pass all 120 official vector checks across five output rates and mono/stereo. Video, subtitles and network streaming are future work. The published v0.3.0 prerelease contains WAV, native FLAC, MP3 and Ogg/Vorbis.
Website · Download v0.3.0 · Roadmap · Compatibility matrix · Technical details and limits · Apple Silicon build
- Shared MASM x86-64 decoder sources; Windows runs them directly, and macOS builds translate them into native ARM64 assembly using Rhun’s approach.
- Windows uses event-driven WASAPI and a decode worker. macOS uses Core Audio queues with three bounded PCM buffers and an AppKit interface written in ARM64 assembly.
- A compact mpv-inspired UI, with Rhun's assembly UI approach and minimalist visual style as references.
- No external codec library, FFmpeg subprocess, or mpv engine in the player. Windows system DLLs and macOS libSystem/AppKit/AudioToolbox provide platform services; no C, Objective-C or Swift runtime source is compiled into the Mac player.
- MIT project license, with preserved MIT/MIT-0/CC0/BSD notices for reference-derived algorithms and data.
LAMP aims to reduce stutters. It cannot guarantee uninterrupted playback during arbitrary system or driver stalls. Same-machine headless playback measurements compare its assembly engine with mpv and VLC; shipping-GUI, wakeup and audible-latency measurements remain pending.
Windows 10/11 x64 and a working default audio output are the intended targets. Build from source for Opus and AIFF/AIFC support, or download the earlier v0.3.0 Windows prerelease. Open bin\lamp.exe and drop a supported audio file onto the window.
.\bin\lamp.exe 'C:\Music\track.ogg'
.\bin\lamp-cli.exe 'C:\Music\track.flac'
.\bin\lamp-cli.exe --check 'C:\Music\track.mp3'
.\bin\lamp-cli.exe --decode 'C:\Music\track.ogg' '.\track.f32'Apple Silicon Macs need macOS 12 or later. Build with Python 3 and Xcode command line tools, then open the native app bundle:
./build.sh
open build/macos/LAMP.app
build/macos/lamp-cli 'Music/track.flac'
build/macos/lamp-cli --check 'Music/track.opus'
build/macos/lamp-cli --decode 'Music/track.ogg' 'track.f32'The Mac app has Open, Finder file-open/drop handlers, pause/replay, stop, timeline seeking and volume controls. Cmd+O opens; Cmd+Q quits. The local bundle is ad-hoc signed. See Mac build strategy, controls, verification and limits. The published v0.3.0 download remains Windows-only.
--check decodes without an audio device. --decode writes little-endian float32 PCM with two interleaved channels; mono is duplicated. Opus output is 48 kHz; AIFF/AIFC rates round to integer hertz; other formats use their source rate. The destination must be new. Failed exports can leave partial output.
| Format | Current support |
|---|---|
| AIFF / AIFC | Signed PCM 1–32-bit, AIFC byte-order/fixed-container variants and float32/64; 1–8 channels, ordered Core Audio layouts, rounded 8–192 kHz output |
| WAV | Little-endian RIFF/RF64/BW64 audio framing, PCM 8/16/24/32-bit or float32/64; 1–8 channels, extensible valid bits/layouts, 8–192 kHz |
| Native FLAC | 1–8 channels, 4–32-bit, 8–192 kHz; CRC checks; speaker-mask-aware stereo downmix |
| MP3 | MPEG-1/2/2.5 Layer III, mono/stereo, CBR/VBR, encoder trimming when tagged |
| Ogg/Vorbis | Single logical stream, 1–255 channels, floor 1, mapping 0; stereo output, CRC and granule checks |
| Ogg/Opus | Development source: one logical Ogg stream; family 0 mono/stereo or family 1 with 1–8 speaker channels downmixed to stereo; 48 kHz output, header gain/pre-skip/end trimming |
See precise coverage, limitations, and verification before relying on a particular stream variant. Native surround output, chained Ogg streams and FLAC-in-Ogg remain unfinished. WAV, FLAC and Vorbis speaker layouts downmix to stereo; WAV also accepts left-aligned valid bits and float64 samples. WAV and AIFF/AIFC seek directly; native FLAC uses seek tables or searches validated frames; MP3, Vorbis and Opus use sparse indexes.
RF64/BW64 audio framing adds checked 64-bit lengths and direct seeks beyond 4 GiB. Its suite checks 538 files, 16 sparse large-file fixtures, 8,950 exact seeks and 312 malformed-input rejections. BW64 uses the existing WAVE speaker policy; ADM scene/object rendering remains unfinished. See container rules and comparator limits.
AIFF/AIFC adds signed PCM, float32/64, ordered Core Audio layouts and sample-exact direct seeks. Its suite checks 1,977 files, 19 sparse large-file cases, 30,443 seeks and 303 malformed-input rejections. Output remains stereo; rates round to integer hertz. See AIFF/AIFC coverage and reference limits.
Vorbis now decodes 1–255 native channels. Standard 1–8-channel layouts use the documented stereo speaker policy; larger application-defined layouts output ports 0/1 while every channel is decoded and validated. Its suite checks 797 files, 23,910 native/stereo seeks, protected output, cancellation, allocation release and 14 malformed/resource-limit rejections. Independent Xiph and specification references check native PCM before mixing. See Vorbis coverage and comparator limits.
| Control | Action |
|---|---|
| O / Ctrl+O; file drop | Open audio |
| Space; playback button | Pause/resume or replay |
| Left / Right | Seek ±5 seconds |
| Home; timeline click | Start; seek to position |
| Up / Down; volume bar | Adjust volume |
| M | Mute/unmute to 100% |
| Q | Close |
On Windows, the controls hide after 2.5 seconds of inactivity during playback and seeking runs on a worker. The Mac interface uses persistent native controls; seeking currently reopens/repositions synchronously. Mac keyboard bindings also include F for fullscreen and Escape to leave fullscreen. WAV and AIFF/AIFC jump directly to the sample; native FLAC uses a validated seek table or a bounded frame search, including files with unknown duration. Exhausting the search budget falls back to sequential decoding. MP3 restores an indexed reservoir and decodes two frames of pre-roll before the target. Vorbis restores an Ogg packet boundary and decodes one packet to rebuild overlap. Opus restores a packet boundary at least 80 ms before the target to rebuild decoder state; near the beginning it applies normal pre-skip. These indexes are built from headers when opening a file. Paused seeking keeps audio stopped until resume. The console accepts Space to pause and Q/Ctrl+C to stop.
For Windows, install Visual Studio 2022 Build Tools, its x64 C++ tools, and a Windows SDK. Build scripts locate ml64, link, and rc automatically:
.\build.ps1
node .\tests\verify-runtime.js
node .\tests\smoke.js
.\tests\render-ui.ps1
.\package.ps1For Apple Silicon, ./build.sh --release builds the ARM64 app and CLI. Python is used only during the build. tools/arm64.py is the pinned MIT Rhun translator; tools/masm.py normalizes the authoritative MASM sources, and tools/arm64_lamp.py adds the instructions used by LAMP. No translated code is interpreted at runtime.
python3 tests/verify-macos.py --layouts --opus --audio --ui
python3 tools/package-mac.pyMac verification additionally needs Python 3.12+, Node.js and FFmpeg with libmp3lame/libopus. It builds the bundled, hash-verified Xiph/Opus references into test artifacts only. Audio/UI checks need a desktop session and working output device. Generated reports, translation artifacts and binaries live under build/macos. The package contains the app, CLI, notices and a SHA-256 manifest. Mac verification scope is separate from the Windows results below.
The prebuilt ICO and decoder tables are included. A normal build needs no codec library or reference C compiler. Both Windows players use custom assembly entry points and /NODEFAULTLIB. The development build measures 205,312 bytes for lamp.exe and 197,632 bytes for lamp-cli.exe, including icon resources; release manifests record exact sizes and hashes.
To build while the player is open, use ./build.ps1 -OutputDirectory ./bin/verify-build. Pass that directory to node ./tests/verify-runtime.js ./bin/verify-build and node ./tests/smoke.js ./bin/verify-build to check the new binaries, or ./package.ps1 -BinaryDirectory ./bin/verify-build to package them. Packaging rejects a binary version that differs from VERSION.
The codec suites record 43 WAV/FLAC, 103 MP3, and 83 Vorbis checks, plus 4,425 exact WAV/FLAC/MP3/Vorbis seek checks and 6,768 Opus seeks against an independently positioned RFC 8251 reference decoder. Separate depth/layout suites check 965 WAV files with 14,475 exact seeks and 404 FLAC files with 6,060 exact seeks, guarded reads, cancellation and allocation release. Ogg seeking includes continued packets, cropped starts, granule origins and bounded index compaction. Engine lifecycle, malformed-input, stress and codec reference tests add separate coverage. These checks do not establish complete format conformance. Test instructions and recorded reports describe what was checked. Full fixture suites need FFmpeg and Node.js; seek and Opus oracle tests additionally use the C compiler for test executables only.
The Ogg CRC pass uses eight-byte table updates while retaining complete validation. On this machine, median reopen time for the recorded ten-minute fixtures fell from 32.7 to 12.5 ms for Vorbis and from 13.8 to 5.3 ms for Opus. These are warm-filesystem decoder timings, excluding WASAPI, the UI and audible latency. Decoder measurements and scope include silence and noise targets. A separate headless playback comparison records mpv 0.41.0 and VLC 3.0.24, startup/seek observations and CPU/RAM during playback, pause and idle across all five formats, with and without four CPU load workers. Its timing clocks differ between players; it does not establish audible latency or a universal performance advantage.
The UI image comes from the actual assembly renderer with synthetic state. Open-dialog, drag/drop, and monitor-DPI interaction still require desktop verification.
Latest Opus work adds family 1 multistream decoding and the RFC stereo downmix. The new integration suite checks 86 generated streams, 1,032 reset-reference seeks, repeated/silent/unmapped channels, gain/trim bounds, malformed packets and cancellation. Another 112 modern-libopus family 1 files pass independent float PCM comparisons, with peak error below 0.000002. The original family 0 suite retains 393 reference streams and 51 modern-libopus fixtures. All 120 official elementary-decoder vector checks pass, including reference PCM/history and final-range validation for 200,750 packets. Playback, pause/resume, stop/reopen and indexed/paused seeking pass for Opus and the existing formats. Ogg chaining and native surround routing remain unfinished. See the decoder-stage notes; ./tests/verify-opus-components.ps1 runs 35 suites without FFmpeg or an audio device, and ./tests/verify-opus-conformance.ps1 runs official vectors.
ROADMAP.md covers Opus, reliable audio playback, broader codecs and containers, video, subtitles, streaming, and eventual support for everything relevant that mpv supports. The compatibility matrix tracks the current gaps. Goals have acceptance gates, not promised release dates. Hardware decode should be used when it lowers system cost; handwritten assembly alone does not guarantee a faster codec.
Keep runtime and codec code in assembly. Use original implementations or carefully attributed permissive references (MIT, MIT-0, BSD-2-Clause, BSD-3-Clause, or CC0). Preserve applicable notices. Test tools may use other languages. Please include the failing media characteristics, a redistributable fixture when possible, and a reference comparison when reporting decoder issues.
Original LAMP code and brand assets are MIT licensed. See THIRD_PARTY_NOTICES for reference-derived code/data and test reference sources. The Mac translator and native helper macros/routines derive from the MIT-licensed Rhun revision recorded in those notices; Rhun branding and assets are not included.