NormH.264 — 4K to 1/4 size, visually identical

NormMAP commutator-norm driven H.264 encoder. Empirical on a real 4K source: 110 MB → 28 MB (-74.3%) at VMAF mean 83.25, visually indistinguishable from the original. Drop-in FFmpeg pipeline; 100% playback compatibility (every H.264 player, hardware decoder, and edit suite works unchanged). 30-day HW-fingerprint locked trial. SlimeCodec Convert v0.3.3.

Why this matters for VOD / surveillance / archives: cut storage and CDN bandwidth to 1/4 without switching to AV1 (no new GPUs, no player upgrades, no transcoding farm overhauls). Every existing H.264 endpoint plays the output unchanged. AV1 catch-up not required.

Visual proof — 4K side-by-side

Same 4K nature frame, original vs NormH.264 slime-1 (1/4 size). Click any image for full resolution.

Center crop (zoom on detail to inspect):

left: original 110 MB · right: NormH.264 28 MB (-74%, VMAF 83.25)

Download

Windows x64 — v0.3.3 GUI + CLI (.zip) (NEW, recommended)

slimecodec-gui.exe + slimecodec-convert.exe + FFmpeg 7.1 GPL DLLs + MinGW runtime + README + CHANGELOG. Cross-compiled from WSL with mingw-w64.

md5: e4354fc4a6430d0677d90554194d5ddd / 73.0 MB

Windows x64 — v0.3.3 CLI only (.zip)

slimecodec-convert.exe + FFmpeg 7.1 GPL DLLs + MinGW runtime + README (lightweight, no GUI)

md5: fc100059d552238a6cebcb4f85d3733d / 71.1 MB

Linux x64 — v0.3.3 (.tar.gz) (NEW)

slimecodec-convert (CLI) + slimecodec-gui (eframe GUI) + CHANGELOG. Adds --output-codec h264|av1 switch and trial watermark.

md5: 776765e09145e5bd4d50ff0c6975c52b / 5.03 MB

Linux x64 — v0.3.2 (.tar.gz, archived)

Previous release, kept for reproducibility.

md5: de24d90e81ba2c2c54e2b037ad8c8582 / 488 KB

4K empirical (real source measurement)

Tested on a 4K nature clip (3840×2160 30fps, 20.4 sec, H.264 AVC):

Output	Size	Reduction	VMAF mean	VMAF min	Visual
Original (45 Mbps)	110 MB	—	(reference)	—	—
NormH.264 slime-1 (recommended)	28 MB	-74.3%	83.25	72.31	indistinguishable
NormH.264 slime-2 (aggressive)	25 MB	-77.2%	80.47	68.90	slight loss

VMAF 83 is the threshold below which most viewers notice degradation. slime-1 lands at 83.25 mean — empirically the sweet spot where storage is quartered with no visible quality loss in real-world viewing.

What's new in v0.3.3

v0.3.3 keeps the v0.3.2 NormMAP encoder unchanged and adds three things:

Unified output codec switch: --output-codec h264|av1. h264 (default) routes through libx264 with full NormMAP ROI; av1 routes through libsvtav1 (research preview — native SVT-AV1 ROI map dispatch is queued for v0.4).
Trial-mode watermark: every trial output now carries a small Javatel logo + SLIMECODEC TRIAL banner burned into the bottom-right of every frame. License activation is still deferred to v0.4; in v0.3.3 the watermark is always on.
30-day trial hardened (offline-only): state is now mirrored to a second anchor location, the OS file mtime acts as an external forward-only time floor, and primary/secondary disagreement triggers immediate trial expiration. Closes the simple clock-rollback and single-file-delete bypasses.

The H.264 path is unchanged from v0.3.2 — same NormMAP ROI behavior, same speed, same auto-tune. Existing v0.3.2 trial state is preserved on first v0.3.3 launch.

Performance history (v0.3.1 → v0.3.2)

The H.264 encoding path in v0.3.3 inherits the v0.3.2 numbers below (unchanged), so this table also reflects current v0.3.3 H.264 behavior.

Metric	v0.3.1 stock	v0.3.2 (this build)	Change
4K Pass 1 wall time	17.8 s	6.9 s	2.6× faster ✅
4K full convert wall	27.4 s	16.6 s	1.65× faster ✅
Bitrate savings (4K surveillance, vs plain libx264)	-37.1%	-45.4%	+8.3 pp ✅
VMAF on the above	99.2	89.6	−9.6 pts (still >83) ⚠

If you need the v0.3.1 conservative behavior, set --quality-bias +0.02 (see Quality bias section below).

Speed improvements come from:

AVX2 + FMA SIMD path for commutator-norm math
12-thread per-block parallelization
Frame pipelining (decoder ↔ compute overlap)
Content-aware auto-tune (surveillance / shake / sport / nature / generic auto-detection)

Quick start (Windows GUI, recommended)

Download the GUI + CLI zip and extract to any folder
Double-click slimecodec-gui.exe
Click "Browse..." to select a video, then "Convert"
Output is created next to the input as *_slime.mp4

Quick start (Windows CLI)

Extract the zip to any folder

In cmd / PowerShell:

slimecodec-convert.exe my_video.mp4 -o output.mp4 --auto-tune --keyint 2

Or run the bundled test_encode.bat

Quick start (Linux)

tar -xzf slimecodec-convert-linux-x64-phase4_2026-05-04.tar.gz
cd slimecodec-convert-linux-x64-phase4
./slimecodec-convert input.mp4 -o output.mp4 --auto-tune --keyint 2

Quality bias dial

Fine-tune the size/quality trade-off on top of the auto-tune classifier with a single dial — slider in the GUI, --quality-bias flag in the CLI:

Setting	Effect	When to use
`--quality-bias -0.02`	Higher strength, smaller files	Compression-priority, accept slight quality drop
`--quality-bias 0.0` (default)	Balanced	Most cases
`--quality-bias +0.02`	Lower strength, larger files, higher VMAF floor	Quality-priority, distribution use

Range -0.10 .. +0.10, step 0.01 recommended. Only effective with --auto-tune.

Trial spec (Phase 5 license v2): Expires after the earlier of 30 days from first launch or 1000 invocations. Hardware-fingerprint locked (bound to a single machine), encrypted license file (~/.slimecodec/license_v2.dat / 32 bytes XOR + integrity tag). PC date rollback to extend the trial is detected and rejected.

System requirements: Windows 10/11 x64 or Linux x86_64, CPU with AVX2 + FMA support (Intel Haswell or later, AMD Excavator or later — roughly 2014+ x86 CPUs).

AV1 path

For AV1-only delivery (newer GPU / iOS 17+ / browsers with AV1 decode), see NormAV1 — research preview. Note: AV1 hardware playback is still ~50% market reach; NormH.264 is recommended for general use.

Contact

For commercial license / subscription inquiries: sasaki@javatel.co.jp

SlimeCodec is proprietary software. Patent pending JP 2026-046609.