FPNG Java¶

FPNG-Java provides Java wrappers around two native, SIMD-optimised PNG encoders — FPNG (SSE2) and FPNGE (AVX2). Both produce fully compliant PNG files at significantly higher throughput than javax.imageio.

The JDK23+ version of the encoders uses Foreign Function & Memory API and is the fastest. Otherwise JNI is used via JNA, which comes with some overhead.

Latest stable release: fpng-java-1.4.1.jar

GitHub Repository: https://github.com/manticore-projects/fpng-java

Features¶

Two encoders with automatic runtime selection
- FPNG — SSE2/SSE4.1/PCLMUL, works on any x86-64 CPU
- FPNGE — AVX2, used automatically when the CPU supports it
FFM for JDK22+, JNI/JNA for older JDKs
Runtime hasAVX2() CPUID probe — no AVX2 library is loaded on unsupported hardware
Encodes BufferedImage directly — 3-channel (RGB) and 4-channel (RGBA)
Handles Java’s native TYPE_3BYTE_BGR / TYPE_4BYTE_ABGR channel order in C via SIMD byte shuffles
Interleaved Adler32 checksum — no redundant full-image pass
PCLMUL-accelerated CRC32
Supports Java 8, Java 11, Java 17 and Java 21
Platforms: Linux x86-64, Windows x86/x86-64, macOS x86-64

Benchmarks¶

Run the JMH benchmarks with:

./gradlew jmh

Results are written to benchmark/build/results/jmh/results.json.

JMH PNG Encoder Benchmark Report

PNG Encoder Benchmark Report

Generated by Manticore Projects · JMH ms/op · lower is better

3 ch example.png

Encoder	Score (ms/op)	Error	vs Winner
FPNGE (Java 23 FFM)	2.706	±0.143	baseline
FPNGE (JNI)	3.261	±0.691	+20.5%
FPNG Encoder (JNI)	3.987	±0.818	+47.3%
FPNG Encoder (Java 23)	5.002	±1.122	+84.9%
PNGEncoder (fastest)	20.986	±12.699	+675.7%
ObjectPlanet PNG	41.352	±2.925	+1428.4%
PNGEncoder	44.550	±23.990	+1546.6%
ImageIO	50.375	±4.578	+1761.9%

3 ch looklet-look-scale6.png

Encoder	Score (ms/op)	Error	vs Winner
FPNGE (Java 23 FFM)	139.807	±33.887	baseline
FPNGE (JNI)	166.635	±126.279	+19.2%
FPNG Encoder (JNI)	302.257	±141.186	+116.2%
FPNG Encoder (Java 23)	337.719	±28.268	+141.6%
PNGEncoder (fastest)	346.707	±111.700	+148.0%
PNGEncoder	1176.420	±115.739	+741.5%
ImageIO	1238.361	±568.947	+785.8%
ObjectPlanet PNG	1756.963	±427.382	+1156.7%

4 ch example.png

Encoder	Score (ms/op)	Error	vs Winner
FPNGE (Java 23 FFM)	4.223	±0.587	baseline
FPNGE (JNI)	4.625	±1.513	+9.5%
FPNG Encoder (Java 23)	6.605	±1.217	+56.4%
FPNG Encoder (JNI)	8.457	±2.726	+100.3%
PNGEncoder (fastest)	24.527	±21.807	+480.9%
PNGEncoder	50.895	±4.062	+1105.3%
ObjectPlanet PNG	51.795	±24.218	+1126.6%
ImageIO	63.420	±37.017	+1401.9%

4 ch looklet-look-scale6.png

Encoder	Score (ms/op)	Error	vs Winner
FPNGE (Java 23 FFM)	197.625	±39.119	baseline
FPNGE (JNI)	271.884	±56.459	+37.6%
PNGEncoder (fastest)	423.605	±168.635	+114.3%
FPNG Encoder (Java 23)	440.591	±53.450	+122.9%
FPNG Encoder (JNI)	476.420	±445.912	+141.1%
ImageIO	1484.558	±1000.757	+651.2%
PNGEncoder	1511.124	±147.042	+664.6%
ObjectPlanet PNG	2145.475	±202.674	+985.6%