https://github.com/gen2brain/jpegn

Baseline JPEG decoder with SIMD optimizations
https://github.com/gen2brain/jpegn

Last synced: 10 months ago
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Baseline JPEG decoder with SIMD optimizations

• Host: GitHub
• URL: https://github.com/gen2brain/jpegn
• Owner: gen2brain
• License: mit
• Created: 2025-08-28T20:21:48.000Z (10 months ago)
• Default Branch: main
• Last Pushed: 2025-08-28T20:33:05.000Z (10 months ago)
• Last Synced: 2025-08-29T02:06:47.512Z (10 months ago)
• Language: Go
• Size: 401 KB
• Stars: 3
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
## jpegn

[![Status](https://github.com/gen2brain/jpegn/actions/workflows/test.yml/badge.svg)](https://github.com/gen2brain/jpegn/actions)

[![Go Reference](https://pkg.go.dev/badge/github.com/gen2brain/jpegn.svg)](https://pkg.go.dev/github.com/gen2brain/jpegn)

Baseline JPEG decoder with SIMD optimizations. It is based on [NanoJPEG](https://keyj.emphy.de/nanojpeg/).

For unsupported formats, such as progressive or CMYK JPEGs, it gracefully falls back to the standard `image/jpeg`.

### Benchmark

Compared to the standard library:

```

BenchmarkDecode420-8                     	    1062	   1222948 ns/op	  426839 B/op	       6 allocs/op

BenchmarkDecode420StdLib-8               	     542	   2156193 ns/op	  407088 B/op	       5 allocs/op

BenchmarkDecodeConfig-8                  	 1442437	       859.4 ns/op	      53 B/op	       1 allocs/op

BenchmarkDecodeConfigStdLib-8            	  758470	      1369 ns/op	   13616 B/op	       2 allocs/op

BenchmarkDecodeToRGBANearestNeighbor-8   	     517	   2353340 ns/op	 1999821 B/op	      10 allocs/op

BenchmarkDecodeToRGBACatmullRom-8        	     546	   2180485 ns/op	 2263200 B/op	      13 allocs/op

BenchmarkDecodeToRGBAStdLib-8            	     414	   2903516 ns/op	 1455734 B/op	       7 allocs/op

```

Difference with assembly optimizations:

```

benchmark                                  old ns/op     new ns/op     delta

BenchmarkDecode420-8                       1621872       1068240       -34.14%

BenchmarkDecodeConfig-8                    824           754           -8.46%

BenchmarkDecodeToRGBANearestNeighbor-8     2726279       2071692       -24.01%

BenchmarkDecodeToRGBACatmullRom-8          4068463       2156728       -46.99%

BenchmarkIdct-8                            135           40.7          -69.93%

BenchmarkUpsampleNearestNeighbor-8         318541        124015        -61.07%

BenchmarkUpsampleCatmullRom-8              3548015       411422        -88.40%

```

### Build tags

* `noasm` - do not use SIMD optimizations