myiapoole / dfjpegturbo

Objective-C libjpeg-turbo wrapper

DFJPEGTurbo (Deprecated)

Objective-C libjpeg-turbo wrapper (JPEG image codec that uses SIMD instructions (MMX, SSE2, NEON) to accelerate baseline JPEG compression and decompression on x86, x86-64, and ARM systems). DFJPEGTurbo uses libjpeg-turbo version 1.4.1, which now includes arm64 support.

Requirements

• iOS 6.0

Examples

Decompressing JPEG

NSData *jpegData;
UIImage *image = [DFJPEGTurboImageDecoder imageWithData:data];

Decompressing JPEG with one of the libjpeg-turbo scale factors

NSData *jpegData;
// Scale must be implemented by libjpeg-turbo which supports only several scaling factors (1/1, 1/2, 1/4 etc).
DFJPEGScale scale = DFJPEGScaleMake(1, 2); // 0.5 scale
UIImage *image = [DFJPEGTurboImageDecoder imageWithData:jpegData orientation:UIImageOrientationDown scale:scale];

Benchmark (Baseline JPEG)

Benchmark on older ARM-based systems (iPhone 4S, iPhone 5C) shows that libjpeg-turbo provides a very noticable performance boost over native CGContextDrawImage. However, libjpeg-turbo underperforms on newer systems (iPhone 6). For benchmark implementation see Demo/DFJPEGTurboBenchmark in a project folder.

iPhone 6 (Apple A8)

Input Image	CGContextDrawImage	libjpeg-turbo
1024x768, 0.3 compression quality	10.51 ms	9.75 ms
1024x768, 0.5 compression quality	10.56 ms	10.15 ms
1024x768, 0.7 compression quality	10.14 ms	11.61 ms
1024x768, 0.9 compression quality	10.13 ms	12.44 ms
2048x1536, 0.3 compression quality	41.60 ms	36.98 ms
2048x1536, 0.5 compression quality	33.46 ms	40.56 ms
2048x1536, 0.7 compression quality	33.85 ms	45.53 ms
2048x1536, 0.9 compression quality	34.79 ms	52.60 ms

iPhone 5C (Apple A6)

Input Image	CGContextDrawImage	DFJPEGTurbo
1024x768, 0.3 compression quality	42.47 ms	22.26 ms
1024x768, 0.5 compression quality	40.75 ms	23.28 ms
1024x768, 0.7 compression quality	40.51 ms	26.11 ms
1024x768, 0.9 compression quality	39.82 ms	29.77 ms
2048x1536, 0.3 compression quality	130.72 ms	81.95 ms
2048x1536, 0.5 compression quality	129.83 ms	86.50 ms
2048x1536, 0.7 compression quality	130.42 ms	98.17 ms
2048x1536, 0.9 compression quality	130.03 ms	106.18 ms

Installation using CocoaPods

To install DFJPEGTurbo add a dependency in your Podfile.

pod 'DFJPEGTurbo'

Contacts

License

DFJPEGTurbo is available under the MIT license. See the LICENSE file for more info.