OpenCL JPEG Encoder

Encodes an RGB image buffer to JPEG using OpenCL. Beside the final run length encoding, all previous steps such as color transformation, downsampling, discrete cosine transformation and quantification are performed on the OpenCL Device.

Building

Beside the OpenCL C++ Wrapper and make there are no dependencies. The program can be built calling

make

Running

The program encodes a raw ppm image to an jpeg image

./jpeg_enc src.ppm out.jpg <quality>

Usage

/* Create the encoder */
jpeg::JPEGEncoder encoder(<cl_device_type>, <quality>);

/* Encode the image */
encoder.encode_image(<input_buffer>, <width>, <height>, <output_file>);

Performance

The performance was measured running on a Radeon R9 290 encoding an image with 12079x7025 pixels showing a cove.

• Color conversion: 8.4ms
• Downsampling: 9.5ms
• DCT + Quantification: 20ms
• Time to copy buffers: 40ms