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Brotli-G SDK

This project contains the specifications and reference implementations for the Brotli-G compression format:

Brotli-G Bitstream Spec

The use of this technical documentation is goverened by the License.

Source

  • src/decoder/BrotliGCompute.hlsl - start here to read the HLSL source of the GPU decompressor
  • src/decoder/PageDecoder.cpp - start here to read the source of the CPU decompressor
  • src/BrotligDecoder.cpp - this contains the code driving the CPU decompressor
  • src/encoder/PageEncoder.cpp - start here to read the source of the compressor
  • src/BrotligEncoder.cpp - entry point for the compressor

Getting Started

The repo uses CMake build system. Install CMake >= 3.11 if not installed.

Building

Run "Build.bat" from a Visual Studio Developer Command Prompt to generate build files. Open the build files in compiler of choice and compile. Outputs are static libraries build\external\brotli\Release\brotli.lib and build\Release\brotlig.lib.

Usage

To use in a visual studio project, include inc external and external\brotli\c\include as include directories and link build\external\brotli\Release\brotli.lib and build\Release\brotlig.lib as external libraries.

Relevant header files:

  • inc/BrotligEncoder.h - function declarations for Brotli-G compressor
  • inc/BrotligDecoder.h - function declarations for Brotli-G CPU decompressor
  • inc/BrotliG.h - Brotli-G API header file for both compressor and CPU decompressor
  • inc/DataStream.h - data structures for Brotli-G datastream

Code examples:

// Compression
void Compress(size_t srcSize, uint8_t* src, size_t& dstSize, uint8_t*& dst)
{
    dstSize = BrotliG::MaxCompressedSize(srcSize);
    dst = new uint8_t[dstSize];
	
    size_t actualSize = 0;
	
    BrotliG::Encode(
			srcSize, 		// input size (bytes) 
			src, 			// input data
			&actualSize,		// actual compressed size (bytes) 
			dst, 			// compressed output
			65536,			// page size (bytes)
			nullptr			// handle to an application defined progress function
		);
	
    dstSize = actualSize;
}

// CPU Decompression
void DecompressCPU(size_t srcSize, uint8_t* src, size_t& dstSize, uint8_t*& dst)
{
   dstSize = BrotliG::DecompressedSize(src);
   dst = new uint8_t[dstSize];
   
   size_t actualSize = 0;
	
   BrotliG::DecodeCPU(
			srcSize, 		// compressed size (bytes) 
			src, 			// compressed data
			&actualSize,		// decompressed size (bytes) 
			dst, 			// decompressed output
			nullptr			// handle to an application defined progress function
		);
		
   dstSize = actualSize;
}

Example root signature for BrotliGCompute.hlsl:

CD3DX12_ROOT_PARAMETER1 rootParameters[RootParametersCount];
rootParameters[RootSRVInput].InitAsShaderResourceView(0);		// Compressed data buffer (SRV input)
rootParameters[RootUAVControl].InitAsUnorderedAccessView(0);		// Compressed metadata buffer (UAV input)
rootParameters[RootUAVOutput].InitAsUnorderedAccessView(1);		// Decompressed data buffer (UAV output)

Sample

Source code of a sample demostrating the usage of Brotli-G APIs is provided in the sample directory.Build.bat builds the sample by default.

Sample build output bin\Release\brotlig.exe.

Using the sample:

  • Brotli-G CPU compression: brotlig.exe <filepath>
  • Brotli-G CPU deccompression: brotlig.exe <filepath>.brotlig
  • Brotli-G GPU decompression: brotlig.exe -gpu <filepath>.brotlig
  • Help: brotlig.exe