DDS conversion tool for legacy GLI B5G6R5 formats captured with RTX Remix.

convert-gli-b5g6r5-header.py

import struct
import argparse

def main(inputFilePath, outputFilePath):
    
    with open(inputFilePath, 'rb') as file:
    
        binaryData = bytearray(file.read())
        ddsHeaderMagic = struct.unpack('>L', binaryData[0x0:0x4])[0]
        ddsHeaderLength = struct.unpack('L', binaryData[0x4:0x8])[0]
        
        if (ddsHeaderMagic != 0x44445320 or # 'DDS '
            ddsHeaderLength != 0x7C):
            print('DDS header magic or length didn\'t match')
            return
            
        ddsFourCC = struct.unpack('>L', binaryData[0x54:0x58])[0]      # DDS_PIXELFORMAT.dwFourCC
        ddsBitsPerPixel = struct.unpack('L', binaryData[0x58:0x5C])[0] # DDS_PIXELFORMAT.dwRGBBitCount
        ddsChannelMasks = struct.unpack('LLLL', binaryData[0x5C:0x6C]) # DDS_PIXELFORMAT.dwRGBABitMask

        if ddsFourCC != 0x474C4931: # 'GLI1'
            print('DDS doesn\'t use GLI1 extension')
            return
            
        if (ddsBitsPerPixel != 16 or
            ddsChannelMasks[0] != 0x1F or    # 5 bits R
            ddsChannelMasks[1] != 0x7E0 or   # 6 bits G
            ddsChannelMasks[2] != 0xF800 or  # 5 bits B
            ddsChannelMasks[3] != 0x0):      # 0 bits A
            print('DDS not a 16-bit B5G6R5 format')
            return

        struct.pack_into('>L', binaryData, 0x54, 0x44583130) # 'DX10'
        struct.pack_into('L', binaryData, 0x80, 0x55)        # DDS_HEADER_DXT10.dxgiFormat = DXGI_FORMAT_B5G6R5_UNORM
        
        with open(outputFilePath, 'wb') as outFile:
            outFile.write(binaryData)

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="DDS conversion tool for legacy GLI formats captured from RTX Remix.")
    parser.add_argument("input_file", help="Path to the input DDS/GLI file.")
    parser.add_argument("output_file", help="Path to the output DDS file.")
    args = parser.parse_args()

    main(args.input_file, args.output_file)