etc1tool - ETC1 conversion tool

       The Android Open Source Project.

                                                                                                     ETC1TOOL(1)

etc1tool is a command line utility that lets you encode PNG images to the ETC1 compression  standard  and
       decode ETC1 compressed images back to PNG.

       Default is --encode

       etc1tool - ETC1 conversion tool

infile The input file to compress.

       --help Print this usage information.

       --encode
              Create an ETC1 file from a PNG file.

       --encodeNoHeader
              Create a raw ETC1 data file (without a header) from a PNG file.

       --decode
              Create a PNG file from an ETC1 file.

       --showDifference difffile
              Write difference between original and encoded image to difffile.  (Only valid when encoding).

       -o outfile
              Specify  the name of the output file.  If outfile is not specified, the output file is constructed
              from the input filename with the appropriate suffix (.pkm or .png).

       https://developer.android.com/tools/help/etc1tool.html

etc1toolinfile  [--help  |  --encode  |  --encodeNoHeader  |  --decode] [--showDifference difffile] [-o
       outfile]