DOKK / manpages / debian 12 / etc1tool / etc1tool.1.en
ETC1TOOL(1) ETC1TOOL(1)

etc1tool - ETC1 conversion tool

etc1tool infile [--help | --encode | --encodeNoHeader | --decode] [--showDifference difffile] [-o outfile]

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

The input file to compress.
Print this usage information.
Create an ETC1 file from a PNG file.
Create a raw ETC1 data file (without a header) from a PNG file.
Create a PNG file from an ETC1 file.
Write difference between original and encoded image to difffile. (Only valid when encoding).
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

The Android Open Source Project.