etc1tool

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.

The usage for etc1tool is:

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

Option	Description
`infile`	The input file to compress
`—help`	Print usage information
`—encode`	Create an ETC1 file from a PNG file. This is the default mode for the tool if nothing is specified.
`—encodeNoHeader`	Create a raw ETC1 data file (without a header) from a PNG file.
`—decode`	Create a PNG file from an ETC1 file
`—showDifference diff-file`	Write the difference between the original and encoded image to `diff-file` (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`).