07- Block Compression

The method of compression is strikingly similar to the previously published Color Cell Compression,[3] which is in turn an adaptation of Block Truncation Coding published in the late 1970s. Unlike some image compression algorithms (e.g. JPEG), S3TC’s fixed-rate data compression coupled with the single memory access.

The wide use of S3TC has led to a de facto requirement for OpenGL drivers to support it, but the patent-encumbered status of S3TC presented a major obstacle to open source implementations,[ while implementation approaches which tried to avoid the patented parts existed.

While S3 Graphics is no longer a competitor in the graphics accelerator market, license fees have been levied and collected for the use of S3TC technology until October 2017.