8 bit ADPCM compression for low quality low bitrate voice transmission

[trastikata]

Hello all,

I started a new project, using 8 bit Adaptive Differential Pulse Code Modulation compression. My initial research and work is based on this MC document, which provides a complete framework for ADPCM:

https://ww1.microchip.com/downloads/en/AppNotes/00643b.pdf

If someone has experience with 8 bit ADPCM compression or better way to compress voice audio for low quality low bitrate voice transmission, I'd be glad to hear your input.