• Variable playback speed (from 0.5x to 3.5x)
• Support for chapters in m4b and mp3 files
• Dual pane landscape mode
• Light theme, automatic theme switch based on time of day
• Customizable seek buttons, both in app and in notification
• Delayed pause, useful for listening before sleep
• Playback control via remote buttons
This software uses libraries from the FFmpeg project under the LGPLv2.1.
Source code for the native component is available at https://github.com/mdmt1/sabp_native
If you're searching for an audiobook player for your offline files, give this a try. It offers multiple features for kinds of demands, and the developer is very responsive. Though the free version is good enough for daily use, the full version still worths every penny.