Convert ZAB to MP4

Converting Zipped Audio Books directly to MP4 Videos (.zab to .mp4 conversion) is, per se, not possible; at least not without a workaround.

First you need to decompress your ZAB file using one of numerous available ZIP format supporting programs, such as WinZIP, WinRAR, 7-Zip etc. You can then easily convert the resulting data to MP3 format using tools, such as Switch Audio Converter. 

To finally generate your MP4 video, simply convert MP3 to MP4.

We are not aware of any third-party solution capable of converting ZAB to MP4 directly.