How to convert .mp3 audio to .avr format.
Converting MP3 Audio Files directly to Audio Visual Research Files (.mp3 to .avr conversion) should be possible, even though your options might be limited.
Try using a media editing program or conversion tool, such as Filestar, which should be capable of converting .mp3 to .avr.
Alternatively, you can try some online conversion solution.
Audio editting software with huge format support
A file conversion and management software.