Following his previous updates, today PlayStation developer @BenMitnicK let us know he's updated his BMK AT9 & AT3 Converter to version 2.2 for PS3 / PSP / PS Vita platforms with the latest changelog detailed below. 
Download: AT9_AT3_Converter_V2.2.zip / AT9_AT3_Converter_V2.2.zip (1.79 MB - Mirror) / AT9_AT3_Converter_V2.2.zip (Mirror #2)
To quote from his Official Site: AT9&AT3 Converter V2.2
Little program for convert your files Wav/MP3 To At9/At3 and At9/At3 To Wav/Mp3 nothing special you must have .NET framework 4.5 installed and the files to be converted must be in the same directory as the application.
The At9&At3 format are used by Sony on PS Vita, PSP and PS3 especially for the sounds of themes.
At9&At3_Converter allows you to convert these sound files to other formats.
ChangeLog V2.2
Download: AT9_AT3_Converter_V2.2.zip / AT9_AT3_Converter_V2.2.zip (1.79 MB - Mirror) / AT9_AT3_Converter_V2.2.zip (Mirror #2)
To quote from his Official Site: AT9&AT3 Converter V2.2
Little program for convert your files Wav/MP3 To At9/At3 and At9/At3 To Wav/Mp3 nothing special you must have .NET framework 4.5 installed and the files to be converted must be in the same directory as the application.
The At9&At3 format are used by Sony on PS Vita, PSP and PS3 especially for the sounds of themes.
At9&At3_Converter allows you to convert these sound files to other formats.
ChangeLog V2.2
- Add BitRate support for AT9 and AT3
- Add Uppercase extention
- Add Compatibility PSP/PS3 for AT3
- Add Some verifications
- Add More compatibility for Sampling Rate 48000[kHz] and 44100[kHz]
- Add Status bar
- Add Info for AT9 and AT3 convertion
- Improved UI