Ok, I looked into the OmgUtils.dll - this is a library SS use for parcing .oma files. Among some other things it contains a code that extracts codec_id and codec specific parameters from the .oma container. Each .oma file has a header starting with "EA3" - this is the sony specific header that will be recognized by devices. The byte at the offset +32 from the start of this header tell which codec was used to encode the context. Here a small list of the ids I was able to extract from this code: 0 - ATRAC3 (94Kbps, 105Kbps, 132Kbps) 1 - ATRAC3Plus 2 - unknown 3 - MP3 (see below) 4 - LPCM (linear PCM, not compressed) 5 - Windows Media Audio (WMA) 32/33/34 - ATRAC Advanced Lossless I'm one of the maintainers of the ffmpeg's parser for the .oma files (see http://svn.mplayerhq.hu/ffmpeg/trunk/libav...oma.c?view=log). While playing around with oma files in order to test my code I accidentally came across an .oma file that contains a MP3 encoded track, so I was able to figure out the codec_id and codec specific parameters. Now I can play this file back using the ffmpeg's mp3 decoder. That's why I proceed on the assumtion that Sony has introduced some devices are capable of decoding WMA and MP3 also. The most oma files I have were encoded using ATRAC/ATRAC+. I have only one sample with MP3, but no one with WMA and LPCM. I just add a support for the codecs mentioned above to our parcer for completeness. But it's not very necessary because the most of files were encoded using ATRAC...