SoundCodecWMA Integer Decoder Project

General

In the summer of 2006, Paul Jones began work on converting the ffmpeg SoundCodecWMA decoder to fixed point so that it could be used with Rockbox (FS#4984). Although he did not complete the project, it raised interest in eventually getting ffmpeg's decoder working in Rockbox. This Google Summer of Code 2007 project completed his task.

Status

Codec is currently in SVN and functioning in real time on all software targets. Results appear accurate for nearly all files. Noise coding and line spectral pairs are implemented, though several issues have been identified with these features when used at very low bitrates (<= 16kbps). Seeking has been implemented and appears robust.

Both WMA Std. flavors are supported. No special WMA variants are supported (Pro, Voice, Lossless) due to lack of an open source decoder.

Todo:

• Make better use of memory and IRAM so that performance on Coldfire and the PP5002 is better (50% done)
• Further ASM improvements to iMDCT. Merge iMDCT with FAAD to speed up that codec.

Who's working on this

• Michael Giacomelli (saratoga)

with lots of help from:

• preglow
• linuxstb (developed the ASF parser)
• marsdaddy (Paul Jones)