Software

Portable player management

EasyPMP (PMPlib)
Portable Media Player library (PMPlib) is an open source project for the development of management software/library for various portable media players.
EasyH10
EasyH10 is an open source project for the development of a software suite for iRiver H10 digital audio players.

Audio encoding

CueProc
Cuesheet Processor (CueProc) is a command-line tool for converting audio CD images into another format such as WAV, MP3, Ogg Vorbis, MP4, MPC, WMA, etc.
ACMENC
ACMENC is an audio encoding tool for ACM (ACM Audio Compression Manager) codecs with command-line interface.
ACDIR
(Obsolute). Audio CD Image Reader (ACDIR) is a command-line tool for converting audio CD images into another format such as WAV, MP3, MPC, Ogg Vorbis, etc.

Video encoding

AvsDub
AvsDub is a frontend tool for AviSynth and VirtualDub to convert video files for iriver U10.
DirectShowSource with ConvertFPS
“DirectShowSource with ConvertFPS” is a patch to the official DirectShowSource filter to add a routine for frame rate conversion: it determines the position of the #n frame base on media time information and therefore forces to handle VFR files properly.