heres your need for support of quicktime 6.5 dlls... it looks as if this codec was added in 6.5, i think it was introduced in itunes 4.5. but i cannoy verify. codec does not decode with -ac faad or -ac ffflac. audiocodec qalac info "Quicktime Apple Lossless Audio Codec" status working ;requires quicktime 6.5 format 0x63616C61 driver qtaudio dll "QuickTime.qts" mplayer sig8 on init audio codec with quicktime 6.5.2.10 qts version. mplayer with quicktime.qts 6.00.0002.0010 reports Opening audio decoder: [qtaudio] QuickTime Audio Decoder ADecoder preinit failed :( ADecoder init failed :( Cannot find codec for audio format 0x63616C61. Read DOCS/HTML/en/codecs.html! uploaded sample clip to incoming/ as quicktime-newcodec-applelosslessaudiocodec.m4a