bruno1234 wrote: >Hi, i try to seek in a .mkv file while it's writing. My reader is MP9. > Did you try VLC already ? http://www.videolan.org . While it doesnt support all codecs in MKV, it supports most of them, also MPEG4 video ( DivX, XviD ), MP3, AAC, FLAC, MPEG1/2 video, etc Christian matroska project admin