hello i'm trying to concat 2 audio/video files using the command: ffmpeg -i concat:"intermediate1.mpg|intermediate2.mpg" -c copy intermediate_all.mpg as is writen in: http://ffmpeg.org/faq.html#Concatenating-at-the-file-level but it does not cancat the 2 files only the first file is copied to the intermediate_all.mpg thanks