While making screencasts I always end up with a file having poorly synced audio and video streams. This is not container specific as this happens with all the formats - ogg, mkv, avi, mp4 etc. I guess this has something to do with ffmpeg.
After searching on Internet, I found that this can be fixed using itsoffset switch in ffmpeg. I also tested it and it works. But the question is how do I find exact lag between audio and video streams in seconds:milliseconds?? I tried ffmpeg -i but it always shows delay to be zero.