If we keep converting a file excample from flv to avi, avi to dat, then dat to mpeg, will quality lose?

Q: If we keep converting a file excample from flv to avi, avi to dat, then dat to mpeg, will quality lose?

A: There is a little confusion in what you are asking.

AVI is not a format - it is a container. If you convert from FLV to uncompressed frames (in an AVI container) there will be no loss. If you convert from FLV to any other lossless format there will be loss.

Again, DAT is not a format. DAT is usually the extensive given to a VCD MPEG stream. Converting to MPEG will again cause loss as MPEG is not a lossless codec.

In reality though, the loss will be minimilized by using reasonable codec bit-rates as FLV formatted videos are generally of low quality anyway. If the recoded videos are done at a high enough bitrate, you should have negligable degradation.

If you don't actually need to convert them, but just want to watch them offline, consider getting VideoLAN (www.videolan.org) which can play FLV's