jiranz: MKV files play OK. I downloaded samples from the divx site and it plays them. It doesn't recognise the .divx extension files. The problem seems to be with AVI files which say they were encoded with xvid. I have converted some of these to FLV and MP4 and then they will play OK. I did not know to convert them to MKV but i have a program which does that just as easily. I think I just have to get stuck in and convert everything. Our family camcorder records in AVI format and that means a lot of videos to convert and it will be ongoing for years to come.
I did not realise that the decoder might be a hardware chip. I have been blaming the linux OS because i had assumed that codecs were downloaded with OS firmware updates like you can download Klite codecs for use with Windows programs. I can see its complicated. If it is hardware related for sure then I would have no problem going back to the suppliers again. I wish I knew how to find out for certain.
OK - so it plays the files from the divx site without problem so that says that there is no problem with your player. In all probability the problem is with your original files. If they are being generated by your camcorder then you might want to take a look closely at its settings and see what can be adjusted. It may be possible to record to a different format or it may be possible to adjust the settings and continue using xvid/divx. (often, audio sync issues can be caused by the audio being saved in a variable bitrate. Audio within video files should really be saved at a constant or average bitrate)
If you are going to re-encode the files I'd suggest saving them as h264 (avc) in either an avi, mp4 or mkv container. (using aac or ac3 as the audio encoder)
If they are just basic video files then it doesn't really matter which container you use.
There are a number of tools that will do this for you. I'd suggest Avidemux. It is an easy to use, free tool that can batch process all your files.
However, it may not be necessary to re-encode all your files. It may simply be a matter of making some minor adjustments to them. Again, if we could see a sample this may help.
Trust me, your issues will have nothing whatsoever to do with the fact that the player you are using is Linux based. I have been a Linux user for many years and have no problem with viewing all sorts of video content. Usually I have much less trouble with various file formats than my Windows friends and colleagues. If I come across a file that wont play correctly on my Linux machine 99.99999% of the time it is the fault of the file.