Question Author
Many thanks for answers -
pug100 - This is the device you gave link to - iAudio 7 8gb. It's compatible with practically all formats.
TEAK36 - The software cd with the player has the download for the Cowon Music Centre and device management option, which has a format convert option.
The video I've been experimenting with plays ok in the pc program, so I presume it should transfer to the player ok . I have had some success - about 40 seconds or so transferred to the player - I'm not sure how I did that, and I suppose I must have clicked something to terminate that procedure. The trouble for me is that there is no clear instructions to follow. Anyhow, thanks again for your interest. I'll just keep fiddling about with it. I must say, though, that it is an amazing little device, with all kinds of functions.