since Alan Davey has been brought up

[Carl Edlund Anderson]

On 28 Aug 2013, at 06:47 , Jonathan Smith <smithjm77x7 at GMAIL.COM> wrote:
> 
> Thanks for clearing up the M4A mystery. I thought it was not quite lossless
> (the size seemed a bit small) but pretty good.

Well, the "M4A" extention simply designates the "wrapper" for whatever the "real" audio in the file is. So you might have an .m4a file with lossily compressed audio inside, or you might have an .m4a file with losslessly compressed audio inside. But, yes, the size of the file is usually a guide, and you can use some kind of file inspector (iTunes will do this) that tells you about the audio type, bit rate, etc.

Cheers,
Carl

--
Carl Edlund Anderson
http://www.carlaz.com/