Alex Feltham said:
What is .m4a, Apple lossless ? I have many FLAC files, m4a conversion is about the same size, but AIFF nearly doubles the size of the FLAC. An Apple device will import either of these, although m4a seems more reliable. So which is better ?
There is a simple answer: lossless is lossless. It's impossible to answer the question which is better. Since file size is important, you could say that ALAC (m4a) is better than AIFF. It won't make any difference in sound quality. We rip everything to ALAC.
Basically lossless compression works like a zip file in computers. The original file is compressed and when decompressed is exactly the same as the original file.
AIFF is Apple's version of WAV and is uncompressed PCM (CD quality). These files can be compressed to Apple Lossless (m4a) or FLAC. Both files can be decompressed to AIFF and WAV. FLAC files can be converted to ALAC (Apple Lossless) without any loss in data.
In the Apple ecosystem ALAC works much better because iTunes and all Apple devices support them. It's also in the protocol for streaming through AirPlay to an Airport Express. But if you have FLAC files, there are many software options to batch convert them from FLAC to ALAC (or vice versa) and thus have both a FLAC and an ALAC version of the same file.