AIFC quality vs. AIFF

Greetings!

AIFC is a compressed file format.

As with all compressed file formats, you are highly dependent on the CODEC that converted the file. However, with such a high bit rate (at least for compressed files), there is likely to be little audio loss on that resultant file. WIth MP3, 320mbps is generally considered to be as good as it gets and would be indistinguishable on most speakers systems to most people.

If you're planning on doing any work on the file later, however, you should never save as a compressed file format. For instance, frequency bands that are inaudible because of louder bands elsewhere in the mix may be dropped during compression. If, however, you later want to apply EQ to level these bands out, you can't do that if one has been stripped from the file.

On to your quetions specifically:

1) No, it is a lossy format. At a bit rate, you should get good results. However, at low bit rates, you would get poor results (although it depends on the purpose of the final file). I doubt you would notice much difference between AIFF and AIFC at > 300kbps

2) This depends entirely on the CODEC. I would always go to full-fat first and have a listen to that before converting down. However, if you're doing batch conversions, just try one and see what you think. As I mentioned earlier, it depends on the target use. If you're knocking it down to listen to on earbuds from an MP3 player, then the quality loss of the small earbud speakers is such that 192kbps may well be enough. In that case, a direct conversion should be good enough. Going from AIFC to AIFF should not make much of a loss to your file, though there will be some impact. Going from AIFF to Wav ought to make no difference whatsoever, since both are PCM files. However, do check on bit depth and sample rate. ANy time you change either of those, there will be a loss, even going from smaller values to higher.

If the music is from a streamed source then the original quality is going to be quite low anyway, perhaps no more than 128kbps. Even though you recorded it at a higher rate, the quality will not have been improved from the original. Therefore, you shouldn't worry about the quality loss by shifting it further - there will probably be little impact.

As for compatibility, your recipients should have no problems playing AIFC. If in doubt, check out this knowledgebase item:

http://support.microsoft.com/kb/316992

That says that AIFC is supported in all recent versions of Windows Media Player (including V9, V10 and V11). So, let them have the AIFC with impunity!

Pete