I'd say bitrate is not arbitrary on ALAC files. Rather a measure of 'complexity'. If what you mean by arbitrary is that you have no control over it, that's also true. But not in the sense that somebody just picked a number. ALAC would seem to end up about 30% to 35% reduced from the original.
Very complex, rapidly changing or 'dense' music will get a higher bitrate than sine waves. Maybe I'll test this, later today. I think you may be on to something with file size/length math. I'll look over some of the large number of songs I've got in ALAC and look for a pattern.
The idea behind lossy files...and this applies to photography, too, is to only discard the least significant data. That which couldn't be heard (seen?) anyway.
Of course, this doesn't work well, at least at higher compressions. In Photoshop, I have a choice of 10 or more 'levels' of compression. Using extreme enlarements of small parts of a picture, you can clearly see what changes. The changes are most readily apparent in more.....complex parts of an image. Big enlargements are hurt worse than small prints. Images for monitor use are nearly immune!
Yes, processer overhead makes sense. Again, using photoshop as an example, when I make a big change to a photo, It can take several seconds to process.
I just decided early on, after experimenting with FLAC, to change over to ALAC. It was more.....painless, for me. And I Tunes makes it easy to 'downconvert' to a much smaller but still listenable MP3-160 bitrate. Album art is more easily manged, at least for me. That, and the fact I can stream music wirelessly to my stereo is the icing on the cake. I only wish the Airport Express were better clocked.
Very complex, rapidly changing or 'dense' music will get a higher bitrate than sine waves. Maybe I'll test this, later today. I think you may be on to something with file size/length math. I'll look over some of the large number of songs I've got in ALAC and look for a pattern.
The idea behind lossy files...and this applies to photography, too, is to only discard the least significant data. That which couldn't be heard (seen?) anyway.
Of course, this doesn't work well, at least at higher compressions. In Photoshop, I have a choice of 10 or more 'levels' of compression. Using extreme enlarements of small parts of a picture, you can clearly see what changes. The changes are most readily apparent in more.....complex parts of an image. Big enlargements are hurt worse than small prints. Images for monitor use are nearly immune!
Yes, processer overhead makes sense. Again, using photoshop as an example, when I make a big change to a photo, It can take several seconds to process.
I just decided early on, after experimenting with FLAC, to change over to ALAC. It was more.....painless, for me. And I Tunes makes it easy to 'downconvert' to a much smaller but still listenable MP3-160 bitrate. Album art is more easily manged, at least for me. That, and the fact I can stream music wirelessly to my stereo is the icing on the cake. I only wish the Airport Express were better clocked.