I do have question about bitrate: I often play flac-ripped cd's that have a bitrate of about 450 to 950kbps. 16 bit is clear of course but why is that bitrate so low, they are regular cd's I rip myself.
This is because it is showing the bitrate of the compressed file as it plays. i.e. it is the size of the file in kilobits, divided by how long the track is in seconds. Considering that redbook 16 bit, 44.1KHz is 1411kbps, that means it is reading 1411kbps of data every second from the source. With a flac, this is using lossless compression - so to get exactly the same information, it can do it in 450 or 950kbps as you have stated. The smaller a track is able to be compressed to flac - the lower the bitrate will be - even though the exact same information is being produced.
I was looking for a table with the bitrates belonging to the various resolutions from mp3 to hires flac but cannot find it anymore, could you point me to this?
What do you mean by hires? Bitrate is separate from other things. You can compress a 96Khz/24bit file to 128kbps for example while you could have the exact same track in 44.1KHz/16bit compressed at 320kbps. The 128kbps file is likely to sound worse, even thought it is 96/24 - because it won't be able to as accurately approximate the waveform compared to 44.1/16 at 320kbps. Bitrates can be a bit of a black art sometimes - but it is even worse with video! People sometimes ask, does a 720p or 1080p file look best at the same bitrate and the answer is does that depend - a lower bitrate implies that there will be more compression artefacts and blocks so - particularly in the 1080p file which can make 720p look better, but if the bitrate is high enough, it won't be noticable and 1080p will be better. It is no different with audio - that said most lossy (mp3 etc) stuff I have seen seems to be 44.1/16.
The point is - while bitrate is linked to the sampling rate and bit depth (i.e. 44.1/16), it doesn't imply it, or vice versa.
Flac is a lossless format - so the bitrate there is irrelevant. The algorithm has encoded the file to the smallest it can (lowest bitrate) where it is losing no information. A bit like a zip file on your computer.