[fzzzbux]

i'm pretty new dowloading and recording digital media so i'm trying to learn so i can store the best qualty audio on my pc . iv'e been searching the web to get a grasp on bit rates and so on and thought i getting somewhere when i read ( on several sites) about the basic principles of how a cd is created .

a bit depth of 16 per sample and a sample rate 0f 44100 times per second per single channel of sound . that seems straight forward so i do the maths ... 16x 44100 x 2( for stereo ) = 1411kbps.. and that's what the sdandard is in cd manufacuring.

right i can grasp that so next i look for donwloads that are rated aT 16/44.1 which is flac/ lossless but after i've dowloaded them and check the properties it reads things like
sample rate 44.1
bit rate 16
kbps 860. or 7 hundred and something or 9 hundred and some thing . and that's where i end up scratching my head .. the maths don't work out how is that , i don't know . can someone explain please coz when i put my new 24 bit sound card in next week it's gunna fry my brain even more..

aprt from that ,,, hello ,, nice to be here . this is my first post

[MarkTaylor]

I'll move this over to the music section where you should get more help.

One thing though, do remember when posting that the only downloads we talk about here are legal ones, no problem so far, but easy to step over the line if not careful when talking about downloads and bit rates etc.

[GaryB]

The figure that you're looking at is probably before decompression. FLAC files are typically around 50-60% of their original size, so that would fit with the figure shown.

[Palladio]

Probably plenty on here who can help and I certainly don't have the technical expertise to answer your question but have always found Wikipedia very helpful when trying to get my head round different formats etc.

Apologies if you've already tried this route.

Another good forum would be Hydrogenaudio Forums - Portal Ummm not sure I should be mentioning other forums here...

[spl23]

Originally Posted by fzzzbux

a bit depth of 16 per sample and a sample rate 0f 44100 times per second per single channel of sound . that seems straight forward so i do the maths ... 16x 44100 x 2( for stereo ) = 1411kbps.. and that's what the sdandard is in cd manufacuring.

right i can grasp that so next i look for donwloads that are rated aT 16/44.1 which is flac/ lossless but after i've dowloaded them and check the properties it reads things like
sample rate 44.1
bit rate 16
kbps 860. or 7 hundred and something or 9 hundred and some thing . and that's where i end up scratching my head .. the maths don't work out

OK, so your maths on the bit rate of a CD is correct. So if you were downloading a WAV file, which is uncompressed, you'd expect exactly the same bit rate as on CD. However, FLAC is compressed - albeit in a fashion which means that it is possible to decompress it and get back exactly the same bits as went in, hence "lossless" compression. However, the whole point of compression is to make the file smaller. So the bit rate quoted for a lossless file such as FLAC is the equivalent bit rate of the compressed data. FLAC typically achieves a compression ratio of somewhere less than 1:2, so you would expect the compressed bit rate to be somewhere between 1411 kbps and 700 kbs - which is what you are seeing.

Compare this to a typical MP3 bit rate of 128 kbps or 160 kbps - the bit rate is much lower in this case, as the compression is lossy (more drastic) - when you decompress an MP3 file, you still end up with a 1411 kbps stream, as a WAV file is recovered from the data, but the lower quality is reflected by the lower bit rate.

In short - the bit rate of any compressed file when it is played back is exactly the same as CD (assuming it was sourced from 44.1/16 material), so the bit rate which is quoted is the bit rate of the file when it is in the compressed form.