bit rate entry

[whyterabbyt]

The bit rate entry is obviously technically correct, but a lot of people take the meaning to be the same as 'sample rate'.

As such, would it be better to fill out the entries for bit depth and sample rate, and restate bit rate with relation to them?

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[mbell]

Feel free to add more clarification to that entry. I just wanted to get some basic info in there as a start.

[circuitbentpirate]

Feel free to add more clarification to that entry. I just wanted to get some basic info in there as a start.

I didn't want to go and erase what you've written. It is an easy thing to confuse. People in the industry do it all the time.

The bit rate you use depends on the highest frequency you will need to record. The bit rate you use must be at least double the highest frequency you want to record.

The bit depth depends on what medium the final product is. Ex: A CD, use 16 bit. A DVD use 24 bit or higher.
If you use a bit rate higher than the medium you will have to dither, and then you also need to understand dithering.

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[jtxx000]

AFAIK bit rate actually depends on both the bit depth and the sample rate, or neither if the audio is stored in a different way. Bit rate is the number of bits per second like for example 192 kbps in mp3.

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[whyterabbyt]

ps. the definitions I have used were sort-of-agreed between mbell, me, and rabyt. Not just me.

Well, I made various checks that there was a concrete difference between Bit Rate, and Bit Depth, and there is. Someone stomped on that, though, so it wasnt really 'sort of agreed', it was just changed.

Bit Rate is a measure of bandwidth ie the total information passed in a given period of time. A bit is the smallest unit of digital information. It is the product of bit depth and sample rate.

Bit Depth is the resolution of a single sample, ie the number of bits used to enocde one single signal amplitude.

Sample Rate is the number of discrete samples taken over a unit of time.

To point out the difference, consider that a 22kHz sample at 16bit has the same bitrate as a 44kHz sample at 8bit.

In short, bit rate is not the same as bit depth. Check the wikipedia or a hundred different links off Google if you're unsure, or even just the link I posted in the original definition of 'bit depth' before someone changed it to say the opposite of what I originally wrote.

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[whyterabbyt]

I don't think you can say that you didn't have the same idea as me about bit depth and rate being two different ways of saying the same thing. Otherwise you would have said 'the bit rate entry is wrong.' so don't go off on one and try and make me look stupid. We were all wrong, nevermind. We can all learn

The entry as it originally stood, when I posted that comment, was technically correct for bit depth. That was what I meant; that the original definition was based on a common misuse of the term, and that the term being defined was what was wrong. However that was probably unclear; the reason I posted here rather than just changing it was primarily because I didnt recognise the original author.

Nobody is 'going off on one', except perhaps you if you think my correction has anything to do with making you look 'stupid'. Be a little less precious, perhaps. The idea is about improving the information for the community, not being the 'rightest'. I know Im probably gonna make dumb mistakes myself , so Im not really in a position to be calling you stupid, y'know?

(PS I only altered the wiki a little, I assumed you made the major changes to the bit depth and bit rate pages when we spoke about it here?)

I'd waited regarding changing bit rate. However I actually added the original bit depth article to replace it, and stated in it that it definitely wasnt the same as bit rate. Its lost attribution, though, for some reason. Someone made the bit depth entry ambiguous again afterwards, Im afraid.

[jtxx000]

Correct. But an mp3 does not have say 16bit or 32bit choices does it? the Bit Rate of an mp3 might be 128kb/s but a wav has a bit rate of 16bit or 24bit. (I think...)

The 16, 24, or 32 bits for wavs are the bit depth (bits per sample) as opposed to bit rate (bits per second).

[Ben [KVR]]

Some of this confusion may stem from the fact there there were two entries for Bit Depth, one with the space and one without (Bit Depth and BitDepth), which the wiki obviously sees as two different pages. I copied what looked like the correct text from the one without the space to the one with the space and removed the one without.

er, if that make sense. So, I may have f**ked up the entries

[whyterabbyt]

Some of this confusion may stem from the fact there there were two entries for Bit Depth, one with the space and one without (Bit Depth and BitDepth), which the wiki obviously sees as two different pages. I copied what looked like the correct text from the one without the space to the one with the space and removed the one without.

er, if that make sense. So, I may have f**ked up the entries

Calling the first one 'BitDepth' was my fault. Style Guide note : dont concatenate words, since it does that weird AutomaticWikiNisation thing.

[peejunk]

Correct. But an mp3 does not have say 16bit or 32bit choices does it? the Bit Rate of an mp3 might be 128kb/s but a wav has a bit rate of 16bit or 24bit. (I think...) if you read the definition I wrote above you'll see how it applies to the mp3 example just as well as the common idea of '16bit / 24bit' that everybody else is talking about.
Good point. made me think anyway...

16bit and 24bit are bit DEPTH and not bit RATE.

For a standard PCM wave format (as in wav and aif) the bitrate is simply numchannels * bitdepth * samplerate.

So at a bitdepth of 16bits and samplerate of 44100 kHz and stereo (standard CD audio) it's:

2 * 16 * 44100 = 1411200 bps or roughly 1138kbps

Obviously for compressed format bitrate depends on more complicated factors.

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