In data communications a Kilobit is one thousand bits. It is used to measure the amount of data transferred per second. Kilobits per second is shortened to kb/s, Kbps or kbps (as opposed to KBps, which is Kilobytes per second. Note the capitalization.) The lowercase b is commonly used to denote bits, while the uppercase B is used for bytes. source
In order not to misunderstand YouTube's audio needs, quotes from support.google.com
Encoding specifications for music videos. The media files you deliver to YouTube for music videos must conform to these specifications. HERE
Although it is not recommended, YouTube accepts compressed audio. YouTube transcodes from the delivered format; audio quality is much better when transcoded from a lossless format compared to re-compressing a lossy audio format.
If you must deliver compressed audio, use these specifications:
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