What determines streaming sample rates?

Updated 1 month ago by Bryan Jones

Scope

This document covers a number of current and legacy Telos and Omnia streaming products and aims to answer questions about what determines the bit rate of a stream.

For purposes of this document we will only discuss MP3 streams. AAC streams are a much different discussion as there are AAC formats that are designed for different situations.

Description

MP3 output streaming formats are affected by the sample rate of the original content, and, the number of output channels (stereo or mono) and bit rate of the MP3 stream.

Note, the output sample rate will never be higher than the sample rate of the original source

Stream Bit Rate

Output SR Stereo 48k Input

Output SR Mono 48k Input

Output SR Stereo 44.1 Input

Output SR Mono 44.1 Input

8 Kbps

NA

8,000

NA

11,025

16 Kbps

NA

16,000

NA

11,025

20 Kbps

12,000

16,000

NA

NA

24 Kbps

16,000

24,000

11,025

11,025

32 Kbps

16,000

24,000

11,025

22,050

48 Kbps

24,000

24,000

22,050

22,050

56 Kbps

24,000

48,000

22,050

44,100

64 Kbps

24,000

48,000

22,050

44,100

96 Kbps

32,000

48,000

44,100

44,100

128 Kbps

48,000

48,000

44,100

44,100

192 Kbps

48,000

NA

44,100

NA

256 Kbps

48,000

NA

44,100

NA

320 Kbps

48,000

NA

44,100

NA

Final thoughts

Sample rate affects the overall frequency response. Often referred to as Nyquist theory or Nyquist frequency, the premise is that the frequency response is roughly half the sample rate. More info on this in Wikipedia

Not all output rates can be achieved by all inputs rates. For example, note that a 44.1 input sample rate can not produce a 20 Kbps output stream. The sample rates are not evenly divisible in these cases.

Generally, mono output signals can use higher sample rates as there are half as many bits in mono as there are for stereo.

Let us know how we can help

If you have further questions on this topic or have ideas about how we can improve this document, please contact us.


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