View source for Bit Rate Calculation

<big>'''BIT RATE CALCULATION WITH BARIX DEVICES'''</big>

With this document we want to explain how to calculate the total bit rate flowing on an Ethernet cable connected to a Barix device.

The total bit rate is equal at the audio bit rate plus the overhead due to the encapsulation of audio packet inside the layers of OSI stack [http://en.wikipedia.org/wiki/Osi_model].

We have used for the test an Instreamer 100 (with standard firmware) configured first in RAW UDP and then in RTP, and an Exstreamer 1000 (with STL firmware). 


'''RAW UDP STREAMING MODE'''

For the structure of the Ethernet packet see here: [http://en.wikipedia.org/wiki/Ethernet]

The Total Ethernet Overhead per packet is 300 bit.


For the structure of the IP packet see here: [http://en.wikipedia.org/wiki/Ipv4]

The Total IP Overhead per packet is 160 bit.


For the structure of the UDP packet see here: [http://en.wikipedia.org/wiki/UDP_packet]

The Total UDP Overhead per packet is 64 bit. 


'''Total Bit of Overhead per Packet =''' '''Ethernet Overhead + IP Overhead + UDP Overhead = 524 bit'''


The Audio Bit rate is expressed in bit/sec but the Overhead is expressed in bit/packet.
So we have to translate the Overhead (bit/packet) in Overhead rate (bit/sec).
For this we need to know the amount of packet/sec, that depends by Audio Format and is measurable with Network Protocol Analyzer software like Wireshark.


The values of Audio Data for audio format, sampling frequency and quality (MP3 bitrate average), come from Instreamer Manual (firmware V3.10 – page 18 - [http://www.barix.com/downloads/Instreamer_Standard_Firmware/1981/])

For MPEG1/2 Layer3 (MP3) bit rate 

the following Encoding range is supported as Variable Bit Rate in IPAM100 based devices:

28kbps (MPEG2@16KHz mono) - 192kbps (MPEG1@48KHz stereo)

Decoding range on both IPAM100 and IPAM300 as Constant or Variable Bit Rate is: 

8kbps (MPEG2@16KHz mono) - 320kbps (MPEG1@48KHz stereo)


'''Overhead/sec = Overhead/Packet x Packet/sec'''

'''Total Bit Rate (Kbit/sec) = Audio Data Rate (Kbit/sec) + Overhead/sec (Kbit/sec)'''

<sup>''(1 Kbit = 1000 bit)''</sup>


{| class="wikitable" border="1" cellspacing="0"
| <center>'''Audio Format'''</center>
| <center>'''Audio Data Rate (Kbit/sec)'''</center>
| <center>'''Packet/sec (Wireshark)'''</center>
| <center>'''Overhead (bit)'''</center>
| <center style="background-color:#FFB6C1">'''Total Bit Rate (Kbit/sec)'''</center>

|-
| <center>PCM 16 bit 8 KHz, mono</center>
| <center>128</center>
| <center>13.551</center>
| <center>524</center>
| <center style="background-color:#FFB6C1">135.1</center>

|-
| <center>PCM 16 bit 24 KHz, mono</center>
| <center>384</center>
| <center>42.213</center>
| <center>524</center>
| <center style="background-color:#FFB6C1">406.12</center>

|-
| <center>uLaw 8 KHz, mono</center>
| <center>64</center>
| <center>6.7</center>
| <center>524</center>
| <center style="background-color:#FFB6C1">67.5</center>

|-
| <center>ALaw 8 KHz, mono</center>
| <center>64</center>
| <center>6.7</center>
| <center>524</center>
| <center style="background-color:#FFB6C1">67.5</center>

|-
| <center>ALaw 24KHz, mono</center>
| <center>192</center>
| <center>20.28</center>
| <center>524</center>
| <center style="background-color:#FFB6C1">202.62</center>

|-
| <center>uLaw 24 KHz, mono</center>
| <center>192</center>
| <center>20.28</center>
| <center>524</center>
| <center style="background-color:#FFB6C1">202.62</center>

|-
| <center>MPEG1 48KHz quality 0, stereo</center>
| <center>88</center>
| <center>16.46</center>
| <center>524</center>
| <center style="background-color:#FFB6C1">96.62</center>

|-
| <center>MPEG1 48KHz quality 4, stereo</center>
| <center>144</center>
| <center>22.56</center>
| <center>524</center>
| <center style="background-color:#FFB6C1">155.82</center>

|-
| <center>MPEG1 48KHz quality 7</center>
| <center>192</center>
| <center>27.81</center>
| <center>524</center>
| <center style="background-color:#FFB6C1">206.57</center>

|-
| <center>MPEG1 48KHz quality 4, mono</center>
| <center>96</center>
| <center>16.08</center>
| <center>524</center>
| <center style="background-color:#FFB6C1">104.42</center>

|-
| <center>MPEG1 44.1KHz, quality 0, mono</center>
| <center>65</center>
| <center>12.27</center>
| <center>524</center>
| <center style="background-color:#FFB6C1">71.43</center>

|-
| <center>MPEG1 44.1KHz, quality 4, mono</center>
| <center>90</center>
| <center>15.76</center>
| <center>524</center>
| <center style="background-color:#FFB6C1">98.25</center>

|-
| <center>MPEG1 44.1KHz, quality 7, mono</center>
| <center>140</center>
| <center>25</center>
| <center>524</center>
| <center style="background-color:#FFB6C1">153.1</center>

|-
| <center>MPEG2 16KHz quality 0, mono</center>
| <center>28</center>
| <center>5.8</center>
| <center>524</center>
| <center style="background-color:#FFB6C1">31.03</center>

|-
| <center>MPEG2 16KHz quality 4, mono</center>
| <center>44</center>
| <center>7.58</center>
| <center>524</center>
| <center style="background-color:#FFB6C1">47.97</center>

|-
| <center>MPEG2 16KHz quality 7</center>
| <center>64</center>
| <center>11.5</center>
| <center>524</center>
| <center style="background-color:#FFB6C1">70</center>

|}


'''Without Ethernet Overhead'''

{| class="wikitable" border="1" cellspacing="0"
| <center>'''Audio Format'''</center>
| <center>'''Audio Data Rate (Kbit/sec)'''</center>
| <center>'''Packet/sec (Wireshark)'''</center>
| <center>'''Overhead (bit)'''</center>
| <center style="background-color:#FFB6C1">'''Total Bit Rate (Kbit/sec)'''</center>

|-
| <center>PCM 16 bit 8 Khz, mono</center>
| <center>128</center>
| <center>13.551</center>
| <center>224</center>
| <center style="background-color:#FFB6C1">131.4</center>

|-
| <center>PCM 16 bit 24 Khz, mono</center>
| <center>384</center>
| <center>42.213</center>
| <center>224</center>
| <center style="background-color:#FFB6C1">393.46</center>

|-
| <center>uLaw 8 Khz, mono</center>
| <center>64</center>
| <center>6.7</center>
| <center>224</center>
| <center style="background-color:#FFB6C1">65.5</center>

|-
| <center>ALaw 8 Khz, mono</center>
| <center>64</center>
| <center>6.7</center>
| <center>224</center>
| <center style="background-color:#FFB6C1">65.5</center>

|-
| <center>ALaw 24KHz, mono</center>
| <center>192</center>
| <center>20.28</center>
| <center>224</center>
| <center style="background-color:#FFB6C1">196.54</center>

|-
| <center>uLaw 24 Khz, mono</center>
| <center>192</center>
| <center>20.28</center>
| <center>224</center>
| <center style="background-color:#FFB6C1">196.54</center>

|-
| <center>MPEG1 48KHz quality 0, stereo</center>
| <center>88</center>
| <center>16.46</center>
| <center>224</center>
| <center style="background-color:#FFB6C1">91.69</center>

|-
| <center>MPEG1 48KHz quality 4, stereo</center>
| <center>144</center>
| <center>22.56</center>
| <center>224</center>
| <center style="background-color:#FFB6C1">149.05</center>

|-
| <center>MPEG1 48KHz quality 7, stereo</center>
| <center>192</center>
| <center>27.81</center>
| <center>224</center>
| <center style="background-color:#FFB6C1">198.23</center>

|-
| <center>MPEG1 48KHz quality 4, mono</center>
| <center>96</center>
| <center>16.08</center>
| <center>224</center>
| <center style="background-color:#FFB6C1">99.6</center>

|-
| <center>MPEG1 44.1KHz quality 0, mono</center>
| <center>65</center>
| <center>12.27</center>
| <center>224</center>
| <center style="background-color:#FFB6C1">67.75</center>

|-
| <center>MPEG1 44.1KHz quality 4, mono</center>
| <center>90</center>
| <center>15.76</center>
| <center>224</center>
| <center style="background-color:#FFB6C1">93.53</center>

|-
| <center>MPEG1 44.1KHz quality 7, mono</center>
| <center>140</center>
| <center>25</center>
| <center>224</center>
| <center style="background-color:#FFB6C1">145.6</center>

|-
| <center>MPEG2 16KHz quality 0, mono</center>
| <center>28</center>
| <center>5.8</center>
| <center>224</center>
| <center style="background-color:#FFB6C1">29.3</center>

|-
| <center>MPEG2 16KHz quality 4, mono</center>
| <center>44</center>
| <center>7.58</center>
| <center>224</center>
| <center style="background-color:#FFB6C1">45.7</center>

|-
| <center>MPEG2 16KHz quality 7, mono</center>
| <center>64</center>
| <center>11.5</center>
| <center>224</center>
| <center style="background-color:#FFB6C1">66.58</center>

|}


'''RTP STREAMING MODE'''

For the structure of the RTP packet see here: [http://en.wikipedia.org/wiki/Real-time_Transport_Protocol]

The Total RTP Overhead per packet is 128 bit (counting also the MP3 MPA wrapper inside the RTP payload, which has an extra 32 bit header).


'''Total Bit of Overhead per Packet ='''

'''Ethernet Overhead + IP Overhead + UDP Overhead + RTP Overhead = 652 bit'''


The values of Audio Data for audio format, are the same of above, since the transmission protocol doesn't affect audio bit rate.


'''Overhead/sec = Overhead/Packet x Packet/sec'''

'''Total Bit Rate (Kbit/sec) = Audio Data Rate (Kbit/sec) + Overhead/sec (Kbit/sec)'''

<sup>''(1 Kbit = 1000 bit)''</sup>


{| class="wikitable" border="1" cellspacing="0"
| <center>'''Audio Format'''</center>
| <center>'''Audio Data Rate (Kbit/sec)'''</center>
| <center>'''Packet/sec (Wireshark)'''</center>
| <center>'''Overhead (bit)'''</center>
| <center style="background-color:#FFB6C1">'''Total Bit Rate (Kbit/sec)'''</center>

|-
| <center>MPEG1 48KHz quality 0, stereo</center>
| <center>88</center>
| <center>41.7</center>
| <center>652</center>
| <center style="background-color:#FFB6C1">115.2</center>

|-
| <center>MPEG1 48KHz quality 4, stereo</center>
| <center>144</center>
| <center>41.7</center>
| <center>652</center>
| <center style="background-color:#FFB6C1">171.2</center>

|-
| <center>MPEG1 48KHz quality 7, stereo</center>
| <center>192</center>
| <center>41.7</center>
| <center>652</center>
| <center style="background-color:#FFB6C1">219.2</center>

|-
| <center>MPEG1 48KHz quality 4, mono</center>
| <center>96</center>
| <center>41.7</center>
| <center>652</center>
| <center style="background-color:#FFB6C1">123.2</center>

|-
| <center>MPEG1 44.1KHz quality 0, mono</center>
| <center>65</center>
| <center>38.3</center>
| <center>652</center>
| <center style="background-color:#FFB6C1">90</center>

|-
| <center>MPEG1 44.1KHz quality 4, mono</center>
| <center>90</center>
| <center>38.3</center>
| <center>652</center>
| <center style="background-color:#FFB6C1">114.97</center>

|-
| <center>MPEG1 44.1KHz quality 7, mono</center>
| <center>140</center>
| <center>38.3</center>
| <center>652</center>
| <center style="background-color:#FFB6C1">164.97</center>

|-
| <center>MPEG2 16KHz quality 0, mono</center>
| <center>28</center>
| <center>27.8</center>
| <center>652</center>
| <center style="background-color:#FFB6C1">46.12</center>

|-
| <center>MPEG2 16KHz quality 4, mono</center>
| <center>44</center>
| <center>27.8</center>
| <center>652</center>
| <center style="background-color:#FFB6C1">62.12</center>

|-
| <center>MPEG2 16KHz quality 7, mono</center>
| <center>64</center>
| <center>27.8</center>
| <center>652</center>
| <center style="background-color:#FFB6C1">82.12</center>

|}



{| class="wikitable" border="1" cellspacing="0"
| <center>'''Audio Format (STL)'''</center>
| <center>'''Audio Data Rate (Kbit/sec)'''</center>
| <center>'''Packet/sec (Wireshark)'''</center>
| <center>'''Overhead (bit)<sup>1'''</sup>'''</center>
| <center style="background-color:#FFB6C1">'''Total Bit Rate (Mbit/sec)<sup>2'''</sup>'''</center>

|-
| <center>ALaw 8 Khz, mono</center>
| <center>64</center>
| <center>50</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">0.09</center>

|-
| <center>PCM MSB 16 bit 8 KHz mono</center>
| <center>128</center>
| <center>50</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">0.16</center>

|-
| <center>PCM MSB 16 bit 11.025 KHz mono</center>
| <center>176.4</center>
| <center>50</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">0.2</center>

|-
| <center>PCM MSB 16 bit 12 KHz mono</center>
| <center>192</center>
| <center>50</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">0.22</center>

|-
| <center>PCM MSB 16 bit 16 KHz mono</center>
| <center>256</center>
| <center>50</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">0.29</center>

|-
| <center>PCM MSB 16 bit 22.050 KHz mono</center>
| <center>352.8</center>
| <center>50</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">0.38</center>

|-
| <center>PCM MSB 16 bit 24 KHz mono</center>
| <center>384</center>
| <center>50</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">0.41</center>

|-
| <center>PCM MSB 16 bit 32 KHz mono</center>
| <center>512</center>
| <center>50</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">0.54</center>

|-
| <center>PCM MSB 16 bit 44.1 KHz mono</center>
| <center>705.6</center>
| <center>70</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">0.75</center>

|-
| <center>PCM MSB 16 bit 48 KHz mono</center>
| <center>768</center>
| <center>75</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">0.81</center>

|-
| <center>PCM MSB 16 bit 8 KHz stereo</center>
| <center>256</center>
| <center>50</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">0.29</center>

|-
| <center>PCM MSB 16 bit 11.025 KHz stereo</center>
| <center>352.8</center>
| <center>50</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">0.38</center>

|-
| <center>PCM MSB 16 bit 12 KHz stereo</center>
| <center>384</center>
| <center>50</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">0.41</center>

|-
| <center>PCM MSB 16 bit 16 KHz stereo</center>
| <center>512</center>
| <center>50</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">0.54</center>

|-
| <center>PCM MSB 16 bit 22.050 KHz stereo</center>
| <center>705.6</center>
| <center>70</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">0.75</center>

|-
| <center>PCM MSB 16 bit 24 KHz stereo</center>
| <center>768</center>
| <center>75</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">0.81</center>

|-
| <center>PCM MSB 16 bit 32 KHz stereo</center>
| <center>1024</center>
| <center>100</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">1.08</center>

|-
| <center>PCM MSB 16 bit 44.1 KHz stereo</center>
| <center>1411.2</center>
| <center>137</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">1.5</center>

|-
| <center>PCM MSB 16 bit 48 KHz stereo</center>
| <center>1536</center>
| <center>150</center>
| <center>620</center>
| <center style="background-color:#FFB6C1">1.63</center>

|}
<sup>''1 - in PCM and A/uLaw streaming mode, there is not MPA wrapper.''</sup>

<sup>''2 - 1 Mbit = 1000 Kbit.''</sup>


'''Without Ethernet Overhead'''

{| class="wikitable" border="1" cellspacing="0"
| <center>'''Audio Format'''</center>
| <center>'''Audio Data Rate (Kbit/sec)'''</center>
| <center>'''Packet/sec (Wireshark)'''</center>
| <center>'''Overhead (bit)'''</center>
| <center style="background-color:#FFB6C1">'''Total Bit Rate (Kbit/sec)'''</center>

|-
| <center>MPEG1 48KHz quality 0, stereo</center>
| <center>88</center>
| <center>41.7</center>
| <center>352</center>
| <center style="background-color:#FFB6C1">102.67</center>

|-
| <center>MPEG1 48KHz quality 4, stereo</center>
| <center>144</center>
| <center>41.7</center>
| <center>352</center>
| <center style="background-color:#FFB6C1">158.67</center>

|-
| <center>MPEG1 48KHz quality 7, stereo</center>
| <center>192</center>
| <center>41.7</center>
| <center>352</center>
| <center style="background-color:#FFB6C1">206.67</center>

|-
| <center>MPEG1 48KHz quality 4, mono</center>
| <center>96</center>
| <center>41.7</center>
| <center>352</center>
| <center style="background-color:#FFB6C1">110.67</center>

|-
| <center>MPEG1 44.1KHz quality 0, mono</center>
| <center>65</center>
| <center>38.3</center>
| <center>352</center>
| <center style="background-color:#FFB6C1">78.48</center>

|-
| <center>MPEG1 44.1KHz quality 4, mono</center>
| <center>90</center>
| <center>38.3</center>
| <center>352</center>
| <center style="background-color:#FFB6C1">103.48</center>

|-
| <center>MPEG1 44.1KHz quality 7, mono</center>
| <center>140</center>
| <center>38.3</center>
| <center>352</center>
| <center style="background-color:#FFB6C1">153.48</center>

|-
| <center>MPEG2 16KHz quality 0, mono</center>
| <center>28</center>
| <center>27.8</center>
| <center>352</center>
| <center style="background-color:#FFB6C1">37.78</center>

|-
| <center>MPEG2 16KHz quality 4, mono</center>
| <center>44</center>
| <center>27.8</center>
| <center>352</center>
| <center style="background-color:#FFB6C1">53.78</center>

|-
| <center>MPEG2 16KHz quality 7, mono</center>
| <center>64</center>
| <center>27.8</center>
| <center>352</center>
| <center style="background-color:#FFB6C1">73.78</center>

|}


{| class="wikitable" border="1" cellspacing="0"
| <center>'''Audio Format (STL)'''</center>
| <center>'''Audio Data Rate (Kbit/sec)'''</center>
| <center>'''Packet/sec (Wireshark)'''</center>
| <center>'''Overhead (bit)<sup>1'''</sup>'''</center>
| <center style="background-color:#FFB6C1">'''Total Bit Rate (Mbit/sec)<sup>2'''</sup></center>

|-
| <center>ALaw 8 Khz, mono</center>
| <center>64</center>
| <center>50</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">0.08</center>

|-
| <center>PCM MSB 16 bit 8 KHz mono</center>
| <center>128</center>
| <center>50</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">0.14</center>

|-
| <center>PCM MSB 16 bit 11.025 KHz mono</center>
| <center>176.4</center>
| <center>50</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">0.2</center>

|-
| <center>PCM MSB 16 bit 12 KHz mono</center>
| <center>192</center>
| <center>50</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">0.2</center>

|-
| <center>PCM MSB 16 bit 16 KHz mono</center>
| <center>256</center>
| <center>50</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">0.27</center>

|-
| <center>PCM MSB 16 bit 22.050 KHz mono</center>
| <center>352.8</center>
| <center>50</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">0.36</center>

|-
| <center>PCM MSB 16 bit 24 KHz mono</center>
| <center>384</center>
| <center>50</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">0.4</center>

|-
| <center>PCM MSB 16 bit 32 KHz mono</center>
| <center>512</center>
| <center>50</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">0.52</center>

|-
| <center>PCM MSB 16 bit 44.1 KHz mono</center>
| <center>705.6</center>
| <center>70</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">0.72</center>

|-
| <center>PCM MSB 16 bit 48 KHz mono</center>
| <center>768</center>
| <center>75</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">0.8</center>

|-
| <center>PCM MSB 16 bit 8 KHz stereo</center>
| <center>256</center>
| <center>50</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">0.27</center>

|-
| <center>PCM MSB 16 bit 11.025 KHz stereo</center>
| <center>352.8</center>
| <center>50</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">0.36</center>

|-
| <center>PCM MSB 16 bit 12 KHz stereo</center>
| <center>384</center>
| <center>50</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">0.4</center>

|-
| <center>PCM MSB 16 bit 16 KHz stereo</center>
| <center>512</center>
| <center>50</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">0.52</center>

|-
| <center>PCM MSB 16 bit 22.050 KHz stereo</center>
| <center>705.6</center>
| <center>70</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">0.72</center>

|-
| <center>PCM MSB 16 bit 24 KHz stereo</center>
| <center>768</center>
| <center>75</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">0.8</center>

|-
| <center>PCM MSB 16 bit 32 KHz stereo</center>
| <center>1024</center>
| <center>100</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">1.05</center>

|-
| <center>PCM MSB 16 bit 44.1 KHz stereo</center>
| <center>1411.2</center>
| <center>137</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">1.45</center>

|-
| <center>PCM MSB 16 bit 48 KHz stereo</center>
| <center>1536</center>
| <center>150</center>
| <center>320</center>
| <center style="background-color:#FFB6C1">1.58</center>

|}
<sup>''1 - in PCM and A/uLaw streaming mode, there is not MPA wrapper.''</sup>

<sup>''2 - 1 Mbit = 1000 Kbit.''</sup>


The PDF version of the original document is downloadable here [[[[media:bit_rate_calculation_3_0.pdf]]]].


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