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EN-30 Audio Capabilities

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Posted: 04 Mar, 2014
by: Gedanken J.
Updated: 20 Nov, 2014
by: Gedanken J.

EN-30 Audio Capabilities Documentation 3/3/2014 MO

Important Information:

            The EN-30 has a PC83 audio board with two PC112 boards.  This configuration of audio boards is the same as in the EN-100.  The PC83 is responsible for SDI input encoding and the PC112’s interface the PC83 with AES and Analog input.

            Unlike the EN-100 there are some audio limitations to the EN-30 due to the fact that the PC83 has to support two services and the space available on the rear panel.  The 8 pairs of Audio are divided equally between each Service (4 pairs each).

     There are 4 AES inputs.  These inputs are hard wired to the following configuration

     AES Input 1 → Service 1, Audio 1

     AES Input 2 → Service 1, Audio 2

     AES Input 3 → Service 2, Audio 1

     AES Input 4 → Service 2, Audio 2

     Analog Audio input is hard wired to the following DB9 pinout:

 

PIN

1

2

3

4

5

6

7

8

9

Signal

+L A1

-L A1

Gnd

-R A1

+R A1

+L A2

-L A2

-R A2

+R A2

 

     Audio 3 and Audio 4 can only be set to SDI input for both services

     Passthru is only an option for Audio 1 and Audio 2 for both services

     The PC83 resources are divided 50/50 between Service 1 and Service 2

     Even if Service 2 is set to OFF, Service 1 can still only allocate 50% of the Audio resources

 

Encoding:

            The EN-30 has the following Audio Encoding capabilities and resources.  Different CODECs require a different amount of resources.  The EN-30 has logic built-in so that the user cannot exceed the PC83 resources.

            Example:  If the user encodes Dolby Digital on audio pairs 1 and 2 for Service 1, the resources are completely used up so pairs 3 and 4 can only be set to OFF.  The table below gives % usage per pair for the different types of encoding.  The combination of the 4 pairs cannot exceed 50% (half the PC83).  If you refer to the table , you will see that DD 2/0 uses 25% resources and that is why only 2 pair of DD encoding uses up all 50%.  If the user wants to encode four pairs of Audio (excluding surround), there are only 6 configurations that are acceptable:

1.    All four pair are set to MU → 9 * 4 = 36%

2.    Three pair are set to MU and one pair set to AAC-LC → 9 * 3 + 20  = 47%

3.    Three pair are set to MU and one pair set to AAC-HEv1 → 9 * 3 + 18  = 45%

4.    Three pair are set to MU and one pair set to AAC-HEv2 → 9 * 3 + 14  = 43%

5.    Two pair are set to MU and two pair are set to AAC-HEv2 → 9 * 2 + 14 * 2 = 46%

6.    Two pair are set to MU, one pair to AAC-HEv1, one pair to AAC-HEv2

                        → 9 * 2 + 14 +18 = 50%

CODEC

MODE

% Usage per Pair

MPEG1(2) Layer 2 -- MU

Stereo

9%

Dolby Digital AC3 (x06 & x81)  -- DD

2/0

25%

AAC-LC

2/0

20%

AAC-HEv1

2/0

18%

AAC-HEv2

2/0

14%

Surround CODEC

 

 

Dolby Digital AC3 (x06 & x81)  -- DD

5/1

42%

AAC-HEv1

5/1

41%

AAC-LC

6/0

31%

AAC-6

6/0

25%

 

The important thing is to be aware of different configurations and how resource intensive they are.  If an EN-30 is not accepting the settings being attempted by the user, then check the other pairs of audio and ensure the threshold is not being exceeded.  

**Passthru does not require any resources from PC83**

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