Search: Advanced search
Browse by category:
EN-30 Audio Capabilities
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:
● 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
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%
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**
|Others in this Category|
|VITC Application Note|
|PID conflict in MPEG-4|
|Null Packet Stuffing in MPEG Transport Stream|
|» More articles|