Extron electronic 325 - page 46

Forward error correction (FEC) panel

3b

3c

3a

Figure 28. Audio Encoder FEC Panel

NOTES: • FEC is only applied to the audio data channel; it is not applied to the video

channel.

• FEC is effective only for RTP transports. It should not be used for TCP

transport.

• FEC is not required, and is not applied when the encoder is configured in

stereo mode.

Forward error correction can be applied to the audio data in data streams that use the

RTP transport to protect audio data against data loss. Forward error correction enables the

decoder to recreate data that has been lost or corrupted without retransmission. FEC adds

additional data to the stream that the decoder can use to detect and reconstruct any lost

packets. The FEC data is sent separately from the image and audio data.

The level of FEC can be set to protect against different levels of data loss. This produces a

corresponding change in the amount of data that is transported and thus, the bit rate is

increased or decreased in proportion to the amount of FEC applied.

The VN-Matrix 325 products implement the recommendations defined by the PRo-MPEG

Code of Practice #3 (CoP3)/SMPTE 2022 standard.

Ñ FEC Mode — The FEC can be applied as either column only or row and

column.

• Row FEC protects against the loss of a single packet. It is the

simplest method of protection and results in the lowest overhead in

terms of bit rate and latency. However, it cannot handle consecutive packet losses

(burst packet loss).

• Column FEC protects against burst packet loss, providing that the burst of packet

losses are not in the same row. Since correction data is only calculated on one

dimension, column FEC is known as 1-dimensional (1-D) FEC.

By using both FEC methods together, 2-dimensional (2-D) FEC, the combined effect

protects against more loss combinations than either scheme by itself.

P1 P2 P3 P4 FR1The chart at left shows the FEC scheme applied

to a 4 column x 5 row structure. This scheme

adds 5 row FEC packets (FR1 through FR5) and 4

column FEC (FC1 through FC4) packets to every

20 data packets. This scheme can protect for

burst packet losses up 5 packets long.

P5 P6 P7 P8 FR2

P9 P10 P11 P12 FR3

P13 P14 P15 P16 FR4

P17 P18 P19 P20 FR5

FC1 FC2 FC3FC4

VN-Matrix 325 Serial Digital Over IP CODEC • Operation 40

Contents

Main Caution Warning Attention Avertissement Safety Instructions English Consignes de Scurit Franais Sicherheitsanleitungen Deutsch Achtung Vorsicht FCC Class A Notice Conventions Used in this Guide Copyright Trademarks Contents Introduction ............................................1 Installation and Setup ............................ 5 Operation ...............................................31 Alarms and SNMP ..................................59 Page Introduction Page Features Page Installation and Setup Installation and Setup Overview Rear Panel Features a b c d e f g h Network Netw Page Page Example 1: Switched and isolated network configuration Page Example 2: Switched and isolated network configuration Page Example 3: Routed Network Configuration Configuring Network Settings Serial Port Wiring Low-level Network Configuration Page Configuration Selections Making Remaining Connections RS-232 Over LAN Port LAN Ports d e RJ-45 port wiring Video Input, Output, and Loop Connections Encoder configuration a b c Network Decoder configuration a b Configure Encoders and Decoders Startup and Login Page Configure the Units as Encoders or Decoders Page Page Enable multicast streaming Operation Indications and Controls a b c Network Interface Device List Page Device Field Device Mode Removing a device from the network Page Device summary panel Licensed features panel Device setup panel Configuration panel Configuration Page Video Encoder Streams panel Configuration Page Audio Encoder Name panel ANC (Audio) panel Forward error correction (FEC) panel Streams panel Configuration Page Colfec and Rowfec Encoders Bandwidth Management Page and Typical Bit Rates a b Bandwidth management standard controls panel Advanced Controls panel Typical bit rates Decoder Display and Configuration Page a b Decoder Video Configuration Panel Decoder Streams Configuration Panel Decoder Bit Rate and Stream Page a b c d e Dropped packets row Displays the number of data packets dropped during the G Page Configuring a Serial Pass-through Group Firmware Upgrade Page Uploading the upgrade to the controller codec Installing the firmware (prepare, activate, and commit stages) License Page Accounts Page (Passwords and Clock Management) Passwords Panel Clock Management Panel Controller Licensing Panel Alarms and SNMP Alarms Alarms Page Filter settings panel a b c d e Alarm list panel Alarm types and descriptions Page Alarm Logs page Simple Network Management Protocol SNMP Password Value Page Reference Information Specifications Video Video input and loop through encoder Video processing codec Sync genlock decoder Audio input and output NOTE: Audio processing Control host ports codecs, decoders Network transport General Specifications are subject to change without notice. Part Numbers and Accessories Codec Part Number and Included Parts Mounting and Power Options Optional SFP Module Cables Mounting the Codec Tabletop Use Mounting kits UL Rack-Mounting Guidelines Test Pattern Extron Warranty