# Genesys Quality Management Suite 8.1.520 : Configuring Decoders

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This chapter describes how to identify the decoder servers and configure decoding parameters in the Decoders tab.

Decoders are responsible for encoding media streams into playable media files (wav, mp3). If an RTP stream cannot be decoded by the decoder, the decoder creates zip files, which include both pcap files.

You can have one or more decoders. If you have more than one decoder, they process the pcap files simultaneously.

## Configuring Decoder

Navigate to Settings > Configuration > Decoders > Decoder Servers Configuration.
By default on a single server installation Call Recording has one decoder with two decoder processes running. In installations with a lot of concurrent calls, two decoder processes may not be sufficient, which would lead to extended waiting times for media to be played. It is possible to add new decoding processes.

To add decoder processes:

1. Increase the value of the Number of decoders in Decoder1. This value must always be less than the number of available CPUs on the server.
2. Click Save Configuration to save the new Decoder server settings.

### Additional Parameters for Decoder

In addition to the parameters below for a new decoder, Decoder1 has extra parameters, enabling you to define a Filter Factory. There are two filters included in a default Call Recording installation, available in the Filter factory drop-down list:
File size controller: This filter must define a Max size of file, in megabytes, which is the maximum size of files created. If the file size is larger than the set maximum size, it is split into multiple files.
Blowfish ciphering filter: When you select this filter, you are asked for the Path to key file – the path where the ciphering key is stored. Please note that the key size is limited to 16 bytes. It is possible to use any random string with a maximum of 16 characters.

## Adding a New Decoder Server

In multi-server installations it is possible to have decoders on more than one server. If there are sufficient concurrent calls, the installation may even require a dedicated server for decoding. In either case add a new decoder server.
To add a new decoder server:

1. Scroll down to the Add new decoder form.
2. Click New to create a form for the new decoder.
3. Type a unique Decoder name: for the new decoder server, for example, Decoder2.
4. Click the Application communicator bind name field and the name of the new decoder server updates.
5. Enter the following parameters:
   - Application communicator bind name: This is the RMI bind name for the selected decoder. This must be the same for all decoders; for example, DMCommunicator.
   - Application communicator registry address: This is the server that this decoder runs on, for example, Decoder2. Select the server from the drop-down list. These are defined in Settings > Call Recording Core > Servers.
   - Path to save recordings: This is the path for storing recorded files – the local path on the server selected in the Application communicator registry address drop-down list.
   - Path to database: This is the media file path stored in the database – the local path on the server selected in the Application communicator registry address drop-down list.
   - Save sub directory: This is the time interval selected for the creation of unique subdirectories – if day is selected, a new subdirectory is created every 24 hours. The subdirectory name is generated as a timestamp, for example, 20100424.
   - Number of decoders: This is the number of decoder processes on this server. The default number is two processes, increase the number if necessary.This value must always be less than the number of available CPUs on the server.
   - Time to destroy decoder: Timeout in seconds. If a decoder stops responding within the time of this interval, the connection is terminated and reinitiated.
   - MP3 bitrate : The quality of recorded audio if you are using the MP3 codec. The bitrate can be selected from 16 – 128 kbps, where 8 kbps is the lowest quality and 128 kbps is the highest. The default value is 24 kbps.
6. Click Save Configuration to save the new Decoder server settings.

### Audio Quality settings

By default Call Recording stores all decoded calls as MP3 files with a 24 kbps bitrate. You can also choose uncompressed WAV. Change the quality settings to minimize storage space, or maximize audio quality.

### MP3 Codex Quality Settings:

Bitrate (kbps) | Storage Space for 1 min (MB)
--- | ---
16 | 0,11
24 | 0,17
32 | 0,23
40 | 0,29
48 | 0,34
56 | 0,4
64 | 0,46
80 | 0,57
96 | 0,69
112 | 0,8
128 | 0,92

The following are known limitations of the decoder:

- WAV files are uncompressed in the Call Recording system, and the bit rate cannot be adjusted.
- The decoder server requires both streams to be in the same payload or codec, otherwise the decoder cannot process the voice data. For example, if one channel is encoded by the G.711 codec and another is decoded by the G.729 codec, the decoding of the call fails.

You are here: Configuring Decoders > Changing Audio Gain Settings for the Decoder

## Changing Audio Gain Settings for the Decoder

If the volume of the MP3 files is too loud or too quiet, it is possible to change the gain that the decoder produces for new files.

The parameter for mp3 gain change is in decoders.xml in:

    <SpecifiedConfiguration name="decoders"> <EqualGroup name="decoder" egName="Decoder1"> <Group name="decoderSetting"> <Value name="mp3gainChange">0</Value>

If the value is not present then the default value is 0, this is a normal gain. One step in value equals + or - 1.5dB. To double the volume of the mp3 use a value of 4 (+ 6dB).The value can be between -128 and 127. Only new files are affected.

## Configuring the Decoder Server Communicator

Navigate to Settings > Configuration > Decoders > Decoder Servers Configuration.

Select or deselect file types in File type preference and Email type preference.

The Decoder Server Communicator settings specify the decoder registry address, for example, the RMI bind path, and determine the format for saving audio files and sending them via email. If the first format is unavailable, the second is used. Use the Up and Down buttons to change the order.

- mp3: The default storage format is mp3
- zip: Files are compressed into zip files (according to primary audio format)
  Note: ZIP cannot be selected as the primary format.
- wave: Files are put into uncompressed WAV audio format

If a format is deselected, this file type becomes unavailable.

The Store source files option is only for testing. If this option is selected, both raw and compressed recordings are stored on the decoder server, consuming a large amount of disk space.