Audio (General) Tab


Here you can define some settings for the audio output.

DTMF settings

          Here you can define an output DTMF signal to be generated by the X-Pert Playout application. Press the DTMF settings button to open the DTMF set-up window.

Output settings: Here you can define the parameters of the DTMF tone – Frequency, Bits per sample, number of Mono Channels, and Channels Mask.

Depending on the Channels Mask, the DTMF tone is sent to a specific audio channel. If Channels Mask is zero (0), the DTMF is not sent. If it is one (1), DTMF is sent to the 1st mono channel. If it is two (2), DTMF is sent to the 2nd mono channel.

Length of the standard Symbol in DTMF sequence – numbers from 0 to 9 and letters A, B, C, D

Pause Length – length of the pause between symbols

Specific Symbols Length – Specific symbols are all symbols in the DTMF strings, different from numbers from 0 to 9, and letters A, B, C, D

Signal Level % – the signal level in percent

Working Mode here you can set the DTMF to either be Mixed with the output audio, or to Replace the output audio.


The Normalization field

This new functionality is developed in accordance with EBU Rec. R 128. It is designed for our clients to benefit from the following:

Performing monitoring and control over the perceived loudness of audio sources.

Reducing the loudness differences between programmes. This is applicable when the nature and content of audio matherial(s) changes frequently. For example, such a problem most commonly occurs at the breaks for advertising, when there is a jump between audio levels.

X-Pert Playout performs the audio normalization by using a loudness metadata that describes how loud each program is. The loudness metadata is provided by the X-Pert Quality Check tool.

X-Pert Quality Check performs quality control tests of the media content. After that it stores the test results as metadata into a file with extension *.mtd. Such an *.mtd file is generated separately for each media file tested.

Based on the metadata, provided by X-Pert Quality Check for each media file, X-Pert Playout will adjust the audio levels of all media sources separately.

IMPORTANT: X-Pert Playout does not process the audio by applying any permanent modification of the source content (such as compression, peak limits, EQ). It just changes the audio during playout by adjusting the audio levels.

A basic explanation of the workflow of the entire process is described below:

Loading the playlist

Accessing the *.mtd files, which correspond to the content and are created by the X-Pert Quality Check tool for reference

Reading the Program Loudness values, described for each *.mtd file. Program Loudness refers to the average loudness of a program.

Based on that, X-Pert Playout performs a correction of the audio, in order to reach the referent -23/-24 LUFS. This value is configurable through the output settings, provided into this window, as follows:

Tick the  Enabled check-box in order to activate the normalizing process.
When normalizing, the operations, described below will follow:

Performing a level shifting

X-Pert Playout does not perform any processing of the source sound internally. It normalizes the loudness of the whole program (file-based playout channel) by the means of level adjusting. For example, if there is a source file with average program loudness of -32 dBFS, it will be increased with 9 dB in order to reach the referent -23 dBFS, specified in the X-Pert Playout output adjustments.

Keeping track
of the Maximum True Peak level of the audio. If the maximum peak level exceeds zero dB, there will be a clipping introduced. Therefore, if the maximum true peak level exceeds the value, specified in the X-Pert PlayoutOutput -> Settings, X-Pert Playout assumes that the source is not prepared in a good manner by the sound engineer. In such a case X-Pert Playout will not reproduce the relevant media source.

Let us follow the latter example with the source media file, having average program loudness of -32 dBFS. If the maximum true peak level of this file is -8 dB, when increased with 9 dB the peak will jump to 1 (above zero). As mentioned above, exceeding the zero may introduce clipping or other audible distortions, and exceeding the Max TPL value, specified for the X-Pert Playout output settings (it is recommended for this value to be -1 dB), will cause skipping of the source’s playback.

A value of -23 dBFS corresponds to the Referent Zero Level (by default). This is a target level, according to which the program loudness levels should be normalized, as recommended in EBU Tech. Rec. R 128. There is a tolerance of 1.0 LU, which exists for programs, where an exact normalization is not achievable in practice.

For the Max True Peak dBFS string you should indicate the maximum TPL allowed. According to EBU R 128, it is -1dBTP (measured with a True Peak meter).