Settings for Deltacast HD Mixed Output

Video settings

The Deltacast playout module supports the creation of Genlock. GenLock (short for generator lock) is a common technique, where the video output of one source, or a specific reference signal, is used to synchronize other television picture sources together.

Press the Genlock button in the video settings window to open the GenLock settings dialog.

Here you can define a Source Genlock and Offset of Horizontal and Vertical resolution.

The Genlock sources could be Local (generated internally from the Deltacast HD card) or Blackburst (coming from an external source, connected to the black burst port of the card).

The Offset is defined in pixels.

 

Audio settings

The Deltacast playout module supports Dolby Digital audio output type.

The Dolby Digital functionality is being provided by SurCode for Dolby Digital. SurCode for Dolby Digital and is manufactured under a license from Dolby Laboratories. SurCode is a trademark of Minnetonka Audio Software.

Select a Dolby Digital as an Audio Output type in the audio-stream settings window, and then press Output settings button to open the SurCode for Dolby Digital window.

Below, there is a description of SurCode windows as per SurCode user’s guides.

 

Main settings

Audio Services

Audio Coding Mode – from this pull-down window, you can select the  input mode - mono, stereo, or surround input;

Data Rate -it indicates/sets the sound file sample rate.

Bitstream Mode

The Bitstream Mode parameter indicates the type of audio service that the bitstream conveys. Complete Main (CM) is the normal mode of operation and contains a complete audio program including dialog, music, and effects. The CM and ME Main Services can be further enhanced by means of Associated Services.

The Bitstream Modes and audio service types are:

Main Service: Complete Main (CM)

Main Service: Music and Effects (ME)

Associated Service: Visually-Impaired (VI)

Associated Service: Hearing-Impaired (HI)

Associated Service: Dialog (D)

Associated Service: Commentary (C)

Associated Service: Emergency (E)

Associated Service: Voice Over (VO) / Karaoke

4-29

Dialog Normalization (dialnorm)

The Dialog Normalization (dialnorm) value indicates how far the average dialog level of the encoded program is below digital 100% full scale (0 dBFS). Valid settings are 1 dB to -31 dB. This parameter determines the audio reproduction level and affects other parameters and decoder operation.

Bitstream Information

The parameters in this group directly relate to the Dolby Digital Bitstream

Information (BSI) fields.

Center Downmix Level

The Center Downmix Level parameter indicates the nominal Lo/Ro downmix level of the Center channel with respect to the Left and Right channels. This parameter setting does not affect Lt/Rt downmixes.

This parameter appears in the bitstream only when three front channels are in use, i.e., only when the Audio Coding Mode is set to 3/0, 3/1, or 3/2

Surround Downmix Level

The Surround Downmix Level parameter indicates the nominal Lo/Ro downmix level of the Surround channel(s) with respect to the Left and Right channels (consistent with the ITU BR specification). This parameter setting does not affect Lt/Rt downmixes.

This parameter appears in the bitstream only when a Surround channel is in use, i.e., only when the Audio Coding Mode is set to 2/1, 2/2, 3/1, or 3/2. It is recommended that the parameter be user-adjustable only when one of these modes has been selected.

Audio Production Information Exists

The Audio Production Information Exists flag indicates whether the Mixing Level and Room Type parameters explained below exist within the Dolby Digital bitstream.

Room Type

The Room Type informational parameter indicates the type and calibration of the mixing room used for the final audio mixing session. The Room Type value is not normally used within the Dolby Digital decoder but can be used by other elements in the audio system. This parameter appears in the bitstream only when the Audio Production Information Exists parameter is set to 1, or yes.

Valid values for Room Type: Large room; Small room; Not indicated

Mixing Level

The Mixing Level informational parameter indicates the absolute Sound Pressure Level (SPL) of the audio program as heard by the original mixing engineer. This information makes it possible to replay the program at exactly the same loudness, or at a known difference in loudness. By knowing how much lower a program is played at home, for example, it is now possible to apply the correct degree of loudness compensation.

The value for Mixing Level represents the theoretical loudness of a full-scale (0 dBFS) tone in one channel.

Copyright Exists

The Copyright Bit informational parameter sets the value of a single bit within the Dolby Digital bitstream. If this bit has a value of 1 (the check-box is checked), the information in the bitstream is indicated as protected by copyright. If it has a value of 0 (the check-box is not checked), the information is not copyright protected.

Original Bitstream

The Original Bitstream informational parameter sets the value of a single bit within the Dolby Digital bitstream. This bit has a value of 1 (the check-box is checked) if the bitstream is an original. If it is a copy of an original bitstream, it has a value of 0 (the check-box is not checked).

 

Advanced settings

LFE Lowpass Filter

The LFE Lowpass Filter parameter can be used to activate a 120 Hz low-pass filter applied to the LFE input channel. If the digital signal fed to the LFE input does not contain information above 120 Hz, this filter can be disabled. This parameter is user adjustable only when the LFE channel is enabled.

Channel Bandwidth Lowpass Filter

The Channel Bandwidth Lowpass Filter parameter can be used to activate a low-pass filter with a cut-off near the specified audio bandwidth that is applied to the main input channels. If the digital signal fed to the main input channels does not contain information above the specified audio bandwidth, this filter can be disabled.4-37

DC Highpass Filter

This parameter can be used to activate the DC Highpass filter for all input channels. The DC Highpass filter should always be enabled unless the encoding engineer is absolutely sure that there is no DC in the input audio.

Surround Channel 90-Degree Phase-Shift

The Surround Channel 90-Degree Phase-Shift feature is useful for generating multichannel Dolby Digital bitstreams that can be downmixed in an external two-channel decoder to create a true Dolby Surround compatible output. This parameter is user-adjustable only when Surround channels are present in the bitstream, i.e., only when Audio Coding Mode is set to 2/1, 2/2, 3/1, or 3/2. The 90-Degree Phase-Shift parameter should always be left enabled except under specific conditions. These include, but are not necessarily limited to, system calibration, encoding of certain test signals, and in the extremely rare case when the discrete playback of highly coherent program material may be compromised.

Surround Channel 3 dB Attenuation

The Surround Channel 3 dB Attenuation function is useful for applying a 3 dB attenuation to the Surround channels of a multichannel soundtrack created in a room with film style calibration, when encoding it for consumer home theater playback. Cinema soundtrack Surround channels are mixed +3 dB relative to the front channels in order to account for cinema calibration standards. Home theater Surround channel gains are calibrated differently, and so a -3 dB adjustment to the Surround tracks is necessary. This parameter is user-adjustable only when Surround channels are present in the bitstream, i.e., only when Audio Coding Mode is set to 2/1, 2/2, 3/1, or 3/2.

RF Overmodulation Protection (RF Pre-emphasis Filter)

The RF Overmodulation Protection parameter determines whether or not an RF preemphasis filter is used in the overload protection algorithm to prevent RF overmodulation in set-top box decoders. It is primarily used for broadcast applications.

Dolby Surround Mode

Digital De-emphasis

Dolby Digital encoders can allow activation of digital de-emphasis applied to the linear PCM input signals whenever it is detected that the input has been preemphasized. Detection is typically achieved by monitoring the pre-emphasis flags within the channel status data of the incoming digital audio signal (e.g., AES/EBU or S/PDIF). Since the value of this parameter depends on some other parameter(s) or condition(s), it does not require explicit user control and can be adjusted automatically by the encoder.