This version (21 Sep 2022 19:14) was approved by Ashwin PS.The Previously approved version (13 May 2021 06:23) is available.
Table of Contents
Click here to return to the ADI Algorithms page
Automatic Volume Control
Description
This algorithm is intended for TV sound applications. The perceived volume level often changes considerably from channel to channel, and also within a channel, especially for commercials. This algorithm will automatically compensate for the different levels.
Usage
This algorithm supports growing the input channels for 5.1/7.1 applications. However, the volume detection is calculated from the first 2 inputs only (left and right) and the resulting level compensation and delay is applied to all other channels.
Targets Supported
| Name | ADSP-214xx | ADSP-215xx/SC5xx | ADAU145x/146x |
|---|---|---|---|
| ————————————-- | ——————-- | ——————————-- | —————————- |
| AVC | NA | NA | S |
Pins
Input
| Name | Type | Description |
|---|---|---|
| ———————- | ————-- | ———————- |
| Input0 | Audio | First input channel |
| Input1 | Audio | Second input channel |
Output
| Name | Type | Description |
|---|---|---|
| —————————- | ————-- | ———————- |
| Output0 | Audio | First output channel |
| Output1 | Audio | Second output channel |
Configurable Parameters
| GUI Parameter | Default Value | Range | Function Description |
|---|---|---|---|
| —————————————- | ———————- | —————— | —————————————- |
| Enable | Off | On or Off | Turns the processing on and off. This is a bypass switch; changing its position will immediately affect the output signal |
| DecayRate | 4 sec | 0.02 - 12 | Controls the time to bring a low signal upward to the target level |
| MaxAttenuation | 18 | 11 - 18 | The maximum attenuation that will be applied to a loud signal as the algorithm attempts to maintain a target output level |
| OutputLevel | -18 | -18 - -3 | The target output level (in RMS) that the algorithm will try to maintain |
| MaxGain | 12 | 0 - 15 | The maximum gain that will be applied to a quiet signal as the algorithm attempts to maintain a target output level |
| FreezeLevel | -36 | -36 - -20 | The threshold below which the algorithm considers a signal to be “noise” that is not suitable for amplification. When the audio input goes below this level, the output gain will remain unchanged. This effectively lets the algorithm ignore background noise when the main signal of interest is not present. Note that, there is a slow 'Decay Rate' of 12 seconds for the envelope below the freeze level |
| SideChainFilter | B-Weighting Filter | Side chain filter selected |
DSP Parameters
| Parameter Name | Description | ADAU145x/146x |
|---|---|---|
| —————————————- | —————————————————————- | —————————————- |
| hp1_b1 | Filter Coefficient | 8.24 Format |
| hp1_b0 | Filter Coefficient | 8.24 Format |
| hp1_a1 | Filter Coefficient | 8.24 Format |
| hp2_b1 | Filter Coefficient | 8.24 Format |
| hp2_b0 | Filter Coefficient | 8.24 Format |
| hp2_a1 | Filter Coefficient | 8.24 Format |
| lp_b1 | Filter Coefficient | 8.24 Format |
| lp_b0 | Filter Coefficient | 8.24 Format |
| lp_a1 | Filter Coefficient | 8.24 Format |
| Decay | Decay coefficient | 8.24 Format |
| attack_rate | Attack coefficient | 8.24 Format Array |
| n10 | Integer | |
| nm1 | Integer | |
| Freeze | Freeze | 8.24 Format |
| Decay_Freeze | Freeze Decay | 8.24 Format |
| Output_Level_db | Output level | 8.24 Format |
| Max_Atten_db | Max attenuation | 8.24 Format |
| Max_Gain_db | Max gain | 8.24 Format |
| gain_target | Target gain | 8.24 Format |
| alpha | alpha | 8.24 Format |
| om_alpha | 1-alpha | 8.24 Format |
| smooth | Smoothing coefficient | 8.24 Format |
resources/tools-software/sigmastudiov2/modules/adialgorithms/avc.txt · Last modified: 21 Sep 2022 19:14 by Ashwin PS