Audio Level: Configuration & Usage
From AVObjects Knowledge Base
Brief description of the Audio Level DirectShow filter capabilities. Interface IMLAudioLevel can be found in file <filter installation directory>\Idl\ALevel.idl
Configuration & Usage
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Number of channels
The number of channels in the connected audio stream can be obtained using the IMLAudioLevel::GetChannels() function. Maximum possible number of channels: 32.
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VU-meter
The current sound level in dB for the specified channel can be get using IMLAudioLevel::GetLevel() method.
VU-meter properties (attack and release time in ms) are set using methods IMLAudioLevel::SetAttackTime() and SetReleaseTime().
The attack (rise) time is the time to reach an amplitude of 90% (-2dB) for a step signal of 0 -> 1, and the release (fall) time is an amplitude of 10% (-20dB) for a step signal of 1 -> 0.
If the VU-meter is not needed, then its operation can be disabled using the IMLAudioLevel::EnableProcessing() method.
