ILMAC3Encoder

This is the interface for the LEAD AC3 Encoder.

Data Types

LEncAC3_APILEVEL

typedef enum  
{ 
   LEncAC3_APILEVEL_1, 
} LEncAC3_APILEVEL; 

Lists the valid values for the ApiLevel parameter that can be passed to the ResetToDefaultsEx method.

Enumeration Description
LEncAC3_APILEVEL_1 Use the defaults from the current version of the codec.

eAC3OutputChannels

enum 
{ 
   LENCAC3_UNCHANGED = 0, 
   LENCAC3_FORCE_MONO = 1, 
   LENCAC3_FORCE_STEREO = 2, 
   LENCAC3_FORCE_6CHANNELS = 6 
} eAC3OutputChannels; 
Enumeration Description
LENCAC3_UNCHANGED The number of output channels equals the number of input channels.
LENCAC3_FORCE_MONO There is 1 output channel.
LENCAC3_FORCE_STEREO There are 2 output channels.
LENCAC3_FORCE_6CHANNELS There are 6 output channels.

Properties

Type Name Description
long OutputBitrate Sets the output bitrate of the compressed audio data. The bitrate is the average number of bits that one second of audio data will take up in the compressed bitstream. The bitrate represents the strength of compression. It also influences quality: the higher the bitrate, the higher the quality. The unit of measure for the bitrate is in kbps. To calculate the number of bytes per second of audio data, divide the bitrate value by eight. The following bitrate values are valid: 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384, 448, 512, 576, 640.
eAC3OutputChannels OutputChannelsFlag An enumeration that specifies the number of output channels.
BOOL SimulateSurround Enables or disables surround sound simulation. The following values are possible:
• TRUE - Enables surround sound simulation.
• FALSE - Disables surround sound simulation. This property is used only if the LENCAC3_FORCE_6CHANNELS eAC3OutputChannels value is selected.
long OutputSampleRate The output sample rate, in samples per second (Hz).The following values are possible: 32000, 44100, 48000.

Methods

HRESULT ResetToDefaultsEx(LEncAC3_APILEVEL ApiLevel);

Description

Resets the filter to default values.

Parameters

ApiLevel

Specifies which defaults should be used by the filter. Current applications should set ApiLevel to LEncAC3_APILEVEL_1 = 0.

Comments

The filter might change in the future and have different properties or default behavior. Calling this method ensures future versions of the filter will behave the same way as when the application was developed.

It is best to call ResetToDefaultsEx(LEncAC3_APILEVEL_1) before you start setting properties and start calling other methods for this interface.

Returns

Value Meaning
S_OK Successful
< 0 An error occurred.
E_INVALIDARG The ApiLevel parameter is invalid.

HRESULT ResetToDefaults();

Description

Resets the filter properties to their default values.

Comments

Calling this method can cause the filter to reconnect its output pin.

The default values are:

Property Default Value
ForceOutChannels LENCAC3_UNCHANGED
SimulateSurround FALSE
OutputBitrate 192
OutputSampleRate 0

Returns

Return Description
S_OK Successful
< 0 An error occurred.
VFW_E_WRONG_STATE The filter is in the wrong state.
Help Version 22.0.2022.6.24
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LEADTOOLS Filters C API Help

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© 1991-2022 LEAD Technologies, Inc. All Rights Reserved.