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MediaFormat.KeyAacDrcTargetReferenceLevel Field

Definition

A key describing the Target Reference Level (Target Loudness).

[Android.Runtime.Register("KEY_AAC_DRC_TARGET_REFERENCE_LEVEL")]
public const string KeyAacDrcTargetReferenceLevel;
[<Android.Runtime.Register("KEY_AAC_DRC_TARGET_REFERENCE_LEVEL")>]
val mutable KeyAacDrcTargetReferenceLevel : string

Field Value

Attributes

Remarks

A key describing the Target Reference Level (Target Loudness).

For normalizing loudness across program items, a gain is applied to the audio output so that the output loudness matches the Target Reference Level. The gain is derived as the difference between the Target Reference Level and the Program Reference Level (Program Loudness). The latter can be given in the bitstream and indicates the actual loudness value of the program item.

The Target Reference Level controls loudness normalization for both MPEG-4 DRC and MPEG-D DRC.

The value is given as an integer value between 40 and 127, and is calculated as -4 * Target Reference Level in LKFS. Therefore, it represents the range of -10 to -31.75 LKFS.

For MPEG-4 DRC, a value of -1 switches off loudness normalization and DRC processing.

For MPEG-D DRC, a value of -1 switches off loudness normalization only. For DRC processing options of MPEG-D DRC, see #KEY_AAC_DRC_EFFECT_TYPE

The default value on mobile devices is 64 (-16 LKFS).

This key is only used during decoding.

Java documentation for android.media.MediaFormat.KEY_AAC_DRC_TARGET_REFERENCE_LEVEL.

Portions of this page are modifications based on work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.

Applies to