AacUtil (ExoPlayer library)

java.lang.Object
- com.google.android.exoplayer2.audio.AacUtil

```
public final class AacUtil
extends Object
```
Utility methods for handling AAC audio streams.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static interface`	`AacUtil.AacAudioObjectType`	Valid AAC Audio object types.
`static class`	`AacUtil.Config`	Holds sample format information for AAC audio.

Field Summary

Fields
Modifier and Type	Field	Description
`static int`	`AAC_ELD_MAX_RATE_BYTES_PER_SECOND`	Maximum rate for an AAC ELD audio stream, in bytes per second.
`static int`	`AAC_HE_AUDIO_SAMPLE_COUNT`	Number of raw audio samples that are produced per channel when decoding an AAC HE access unit.
`static int`	`AAC_HE_V1_MAX_RATE_BYTES_PER_SECOND`	Maximum rate for an AAC HE V1 audio stream, in bytes per second.
`static int`	`AAC_HE_V2_MAX_RATE_BYTES_PER_SECOND`	Maximum rate for an AAC HE V2 audio stream, in bytes per second.
`static int`	`AAC_LC_AUDIO_SAMPLE_COUNT`	Number of raw audio samples that are produced per channel when decoding an AAC LC access unit.
`static int`	`AAC_LC_MAX_RATE_BYTES_PER_SECOND`	Maximum rate for an AAC LC audio stream, in bytes per second.
`static int`	`AAC_LD_AUDIO_SAMPLE_COUNT`	Number of raw audio samples that are produced per channel when decoding an AAC LD access unit.
`static int`	`AAC_XHE_AUDIO_SAMPLE_COUNT`	Number of raw audio samples that are produced per channel when decoding an AAC XHE access unit.
`static int`	`AAC_XHE_MAX_RATE_BYTES_PER_SECOND`	Maximum rate for an AAC XHE audio stream, in bytes per second.
`static int`	`AUDIO_OBJECT_TYPE_AAC_ELD`
`static int`	`AUDIO_OBJECT_TYPE_AAC_ER_BSAC`
`static int`	`AUDIO_OBJECT_TYPE_AAC_LC`
`static int`	`AUDIO_OBJECT_TYPE_AAC_PS`
`static int`	`AUDIO_OBJECT_TYPE_AAC_SBR`
`static int`	`AUDIO_OBJECT_TYPE_AAC_XHE`

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static byte[]`	`buildAacLcAudioSpecificConfig(int sampleRate, int channelCount)`	Builds a simple AAC LC AudioSpecificConfig, as defined in ISO 14496-3 1.6.2.1
`static byte[]`	`buildAudioSpecificConfig(int audioObjectType, int sampleRateIndex, int channelConfig)`	Builds a simple AudioSpecificConfig, as defined in ISO 14496-3 1.6.2.1
`static int`	`getEncodingForAudioObjectType(int audioObjectType)`	Returns the encoding for a given AAC audio object type.
`static AacUtil.Config`	`parseAudioSpecificConfig(byte[] audioSpecificConfig)`	Parses an AAC AudioSpecificConfig, as defined in ISO 14496-3 1.6.2.1
`static AacUtil.Config`	`parseAudioSpecificConfig(ParsableBitArray bitArray, boolean forceReadToEnd)`	Parses an AAC AudioSpecificConfig, as defined in ISO 14496-3 1.6.2.1

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - AAC_LC_AUDIO_SAMPLE_COUNT
```
public static final int AAC_LC_AUDIO_SAMPLE_COUNT
```
    Number of raw audio samples that are produced per channel when decoding an AAC LC access unit.
    
    See Also:
    
    Constant Field Values
  - AAC_XHE_AUDIO_SAMPLE_COUNT
```
public static final int AAC_XHE_AUDIO_SAMPLE_COUNT
```
    Number of raw audio samples that are produced per channel when decoding an AAC XHE access unit.
    
    See Also:
    
    Constant Field Values
  - AAC_HE_AUDIO_SAMPLE_COUNT
```
public static final int AAC_HE_AUDIO_SAMPLE_COUNT
```
    Number of raw audio samples that are produced per channel when decoding an AAC HE access unit.
    
    See Also:
    
    Constant Field Values
  - AAC_LD_AUDIO_SAMPLE_COUNT
```
public static final int AAC_LD_AUDIO_SAMPLE_COUNT
```
    Number of raw audio samples that are produced per channel when decoding an AAC LD access unit.
    
    See Also:
    
    Constant Field Values
  - AAC_LC_MAX_RATE_BYTES_PER_SECOND
```
public static final int AAC_LC_MAX_RATE_BYTES_PER_SECOND
```
    Maximum rate for an AAC LC audio stream, in bytes per second.
    
    See Also:
    
    Constant Field Values
  - AAC_HE_V1_MAX_RATE_BYTES_PER_SECOND
```
public static final int AAC_HE_V1_MAX_RATE_BYTES_PER_SECOND
```
    Maximum rate for an AAC HE V1 audio stream, in bytes per second.
    
    See Also:
    
    Constant Field Values
  - AAC_HE_V2_MAX_RATE_BYTES_PER_SECOND
```
public static final int AAC_HE_V2_MAX_RATE_BYTES_PER_SECOND
```
    Maximum rate for an AAC HE V2 audio stream, in bytes per second.
    
    See Also:
    
    Constant Field Values
  - AAC_XHE_MAX_RATE_BYTES_PER_SECOND
```
public static final int AAC_XHE_MAX_RATE_BYTES_PER_SECOND
```
    Maximum rate for an AAC XHE audio stream, in bytes per second.
    Fraunhofer documentation says "500 kbit/s and above" for stereo, so we use a rate generously above the 500 kbit/s level.
    
    See Also:
    
    Constant Field Values
  - AAC_ELD_MAX_RATE_BYTES_PER_SECOND
```
public static final int AAC_ELD_MAX_RATE_BYTES_PER_SECOND
```
    Maximum rate for an AAC ELD audio stream, in bytes per second.
    Fraunhofer documentation shows AAC-ELD as useful for up to ~ 64 kbit/s so we use this value.
    
    See Also:
    
    Constant Field Values
  - AUDIO_OBJECT_TYPE_AAC_LC
```
public static final int AUDIO_OBJECT_TYPE_AAC_LC
```
    See Also:
    
    Constant Field Values
  - AUDIO_OBJECT_TYPE_AAC_SBR
```
public static final int AUDIO_OBJECT_TYPE_AAC_SBR
```
    See Also:
    
    Constant Field Values
  - AUDIO_OBJECT_TYPE_AAC_ER_BSAC
```
public static final int AUDIO_OBJECT_TYPE_AAC_ER_BSAC
```
    See Also:
    
    Constant Field Values
  - AUDIO_OBJECT_TYPE_AAC_ELD
```
public static final int AUDIO_OBJECT_TYPE_AAC_ELD
```
    See Also:
    
    Constant Field Values
  - AUDIO_OBJECT_TYPE_AAC_PS
```
public static final int AUDIO_OBJECT_TYPE_AAC_PS
```
    See Also:
    
    Constant Field Values
  - AUDIO_OBJECT_TYPE_AAC_XHE
```
public static final int AUDIO_OBJECT_TYPE_AAC_XHE
```
    See Also:
    
    Constant Field Values
- Method Detail
  - parseAudioSpecificConfig
```
public static AacUtil.Config parseAudioSpecificConfig(byte[] audioSpecificConfig)
                                               throws ParserException
```
    Parses an AAC AudioSpecificConfig, as defined in ISO 14496-3 1.6.2.1
    
    Parameters:
    
    audioSpecificConfig - A byte array containing the AudioSpecificConfig to parse.
    
    Returns:
    
    The parsed configuration.
    
    Throws:
    
    ParserException - If the AudioSpecificConfig cannot be parsed because it is invalid or unsupported.
  - parseAudioSpecificConfig
```
public static AacUtil.Config parseAudioSpecificConfig(ParsableBitArray bitArray,
                                                      boolean forceReadToEnd)
                                               throws ParserException
```
    Parses an AAC AudioSpecificConfig, as defined in ISO 14496-3 1.6.2.1
    
    Parameters:
    
    bitArray - A ParsableBitArray containing the AudioSpecificConfig to parse. The position is advanced to the end of the AudioSpecificConfig.
    
    forceReadToEnd - Whether the entire AudioSpecificConfig should be read. Required for knowing the length of the configuration payload.
    
    Returns:
    
    The parsed configuration.
    
    Throws:
    
    ParserException - If the AudioSpecificConfig cannot be parsed because it is invalid or unsupported.
  - buildAacLcAudioSpecificConfig
```
public static byte[] buildAacLcAudioSpecificConfig(int sampleRate,
                                                   int channelCount)
```
    Builds a simple AAC LC AudioSpecificConfig, as defined in ISO 14496-3 1.6.2.1
    
    Parameters:
    
    sampleRate - The sample rate in Hz.
    
    channelCount - The channel count.
    
    Returns:
    
    The AudioSpecificConfig.
  - buildAudioSpecificConfig
```
public static byte[] buildAudioSpecificConfig(int audioObjectType,
                                              int sampleRateIndex,
                                              int channelConfig)
```
    Builds a simple AudioSpecificConfig, as defined in ISO 14496-3 1.6.2.1
    
    Parameters:
    
    audioObjectType - The audio object type.
    
    sampleRateIndex - The sample rate index.
    
    channelConfig - The channel configuration.
    
    Returns:
    
    The AudioSpecificConfig.
  - getEncodingForAudioObjectType
```
@Encoding
public static int getEncodingForAudioObjectType(@AacAudioObjectType
                                                int audioObjectType)
```
    Returns the encoding for a given AAC audio object type.

Class AacUtil

Nested Class Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

AAC_LC_AUDIO_SAMPLE_COUNT

AAC_XHE_AUDIO_SAMPLE_COUNT

AAC_HE_AUDIO_SAMPLE_COUNT

AAC_LD_AUDIO_SAMPLE_COUNT

AAC_LC_MAX_RATE_BYTES_PER_SECOND

AAC_HE_V1_MAX_RATE_BYTES_PER_SECOND

AAC_HE_V2_MAX_RATE_BYTES_PER_SECOND

AAC_XHE_MAX_RATE_BYTES_PER_SECOND

AAC_ELD_MAX_RATE_BYTES_PER_SECOND

AUDIO_OBJECT_TYPE_AAC_LC

AUDIO_OBJECT_TYPE_AAC_SBR

AUDIO_OBJECT_TYPE_AAC_ER_BSAC

AUDIO_OBJECT_TYPE_AAC_ELD

AUDIO_OBJECT_TYPE_AAC_PS

AUDIO_OBJECT_TYPE_AAC_XHE

Method Detail

parseAudioSpecificConfig

parseAudioSpecificConfig

buildAacLcAudioSpecificConfig

buildAudioSpecificConfig

getEncodingForAudioObjectType