Ac4Util (ExoPlayer library)

java.lang.Object
- com.google.android.exoplayer2.audio.Ac4Util

```
public final class Ac4Util
extends Object
```
Utility methods for parsing AC-4 frames, which are access units in AC-4 bitstreams.

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class Ac4Util.SyncFrameInfo
Holds sample format information as presented by a syncframe header.

Nested Classes
Modifier and Type	Class	Description
`static class`	`Ac4Util.SyncFrameInfo`	Holds sample format information as presented by a syncframe header.

Field Summary

Fields
Modifier and Type	Field	Description
`static int`	`AC40_SYNCWORD`
`static int`	`AC41_SYNCWORD`
`static int`	`HEADER_SIZE_FOR_PARSER`	The header size for AC-4 parser.
`static int`	`MAX_RATE_BYTES_PER_SECOND`	Maximum rate for an AC-4 audio stream, in bytes per second.
`static int`	`SAMPLE_HEADER_SIZE`	The AC-4 sync frame header size for extractor.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static void`	`getAc4SampleHeader(int size, ParsableByteArray buffer)`	Populates `buffer` with an AC-4 sample header for a sample of the specified size.
`static Format`	`parseAc4AnnexEFormat(ParsableByteArray data, String trackId, String language, DrmInitData drmInitData)`	Returns the AC-4 format given `data` containing the AC4SpecificBox according to ETSI TS 103 190-1 Annex E.
`static int`	`parseAc4SyncframeAudioSampleCount(ByteBuffer buffer)`	Reads the number of audio samples represented by the given AC-4 syncframe.
`static Ac4Util.SyncFrameInfo`	`parseAc4SyncframeInfo(ParsableBitArray data)`	Returns AC-4 format information given `data` containing a syncframe.
`static int`	`parseAc4SyncframeSize(byte[] data, int syncword)`	Returns the size in bytes of the given AC-4 syncframe.

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

- Field Detail
  - AC40_SYNCWORD
```
public static final int AC40_SYNCWORD
```
    See Also:
    
    Constant Field Values
  - AC41_SYNCWORD
```
public static final int AC41_SYNCWORD
```
    See Also:
    
    Constant Field Values
  - MAX_RATE_BYTES_PER_SECOND
```
public static final int MAX_RATE_BYTES_PER_SECOND
```
    Maximum rate for an AC-4 audio stream, in bytes per second.
    
    See Also:
    
    Constant Field Values
  - SAMPLE_HEADER_SIZE
```
public static final int SAMPLE_HEADER_SIZE
```
    The AC-4 sync frame header size for extractor. The seven bytes are 0xAC, 0x40, 0xFF, 0xFF, sizeByte1, sizeByte2, sizeByte3. See ETSI TS 103 190-1 V1.3.1, Annex G
    
    See Also:
    
    Constant Field Values
  - HEADER_SIZE_FOR_PARSER
```
public static final int HEADER_SIZE_FOR_PARSER
```
    The header size for AC-4 parser. Only needs to be as big as we need to read, not the full header size.
    
    See Also:
    
    Constant Field Values
- Method Detail
  - parseAc4AnnexEFormat
```
public static Format parseAc4AnnexEFormat(ParsableByteArray data,
                                          String trackId,
                                          String language,
                                          @Nullable
                                          DrmInitData drmInitData)
```
    Returns the AC-4 format given data containing the AC4SpecificBox according to ETSI TS 103 190-1 Annex E. The reading position of data will be modified.
    
    Parameters:
    
    data - The AC4SpecificBox to parse.
    
    trackId - The track identifier to set on the format.
    
    language - The language to set on the format.
    
    drmInitData - DrmInitData to be included in the format.
    
    Returns:
    
    The AC-4 format parsed from data in the header.
  - parseAc4SyncframeInfo
```
public static Ac4Util.SyncFrameInfo parseAc4SyncframeInfo(ParsableBitArray data)
```
    Returns AC-4 format information given data containing a syncframe. The reading position of data will be modified.
    
    Parameters:
    
    data - The data to parse, positioned at the start of the syncframe.
    
    Returns:
    
    The AC-4 format data parsed from the header.
  - parseAc4SyncframeSize
```
public static int parseAc4SyncframeSize(byte[] data,
                                        int syncword)
```
    Returns the size in bytes of the given AC-4 syncframe.
    
    Parameters:
    
    data - The syncframe to parse.
    
    syncword - The syncword value for the syncframe.
    
    Returns:
    
    The syncframe size in bytes, or C.LENGTH_UNSET if the input is invalid.
  - parseAc4SyncframeAudioSampleCount
```
public static int parseAc4SyncframeAudioSampleCount(ByteBuffer buffer)
```
    Reads the number of audio samples represented by the given AC-4 syncframe. The buffer's position is not modified.
    
    Parameters:
    
    buffer - The ByteBuffer from which to read the syncframe.
    
    Returns:
    
    The number of audio samples represented by the syncframe.
  - getAc4SampleHeader
```
public static void getAc4SampleHeader(int size,
                                      ParsableByteArray buffer)
```
    Populates buffer with an AC-4 sample header for a sample of the specified size.

Class Ac4Util

Nested Class Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

AC40_SYNCWORD

AC41_SYNCWORD

MAX_RATE_BYTES_PER_SECOND

SAMPLE_HEADER_SIZE

HEADER_SIZE_FOR_PARSER

Method Detail

parseAc4AnnexEFormat

parseAc4SyncframeInfo

parseAc4SyncframeSize

parseAc4SyncframeAudioSampleCount

getAc4SampleHeader