Ac3Util (ExoPlayer library)

java.lang.Object
- com.google.android.exoplayer2.audio.Ac3Util

```
public final class Ac3Util
extends Object
```
Utility methods for parsing Dolby TrueHD and (E-)AC-3 syncframes. (E-)AC-3 parsing follows the definition in ETSI TS 102 366 V1.4.1.

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class Ac3Util.SyncFrameInfo
Holds sample format information as presented by a syncframe header.

Nested Classes
Modifier and Type	Class	Description
`static class`	`Ac3Util.SyncFrameInfo`	Holds sample format information as presented by a syncframe header.

Field Summary

Fields
Modifier and Type	Field	Description
`static int`	`AC3_MAX_RATE_BYTES_PER_SECOND`	Maximum rate for an AC-3 audio stream, in bytes per second.
`static int`	`E_AC3_MAX_RATE_BYTES_PER_SECOND`	Maximum rate for an E-AC-3 audio stream, in bytes per second.
`static int`	`TRUEHD_MAX_RATE_BYTES_PER_SECOND`	Maximum rate for a TrueHD audio stream, in bytes per second.
`static int`	`TRUEHD_RECHUNK_SAMPLE_COUNT`	The number of samples to store in each output chunk when rechunking TrueHD streams.
`static int`	`TRUEHD_SYNCFRAME_PREFIX_LENGTH`	The number of bytes that must be parsed from a TrueHD syncframe to calculate the sample count.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static int`	`findTrueHdSyncframeOffset(ByteBuffer buffer)`	Returns the offset relative to the buffer's position of the start of a TrueHD syncframe, or `C.INDEX_UNSET` if no syncframe was found.
`static Format`	`parseAc3AnnexFFormat(ParsableByteArray data, String trackId, String language, DrmInitData drmInitData)`	Returns the AC-3 format given `data` containing the AC3SpecificBox according to Annex F.
`static int`	`parseAc3SyncframeAudioSampleCount(ByteBuffer buffer)`	Reads the number of audio samples represented by the given (E-)AC-3 syncframe.
`static Ac3Util.SyncFrameInfo`	`parseAc3SyncframeInfo(ParsableBitArray data)`	Returns (E-)AC-3 format information given `data` containing a syncframe.
`static int`	`parseAc3SyncframeSize(byte[] data)`	Returns the size in bytes of the given (E-)AC-3 syncframe.
`static Format`	`parseEAc3AnnexFFormat(ParsableByteArray data, String trackId, String language, DrmInitData drmInitData)`	Returns the E-AC-3 format given `data` containing the EC3SpecificBox according to Annex F.
`static int`	`parseTrueHdSyncframeAudioSampleCount(byte[] syncframe)`	Returns the number of audio samples represented by the given TrueHD syncframe, or 0 if the buffer is not the start of a syncframe.
`static int`	`parseTrueHdSyncframeAudioSampleCount(ByteBuffer buffer, int offset)`	Reads the number of audio samples represented by a TrueHD syncframe.

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

- Field Detail
  - AC3_MAX_RATE_BYTES_PER_SECOND
```
public static final int AC3_MAX_RATE_BYTES_PER_SECOND
```
    Maximum rate for an AC-3 audio stream, in bytes per second.
    
    See Also:
    
    Constant Field Values
  - E_AC3_MAX_RATE_BYTES_PER_SECOND
```
public static final int E_AC3_MAX_RATE_BYTES_PER_SECOND
```
    Maximum rate for an E-AC-3 audio stream, in bytes per second.
    
    See Also:
    
    Constant Field Values
  - TRUEHD_MAX_RATE_BYTES_PER_SECOND
```
public static final int TRUEHD_MAX_RATE_BYTES_PER_SECOND
```
    Maximum rate for a TrueHD audio stream, in bytes per second.
    
    See Also:
    
    Constant Field Values
  - TRUEHD_RECHUNK_SAMPLE_COUNT
```
public static final int TRUEHD_RECHUNK_SAMPLE_COUNT
```
    The number of samples to store in each output chunk when rechunking TrueHD streams. The number of samples extracted from the container corresponding to one syncframe must be an integer multiple of this value.
    
    See Also:
    
    Constant Field Values
  - TRUEHD_SYNCFRAME_PREFIX_LENGTH
```
public static final int TRUEHD_SYNCFRAME_PREFIX_LENGTH
```
    The number of bytes that must be parsed from a TrueHD syncframe to calculate the sample count.
    
    See Also:
    
    Constant Field Values
- Method Detail
  - parseAc3AnnexFFormat
```
public static Format parseAc3AnnexFFormat(ParsableByteArray data,
                                          String trackId,
                                          String language,
                                          @Nullable
                                          DrmInitData drmInitData)
```
    Returns the AC-3 format given data containing the AC3SpecificBox according to Annex F. The reading position of data will be modified.
    
    Parameters:
    
    data - The AC3SpecificBox 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-3 format parsed from data in the header.
  - parseEAc3AnnexFFormat
```
public static Format parseEAc3AnnexFFormat(ParsableByteArray data,
                                           String trackId,
                                           String language,
                                           @Nullable
                                           DrmInitData drmInitData)
```
    Returns the E-AC-3 format given data containing the EC3SpecificBox according to Annex F. The reading position of data will be modified.
    
    Parameters:
    
    data - The EC3SpecificBox 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 E-AC-3 format parsed from data in the header.
  - parseAc3SyncframeInfo
```
public static Ac3Util.SyncFrameInfo parseAc3SyncframeInfo(ParsableBitArray data)
```
    Returns (E-)AC-3 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 (E-)AC-3 format data parsed from the header.
  - parseAc3SyncframeSize
```
public static int parseAc3SyncframeSize(byte[] data)
```
    Returns the size in bytes of the given (E-)AC-3 syncframe.
    
    Parameters:
    
    data - The syncframe to parse.
    
    Returns:
    
    The syncframe size in bytes. C.LENGTH_UNSET if the input is invalid.
  - parseAc3SyncframeAudioSampleCount
```
public static int parseAc3SyncframeAudioSampleCount(ByteBuffer buffer)
```
    Reads the number of audio samples represented by the given (E-)AC-3 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.
  - findTrueHdSyncframeOffset
```
public static int findTrueHdSyncframeOffset(ByteBuffer buffer)
```
    Returns the offset relative to the buffer's position of the start of a TrueHD syncframe, or C.INDEX_UNSET if no syncframe was found. The buffer's position is not modified.
    
    Parameters:
    
    buffer - The ByteBuffer within which to find a syncframe.
    
    Returns:
    
    The offset relative to the buffer's position of the start of a TrueHD syncframe, or C.INDEX_UNSET if no syncframe was found.
  - parseTrueHdSyncframeAudioSampleCount
```
public static int parseTrueHdSyncframeAudioSampleCount(byte[] syncframe)
```
    Returns the number of audio samples represented by the given TrueHD syncframe, or 0 if the buffer is not the start of a syncframe.
    
    Parameters:
    
    syncframe - The bytes from which to read the syncframe. Must be at least TRUEHD_SYNCFRAME_PREFIX_LENGTH bytes long.
    
    Returns:
    
    The number of audio samples represented by the syncframe, or 0 if the buffer doesn't contain the start of a syncframe.
  - parseTrueHdSyncframeAudioSampleCount
```
public static int parseTrueHdSyncframeAudioSampleCount(ByteBuffer buffer,
                                                       int offset)
```
    Reads the number of audio samples represented by a TrueHD syncframe. The buffer's position is not modified.
    
    Parameters:
    
    buffer - The ByteBuffer from which to read the syncframe.
    
    offset - The offset of the start of the syncframe relative to the buffer's position.
    
    Returns:
    
    The number of audio samples represented by the syncframe.

Class Ac3Util

Nested Class Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

AC3_MAX_RATE_BYTES_PER_SECOND

E_AC3_MAX_RATE_BYTES_PER_SECOND

TRUEHD_MAX_RATE_BYTES_PER_SECOND

TRUEHD_RECHUNK_SAMPLE_COUNT

TRUEHD_SYNCFRAME_PREFIX_LENGTH

Method Detail

parseAc3AnnexFFormat

parseEAc3AnnexFFormat

parseAc3SyncframeInfo

parseAc3SyncframeSize

parseAc3SyncframeAudioSampleCount

findTrueHdSyncframeOffset

parseTrueHdSyncframeAudioSampleCount

parseTrueHdSyncframeAudioSampleCount