@UnstableApi
class Ac3Util

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.

Summary

Nested types

Holds sample format information as presented by a syncframe header.
@Documented
@Retention(value = RetentionPolicy.SOURCE)
@Target(value = TYPE_USE)
@IntDef(value = )
annotation Ac3Util.SyncFrameInfo.StreamType

AC3 stream types.

Constants
const Int

Maximum rate for an AC-3 audio stream, in bytes per second.
const Int

Maximum rate for an E-AC-3 audio stream, in bytes per second.
const Int

Maximum rate for a TrueHD audio stream, in bytes per second.
const Int

The number of samples to store in each output chunk when rechunking TrueHD streams.
const Int

The number of bytes that must be parsed from a TrueHD syncframe to calculate the sample count.

Public functions
java-static Int

Returns the offset relative to the buffer's position of the start of a TrueHD syncframe, or INDEX_UNSET if no syncframe was found.
java-static Format!
parseAc3AnnexFFormat(
    data: ParsableByteArray!,
    trackId: String!,
    language: String!,
    drmInitData: DrmInitData?
)

Returns the AC-3 format given data containing the AC3SpecificBox according to Annex F.
java-static Int

Reads the number of audio samples represented by the given (E-)AC-3 syncframe.
java-static Ac3Util.SyncFrameInfo!

Returns (E-)AC-3 format information given data containing a syncframe.
java-static Int

Returns the size in bytes of the given (E-)AC-3 syncframe.
java-static Format!
parseEAc3AnnexFFormat(
    data: ParsableByteArray!,
    trackId: String!,
    language: String!,
    drmInitData: DrmInitData?
)

Returns the E-AC-3 format given data containing the EC3SpecificBox according to Annex F.
java-static Int

Returns the number of audio samples represented by the given TrueHD syncframe, or 0 if the buffer is not the start of a syncframe.
java-static Int

Reads the number of audio samples represented by a TrueHD syncframe.

Constants

AC3_MAX_RATE_BYTES_PER_SECOND

const val AC3_MAX_RATE_BYTES_PER_SECOND = 80000: Int

Maximum rate for an AC-3 audio stream, in bytes per second.

E_AC3_MAX_RATE_BYTES_PER_SECOND

const val E_AC3_MAX_RATE_BYTES_PER_SECOND = 768000: Int

Maximum rate for an E-AC-3 audio stream, in bytes per second.

TRUEHD_MAX_RATE_BYTES_PER_SECOND

const val TRUEHD_MAX_RATE_BYTES_PER_SECOND = 3062500: Int

Maximum rate for a TrueHD audio stream, in bytes per second.

TRUEHD_RECHUNK_SAMPLE_COUNT

const val TRUEHD_RECHUNK_SAMPLE_COUNT = 16: Int

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.

TRUEHD_SYNCFRAME_PREFIX_LENGTH

const val TRUEHD_SYNCFRAME_PREFIX_LENGTH = 10: Int

The number of bytes that must be parsed from a TrueHD syncframe to calculate the sample count.

Public functions

findTrueHdSyncframeOffset

java-static fun findTrueHdSyncframeOffset(buffer: ByteBuffer!): Int

Returns the offset relative to the buffer's position of the start of a TrueHD syncframe, or INDEX_UNSET if no syncframe was found. The buffer's position is not modified.

Parameters
buffer: ByteBuffer!

The ByteBuffer within which to find a syncframe.
Returns
Int

The offset relative to the buffer's position of the start of a TrueHD syncframe, or INDEX_UNSET if no syncframe was found.

parseAc3AnnexFFormat

java-static fun parseAc3AnnexFFormat(
    data: ParsableByteArray!,
    trackId: String!,
    language: String!,
    drmInitData: DrmInitData?
): Format!

Returns the AC-3 format given data containing the AC3SpecificBox according to Annex F. The reading position of data will be modified.

Parameters
data: ParsableByteArray!

The AC3SpecificBox to parse.
trackId: String!

The track identifier to set on the format.
language: String!

The language to set on the format.
drmInitData: DrmInitData?

DrmInitData to be included in the format.
Returns
Format!

The AC-3 format parsed from data in the header.

parseAc3SyncframeAudioSampleCount

java-static fun parseAc3SyncframeAudioSampleCount(buffer: ByteBuffer!): Int

Reads the number of audio samples represented by the given (E-)AC-3 syncframe. The buffer's position is not modified.

Parameters
buffer: ByteBuffer!

The ByteBuffer from which to read the syncframe.
Returns
Int

The number of audio samples represented by the syncframe.

parseAc3SyncframeInfo

java-static fun parseAc3SyncframeInfo(data: ParsableBitArray!): Ac3Util.SyncFrameInfo!

Returns (E-)AC-3 format information given data containing a syncframe. The reading position of data will be modified.

Parameters
data: ParsableBitArray!

The data to parse, positioned at the start of the syncframe.
Returns
Ac3Util.SyncFrameInfo!

The (E-)AC-3 format data parsed from the header.

parseAc3SyncframeSize

java-static fun parseAc3SyncframeSize(data: ByteArray!): Int

Returns the size in bytes of the given (E-)AC-3 syncframe.

Parameters
data: ByteArray!

The syncframe to parse.
Returns
Int

The syncframe size in bytes. LENGTH_UNSET if the input is invalid.

parseEAc3AnnexFFormat

java-static fun parseEAc3AnnexFFormat(
    data: ParsableByteArray!,
    trackId: String!,
    language: String!,
    drmInitData: DrmInitData?
): Format!

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: ParsableByteArray!

The EC3SpecificBox to parse.
trackId: String!

The track identifier to set on the format.
language: String!

The language to set on the format.
drmInitData: DrmInitData?

DrmInitData to be included in the format.
Returns
Format!

The E-AC-3 format parsed from data in the header.

parseTrueHdSyncframeAudioSampleCount

java-static fun parseTrueHdSyncframeAudioSampleCount(syncframe: ByteArray!): Int

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: ByteArray!

The bytes from which to read the syncframe. Must be at least TRUEHD_SYNCFRAME_PREFIX_LENGTH bytes long.
Returns
Int

The number of audio samples represented by the syncframe, or 0 if the buffer doesn't contain the start of a syncframe.

parseTrueHdSyncframeAudioSampleCount

java-static fun parseTrueHdSyncframeAudioSampleCount(buffer: ByteBuffer!, offset: Int): Int

Reads the number of audio samples represented by a TrueHD syncframe. The buffer's position is not modified.

Parameters
buffer: ByteBuffer!

The ByteBuffer from which to read the syncframe.
offset: Int

The offset of the start of the syncframe relative to the buffer's position.
Returns
Int

The number of audio samples represented by the syncframe.