Package com.google.android.exoplayer2.audio

Class Ac4Util

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

    • Field Detail

      • 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.