@UnstableApi
public final class Av1ObuUtil

Utility methods for AV1 OBUs.

Summary

Public methods
static @Nullable byte[]

Extracts HAGC (ST 2094-50) metadata from the first valid HAGC ITU-T T.35 metadata OBU in the buffer.
static void

Rewrites all ITU-T T35 metadata OBUs from the buffer.
static void

Rewrites all ITU-T T35 metadata OBUs from the buffer that are not HDR10+.

Public methods

extractHagcMetadataAndStripAllT35Metadata

public static @Nullable byte[] extractHagcMetadataAndStripAllT35Metadata(ByteBuffer buffer)

Extracts HAGC (ST 2094-50) metadata from the first valid HAGC ITU-T T.35 metadata OBU in the buffer. If one is found, all ITU-T T.35 metadata OBUs in the buffer (including HAGC and HDR10+) are rewritten as unknown metadata OBUs so that the decoder does not prefer any in-band T.35 metadata over the returned HAGC metadata.

If no valid HAGC metadata OBU is found, buffer remains unchanged. In either case, the position() and limit() of buffer remain unchanged.

Parameters
ByteBuffer buffer

The ByteBuffer containing AV1 OBUs.
Returns
@Nullable byte[]

The HAGC payload without the ITU-T T.35 header and the AV1 OBU trailing bits ( 0x80 followed by any zero padding bytes), or null if no valid HAGC metadata OBU is found.

stripAllT35Metadata

public static void stripAllT35Metadata(ByteBuffer buffer)

Rewrites all ITU-T T35 metadata OBUs from the buffer. This is done to prevent the decoder from prioritizing in-band T.35 metadata (like HDR10+, Dolby Vision, etc.) over out-of-band metadata. If a T.35 metadata OBU is found, buffer will be rewritten with that metadata OBU marked as an unknown metadata OBU. If no T.35 metadata OBUs are found, buffer will remain unchanged. In either case, the position() and limit() of the buffer remain unchanged.

stripNonHdr10PlusT35Metadata

public static void stripNonHdr10PlusT35Metadata(ByteBuffer buffer)

Rewrites all ITU-T T35 metadata OBUs from the buffer that are not HDR10+. This is done to prevent the decoder on older SDK versions from misinterpreting them as HDR10+ metadata. If a non-HDR10+ metadata OBU is found, buffer will be rewritten with that metadata OBU marked as an unknown metadata OBU. If no non-HDR10+ metadata OBUs are found, buffer will remain unchanged. In either case, the position() and limit() of the buffer remain unchanged. This function is needed only when using MediaCodec on older SDK versions and is not necessary for other AV1 decoders.