Zarr Extensions

Appearance

Bytes data type ​

Defines a data type for variable-length byte strings.

Fill value encoding ​

The value of the fill_value metadata key must be one of:

  • an array of integers from the closed interval [0, 255], where each value encodes a byte from a byte string.
  • a string produced by applying base64 encoding to a byte string.

As the string form is more compact, it may be preferred where brevity is desired.

Examples ​

Array fill value encoding ​

The example below shows a fragment of an array metadata document using the bytes data type. The fill value is the byte string 0x01 0x02 0x03 encoded as an array of integers:

json
{
    "data_type": "bytes",
    "fill_value": [1, 2, 3],
    "codecs": [{
        "name": "vlen-bytes"
    }],
}

String fill value encoding ​

The example below shows a fragment of an array metadata document using the bytes data type. The fill value is the byte string 0x01 0x02 0x03 encoded as a string using base64:

json
{
    "data_type": "bytes",
    "fill_value": "AQID",
    "codecs": [{
        "name": "vlen-bytes"
    }],
}

Codec compatibility ​

This data type is compatible with any codec that can encode variable-length sequences of bytes. For example, the "vlen-bytes" codec.

Change log ​

  • Addition of the string-based fill value encoding.

Current maintainers ​