Zarr Extensions

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Zstd codec ​

Defines a bytes -> bytes codec that applies zstd compression.

Codec name ​

The value of the name member in the codec object MUST be zstd.

Configuration parameters ​

level ​

An integer from -131072 to 22 which controls the speed and level of compression (has no impact on decoding). A value of 0 indicates to use the default compression level. Otherwise, a higher level is expected to achieve a higher compression ratio at the cost of lower speed.

checksum (Optional) ​

A boolean that indicates whether to store a checksum when writing that will be verified when reading. Should be omitted if false.

Example ​

For example, the array metadata below specifies that the compressor is the Zstd codec configured with a compression level of 1 and with the checksum stored:

json
{
    "codecs": [{
        "name": "zstd",
        "configuration": {
            "level": 1,
            "checksum": true
        }
    }],
}

Format and algorithm ​

This is a bytes -> bytes codec.

Encoded data should conform to the Zstandard file format RFC8878.

References ​

RFC8878 Y. Collet. Zstandard Compression and the 'application/zstd' Media Type. Februrary 2021. Informational. URL: https://tools.ietf.org/html/rfc8878

Change log ​

No changes yet.

Current maintainers ​

  • Jeremy Maitin-Shepard (@jbms), Google