Encoded (compressed) data in an encoded block format output by a data encoder, having an input including digital input elements from an input stream or file that are divided into blocks that contain Nb individual data elements per block. The encoded block format can include an index that, during decoding, supports random access. A decoder can losslessly decode the encoded block format. Each encoded block contains a header and a payload. The header specifies the unique characteristics of elements used by the payload to describe single-Byte or multi-Byte events that occurred in the input block. The encoded block format is generated by one or more block-oriented encoders (compressors). Blocks having the encoded block format may be consumed by one or more decoders (decompressors) that regenerate Nb elements from each decoded (uncompressed) block.