Video encoding method and device and video decoding method and device for parallel processing

A video decoding apparatus comprising:

• a parser configured to obtain, from a first data unit header including encoding information of a first data unit of an upper level that constitutes a video and is included in a bitstream, a parallel processing syntax indicating a parallel processing type that is applied to a second data unit of a lower level that is included in the first data unit from among a plurality of parallel processing types, and to obtain, from a second data unit header including encoding information of the second data unit based on the obtained parallel processing syntax, a parallel processing flag indicating whether the parallel processing type indicated by the parallel processing syntax from among the plurality of parallel processing types is applied to the second data unit;
• and
• a parallel processing determiner configured to determine whether the parallel processing type indicated by the parallel processing syntax is applied to the second data unit based on the obtained parallel processing flag.

A video encoding apparatus comprising:

• a parallel processing determiner configured to that obtain encoded data of a first data unit that constitutes a video and a second data unit of a level lower than a level of the first data unit, and to determine a parallel processing type that is applied to the second data unit from among a plurality of parallel processing types;
• and
• a parallel processing information output unit configured to encode parallel processing syntax information indicating the parallel processing type that is applied to the second data unit in a first data unit header including encoding information of the first data unit, and to encode a parallel processing flag indicating whether the parallel processing type indicated by the parallel processing syntax is applied to the second data unit in a second data unit header including encoding information of the second data unit.