Digital signal recording apparatus and a digital signal reproducing apparatus

A digital signal recording apparatus comprising:

• a level encoding means for encoding a digital signal into first to N-th level data;
• a buffer memory means for storing the first to N-th level data;
• a memory means having a data storage area which is writable for the first to N-th level data and an auxiliary information storage area;
• a data amount calculating means for calculating the total amount of the first to N-th level data stored in the buffer memory means;
• and
• a write control means for comparing the total amount of the first to N-th level data with a capacity of the data storage area, for selecting data from the first to N-th level data stored in the buffer memory means according to the comparison result, and for storing the selected data into the data storage area and auxiliary information associated with the selected data into the auxiliary information storage area.

A digital signal reproducing apparatus comprising:

• a memory means having a data storage area for storing level data and an auxiliary information storage area for storing auxiliary information indicating the attributes of the level data stored in the data storage area;
• a read control means for reading the level data stored in the data storage area and the auxiliary information stored in the auxiliary information storage area, and for specifying which level is missing in the data storage area, based on the auxiliary information;
• and
• a level decoding means for decoding the level data into a digital signal,
• wherein the level decoding means assigns a predetermined value to data of the specified missing level in accordance with a predetermined rule.

A digital signal recording and reproduction system, comprising:

• (1) digital signal recording apparatus comprising:
• level encoding means for encoding a digital signal into first to N-th level data, N being an integer greater than 1,
• memory means having a data storage area and an auxiliary information storage area, the data storage area being writable for the first to N-th level data, and
• write control means for, when writable area in the data storage area is exhausted, freeing at least a part of an area in the data storage area in which level data other than the first level data are stored, for storing level data including at least the first level data into the freed area in the data storage area, and for storing auxiliary information indicating attributes of the stored level data into the auxiliary information storage area;
• and
• (2) digital signal reproducing apparatus comprising:
• read control means for reading the level data stored in the data storage area and the auxiliary information stored in the auxiliary information storage area, and for specifying which level is missing in the data storage area, based on the auxiliary information, and
• level decoding means for decoding the level data into a digital signal,
• wherein the level decoding means assigns a predetermined value to data of the specified missing level in accordance with a predetermined rule.