Recording device and multiplexing method

A recording device comprising:

• a non-transitory computer readable media configured to store instructions;
• at least one processor operably coupled to the non-transitory computer readable media and configured to execute the instructions to:
• compress and then encode video data pieces by a first unit of data;
• compress and then encode audio data pieces in a second unit of data, a time length of the second unit of data being different from that of the first unit of data;
• and
• when a pair of record instructions made up of a record start instruction and a record stop instruction is repeatedly provided at time intervals, couple the respective video data pieces, which have been encoded, corresponding to a period from the record start instruction to the record stop instruction, and also multiplex the respective video data pieces with the audio data pieces, which have been encoded and which correspond to the respective video data pieces, as one piece of record data, wherein
• the encoding of audio data pieces continues at least from a first one of the record instruction until a last one of the record instruction,
• determine a leading edge of the audio data piece that has been shifted in time by an amount of offset, which has been accumulated, in such a way that, when a starting point of the encoded video data pieces corresponding to a focused record instruction is used as a first reference point, a difference between a starting point of the audio data piece encoded by the second unit of data of the leading edge of the encoded audio data pieces corresponding to the focused record instruction and the first reference point will become less than or equal to half of the time length of the second unit of data,
• determine a trailing edge of the audio data piece that has been shifted in time by the amount of offset, which has been accumulated, in such a way that, when an ending point of the encoded video data pieces corresponding to the focused record instruction is used as a second reference point, a difference between an ending point of the audio data piece encoded by the second unit of data of the trailing edge of the encoded audio data pieces corresponding to the focused record instruction and the second reference point will become less than or equal to the half of the time length of the second unit of data,
• an initial value of the amount of offset is a difference between a leading edge of the encoded video data pieces and a leading edge of the encoded audio data pieces at the time of starting a first record, every time the leading edge of the encoded audio data pieces corresponding to the focused record instruction is determined, a difference between a time length from a point corresponding to a first one of the record start instruction to the determined leading edge and a time length from the point corresponding to the first one of the record start instruction to the first reference point is added to the amount of offset, and every time the trailing edge of the encoded audio data pieces corresponding to the focused record instruction is determined, a difference between a time length from the point corresponding to the first one of the record start instruction to the determined trailing edge and a time length from the point corresponding to the first one of the record start instruction to the second reference point is added to the amount of offset, and
• select the audio data pieces by the second unit of data from the audio data pieces, which have been encoded, in such a way that an amount of temporal shift between the respective video data pieces and the audio data pieces, which have been encoded and which correspond to the respective video data pieces, will become less than or equal to the time length of the second unit of data and then multiplexes the selected audio data pieces with the video data pieces.