Encoded digital audio reproducing apparatus

An encoded digital audio reproducing apparatus comprising:

• a reading control portion which reads from a recording medium an encoded audio file having a data part including audio data as a sequence of frames and a size part including size information on each of the frames;
• a table generating portion which receives the size information on each of the frames, or a size of the audio data and a number of the frames, from the reading control portion, calculates an average frame size, calculates a difference size between the size of each of the frames and the average frame size, and generates a table holding the difference size calculated as to each of the frames;
• a decoding portion which receives the audio data from the reading control portion and sequentially decodes the audio data from a leading frame to output the decoded audio data;
• a reproducing portion which reproduces the decoded audio data;
• and
• a reproduction start position calculating portion which, in the case where a reproduction request from an arbitrary frame in the audio data is inputted, reads from the table the difference size of each of frames from the leading frame in the audio data to the frame immediately preceding the arbitrary frame, totals the read difference sizes, multiplies the average frame size by the number of frames whose difference sizes are read, and adds a total of the difference sizes to a result of the multiplication so as to decide a reproduction start frame for starting reproduction, wherein
• the decoding portion requests the reading control portion to read frames from the reproduction start frame from the recording medium.

An encoded digital audio reproducing apparatus comprising:

• a reading control portion which reads from a recording medium an encoded audio file having a data part including audio data as a sequence of frames and a size part including size information on each of the frames;
• a table generating portion which receives the size information on each of the frames, or a size of the audio data and a number of the frames, from the reading control portion, calculates an average frame size, calculates as to each of the frames an offset size that is a total size from a leading frame to a immediately preceding frame, calculates as to each of the frames a difference size between a result of multiplying the number of frames from the leading frame to the immediately preceding frame by the average frame size and the offset size corresponding the frame, and generates a table holding the difference size calculated as to each of the frames;
• a decoding portion which receives the audio data from the reading control portion and sequentially decodes the audio data from the leading frame to output the decoded audio data;
• a reproducing portion which reproduces the decoded audio data;
• and
• a reproduction start position calculating portion which, in the case where a reproduction request from an arbitrary frame in the audio data is inputted, detects the difference size corresponding to the arbitrary frame from the table, and totals a result of multiplying the number of frames from the leading frame to a frame immediately preceding the arbitrary frame by the average frame size and the detected difference size so as to decide a reproduction start frame for starting reproduction, wherein
• the decoding portion requests the reading control portion to read frames from the reproduction start frame from the recording medium.