Randomized playback of tracks in a multimedia player
AssigneeVisteon Global Technologies, Inc.
InventorsWalter W. Schilling, JR., Jacob Tanana
Life of this patent
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Abstract
An audio reproduction apparatus randomizes or shuffles the playback order of tracks from a prerecorded media such as a compact disc within a multiple-disc changer. Shuffle sequences are generated using a linear congruential random number generator (LCRNG). The shuffle sequence does not have to be stored since a next track in the sequence can always be generated from the LCRNG using a particular set of parameters. The parameters are determined in response to the number of track (or discs) in a sequence and include elements obtained from a lookup table and elements that are randomly selected so that the same sequence is not always generated for a certain sequence length.
Claims20
A method of determining a shuffle sequence for playing tracks from a prerecorded media, comprising the steps of:
- determining a modulus m greater than or equal to the total number of tracks T to be randomized in said shuffle sequence, said tracks being stored on said prerecorded media in a predetermined order xi, where i is an index;
- determining a multiplier a for which (a−1) is a multiple of every prime number less than m that is a factor of m, wherein if m is a multiple of 4 then (a−1) is also a multiple of 4;
- and
- determining an increment c which is relatively prime with m;
- wherein said shuffle sequence is determined in response to a linear congruential random number generator.
A method of operating a multimedia player in a shuffle mode for playing selections from a prerecorded media, comprising the steps of:
- initiating a shuffle mode;
- detecting a trigger event requiring determination of a next random track number;
- detecting whether a shuffle sequence is initialized for said prerecorded media and if not, then:
- determining a modulus m greater than or equal to the total number of tracks T to be randomized in said shuffle sequence, said tracks being stored on said prerecorded media in a predetermined order xi, where i is an index;
- determining a multiplier a for which (a−1) is a multiple of every prime number less than m that is a factor of m, wherein if m is a multiple of 4 then (a−1) is also a multiple of 4;
- and
- determining an increment c which is relatively prime with m;
- and
- determining said next random track number using said determined modulus m, said determined multiplier a, and said determined increment c in a linear congruential random number generator.
Audio apparatus comprising:
- an audio source generating audio signals from a prerecorded media;
- a user control interface for initiating a shuffle mode;
- and
- a controller responsive to said shuffle mode for generating a shuffle sequence in response to a linear congruential random number generator, wherein said controller:
- determines a modulus m greater than or equal to the total number of tracks T to be randomized in said shuffle sequence, said tracks being stored on said prerecorded media in a predetermined order xi, where i is an index;
- determines a multiplier a for which (a−1) is a multiple of every prime number less than m that is a factor of m, wherein if m is a multiple of 4 then (a−1) is also a multiple of 4;
- and
- determines an increment c which is relatively prime with m.
Dependencies are inferred from the claim text.