Random access audio decoder

• US 8,386,523 B2
• Filed: 12/02/2005
• Issued: 02/26/2013
• Est. Priority Date: 12/30/2004
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Rao, Ajit Venkat, Mody, Mihir Narendra, Jain, Ashish
• Primary Examiner(s): Beausoliel, Jr., Robert
• Assistant Examiner(s): BROMELL, ALEXANDRIA Y
• Application Number:
  US11/292,882
• Publication Number:
  US 20060149531A1
• Time in Patent Office: 2,643 Days
• Field of Search: 704/500, 704/503, 707/705, 707/793, 707/792, 707/781, 711/105
• US Class Current: 707/793
• CPC Class Codes: G10L 19/167 Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes

Abstract

Random access decoding start points (audio frame headers) for AMR-type files are found by sequential elimination of types of file points from consideration for a block of file points following a random access selected point. Chaining of file points according to frame header format interpretation gives paths of points through the block, and selection of maximal path(s) includes sums of weights of the points of a path. The next-to-initial points of such a maximal path provides a decoding start point.

Claims

1. A method of a signal processor of a random access for a sequence of encoded frames with frames of variable lengths and headers indicating the lengths, comprising:

(a) selecting an access point utilizing successive reduction of a complete search space, wherein said access point is not available in meta-data;

(b) selecting via the signal processor a sequence of points following said access point;

(c) removing points of said sequence which do not have the form of a header, said removing defining a first subset of said sequence of points, wherein said removal eliminates sequential access points;

(d) removing points of said first subset which do not jump to other points of said first subset when said points are interpreted as headers, said removing defining a second subset of said first subset;

(e) chaining points of said second subset into paths using jumps of said points when interpreted as headers;

(f) weighting each of said paths according to the number of other points jumping to points of a path;

(g) selecting ones of said paths with a maximum weighting, said selecting defining a third subset of said second subset; and

(h) outputting a point from said third subset as a frame header point corresponding to said requested access point wherein said outputted point is within a data stream.

2. An apparatus for a sequence of encoded frames with frames of variable lengths and headers indicating the lengths, comprising:

(a) means for selecting an access point utilizing successive reduction of a complete search space, wherein said access point is not available in meta-data;

(b) means for selecting via the signal processor a sequence of points following said access point;

(c) means for removing points of said sequence which do not have the form of a header, said means for removing defines a first subset of said sequence of points, wherein said removal eliminates sequential access points;

(d) means for removing points of said first subset which do not jump to other points of said first subset when said points are interpreted as headers, said means for removing defines a second subset of said first subset;

(e) means for chaining points of said second subset into paths using jumps of said points when interpreted as headers;

(f) means for weighting each of said paths according to the number of other points jumping to points of a path;

(g) means for selecting ones of said paths with a maximum weighting, said means for selecting defines a third subset of said second subset; and

(h) means for outputting a point from said third subset as a frame header point corresponding to said requested access point wherein said outputted point is within a data stream.