Texas Instruments Corporation

Charles D Lueck

Alec C Robinson

Jonathan L Rowlands

Jeffrey Scott Hayes

According to the present invention, there is developed a proprietary technology for compressing the window tables of audio coders to &frac18; their original size (or less) without any loss of quality. This technology can be applied to all transform based audio coders, or any audio coder that uses a windowing stage. The novel technique for reducing storage requirements for the window tables of audio coders is based on multiple differentiation. Since the difference between any two adjacent samples in the first difference signal is small, so it is more efficient to store this difference. This technique can be carried out several more times, until the returns get smaller, and the computational requirements to &ldquo;undo&rdquo; the compression go up. The optimum number of times to differentiate is dependent on the particular application and the window shape.

TI window compression/expansion method

A method for performing audible fast-forward or reverse of audio content represented in a compressed format, such as, but not limited to, MPEG-1 Layer 3 (MP3) or MPEG-2 Advance Audio Coding (AAC) employs a fast-forward controller which performs fast-forward or reverse by repeatedly skipping forward or reverse in the compressed audio data stream, retrieving a block of data, and then splicing these data blocks back together. A decoder is then used to decode each of these blocks, to detect when a block switch has occurred (a splice in the data stream), and to quickly resynchronize at each transition. Hierarchical or multiplexed data streams may be decoded using a cascade of decoders each employing this technique. The decoder uses a robust sync search for performing resynchronization and error recovery.

Method and apparatus for audible fast-forward or reverse of compressed audio content

A method and device for placement of sound sources in three-dimensional space via two loudspeakers. This technique uses an efficient implementation which consists of binaural signal processing and loudspeaker crosstalk cancellation, followed by panning into the left and right loudspeakers. For many applications, the binaural signal processing and crosstalk cancellation can be performed offline and stored in a file. Because, in this situation, panning is the only required operation, this technique results in a low-computation, real-time system for positional 3D audio over loudspeakers.

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Dallas, TX, United States of America

Charles D Lueck