Intervideo, Inc.

Fahri Surucu

Shahab Layeghi

Chinn Chin

A method for embedding a non-audio file into a compressed audio file is disclosed. The disclosed method is capable of decoding and constructing previously encoded audio files with embedded non-audio information. The method of the present invention also includes steps for embedding the non-audio information at the proper time within the compressed audio file, wherein the decoded non-audio information can link to an Internet document for viewing during playback of the decoded audio source.

Linking internet documents with compressed audio files

A method for an improved QSS (bit allocator) algorithm is disclosed. The disclosed method is capable of greatly improving determination time; thereby, improving the efficiency of converting a signal from an audio format to an MP3 format. The starting point of the QSS determination for a present frame (N) is the QSS of a previous frame (N&#x2212;1). This starting point provides for improved efficiency for determining actual QSS of frame N as QSS[N&#x2212;1] will be closer to QSS[N] than an arbitrary starting point. Thus, fewer iterations are required to determine QSS[N] as compared to conventional encoders. The algorithm of the present is more efficient than conventional methods in that it makes use of the fact that audio signal statistics usually do not change abruptly during the period of one audio frame to another.

Fast convergence method for bit allocation stage of MPEG audio layer 3 encoders

In an MPEG audio encoder, a sign and an absolute value calculation are performed outside of the quantization inner loop, thereby reducing redundant calculations. The stored sign and absolute values can also be used in the frame packing block, also increasing processing efficiency. Thus, the present invention improves the performance of an MPEG audio encoder.

Fast loop iteration and bitstream formatting method for MPEG audio encoding

A fast code length search method for determining the length of a code in a codebook, wherein the method is especially suited for MPEG-compliant audio encoding. A code length table is created which stores pre-calculated code lengths, including any sign bits and linear extension bits necessary, for data value pairs or quadruples. In one embodiment, two code length tables are created, one for determining the code lengths of the codes used for the ones region, and a second code length table for the big values region. When a code length determination is made, the value is simply read from the table, instead of being calculated each time.

Fast code length search method for MPEG audio encoding

A fast codebook search method for finding an optimal Huffman codebook from a group of Huffman codebooks, wherein the method is especially suited for MPEG-compliant audio encoding. In order to select an optimal codebook from among candidate codebooks for a given sub-region, a bit difference table is created, which for any given data pair contains a bit difference value. The bit difference value is the difference between the number of bits needed for a given data pair (or quadruple) in a first candidate codebook and a second candidate codebook &lsqb;N bits&minus;M bits&rsqb;. By summing all such bit difference values for the data samples in a given sub-region, a quick determination can be made as to which codebook would encode the sub-region using the fewest bits (based on the size and/or sign of the sum(s)). For sub-regions having three candidate codebooks, two bit difference sums are calculated. For an implementation of the MPEG-1 Layer III Audio Encoding standard, only 20 bit difference tables are required in order to cover every possible combination of codebook candidates.

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Fremont, CA, United States of America

Fahri Surucu