Huffman decoder used for decoding both advanced audio coding (AAC) and MP3 audio
Aspects of the present invention may be found in a more efficient system and method of implementing Huffman decoding when audio is encoded or decoded using MPEG1 Layer 3 (MP3) or MPEG Advanced Audio Coding (AAC). Various aspects of the invention employ a unified architecture in the implementation of a Huffman decoder. Use of the unified architecture reduces the memory required to implement both MPEG1 Layer 3 (MP3) and MPEG Advanced Audio Coding (AAC) algorithms.
1 . A Huffman decoder for decoding variable length coded data, said Huffman decoder comprising:
a memory for storing symbols, said memory comprising data words, wherein each of the data words stores a first symbol from a first variable length code data corresponding to a first audio compression standard, and a second symbol from a second variable length code data corresponding to a second audio compression standard or first variable length code data corresponding to the first audio compression standard.
2 . The Huffman decoder of claim 1 , wherein the data words comprise a plurality of bits, the plurality of bits storing the first symbol, and wherein a portion of the plurality of bits store the second symbol.
3 . The Huffman decoder of claim 1 , wherein the first audio compression standard comprises advanced audio compression and wherein the second audio compression standard comprises MPEG-1, Layer 3.
4 . A Huffman decoder for decoding variable length data, said Huffman decoder comprising:
a first input for receiving input data;
a second input for receiving a table identifier;
a memory for storing symbols, said memory comprising data words, wherein each of the data words stores a first symbol from a first variable length code corresponding to a first audio compression standard, and a second symbol from a second variable length code corresponding to a second audio compression standard; and
an output for providing one of the symbols based on the input data and the table identifier.
5 . The Huffman decoder of claim 4 , wherein the data words comprise a plurality of bits, the plurality of bits storing the first symbol data, and wherein a portion of the plurality of bits stores the second symbol or first variable length code data corresponding to the first audio compression standard.
6 . The Huffman decoder of claim 4 , wherein the first audio compression standard comprises advanced audio compression and wherein the second audio compression standard comprises MPEG-1, Layer 3.
7 . The Huffman decoder of claim 4 , further comprising another output indicating the number of bits of the input data that are represented by the one of the symbols.
8 . A method for decoding variable length data, said method comprising:
receiving input data;
receiving a table identifier; and
providing a particular symbol based on the input data and the table identifier, from a memory storing a plurality of symbols, the memory comprising data words, wherein each of the data words stores a first symbol from a first variable length code corresponding to a first audio compression standard, and a second symbol from a second variable length code corresponding to a second audio compression standard.
9 . The method of claim 8 , wherein the data words comprise a plurality of bits, the plurality of bits storing the first symbol, and wherein a portion of the plurality of bits store the second symbol or first variable length code data corresponding to the first audio compression standard.
10 . The method of claim 8 , wherein the first audio compression standard comprises advanced audio compression and wherein the second audio compression standard comprises MPEG-1, Layer 3.
11 . The method of claim 8 , further comprising:
indicating the number of bits of the input data that are represented by the particular symbol.