Reentry into compressed data
US6941019B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | May 10, 2000 |
| Grant date | Sep 6, 2005 |
| Priority date | — |
| Expiry date | May 10, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/48
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Apparatus and methods are provided for entering compressed data streams at selected reentry points to initiate decoding thereby allowing efficient manipulation of the compressed data and minimizing storage requirements. The reentry information preferably includes bit-level pointers and sufficient state information to initialize the decoder properly. This enables decoding without having to resume at independently decodable points, such as JPEG restart markers. For example, in the context of a JPEG image, in addition to the typical information available to the decoder that has been passed in earlier markers, the reentry information for a given MCU boundary may include: a bit-level pointer to the first block's DC Huffman code, the position of the output, and a DC predictor for each component of the MCU. This allows decompression to be performed in the appropriate order to accomplish various data manipulation operations, such as rotation, thus significantly reducing buffering requirements. Reentry information into a compressed data stream can be generated during encoding, decoding, partial encoding, partial decoding, entropy encoding, and/or entropy decoding. In addition, a reentry dec…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.