EPG Data Compression via Shared Character References
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Solution Overview
Problem
Existing methods for compressing electronic program guide (EPG) data in one-way broadcast networks are inefficient, leading to high bandwidth requirements and storage needs, especially due to redundant text data in titles and synopses.
Innovation Solution
A two-layer compression method is applied, first by creating a list of unique text entries with associated identifications and then by identifying shared consecutive characters among text items to store references and counts, reducing data volume effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If existing compression methods (run length encoding, LZW encoding, code dictionary) are used for EPG data, then some compression is achieved, but compression efficiency is insufficient leading to high bandwidth requirements
Solution Approach 1:
The compression method segments the EPG data into multiple layers: first creating a list of unique text entries with identifications, then creating a compressed list by identifying shared consecutive characters between entries. This multi-level segmentation achieves 66-71% compression by systematically breaking down and reassembling the data structure.
Solution Approach 2:
The patent implements a nested compression structure where the compressed list references back to the unique entries list, and within the compressed list, entries reference shared character sequences. This nesting of data structures allows efficient compression while maintaining the ability to reconstruct the original data.
2Quantity of substance
If more compression is applied to reduce EPG data volume, then bandwidth requirements decrease, but compression algorithm complexity increases
Solution Approach 1:
The algorithm performs preliminary actions by first creating a list of unique text entries and their identifications before proceeding to create the compressed list. This preliminary organization of data enables the subsequent compression step to operate more efficiently by working with pre-sorted unique entries rather than raw data.
Solution Approach 2:
The compression method uses copying by creating references to shared character sequences. Instead of storing complete text entries multiple times, the system copies only the shared portions and stores them once, reducing redundancy while maintaining data integrity.
Data Source
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AI summary
Broadcast server and method for transmitting electronic program guide data to set top boxes (4) via a broadcast network (6). The broadcast server (8) is arranged to prepare a list of unique entries and associated identifications of the text items received, and to provide a compressed list to the plurality of set top boxes (4). The broadcast server (8) repeats the following steps for each text item in the list: - determining whether a next text item has a number of shared consecutive characters at the start in common with a compressed text item from the compressed list, identifying said compressed text item as a source of shared consecutive characters and determining the number of shared consecutive characters; - storing for the next text item an identification, a reference to the source of shared consecutive characters, the number of shared consecutive characters, and the remaining non-shared text in the compressed list.