Media Sample Access via Pre-calculated Cache Entries
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Solution Overview
Problem
Traditional methods for locating specific samples in media files, such as MPEG-4 files, are time-consuming due to the need for linear searches through large numbers of entries in boxes like STTS and STSC, which are encoded using run-length coding, leading to inefficient data processing.
Innovation Solution
The implementation of pre-processed cache entries and incremental processing to rapidly locate target samples by calculating and storing sample information in cache entries, allowing for binary search and reducing redundant computations, thereby speeding up the access process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If linear search is performed through STTS and STSC boxes to locate target samples, then sample location accuracy is achieved, but processing time increases significantly
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing cumulative sample counts and time offsets for each chunk in the STSC and STTS boxes during file parsing. This allows the system to have sample location data ready in advance, eliminating the need for time-consuming linear searches during playback operations.
Solution Approach 2:
The patent segments the media file into chunks with associated metadata stored in separate boxes (STSC, STTS, STCO). Each chunk has pre-calculated cumulative statistics, allowing the system to divide the large search space into smaller, pre-processed segments that can be quickly queried without scanning entire files.
2Quantity of substance
If run-length coding is used to compress STTS and STSC box data, then storage space is reduced, but data access complexity increases
Solution Approach 1:
The patent resolves the complexity issue by pre-expanding the run-length coded data during initial file parsing and storing the decoded cumulative values in memory. This preliminary action converts compressed data into easily accessible formats, so that during playback, the system accesses pre-computed values rather than decoding run-length sequences in real-time.
3Measurement precision
If complete sample information is stored for all samples, then sample access accuracy is improved, but memory consumption increases
Solution Approach 1:
The patent segments sample information storage by organizing data at the chunk level rather than individual sample level. Each chunk stores cumulative statistics (sample counts, time offsets) that represent groups of samples, reducing memory requirements while maintaining the ability to accurately locate any sample through mathematical calculations based on chunk boundaries.
Solution Approach 2:
The patent applies partial action by storing only the necessary cumulative statistics (sample counts and time offsets) at chunk boundaries rather than complete information for every sample. This partial storage approach provides sufficient data for accurate sample location without the memory overhead of storing full sample metadata for all samples in the file.
Data Source
AI summary
Data processing methods and systems for accessing a target sample in a media data stream. The media data stream has a plurality of samples and corresponding sample information recorded in at least one entry, wherein the sample information for a predetermined number of the entries is calculated and the calculated result is stored in at least one cache entry. Target sample information corresponding to the target sample is provided. One of the cache entries is located by comparing the target sample information with the calculated result of respective cache entries. After locating the cache entry, the target sample from the entries is located corresponding to the located cache entry.