Stitch Point Detection for Trickplay Navigation
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Solution Overview
Problem
Set-top boxes (STBs) face inaccuracies in content repositioning during trickplay operations due to presentation time stamp (PTS) discontinuities in stitched content, leading to breakdowns in navigation systems.
Innovation Solution
A multimedia device detects stitch points in a transport stream based on PTS discontinuities, generates a slot table with sequential PTS values, and maps a target PTS to the appropriate metadata index to accurately fetch frames during trickplay navigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the STB relies on sequential PTS values for trickplay operations, then the navigation system operates simply, but accuracy breaks down when PTS discontinuities occur in stitched content
Solution Approach 1:
The patent segments the content stream by detecting stitch points where PTS discontinuities occur. The metadata is divided into separate segments corresponding to different content portions, with each segment having its own sequential PTS indexing. This allows accurate repositioning within each segment while maintaining overall system functionality.
Solution Approach 2:
The patent introduces an intermediary mechanism that detects PTS discontinuities and inserts strategic point markers in the metadata. These markers act as intermediaries between the PTS values and frame indices, enabling the system to handle non-sequential PTS values while maintaining accurate navigation capability.
2Measurement precision
If the STB searches through all metadata indexes to find the target frame, then accuracy is maintained, but search latency increases
Solution Approach 1:
By segmenting the metadata into portions associated with different stitch points and using slot tables to organize these segments, the system limits the search space to only the relevant segment containing the target PTS. This dramatically reduces search latency compared to searching through all metadata indexes.
Solution Approach 2:
The system performs preliminary organization of metadata into slot tables during content recording or preprocessing. This pre-organization allows the playback system to quickly locate the appropriate metadata segment without performing extensive searches during trickplay operations.
3Adaptability or versatility
If the system processes stitched content with PTS discontinuities, then content versatility is improved, but navigation reliability deteriorates
Solution Approach 1:
The patent uses strategic point markers as intermediaries to bridge PTS discontinuities in stitched content. These markers detect and flag points where content segments are joined, allowing the navigation system to reliably handle PTS non-sequentiality while maintaining support for versatile stitched content formats.
Solution Approach 2:
The system changes the parameter representation by introducing slot tables that map PTS values to metadata indexes through intermediate slot entries. This parameter transformation allows the system to accommodate varying PTS patterns in stitched content while maintaining reliable navigation through the transformed parameter space.
Data Source
AI summary
Methods, systems, and computer readable media described herein may facilitate the detection and use of stitch points during trickplay navigation of a content stream. A multimedia device may automatically detect stitch points in a transport stream based upon PTS (presentation time stamp) discontinuities. The multimedia device may generate a slot table that organizes the frames of a piece of content into segments having sequential or linear PTS values. The multimedia device may compare a target PTS to the various PTS ranges of the slot table to identify a region to be searched for a metadata index associated with the target PTS. Once the target PTS is mapped to the appropriate metadata index, the multimedia device may fetch the appropriate frame for presentation.