Stream Synchronization via Timing Correlation
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Solution Overview
Problem
Existing inter-destination synchronization techniques for multimedia streams, such as IPTV, fail to maintain synchronization when streams are modified for content preparation or regeneration, as they rely on timing information that is altered by stream modification units like transcoders and mixers, making direct synchronization impossible.
Innovation Solution
The method provides synchronization correlation information between modified and unmodified streams by using synchronization points and a media synchronization unit to adjust arrival time information, allowing for synchronization across heterogeneous networks and devices with different service requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If stream modification units (transcoders, mixers) are used to adapt streams to different service requirements, then adaptability and service customization are improved, but timing information is altered making inter-destination synchronization impossible
Solution Approach 1:
The patent introduces a synchronization server as an intermediary that receives timing information from both the original stream and modified streams, processes this information, and generates synchronization control signals. This mediator enables synchronization between streams that have passed through modification units by translating their different timing references into a common synchronization framework.
Solution Approach 2:
The patent changes the timing parameters of modified streams by adjusting presentation time stamps (PTS) and reception time stamps (RTS) based on synchronization information received from the synchronization server. This parameter adjustment allows modified streams to align their playback timing with the original stream despite having different timing references after modification.
2Ease of operation
If different timing information is used in modified streams to meet specific terminal requirements, then ease of operation and terminal compatibility are improved, but measurement precision of arrival times is worsened
Solution Approach 1:
The patent implements a feedback mechanism where terminals report their actual reception and playback timing information to the synchronization server. The server uses this feedback to calculate and send adjusted synchronization signals, continuously refining the timing alignment between original and modified streams across different terminals.
Solution Approach 2:
The patent performs preliminary adjustment of timing parameters before stream playback by pre-calculating the required PTS and RTS adjustments based on synchronization information from the server. This preliminary action ensures that terminals can synchronize their playback without real-time timing conflicts.
3Manufacturing precision
If stream modification is performed for content preparation and regeneration, then manufacturing precision of content delivery is improved, but loss of timing information increases
Solution Approach 1:
The patent performs preliminary establishment of timing relationships before stream modification by recording the original timing information and establishing correlation between original and modified stream timing. This preliminary action preserves timing information that would otherwise be lost during the modification process.
Solution Approach 2:
The patent creates a copy of the original timing information and uses it as a reference for synchronizing the modified stream. The synchronization server maintains timing data from the original stream and uses this copied timing reference to generate synchronization control signals that compensate for timing information lost during modification.
Data Source
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AI summary
A method and system for inter-destination synchronization of at least a first and a second stream is described, wherein the second stream is the output stream of a media stream modification unit using the first stream as an input stream. The method comprises the steps of : providing first arrival time information of a packet in the first stream arriving at a first synchronization point and second arrival time information of a packet in the second stream arriving at a second synchronization point; providing synchronization correlation information on the synchronicity relationship between said input stream and said output stream; and, calculating delay information on the basis of the first and second arrival time information and the synchronization correlation information.