Video Transcoder Latency Management via SCTE-35 Marker Analysis
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Solution Overview
Problem
Video streaming systems face undesirable latencies during transcoding, leading to poor user experiences, especially in live streaming, as different transcoding processes result in misaligned video streams and delays, affecting real-time content synchronization and online watch parties.
Innovation Solution
A system is developed to manage transcoder latencies by detecting SCTE-35 markers, recording timestamps, calculating latency deltas, and taking corrective actions to reduce latency, ensuring accurate and real-time latency measurement and management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If video content is transcoded in real-time for live streaming, then the user can access content immediately, but transcoder latency introduces delays and misalignment in video streams
Solution Approach 1:
The system performs preliminary actions by detecting SCTE-35 markers and recording timestamps before the actual transcoding operation occurs. This allows the system to establish a baseline reference point and proactively measure latency, enabling corrective actions to be taken in advance or during the transcoding process to minimize delays.
Solution Approach 2:
The system implements feedback by continuously monitoring transcoder latency through timestamp comparison and using this information to dynamically adjust transcoding parameters or trigger corrective actions. The latency measurement feedback loop enables real-time optimization of the transcoding process to maintain acceptable delay levels while preserving stream synchronization.
2Adaptability or versatility
If transcoding operations are performed on video segments, then the video can be adapted for different devices and formats, but the transcoding process introduces latency and desynchronization
Solution Approach 1:
The system uses SCTE-35 markers as intermediary reference points that pass through the transcoding process unchanged. These markers serve as synchronization beacons that allow the system to track and maintain temporal alignment between input and output streams despite the format adaptation operations performed during transcoding.
Solution Approach 2:
The system changes parameters by recording and comparing timestamps of SCTE-35 markers before and after transcoding. By monitoring temporal parameter changes rather than altering the video content parameters during transcoding, the system can adapt video formats while maintaining synchronization through precise latency measurement and correction.
3Productivity
If the transcoder processes video segments quickly, then real-time streaming is maintained, but latency measurement and corrective actions require precise timing and marker detection
Solution Approach 1:
The system extracts SCTE-35 markers from the video stream as distinct, identifiable reference points. By separating these timing markers from the main video content processing, the system can precisely measure latency without being affected by the complexity of the video data itself, enabling accurate timing measurements even at high processing speeds.
Solution Approach 2:
The system uses periodically occurring SCTE-35 markers (such as ad insertion tags or chapter markers) as regular reference points for latency measurement. This periodic approach provides multiple measurement opportunities throughout the video stream, allowing statistical analysis and averaging to improve measurement precision while maintaining high transcoding throughput.
Data Source
AI summary
Systems and methods configured to detect and manage video transcoder latencies are described. A manifest is received and is used to request video segments included in a manifest playlist. A transcoder having an input and output is used to transcode video segments. A delta time for a first SCTE-35 marker between the transcoder input and the transcoder output is determined, where the delta time corresponds to a transcoder latency. A determination is made as to whether a corrective action needs to be taken with respect to the latency, and such corrective action is taken as needed. The corrective action may include a transcoder reset. The manifest may be a text file and may be in the form of an HLS or DASH manifest. Additionally, streaming latencies may be reduced by switching content distribution systems, increasing the number of edge systems distributing content to clients, and/or by increasing video cache memory.