Wireless Display Sync Control Using Feedback PTS Adjustment
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Solution Overview
Problem
Current wireless display technologies lack the capability to effectively address lip sync errors, which occur when the timing of the rendered video signal deviates from the timing of the rendered audio signal, leading to synchronization issues during media content transmission.
Innovation Solution
The implementation of a wireless display synchronization control system that utilizes presentation time stamps (PTS) to synchronize audio and video streams, where feedback signals indicative of display sync errors are used to adjust PTS values, ensuring synchronized playback by adjusting the presentation timing of audio and video packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wireless display protocols are used for media transmission, then wireless connectivity and flexibility are improved, but lip sync errors occur due to timing deviations between audio and video streams
Solution Approach 1:
The system implements a feedback mechanism where the sink device monitors lip sync errors between audio and video streams and sends synchronization status information back to the source device. The source device uses this feedback to adjust presentation timestamps and modify encoding parameters, creating a closed-loop control system that continuously corrects synchronization deviations during wireless transmission.
Solution Approach 2:
The invention dynamically changes encoding parameters including presentation timestamps, audio sample rates, and video frame rates based on detected synchronization errors. The system adjusts these parameters in real-time to compensate for timing deviations introduced during wireless transmission, ensuring audio and video remain synchronized despite network variations.
2Reliability
If audio processing time is adjusted to remove lip sync errors, then synchronization accuracy is improved, but device complexity increases due to additional processing requirements
Solution Approach 1:
The source device performs preliminary adjustments to presentation timestamps and encoding parameters before the data is transmitted wirelessly. By pre-calculating and applying compensation factors based on expected transmission characteristics, the system reduces the processing burden on the sink device while maintaining synchronization accuracy.
Solution Approach 2:
The invention introduces an intermediary synchronization control mechanism that operates between the source and sink devices. This intermediary layer handles the complex timing adjustments and coordination, allowing the endpoint devices to remain relatively simple while achieving precise synchronization through the coordinated action of the intermediary control system.
Data Source
AI summary
One or more system, apparatus, method, and computer readable media is described below for wireless display synchronization of audio and video data streams received through a direct wireless link between a content source and sink. In some embodiments, the presentation time stamp (PTS) associated with the encoding of a digital audio and digital video data stream into a compressed packetized data stream at the source is utilized as a control point for synchronization of the digital audio and video stream payloads presented at the sink. In some embodiments, one or more wireless display-synchronized PTS values are determined based on a feedback signal indicative of display synchronization error. A source including an optical camera may generate audio/video (A/V) streams that encoded and packetized by a multiplexer with wireless display-synchronized PTS values. In further embodiments, a media sync user input interface is provided at one or more of the source and sink.