Adaptive Transport Stream Multiplexer for Miracast Latency
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Solution Overview
Problem
Conventional transport stream multiplexing technologies experience latency issues during real-time audio/video streaming over WiFi networks, leading to discontinuous playback on sink devices.
Innovation Solution
A transport stream multiplexer that synchronizes audio/video playback by employing adaptive packet dropping and throttling processes, using a virtual presentation clock reference to adjust packet generation based on network transmission rate, ensuring contemporaneity with the system clock reference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional transport stream multiplexing is used for real-time audio/video streaming, then the system can maintain stable packet transmission, but transmission latency increases causing discontinuous playback
Solution Approach 1:
The multiplexer dynamically adjusts packet processing based on real-time clock synchronization. When the virtual PCR falls behind the system PCR, the system automatically drops packets or throttles generation to reduce latency, and when ahead, it suspends transmission to maintain synchronization, making the system adaptive to varying network conditions
Solution Approach 2:
The system continuously compares the virtual PCR with the system PCR to derive time differences and uses this feedback to control packet dropping, throttling, or suspension. This closed-loop feedback mechanism ensures latency is reduced while maintaining playback continuity through real-time monitoring and adjustment
2Loss of time
If packets are transmitted at high rate to reduce latency, then real-time playback is improved, but synchronization with system clock deteriorates
Solution Approach 1:
The system uses continuous comparison between virtual PCR and system PCR to detect synchronization deviations. When latency is reduced too much causing the virtual PCR to fall behind, the feedback mechanism triggers packet dropping or throttling to realign the clocks, preventing desynchronization
Solution Approach 2:
The multiplexer automatically regulates its own packet generation and transmission rate based on internal clock comparison without external intervention. The system self-corrects synchronization issues by autonomously adjusting transmission timing to maintain contemporaneity between virtual and system clocks
3Reliability
If continuous packet transmission is maintained to ensure smooth playback, then playback continuity is preserved, but power consumption increases
Solution Approach 1:
The system employs periodic suspension of packet transmission when the virtual PCR is ahead of the system PCR, creating intervals of no transmission. This periodic action reduces power consumption during periods when continuous transmission is not needed for synchronization, while maintaining playback continuity when required
Data Source
AI summary
Systems and methods for multiplexing audio/video data and generating transport streams for WiFi network with reduced latency for real time playback at a remote device. A virtual presentation clock reference (PCR) representing a scheduled transmission time of a transport stream packet at a transport stream multiplexer is calculated based on the network transmission rate and generation of the data packets. The virtual PCR is compared with the corresponding system PCR to derive a time difference. Based on the time difference, the transport stream multiplexer is configured to adaptively drop packets or throttle packet generation so as to synchronize the playback of audio/video data on a sink device with the generation of interleaved audio/video packets.