WFD Metadata Transmission via RTSP Request
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Solution Overview
Problem
Current wireless display transmission technologies, such as Miracast, do not efficiently manage metadata transmission, leading to unnecessary burdens in streaming metadata continuously, even when not requested by the receiving device.
Innovation Solution
A method and device for transmitting metadata in WFD systems, where metadata is only transmitted when requested by the WFD sink, allowing the WFD source to switch from a first transport stream without metadata to a second transport stream that includes metadata, reducing streaming burden by controlling metadata transmission based on user requests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metadata is continuously transmitted in the transport stream, then the receiving device can always access metadata information, but the streaming burden and bandwidth consumption increase unnecessarily
Solution Approach 1:
The patent implements periodic action by transmitting metadata only at specific intervals or events rather than continuously. The WFD source transmits metadata in response to RTSP requests from the WFD sink, or includes metadata selectively in certain transport stream packets based on changes in metadata content, creating a periodic transmission pattern that reduces overall data volume while maintaining availability when needed.
Solution Approach 2:
The patent extracts metadata from the continuous transport stream and handles it separately through RTSP protocol interactions. The WFD sink can request metadata specifically through RTSP messages, and the WFD source responds with metadata information independently from the main video/audio stream, separating the metadata transmission burden from the continuous media streaming.
2Loss of energy
If metadata is transmitted only when requested, then the streaming burden is reduced, but the metadata may not be available when needed for display control
Solution Approach 1:
The patent applies preliminary action by having the WFD sink send RTSP requests in advance to obtain metadata before it is needed for display control operations. The capability negotiation procedure and metadata requests are performed beforehand, ensuring that metadata is available when required without delaying the actual display control functions.
Solution Approach 2:
The patent implements feedback through the RTSP protocol interaction where the WFD sink requests metadata and the WFD source responds with the requested information. This request-response mechanism ensures that metadata is delivered precisely when needed based on actual demand, eliminating both continuous transmission overhead and delivery delays.
3Adaptability or versatility
If the system supports both first transport stream without metadata and second transport stream with metadata, then flexibility is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by using the RTSP protocol as a multi-functional mechanism that serves both capability negotiation and metadata transmission purposes. The same RTSP interaction framework is used for different functions (capability exchange, metadata requests, stream control), reducing the need for separate specialized protocols and simplifying the overall system architecture despite supporting multiple transport stream configurations.
Data Source
AI summary
Provided are a method and an apparatus for transmitting metadata in a WFD. More particularly, a WFD source transmits, to a WFD sink, a first transmission stream in which an audio stream and a video stream are superimposed and multiplexed. The WFD source receives, from the WFD sink, a first RTSP request message for requesting transmission of metadata for audio data and video data during the transmission of the first transmission stream. The WFD source transmits, to the WFD sink, a first RTSP response message in response to the first RTSP request message during the transmission of the first transmission stream. The WFD source transmits, to the WFD sink, a metadata stream including the metadata and a second transmission stream in which the audio stream and the video stream are superimposed and multiplexed.