Subtitle Packet Identification for RAP Reproduction
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Solution Overview
Problem
Existing subtitle transmission methods in broadcasting, such as Digital Video Broadcasting (DVB), face challenges in displaying subtitles satisfactorily during rapid (RAP) reproduction and variable-speed reproduction, as they lack efficient mechanisms for identifying and prioritizing subtitle packets.
Innovation Solution
A transmission device and method that generates a multiplexed stream by packetizing video and subtitle streams, with identification information inserted into the header of specific container packets to facilitate efficient extraction and prioritization of subtitle packets, allowing for accurate display during RAP and variable-speed reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If subtitle information is transmitted using bitmap data or text character codes with font expansion, then subtitle transmission is achieved, but efficient identification and extraction of subtitle packets during RAP and variable-speed reproduction is difficult
Solution Approach 1:
An identification information field is introduced as an intermediary element within the subtitle packet structure. This field acts as a marker that enables the receiving device to quickly identify and extract subtitle packets during RAP and variable-speed reproduction without complex processing of the entire packet content.
Solution Approach 2:
The identification information is preliminarily embedded into the subtitle packet structure during encoding. This preliminary marking allows the receiving device to perform efficient packet extraction without requiring complex real-time analysis, thereby improving subtitle display reliability during rapid reproduction modes.
2Loss of information
If multiple subtitle packets are transmitted without priority information, then all subtitle information is preserved, but selecting which subtitle to display during variable-speed reproduction becomes difficult
Solution Approach 1:
Priority information is embedded locally within each subtitle packet's identification field. This allows each subtitle packet to carry its own selection criteria, enabling the receiving device to easily determine which subtitles to display during variable-speed reproduction while preserving all original subtitle information.
3Productivity
If subtitle packets are not efficiently extracted during RAP reproduction, then all data must be processed, but subtitle display latency increases
Solution Approach 1:
The identification information enables the receiving device to extract only the necessary subtitle packets during RAP reproduction by serving as a quick filter. This selective extraction mechanism significantly improves processing efficiency and reduces the time required to display subtitles during rapid reproduction modes.
Data Source
AI summary
Subtitles can be satisfactorily displayed at the time of RAP reproduction and at the time of variable-speed reproduction.A video stream that includes a video packet in which a payload has coded image data is generated. A subtitle stream that includes a subtitle packet in which a payload has subtitle information is generated. A multiplexed stream that includes a container packet obtained by packetizing the video stream and the subtitle stream is generated and transmitted. Into a header of a specific container packet in which a payload includes a first byte of the subtitle packet, first identification information indicating that the payload includes the first byte is inserted. For example, this first identification information further indicates a priority of subtitle displaying based on subtitle information contained in the subtitle packet having the first byte included in the payload of the specific container packet.