Timestamp Adapter for DMB Receiver Channel Switching
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Solution Overview
Problem
Conventional Digital Multimedia Broadcasting (DMB) receivers experience significant delays when switching channels due to network and CODEC delays, resulting in inconvenient service disruptions for users.
Innovation Solution
A play-out apparatus and method that employs a time stamp adapter to modify the timestamp of video data, allowing it to be immediately output from a playback buffer without CODEC delays, thereby reducing the time required to switch channels and improve service continuity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional DMB receivers process video data through standard CODEC decoding, then reliable video playback is ensured, but significant delays occur during channel switching
Solution Approach 1:
The system performs preliminary actions by buffering video data in advance and pre-calculating playback timestamps before channel switching occurs. The playback buffer stores decoded video frames with pre-computed display timestamps, allowing immediate playback resumption after channel change without waiting for CODEC initialization and decoding of new channel data.
Solution Approach 2:
The video processing pipeline is segmented into distinct functional blocks: demultiplexer for extracting video streams, playback buffer for temporary storage, timestamp calculator for timing management, and output controller for synchronized playback. This segmentation allows independent optimization of each module, particularly enabling the timestamp calculator to pre-compute timing information without waiting for complete CODEC processing.
2Stability of the object's composition
If video data is buffered and processed through standard playback mechanisms, then stable playback is achieved, but CODEC delays prevent quick channel switching
Solution Approach 1:
A timestamp calculator acts as an intermediary component between the playback buffer and the output controller. This intermediary pre-calculates and stores display timestamps for buffered video frames, allowing the output controller to immediately retrieve and display frames with correct timing information without invoking the CODEC decoding process, thus eliminating CODEC-related delays while maintaining playback stability.
Solution Approach 2:
The system performs preliminary timestamp calculation for all buffered video frames before channel switching. By pre-computing display timestamps and storing them with corresponding video frames in the playback buffer, the system eliminates the need for real-time CODEC decoding during channel transitions, enabling rapid channel switching while maintaining stable and synchronized playback.
3Measurement precision
If the system waits for complete video decoding before playback, then accurate timing is ensured, but channel switching becomes inconvenient due to delays
Solution Approach 1:
The timestamp calculator pre-calculates display timestamps for video frames based on their sequence numbers and predefined frame rates before playback begins. This preliminary timing calculation allows the output controller to immediately display frames with accurate timing information after channel switching without waiting for CODEC decoding, thus maintaining timing precision while improving operational convenience.
Solution Approach 2:
The system dynamically adapts its processing mode based on operational context: during normal playback, it uses pre-calculated timestamps for efficient display; during channel switching, it immediately switches to displaying buffered frames with their pre-computed timestamps without waiting for new channel data decoding. This dynamic behavior maintains timing accuracy while eliminating unnecessary delays during channel transitions.
Data Source
AI summary
A play-out apparatus and method for switching a channel in a digital multimedia broadcasting receiver are provided which can decrease a delay occurring in a channel switching time. A demultiplexer demultiplexes a signal received from a transmitter and outputs video data. A time stamp adapter changes a time stamp for indicating a play-out time of the video data such that the video data can be immediately output from a playback buffer without a Coder-Decoder (CODEC) delay, and outputs the video data including the changed time stamp. The playback buffer buffers and outputs the video data output from the time stamp adapter according to the changed time stamp. A video decoder decodes and outputs the video data output from the playback buffer according to the changed time stamp. A display unit plays the decoded video data out.