Subtitle Rate Control via Size Estimation and Queuing
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Solution Overview
Problem
Conventional systems face challenges in implementing rate control for real-time transcoding of subtitles in consumer electronics with limited memory, as subtitles have variable duration elements, which are not compatible between different standards and can exceed buffer modeling limits.
Innovation Solution
A system comprising an estimation circuit, a rate control circuit, and a queue circuit that generates size estimates for subtitle elements and controls bitrate by processing and queuing subtitle elements based on available resources, allowing for efficient transcoding even in environments with minimal circuitry and limited memory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional buffer modeling is used for subtitle transcoding, then decoder compatibility is improved, but memory requirements and device complexity increase
Solution Approach 1:
The patent changes the parameter representation from complex buffer models to simple size values that estimate subtitle element bitrates. This allows maintaining decoder compatibility through rate control while reducing memory requirements and device complexity by using lightweight parameter estimation instead of sophisticated buffer modeling.
Solution Approach 2:
The patent uses temporary size value estimates that are computed and then discarded after rate control decisions are made. These disposable size estimates replace persistent complex buffer models, reducing memory requirements while achieving the same rate control functionality.
2Productivity
If real-time encoding is implemented with variable duration subtitle elements, then processing speed is improved, but rate control accuracy deteriorates
Solution Approach 1:
The patent performs preliminary estimation of subtitle element sizes before actual encoding. This preliminary action provides advance rate control information without delaying the real-time encoding process, maintaining both encoding speed and rate control accuracy by preparing size estimates in advance.
Solution Approach 2:
The estimation circuit automatically generates size values for subtitle elements without requiring complex external buffer modeling. This self-service mechanism maintains rate control accuracy while enabling real-time processing, as the system generates its own rate control information internally without external dependencies.
3Reliability
If comprehensive buffer modeling is used to handle variable duration subtitles, then rate control reliability is improved, but memory consumption increases
Solution Approach 1:
The patent extracts only the essential rate control information (size values) from the complex buffer modeling process. By taking out only the necessary bitrate estimation data and discarding the rest of the buffer model complexity, the system maintains rate control reliability while significantly reducing memory consumption.
Solution Approach 2:
The patent uses temporary size value estimates that are computed and then discarded after rate control decisions are made. These disposable size estimates replace persistent complex buffer models, reducing memory requirements while achieving the same rate control functionality.
4Ease of manufacture
If traditional A/V fixed duration element processing is used, then encoding simplicity is improved, but subtitle element compatibility deteriorates
Solution Approach 1:
The patent changes the parameter representation from complex buffer models to simple size values that estimate subtitle element bitrates. This allows maintaining decoder compatibility through rate control while reducing memory requirements and device complexity by using lightweight parameter estimation instead of sophisticated buffer modeling.
Data Source
AI summary
An apparatus comprising an estimation circuit, a rate control circuit, a queue circuit, and an encoder circuit. The estimation circuit may be configured to generate a size value in response to an input signal comprising (i) a plurality of frames and (ii) a plurality of embedded subtitle elements. The rate control circuit may be configured to (i) generate a control signal, (ii) pass through the plurality of frames, (iii) present a first one or more of subtitle elements for current processing in response to the size value, and (iv) present a second one or more of subtitle elements for subsequent processing. The queue circuit may be configured to (i) receive the second one or more subtitle elements, (ii) present the second one or more of subtitle elements for current processing when the control signal is in a first state and (iii) hold a second one or more subtitle elements for subsequent processing when the control signal is in a second state. The encoder circuit may be configured to generate an output signal in response to (i) the plurality of frames, (ii) the first one or more subtitle elements, and (iii) the second one or more subtitle elements.