Variable Frame-Rate Video Recording Apparatus
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Solution Overview
Problem
Conventional video recording apparatuses consume excessive recording media and require special devices for achieving slow motion and quick motion effects, as they record and play back frame rates that are not efficiently compatible with the original frame rates of the input signals.
Innovation Solution
A video recording apparatus that employs a multiplexing device to manage time information and compress picture data, allowing for efficient recording and playback without the need for special devices by adjusting the frame rate and data rate according to the preset playing frame rate, using techniques such as MPEG standard compliance and clock frequency adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional video recording apparatus records 60p picture signals resulted from pull-down process, then the recording can be played back at standard frame rates, but the recording media consumption increases significantly
Solution Approach 1:
The patent changes the fundamental parameter of frame rate recording by allowing the recording apparatus to store picture signals at their original variable frame rates (e.g., 12fps, 24fps) rather than converting them to a fixed high frame rate (60fps). This parameter change enables direct recording at the actual shot rate, eliminating the need for pull-down processing and reducing recording media consumption while maintaining playback compatibility through frame rate conversion during playback.
Solution Approach 2:
The patent inverts the conventional workflow by recording at the lower original frame rate and performing frame rate conversion during playback rather than recording at the high 60p frame rate and playing back at the original rate. This inversion eliminates the redundant pull-down process during recording and reduces the amount of data that needs to be stored.
2Reliability
If conventional video recording apparatus uses intra-frame compression, then any frame can be retrieved from compressed video data, but the recording media consumption increases
Solution Approach 1:
The patent changes the compression parameter from intra-frame compression to inter-frame compression, utilizing temporal redundancy between frames to achieve higher compression ratios. This parameter change reduces the amount of data that needs to be stored while maintaining the ability to retrieve and play back frames at the recorded frame rate.
3Adaptability or versatility
If frame rate is varied by one frame per second from 4fps to 60fps, then slow motion and quick motion effects can be achieved, but the device complexity increases
Solution Approach 1:
The patent applies dynamics by allowing the frame rate to be varied dynamically during playback rather than requiring complex real-time adjustment during recording. The recording apparatus simply records at the actual shot rate, and the playback apparatus dynamically converts the frame rate to achieve desired motion effects (slow motion, quick motion) without adding complexity to the recording device itself.
Data Source
AI summary
A video recording apparatus provides a slow motion effect or a quick motion effect by digitally converting the frame-rate instead of by changing the playback speed of the film, and using few recording media without requiring any special device at playing. A picture encoding part encodes only valid frames by changing a rate-controlling method so that a predetermined playing frame-rate is obtained at a standard data-rate at playing. And a TS multiplexing part multiplexes by converting a frequency of a standard STC clock by only a ratio of valid frame-rate and playing frame-rate, and generating values for PCR, PTS, and DTS.