Audio Signal Volume Control for Variable Video Playback Speed
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Solution Overview
Problem
Existing video and audio playback technologies experience a sense of incongruity when switching from normal to variable speed playback, such as slow-motion or stop-motion, due to the lack of immediate audio volume adjustment, leading to a disconnect between visual and auditory cues.
Innovation Solution
A signal processing apparatus that adjusts the audio playback gain in sync with changes in video playback speed, specifically reducing the volume when switching to variable speed playback to create a cohesive viewing experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the video playback speed is changed to variable speed (slow-motion or stop-motion), then the video expression is enhanced, but the audio volume remains unchanged causing a sense of incongruity
Solution Approach 1:
The patent applies dynamics by making the audio playback gain changeable and adaptable to different video playback speeds. The control unit dynamically adjusts the audio volume based on the detected video playback speed, transitioning from a static volume level to a dynamic one that responds to playback conditions, thereby resolving the incongruity between variable video speed and fixed audio volume.
Solution Approach 2:
The patent implements feedback by having the control unit continuously monitor the video playback speed and use this information to adjust the audio playback gain accordingly. This closed-loop control ensures that audio volume changes in response to video speed changes, maintaining synchronization and eliminating the sense of incongruity that occurs with fixed volume settings.
2Ease of operation
If the audio volume is adjusted gradually after video speed change, then the transition is smooth, but the audio expression does not change immediately when video expression changes
Solution Approach 1:
The patent applies preliminary action by detecting the video playback speed change first and then immediately adjusting the audio playback gain in response. Rather than waiting for a gradual transition, the system proactively changes the audio volume based on the detected playback speed, ensuring that audio expression同步 with video expression from the moment the speed change is detected.
3Duration of action of moving object
If the audio waveform is extended to conform to slow-motion playback, then the audio duration matches the video duration, but the audio frequency shifts to a low range creating incongruity
Solution Approach 1:
The patent applies parameter changes by adjusting the audio playback gain (volume parameter) in response to video playback speed changes. Instead of extending the audio waveform which causes frequency shifting, the system maintains the original audio frequency characteristics while dynamically changing the volume parameter to match the video expression, thereby preserving audio quality while achieving synchronization.
Data Source
AI summary
A signal processing apparatus for controlling an audio signal related to playback of sound to be performed together with playback of video that is based on a video signal is provided. The apparatus obtains information indicating a speed of the video at a point in time that is included in a playback period of the video signal, and controls, in a case where the speed of the video changes from a standard speed to a speed that differs from the standard speed at a specific point in time included in the playback period of the video signal, the audio signal based on the information obtained by the obtaining unit, such that a volume parameter for controlling a playback volume of the audio signal after the specific point in time differs from the volume parameter before the specific point in time.