Media Playback Speed Control for Buffer Fill Management
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Solution Overview
Problem
The existing methods for reproducing digital media in vehicles, such as automobiles, often result in delays and interruptions due to the need for buffering during data transmission, especially when switching between media sources or starting playback, leading to noticeable gaps or interference in audio or video playback.
Innovation Solution
A method that reduces the reproduction speed of media data until the reception buffer is sufficiently filled, using a nonlinear speed profile to smoothly transition back to normal speed, and optionally overlays audio with media effects to mask any delays, ensuring immediate start-up of media playback without interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the reception buffer is filled before playback to ensure stable reproduction, then the quality and stability of media playback is improved, but the start-up delay and interruption time increases
Solution Approach 1:
The system performs preliminary buffering of media data in the reception buffer before playback begins, ensuring that sufficient data is available to compensate for transmission fluctuations. The patent applies this by filling the buffer with incoming data packets before starting reproduction, which guarantees stable playback without interruptions while accepting a controlled start-up delay.
Solution Approach 2:
The system dynamically adjusts the playback speed based on the buffer fill level. When the buffer is insufficiently filled, the system reduces playback speed to allow more time for data accumulation, and increases speed when the buffer is sufficiently filled. This dynamic speed adjustment resolves the contradiction by making the buffer filling process itself flexible rather than fixed.
2Loss of time
If the reproduction speed is reduced to allow buffer filling, then the buffer fill time is sufficient, but the playback quality and listener experience deteriorates due to noticeable slowing
Solution Approach 1:
The system applies periodic speed variations to the playback, creating acceleration and deceleration phases that mask the overall time reduction. By introducing these periodic speed changes, the system can afford to slow down playback temporarily while maintaining perceived quality through the natural variability of the speed profile, preventing monotone slowing that would be noticeable to listeners.
Solution Approach 2:
The system changes the playback speed parameter dynamically based on buffer status and applies nonlinear speed profiles with acceleration and deceleration phases. These parameter changes allow the system to reduce overall playback speed while masking the effect through smooth transitions and variable speed patterns, thereby maintaining playback quality while ensuring sufficient buffer filling time.
3Reliability
If the system waits for the buffer to be sufficiently filled before playback, then transmission fluctuations are compensated, but the responsiveness and immediacy of media playback is reduced
Solution Approach 1:
The system dynamically determines when to start playback based on real-time buffer status rather than using a fixed waiting period. The playback start condition is flexible and adapts to the actual data accumulation rate, allowing the system to begin playback as soon as sufficient data is available, thereby maximizing responsiveness while still ensuring reliable playback through fluctuation compensation.
Solution Approach 2:
The system continuously monitors the buffer fill level and uses this feedback to control the playback start decision. By implementing feedback-based control, the system can immediately start playback when the buffer reaches a sufficient level, improving responsiveness while maintaining reliability through continuous monitoring and adaptive decision-making.
Data Source
AI summary
A method for reproducing, i.e., playing back, media data includes: receiving media data in a receive buffer; determining whether the receive buffer is sufficiently filled; reducing the playback speed over a period until the receive buffer is sufficiently filled, and playing back the media data at the reduced playback speed. The reduced playback speed has a speed profile having at least one non-linear section.