Clock Generator Adjusting Frequency for Buffer Fill in Playback
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Solution Overview
Problem
Existing data synchronized playback systems face interruptions or cutoffs when unable to synchronize with the transmitting side due to clock frequency mismatches, particularly in hardware-limited scenarios or when using software-based AV decoders, leading to performance changes in the overall apparatus.
Innovation Solution
A data synchronized playback apparatus that includes a buffer, a buffer fill measurement unit, a decoder, and a clock generator, which adjusts the clock frequency based on the measured data quantity in the buffer to maintain continuous playback of audio and video data without requiring a PLL circuit, thus preventing performance changes even in software-based AV decoders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PLL circuit is used to synchronize clock frequencies, then data synchronization is improved, but device complexity increases
Solution Approach 1:
The invention extracts the essential function of clock frequency synchronization from the complex PLL circuit and implements it through a simpler buffer-fill-based control mechanism. The system monitors buffer fill levels and adjusts playback speed accordingly, eliminating the need for hardware PLL circuits while maintaining synchronization reliability.
Solution Approach 2:
The invention replaces the mechanical/electronic PLL circuit with a software-based buffer management system. By using buffer fill measurement and digital clock adjustment, the system achieves clock synchronization without requiring dedicated hardware PLL components, thereby reducing device complexity.
2Duration of action of moving object
If clock frequency is adjusted to prevent buffer overflow/underflow, then continuous playback is improved, but apparatus performance changes
Solution Approach 1:
The invention applies local quality by adjusting the clock frequency specifically for the audio playback path rather than for the entire apparatus. The clock generator modifies only the audio clock based on buffer fill levels, while other system operations continue at their original speed, thus maintaining continuous playback without degrading overall apparatus performance.
Solution Approach 2:
The invention segments the clock generation into separate paths: a system clock for general apparatus operation and an audio clock for playback. This segmentation allows independent adjustment of the audio clock based on buffer conditions without affecting other system functions, resolving the contradiction between continuous playback and performance stability.
3Reliability
If buffer fill measurement is performed continuously, then playback synchronization is improved, but processing load increases
Solution Approach 1:
The invention implements periodic action by measuring buffer fill at specific intervals rather than continuously. The buffer fill measurement unit samples the buffer status at predetermined times, providing sufficient synchronization information while minimizing processing load. This periodic sampling approach maintains playback synchronization without excessive computational overhead.
Data Source
AI summary
A data synchronized playback apparatus comprises a buffer which stores streaming data, a buffer fill quantity measurement unit which measures the amount of streaming data stored in the buffer, a decoder which decodes the streaming data and sends decoded data to a D/A converter, a D/A converter which converts the decoded data to an analog signal, a clock generator which generates a clock signal with a frequency that changes according to the measured data quantity, and the digital/analog converter operates based on the clock signal generated by the clock generator.