Musical Sound Generation Device Buffer Management
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Solution Overview
Problem
Conventional musical sound generation devices face performance degradations due to high CPU/memory system bus utilization caused by excessive data transfer traffic, leading to decreased simultaneous sound production and increased operational latency, especially when using smaller waveform buffers that require repeated transfer of loop segments.
Innovation Solution
A musical sound generation device employs a dual-memory system where a first processor transfers waveform data from a high-capacity flash memory to a second memory, utilizing a sound source LSI to dynamically divide waveform buffer regions for efficient data transfer, allowing single-read operations for looped segments and reusing cached waveforms, and using a ring buffer when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If waveform data is stored in a smaller waveform buffer (second memory) to reduce costs, then hardware cost is reduced, but data transfer traffic increases causing CPU/memory system bus utilization to increase and performance to degrade
Solution Approach 1:
The waveform buffer (second memory) is divided into multiple regions, with a first region dedicated to storing waveform data and a second region serving as a ring buffer for data transfer operations. This segmentation allows the system to efficiently manage limited buffer space while reducing the need for frequent data transfers, thereby improving simultaneous sound production capability without requiring a larger buffer.
Solution Approach 2:
The system pre-loads waveform data into the waveform buffer region before it is needed for sound generation. By preparing data in advance and maintaining a ready supply in the buffer, the system reduces the frequency and volume of data transfers during sound production, thus improving performance while keeping the buffer size small.
2Duration of action of stationary object
If waveform data is repeatedly transferred to maintain loop segments during long sound emission, then continuous sound production is maintained, but total data transfer amount increases exceeding original waveform size
Solution Approach 1:
The ring buffer region enables continuous data transfer operations without interruption. By maintaining a continuous supply of waveform data in the buffer through coordinated transfer operations, the system ensures uninterrupted sound emission while optimizing transfer timing to minimize latency and avoid repeated full transfers.
Solution Approach 2:
The system dynamically adjusts data transfer operations based on the current sound emission state. When a loop segment is being played, the system coordinates transfers to maintain the loop in the buffer without requiring complete re-transfers, adapting the transfer strategy to the ongoing sound production needs and reducing total transfer time.
3Quantity of substance
If CPU/memory system bus utilization increases due to excessive data transfer, then data transfer capacity is improved, but operational latency increases and performance decreases
Solution Approach 1:
The system combines the waveform buffer and ring buffer into a single second memory device, with the ring buffer region serving dual purposes as both transfer buffer and sound data source. This merging eliminates the need for separate buffer memories and reduces transfer overhead, improving data transfer efficiency while minimizing operational latency.
Data Source
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AI summary
When transferring waveform data from a waveform region in a high-capacity flash memory to a waveform buffer in a RAM, first, whether a non-ring buffer region that can receive the waveform data can be allocated in the RAM is determined, and if so, the waveform data is transferred to the allocated non-ring buffer region. If such a non-ring buffer region cannot be allocated, then whether a ring buffer region that can receive the waveform data can be allocated in the RAM is determined, and if so, the waveform data is transferred to the ring-buffer region in a ring buffer operational manner.