Audio Buffering Shift Register Repeats Samples
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Solution Overview
Problem
Multimedia receivers experience audio playback distortion due to missing data words caused by errors in the incoming audio signal, leading to irregular output rates and noticeable noise during playback.
Innovation Solution
An audio buffering system that includes a first-in-first-out (FIFO) buffer and a shift register, where the shift register repeats bits to ensure continuous output, maintaining a constant audio rate and preventing distortion by loading data words from the FIFO buffer and repeating previous good samples when errors occur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a FIFO buffer is used to synchronize audio and video, then audio synchronization is improved, but audio playback distortion occurs when data words are lost due to errors
Solution Approach 1:
An error detection and correction mechanism is introduced as an intermediary between the FIFO buffer and the audio output. This intermediary detects lost data words caused by errors and inserts placeholder values (such as repeated previous samples or null values) to maintain continuous audio output, thereby preventing playback distortion while preserving synchronization functionality.
Solution Approach 2:
The system prepares for potential data loss by implementing error detection and correction mechanisms in advance. When errors are detected in the incoming audio stream, the system has pre-established procedures to handle missing data words, ensuring continuous playback without distortion by inserting appropriate placeholder values before the distortion can affect the output.
2Productivity
If the audio processing unit outputs parallel data words for left and right channels, then audio processing efficiency is improved, but data loss due to errors causes distorted noise during playback
Solution Approach 1:
The system implements error detection mechanisms that provide feedback about corrupted data words to the audio processing unit. When errors are detected in the parallel data words for left and right channels, the feedback mechanism allows the system to identify and correct or replace the corrupted data, maintaining data integrity while preserving the efficiency of parallel processing.
Solution Approach 2:
The system changes the parameter of data handling by introducing error detection and correction mechanisms that modify how parallel data words are processed. When errors are detected, the system changes the output parameter by inserting placeholder values or repeating previous samples, thereby maintaining data integrity without sacrificing the efficiency of parallel processing.
3Productivity
If audio data is transmitted during the blanking area of video frames, then audio transmission is improved, but audio data becomes bursty and requires rate matching
Solution Approach 1:
The system performs preliminary buffering of audio data during the blanking area of video frames, accumulating audio samples in advance. This preliminary action allows the system to handle the bursty nature of audio transmission by storing data temporarily and then releasing it at a controlled rate, maintaining consistent audio output despite the irregular transmission pattern.
Solution Approach 2:
The system maintains continuous audio output by using buffers to decouple the bursty transmission from the continuous playback requirement. The buffer continuously stores and releases audio data, ensuring that the audio output remains steady and consistent even though the input transmission is bursty and irregular.
Data Source
AI summary
An audio buffering system in a multimedia receiver includes an audio interface coupled to an incoming audio signal for generating a digital audio signal having transmitted therein a plurality of data words; a first-in-first-out (FIFO) buffer being coupled to the digital audio signal and comprising a plurality of cells being organized sequentially for holding data words of the digital audio signal, wherein a first cell of the FIFO buffer has an input being coupled to the digital audio signal; and a first shift register having a plurality of bits being organized serially, wherein a first bit of the first shift register receives an output from a last bit of the first shift register, and each bit of the first shift register is coupled to a corresponding bit in an outputted data word of the FIFO buffer. The first shift register is loaded with data words outputted from the FIFO buffer.