Audio Output Level Normalization Across Mixed File Formats
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Solution Overview
Problem
Digital audio systems face user inconvenience due to varying output levels of different audio file types, such as MP3, MPEG2, and AC3, resulting from their unique recording levels and formats, requiring frequent volume adjustments when playing multiple files sequentially.
Innovation Solution
A method and apparatus that search for and temporarily store audio data, detect output levels, and adjust the audio amplifier gain to ensure consistent output levels matching the user-set volume, using a digital audio system with a read unit, conversion unit, storage unit, detection unit, and control unit to normalize the output levels of various audio files.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If audio files of various types (MP3, MPEG2, AC3) are stored with their original recording levels and formats, then the audio files can be played back without additional processing, but the output levels of different audio files will vary, causing user inconvenience
Solution Approach 1:
The patent applies preliminary action by detecting the output level of audio data before it is amplified and played back. The audio controller detects the level of decoded audio data from different file types (MP3, MPEG2, AC3) and pre-adjusts the gain accordingly, so that when the audio is played back, all files maintain consistent output levels without requiring user intervention for volume adjustment.
2Ease of operation
If the audio amplifier gain is adjusted for each audio file to maintain consistent output levels, then the playback quality is improved, but the complexity of the audio control system increases
Solution Approach 1:
The patent implements feedback by having the audio controller continuously detect the output level of decoded audio data and use this information to automatically adjust the audio amplifier gain. The detection unit measures the actual output level of each audio file type, and the controller uses this feedback to compute the appropriate gain adjustment, ensuring consistent playback levels across different file formats without manual intervention.
3Measurement precision
If the audio data is processed and stored temporarily before playback to detect output levels, then the output level detection accuracy is improved, but the playback time is increased
Solution Approach 1:
The patent applies partial action by temporarily storing only a portion of the audio data (e.g., a predetermined number of audio frames or a specific time duration) in the buffer memory for level detection, rather than storing the entire audio file. This allows the system to detect the output level with sufficient accuracy while minimizing the buffer storage requirements and reducing the preparation time before playback can begin.
Data Source
AI summary
An apparatus and method for adjusting the output level of audio data to be reproduced can adjust any one of audio files of different types to a consistent or reference level prior to amplifying at a desired level (e.g., user selected volume). Therefore, digital audio systems and methods according to embodiments of the present invention can reproduce audio files of various types such as an MP3 audio type, MPEG2 audio type and AC3 audio type, and the output level of audio data to be reproduced of each of the audio files can be adjusted to a value corresponding to an audio volume level set by a user, which can prevent or reduce the output levels of the audio data from becoming different because of audio recording levels and recording formats of the audio files set in creation or recording processes thereof.