Audio Ducking Metadata for Clearer Narration Playback
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Solution Overview
Problem
Existing audio systems compromise the intelligibility of narration channels when played simultaneously with other audio channels, particularly main dialogue channels, which can interfere with the narration intended for visually impaired users.
Innovation Solution
An audio encoding device generates ducking values to associate with a narration channel, reducing the dynamic range of other channels during playback, thereby emphasizing the narration channel and improving its intelligibility by selectively attenuating other channels based on activity detection and varying the rendering location within the sound field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If narration channel is played simultaneously with main dialogue channels, then visually impaired users can access audio descriptions, but intelligibility of narration channel deteriorates due to interference from other channels
Solution Approach 1:
The system dynamically adjusts the volume level of the narration channel relative to other audio channels based on detected speech activity. When speech is detected in other channels, the narration volume is reduced; when no speech is detected, the narration volume is increased. This dynamic adjustment resolves the contradiction by making the narration intelligible only when necessary, rather than maintaining a static volume level that would either constantly interfere or constantly be inaudible.
Solution Approach 2:
The system changes the audio parameter (volume level) of the narration channel based on detected conditions. By monitoring speech activity in other channels and adjusting the narration volume parameter accordingly, the system optimizes intelligibility while minimizing interference. This parameter change approach allows the narration to be emphasized when needed and suppressed when other channels are active.
2Loss of information
If volume of narration channel is increased to improve intelligibility, then visually impaired users can better understand audio descriptions, but interference with other audio channels increases
Solution Approach 1:
The system uses feedback from speech detection in other audio channels to control the volume of the narration channel. The speech detector monitors other channels and provides feedback that triggers volume adjustments for the narration. This closed-loop feedback mechanism ensures that narration volume is increased only when other channels are inactive, thereby improving intelligibility without causing interference.
Solution Approach 2:
Rather than maintaining a fixed high volume for narration, the system dynamically adjusts the volume based on real-time detection of speech activity in other channels. This dynamic approach allows the narration to be loud enough to be intelligible when needed while automatically reducing volume when other channels are active, thus avoiding the contradiction between intelligibility and interference.
3Loss of information
If selective ducking is applied to reduce interference with narration, then intelligibility of narration channel improves, but complexity of audio processing increases
Solution Approach 1:
The audio system is segmented into distinct functional components: a speech detector that monitors specific channels, a controller that processes detection signals, and volume adjustment mechanisms for the narration channel. This segmentation allows each component to perform its function independently and efficiently, reducing overall processing complexity while achieving selective ducking to improve narration intelligibility.
Data Source
AI summary
An audio encoding device and an audio decoding device are described herein. The audio encoding device may examine a set of audio channels/channel groups representing a piece of sound program content and produce a set of ducking values to associate with one of the channels/channel groups. During playback of the piece of sound program content, the ducking values may be applied to all other channels/channel groups. Application of these ducking values may cause (1) the reduction in dynamic range of ducked channels/channel groups and/or (2) movement of channels/channel groups in the sound field. This ducking may improve intelligibility of audio in the non-ducked channel/channel group. For instance, a narration channel/channel group may be more clearly heard by listeners through the use of selective ducking of other channels/channel groups during playback.