Audio Time Stretching for Travel Duration Alignment

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Solution Overview

Problem

Existing broadcast receivers struggle to align audio content from different sources, such as FM, DAB, and Internet radio, with a user's travel time due to predefined content lengths not matching travel duration, and require seamless transitions between sources.

Innovation Solution

A system and method for time stretching or compressing audio content using an audio time stretch/compress device that incorporates an electronic program guide decoder and audio/video decoder to align playback with estimated travel time, allowing for delay or speed adjustment of audio streams based on transmission delays and user input, using a buffer to maintain seamless transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If audio content from different broadcast domains (FM, DAB, Internet radio) is played back, then users can access multiple audio sources, but the audio content cannot be aligned in time with each other or with travel time

Engineering Contradiction:
Improveability to access multiple audio sourcesVSAvoidtime alignment between audio sources and travel time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system dynamically adjusts the playback rate of audio content based on real-time travel time calculations. The audio playback speed is modified on-the-fly to ensure that audio programs end precisely when the vehicle arrives at the destination, rather than playing at a fixed predetermined rate

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the temporal parameter of audio playback by stretching or compressing the audio timeline. This parameter modification allows predefined-length audio content to adapt to variable travel durations, aligning audio endpoints with arrival times at destinations

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If audio content is stretched or compressed to match travel time, then time alignment with travel is improved, but the listening experience may be degraded

Engineering Contradiction:
Improvetime alignment with travel durationVSAvoidlistening experience quality
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The system applies controlled temporal parameter changes to audio content, stretching or compressing it within perceptual thresholds. The modification is designed to be minimal enough that listeners cannot detect changes in playback rate, while still achieving precise alignment with travel duration

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system introduces an audio processing intermediary that acts as a buffer between the original audio content and the output playback. This intermediary performs time-stretching or time-compressing operations that preserve audio quality while adjusting duration to match travel time

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If seamless transitions between different audio sources are implemented, then source switching is smooth, but time synchronization between sources becomes more complex

Engineering Contradiction:
Improvesmoothness of source transitionsVSAvoidtime synchronization complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The system employs dynamic time alignment that automatically adjusts each audio source's playback rate based on its position in the playlist and the current travel time. This dynamic adjustment enables seamless transitions between sources without manual synchronization, as each source is automatically timed to fit the remaining travel duration

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from travel time calculations to continuously adjust audio playback rates. By monitoring the difference between current playback progress and estimated arrival time, the system real-time synchronizes multiple audio sources, simplifying the complexity of maintaining alignment across different broadcast domains

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3410701B1Audio/video time stretching
Publication Date: 2022.07.20 NXP BV
  • EP3410701B1 patent drawingFigure 1
  • EP3410701B1 patent drawingFigure 2

AI summary

A device is disclosed. The device includes a plurality of ports to receive a plurality of audio streams, an audio content control unit configured to modify playback length of an audio content of at least one of the plurality of audio streams according to an input time interval, an audio decoder and a memory buffer coupled to the audio decoder and the audio content control unit. The memory buffer is used by the audio content control unit to buffer at least one of the plurality of audio streams.