Multi-Channel Audio Encoding with Identical Timestamps

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Solution Overview

Problem

Current audio coding standards, such as MPEG-1 and MPEG-2, do not efficiently support synchronized transmission of individual multi-channel audio components, leading to quality degradation when signals are re-encoded multiple times, especially in limited bandwidth scenarios, and require either proprietary equipment or high data rates for uncompressed audio.

Innovation Solution

A method of encoding and decoding that assigns identical time stamps to temporally co-located audio signals, aligns them into frames, and compresses them using dual-mono audio components within the MPEG-2 transport stream, maintaining synchronization across multiple channels without converting them into a single component.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If surround-sound compression methods are used to reduce bit rate, then data rate requirements are reduced, but audio quality degrades when signals are re-encoded multiple times

Engineering Contradiction:
Improvebit rateVSAvoidaudio quality
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The invention segments the multi-channel audio into separate individual audio components (e.g., left, right, center, surround channels) that are encoded and transmitted independently rather than as a single pre-mixed surround sound component. This allows each channel to be processed separately, maintaining higher quality when re-encoded multiple times while still achieving bit rate reduction through selective compression of individual channels based on their specific characteristics.

Inventive Principle:
Principle #1Segmentation

2Reliability

If uncompressed audio format is used to maintain audio quality, then audio quality is preserved, but data rate requirements increase substantially

Engineering Contradiction:
Improveaudio qualityVSAvoiddata rate
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The invention applies different compression strategies to different audio channels based on their local characteristics. Some channels may be compressed more aggressively while others maintain higher fidelity, allowing the system to achieve acceptable overall audio quality at reduced bit rates compared to uncompressed transmission, while still providing better quality than uniform surround-sound compression.

Inventive Principle:
Principle #3Local quality

3Reliability

If individual multi-channel audio components are transmitted separately, then audio quality and flexibility are improved, but synchronization between channels becomes difficult to maintain

Engineering Contradiction:
Improveaudio qualityVSAvoidchannel alignment
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention implements preliminary synchronization actions by embedding timing information and synchronization markers within each individual audio component during the encoding phase. This preliminary preparation ensures that when the separate channels are transmitted and potentially re-encoded multiple times, they can be automatically resynchronized at the decoder without requiring complex post-processing or proprietary equipment.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If proprietary compression techniques are used to maintain quality, then audio quality is preserved, but equipment cost and operational complexity increase

Engineering Contradiction:
Improveaudio qualityVSAvoidequipment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention employs universal encoding and decoding algorithms that are compatible with standard MPEG audio decoders already widely deployed in consumer equipment. By making the system multi-functional and compatible with existing standards rather than requiring proprietary equipment, it achieves good audio quality without increasing device complexity or operational costs.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3040986B1Method and apparatus for delivery of aligned multi-channel audio
Publication Date: 2018.12.12 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3040986B1 patent drawingFigure 1~2
  • EP3040986B1 patent drawingFigure 3~4
  • EP3040986B1 patent drawingFigure 5

AI summary

There is provided a method of encoding audio and including said encoded audio into a digital transport stream, comprising receiving at an encoder input a plurality of temporally co-located audio signals, assigning identical time stamps per unit time to all of the plurality of temporally co-located audio signals and incorporating the identically time stamped audio signals into the digital transport stream. There is also provided a method decoding said encoded data, and encoding apparatus and decoding apparatus.