Content for TR 26.933 Word version: 19.0.0
4 Size and structure evolution of UEs
5 Microphones used in immersive audio capture
6 Immersive audio capture format
7 Microphone integration in UEs
8 Signal processing
9 Example audio capture processing solutions
10 Conclusions and Recommendations
A UE size
B Stereo AEC
$ Change history
4 Size and structure evolution of UEs p. 11
4.1 Mobile phones p. 11
4.2 Headphones p. 14
4.3 Tablets p. 14
4.4 Laptops p. 15
4.5 Watches p. 15
4.6 XR devices p. 17
4.7 Cars p. 17
4.8 Conclusion p. 18
5 Microphones used in immersive audio capture p. 18
5.1 Introduction p. 18
5.2 Transducer type p. 18
5.2.1 Dynamic microphone p. 18
5.2.2 Condenser microphone p. 18
5.2.3 MEMS microphone p. 19
5.2.4 Contact microphone p. 19
5.3 Directional Microphone p. 19
5.4 Binaural acoustic simulation p. 20
5.5 Conclusion p. 20
6 Immersive audio capture format p. 20
6.1 Stereo capture p. 20
6.1.1 Principle of stereo signal representation p. 20
6.1.2 Characteristic of stereo capture p. 20
6.1.3 Factors that affect stereo capture p. 20
6.1.4 Stereo microphone configurations p. 21
6.1.4.1 Introduction p. 21
6.1.4.2 Near-Coincident p. 21
6.1.4.3 Baffled p. 21
6.1.4.4 Coincident p. 22
6.1.4.5 Spaced p. 23
6.2 Spatial audio capture p. 24
6.2.1 Introduction p. 24
6.2.2 Binaural capture p. 24
6.2.2.1 Principle of binaural signal representation p. 24
6.2.2.2 Possible issues in binaural capture p. 24
6.2.2.3 Factors that affect binaural capture p. 24
6.2.2.4 Differences between binaural and stereo audio p. 24
6.2.3 Parametric spatial audio capture p. 25
6.2.3.1 Principle of parametric spatial audio representation p. 25
6.2.3.2 Characteristics of parametric spatial audio capture and representation p. 26
6.2.3.3 Factors that affect parametric spatial audio capture p. 26
6.2.3.4 Multi-microphone configurations in parametric spatial audio p. 26
6.2.4 Non-parametric spatial audio capture p. 27
6.2.4.1 Principle of non-parametric spatial audio representation p. 27
6.2.4.2 Characteristics of non-parametric spatial audio capture and representation p. 27
6.2.4.3 Factors that affect non-parametric spatial audio capture p. 27
6.2.4.4 Multi-microphone configurations in non-parametric spatial audio p. 27
6.2.4.4.1 Immersive audio ORTF configuration [4] p. 27
6.2.4.4.2 Immersive audio M/S configuration p. 28
6.2.4.4.3 IRT-cross p. 29
6.2.4.5 Comparisons between non-parametric spatial audio capture and parametric spatial audio capture p. 30
6.3 Summary p. 30
7 Microphone integration in UEs p. 30
7.1 Microphone integration in mobile phones p. 30
7.2 Microphone integration in headphones p. 33
7.3 Microphone integration in tablets p. 33
7.4 Microphone integration in laptops p. 34
7.5 Microphone integration in watches p. 35
7.6 Summary p. 36
7.7 Microphone integration and frequency response p. 36
8 Signal processing p. 40
8.1 AEC p. 40
8.1.1 Principle of mono audio AEC p. 40
8.1.2 Challenges for immersive audio AEC p. 40
8.1.3 The current status of the research p. 41
8.1.4 AEC for different UEs p. 41
8.2 Microphone Array Signal Processing on device p. 41
8.2.1 Introduction p. 41
8.2.2 MASP for Channel-based p. 43
8.2.2.1 MASP for Stereo p. 43
8.2.3 MASP for Binaural p. 43
8.2.4 MASP for Scene-based p. 43
8.2.5 MASP for MASA p. 43
8.2.6 MASP for Object-based p. 44
8.2.7 MASP for OMASA p. 44
8.2.8 MASP for OSBA p. 44
8.3 Beamforming p. 44
8.4 Noise reduction p. 46
8.5 Conclusion p. 47
9 Example audio capture processing solutions p. 47
9.1 Capture Scenarios p. 47
9.2 End-user device (UE) characteristics/prerequisites p. 48
9.2.1 General p. 48
9.2.2 Number and placement of microphones p. 48
9.2.3 Loudspeaker number and placement of loudspeakers p. 48
9.3 Capture solution for end-user devices p. 49
9.3.1 Overview p. 49
9.3.2 Compensation p. 49
9.3.3 Enhancement p. 49
9.3.3.1 Introduction p. 49
9.3.3.2 General considerations p. 49
9.3.3.3 AEC p. 49
9.3.3.4 Noise reduction p. 50
9.3.4 Audio format generation p. 50
9.3.4.1 Introduction p. 50
9.3.4.2 Example of stereo processing p. 50
9.3.4.3 Example of scene-based audio processing p. 51
9.3.4.3.1 Introduction p. 51
9.3.4.3.2 Content based processing p. 51
9.3.4.3.3 Ambisonic upmixer p. 51
9.3.4.4 Example of parametric spatial audio processing p. 51
9.3.5 Post-processing p. 52
10 Conclusions and Recommendations p. 52
A UE size p. 52
A.1 Mobile phone size p. 52
A.1.1 Modern mobile phone structure size p. 52
A.1.2 Book-style foldable mobile phone structure size p. 56
A.1.3 Clamshell-style foldable structure size p. 58
A.2 Earbud size p. 60
A.3 Tablet size p. 61
A.4 Laptop size p. 62
A.5 Watch size p. 62
A.6 XR device size p. 63
A.7 Car exterior size p. 63
A.8 Car exterior and interior size p. 64
B Stereo AEC p. 65
$ Change history p. 69
