| commit | author | age | ||
| b36c86 | 1 | ;Authors: |
| MS | 2 | ; A. Nguyen, 2025 |
| 3 | ; M. Schumacher, 2025 | |
| 791513 | 4 | |
| AN | 5 | ; Design limitations: |
| 6 | ; 1) Sounds must have identical sample rate; otherwise, SoX fails silently, literally. | |
| 7 | ||
| 8 | ; Questions: | |
| 197ce0 | 9 | ; 1) Is there a built-in (flatten lst)-function? Yes, om:flat |
| MS | 10 | ; 2) Implement up to which order? <=> CLI issues to be expected (e.g., maximum command character length)? max character length for CLI should be changeable |
| 791513 | 11 | |
| AN | 12 | (in-package :om) |
| 13 | ||
| 14 | ;;; SOX-HOAENCODE ======================== | |
| 15 | ||
| 16 | ; Util | |
| 17 | (defun flatten (structure) | |
| 18 | (cond | |
| 19 | ((null structure) | |
| 20 | nil) | |
| 21 | ((atom structure) | |
| 22 | (list structure)) | |
| 23 | (t | |
| 24 | (mapcan #'flatten structure)) | |
| 25 | ) | |
| 26 | ) | |
| 27 | ||
| 28 | (defun sox-hoaencode-deg-to-rad (x) | |
| 29 | (* (/ x 180) pi) | |
| 30 | ) | |
| 31 | ||
| 32 | (defun sox-hoaencode-double-to-float (lst) | |
| 33 | (mapcar | |
| 34 | (lambda (x) (float x 0.0S0)) | |
| 35 | lst | |
| 36 | ) | |
| 37 | ) | |
| 38 | ||
| 197ce0 | 39 | ; ### Ambisonics ### |
| MS | 40 | |
| e43e60 | 41 | (defun sox-hoaencode-sn3d-factor (order degree) |
| MS | 42 | "This is a placeholder for documentation" |
| 791513 | 43 | (ecase order |
| AN | 44 | (0 1) |
| 45 | (1 1) | |
| 46 | (2 | |
| 47 | (ecase (abs degree) | |
| 48 | (2 (/ (sqrt 3) 6)) | |
| 49 | (1 (/ (sqrt 3) 3)) | |
| 50 | (0 1) | |
| 51 | )) | |
| 52 | (3 | |
| 53 | (ecase (abs degree) | |
| 54 | (3 (/ (sqrt 10) 60)) | |
| 55 | (2 (/ (sqrt 15) 30)) | |
| 56 | (1 (/ (sqrt 6) 6)) | |
| 57 | (0 1) | |
| 58 | ) | |
| 59 | ) | |
| 60 | ) | |
| 61 | ) | |
| 62 | ||
| 63 | (defun sox-hoaencode-azimuth-factor (degree theta_deg) | |
| e43e60 | 64 | "This is a placeholder for documentation" |
| 791513 | 65 | (let* |
| AN | 66 | ( |
| 67 | (theta (sox-hoaencode-deg-to-rad theta_deg)) | |
| 68 | ) | |
| 69 | (if (< degree 0) | |
| 70 | (sin (* (abs degree) theta)) | |
| 71 | (cos (* (abs degree) theta)) | |
| 72 | ) | |
| 73 | ) | |
| 74 | ) | |
| 75 | ||
| 76 | (defun sox-hoaencode-elevation-factor (order degree phi_deg) | |
| e43e60 | 77 | "This is a placeholder for documentation" |
| 791513 | 78 | (let* |
| AN | 79 | ( |
| 80 | (phi (sox-hoaencode-deg-to-rad phi_deg)) | |
| 81 | ) | |
| 82 | (ecase order | |
| 83 | (0 1) | |
| 84 | (1 | |
| 85 | (ecase (abs degree) | |
| 86 | (0 (sin phi)) | |
| 87 | (1 (cos phi)) | |
| 88 | )) | |
| 89 | (2 | |
| 90 | (ecase (abs degree) | |
| 91 | (0 (- (/ (* 3 (expt (sin phi) 2)) 2) (/ 1 2))) | |
| 92 | (1 (/ (* 3 (expt (sin phi) 2)) 2)) | |
| 93 | (2 (* 3 (expt (cos phi) 2))) | |
| 94 | )) | |
| 95 | (3 | |
| 96 | (ecase (abs degree) | |
| 97 | (0 (/ (* (sin phi) (- (* 5 (expt (sin phi) 2)) 3)) 2)) | |
| 98 | (1 (- (* 6 (cos phi)) (/ (* 15 (expt (cos phi) 3)) 2))) | |
| 99 | (2 (* -15 (sin phi) (- (expt (sin phi) 2) 1))) | |
| 100 | (3 (* 15 (expt (cos phi) 3))) | |
| 101 | )) | |
| 102 | ) | |
| 103 | )) | |
| 104 | ||
| 197ce0 | 105 | |
| MS | 106 | |
| 107 | ; ####### High-level API ########## | |
| 108 | ||
| 109 | ||
| 791513 | 110 | (defun sox-hoaencode-gain-single-component (order degree azimuth_deg elevation_deg) |
| 197ce0 | 111 | "Returns the gain value (linear, -1 to 1) for a single ACN-channel" |
| 791513 | 112 | (let |
| AN | 113 | ( |
| 114 | ; It is assumed that azimuth_deg follows the implementation details of SpatDIF, | |
| 115 | ; where azimuth_deg runs counterclockwise. | |
| 116 | ; However, the formulas inside assume that azimuth_deg runs clockwise, i.e. | |
| 117 | ; the sign of azimuth_deg must be inverted. | |
| 118 | (azimuth_deg_inverted (* -1 azimuth_deg)) | |
| 119 | ) | |
| 120 | (* | |
| 121 | (sox-hoaencode-sn3d-factor order degree) | |
| 122 | (sox-hoaencode-azimuth-factor degree azimuth_deg_inverted) | |
| 123 | (sox-hoaencode-elevation-factor order degree elevation_deg))) | |
| 124 | ) | |
| 125 | ||
| 197ce0 | 126 | ; (sox-hoaencode-gain-single-component 1 1 45 0) |
| 6ae8ed | 127 | ; @AN: what is the difference between "order" and "degree"? |
| 197ce0 | 128 | |
| MS | 129 | |
| 791513 | 130 | (defun sox-hoaencode-gains-by-order (order azimuth_deg elevation_deg) |
| 197ce0 | 131 | "Returns the gain values for all components at a specific order" |
| 791513 | 132 | (loop for degree from (* -1 order) to order collect |
| AN | 133 | (sox-hoaencode-gain-single-component order degree azimuth_deg elevation_deg))) |
| 134 | ||
| 197ce0 | 135 | |
| 791513 | 136 | (defun sox-hoaencode-gains-up-to-order (order azimuth_deg elevation_deg) |
| 197ce0 | 137 | "Returns the gain values for all components up to a specific order" |
| 791513 | 138 | (sox-hoaencode-double-to-float |
| AN | 139 | (flatten |
| 140 | (loop for ord from 0 to order collect | |
| 141 | (sox-hoaencode-gains-by-order ord azimuth_deg elevation_deg))))) | |
| 142 | ||
| 143 | ||
| 144 | (defclass! sox-hoaencode (sox-input) | |
| 145 | ( | |
| 6ae8ed | 146 | (gains :accessor gains :initarg :gains :initform nil :documentation *sox-gain-doc*) |
| e43e60 | 147 | (azimuth :accessor azimuth :initarg :azimuth :initform 0 :documentation "azimuth angle in degrees") |
| MS | 148 | (elevation :accessor elevation :initarg :elevation :initform 0 :documentation "elevation angle in degrees") |
| 149 | (order :accessor order :initarg :order :initform 3 :documentation *sox-hoaencode-order-doc*) | |
| 791513 | 150 | ) |
| AN | 151 | (:icon 100) |
| 124c93 | 152 | (:documentation "Sox-hoaencode encodes <sound> into a <order>-th ambisonic (HOA) signal at <positions>. |
| 791513 | 153 | |
| AN | 154 | The signal follows the ambiX convention, i.e. it uses SN3D normalization and ACN channel ordering. The resulting file has (<order>+1)^2 channels (order 0: 1 channel, order 1: 4 channels, order 2: 9 channels, order 3: 16 channels, ...).") |
| 155 | ) | |
| 156 | ||
| 157 | (defmethod initialize-instance :after ((self sox-hoaencode) &rest l) | |
| 158 | (declare (ignore l)) | |
| 159 | (when (sound self) | |
| b36c86 | 160 | (sox-init-sound self 'atom) |
| 791513 | 161 | ) |
| AN | 162 | ) |
| 197ce0 | 163 | |
| MS | 164 | |
