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OpenDAFF C++ API
v1.7
Directional Audio File Format
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OpenDAFF C++ API
v1.7
Directional Audio File Format
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The OpenDAFF project is free, open source software package for directional audio data. It is distributed under the terms of the Apache License Version 2.0. The official website can be found at http://www.opendaff.org
Copyright 2016 Institute of Technical Acoustics, RWTH Aachen University
Licensed under the Apache License, Version 2.0 (the "License"); you may not use the OpenDAFF software package except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
You should also have received a copy of the License with the OpenDAFF software package.
DAFF provides a list of specific content types that can be found in DAFF_CONTENT_TYPES with their respective class definitions:
Everyone has an individual preference when it comes to coordinate systems. And because there is no best solution, DAFF can not provide a way that satisfies everyone. But at the end of the day one definition has to be settled when designing an extensive spatial and/or directional audio data format. DAFF uses the common OpenGL Cartesian coordinate system, where the default view direction of an object points along the -Z axis and the up direction points along +Y axis. For orientations in DAFF, e.g. a right-handed yaw-pith-roll definition, the euler angles are based on this coordinate system. This may appear odd to Matlab users, which might prefer a view direction along +X and an up direction along +Z axis, but is perfectly normal for users from the Virtual Reality sector since it is widely used for 3D visualization. DAFF also uses a common view on the directional data, the user or object view, with a spherical coordinate system where the front direction is defined by the angular pair (phi,theta) = (0,0) and the up direction is (0,pi/2). Phi is a right-hand azimuthal rotation around the up vector (+Y) in the range of [0,2pi). Theta is the elevation angle with a range of [-pi/2,pi/2]. Wherever possible, DAFF will use function and variable names that indicate the units of angles (rad or grad), but if not stated grad values (may be negative) can be expected. However, DAFF also partly supports another view on directional data that is represented by a spatial sampling of equi-angular grids, the so-called data view. This view is only of concern for creators of DAFF content, a user should never use it. The data view starts at south pole with the angular pair (alpha,beta) = (0,0) and ends at north pole with the pair (0,pi). To lock the rotation between object and data view the creator of the DAFF content has to define a rotation that will guarantee that the user or object view will always point to the front direction at angle (0,0) and up direction at (0,pi/2).