Synopsis
Ospac will take a multi-channel recording of an audio podcast conversation
and master this to a high-quality mix-down with support for intro and outro.
Features
Beside other features, ospac includes a robust leveler, two solutions to
avoid crosstalk and soft silence skipping.
Leveler
Ospac provides an energy based leveler. The following plot shows the
original on top and the levelled outcome on the bottom:
Crosstalk Filter
This waveform shows a crosstalk from the first channel in to the second
channel, and some original content in the second half of the second channel:
The included crosstalk gate is a very robust algorithm that results in the
following:
A new experimental crosstalk filter tries to improve the result:
Soft silence skipping
When enabled, ospac may reduce silence above 0.5s to shorter pauses:
Alternatively, ospac can try to reach target lengths (90%, 80%, 70%, 60%,
and 50%) compared to the original:
Of course, the result will only be really acceptible until all silence space is
used up.
Examples
Mix 2 mono voice recordings with crosstalk filter, leveling and normalization:
ospac person1.wav person2.wav --output target.wav
Mix a podcast with stereo intro and outro:
ospac --mix in.wav --overlap 4 \
--voice person1.wav person2.wav --overlap 4 \
--mix out.wav --output target.wav
Motivation
Ospac was developed due to the need of a batch solution for audio podcast
creation. It is a rewrite and compilation of the scripts and methods used
for the Modellansatz podcast, http://modellansatz.de/ .
Installation
Check that you have libsndfile and a c++-compiler on your system.
Then, you may build and install ospac in this way:
$ make ospac && sudo make install
If you have ffmpeg and libav on your system, you may also build ospac with
support for loading of various audio formats and writing aac files:
$ make ospac-ffmpeg && sudo make install-ospac-ffmpeg
On MacOS you can install libsndfile using homebrew simply by:
$ brew install libsndfile
If you want to build the GUI, install the development packages for
fltk-1.3 and then build ospac-gui:
$ make ospac-gui && sudo make install-gui
Since there seem to be some broken fltk-1.3 source packages on linux, you
can alternatively try the following to build a non-statically linked
version:
$ make ospac-gui-linux && sudo make install-gui
To simplify usage tab-completion files for bash and zsh can be generated:
$ make tab-completion
The tab-completion is then usable by appending the following to your
.[bash, zsh]rc file:
source PATH_TO_OSPAC/[zsh, bash]_completion.sh
API Reference
See the doxygen docs
https://github.com/sritterbusch/ospac/raw/master/ospac-internal.pdf
for a detailed API reference.
Tests
You may run tests that create exemplary mixdowns and waveform images
that are used in the API documentation.
$ make test
License
The MIT License (MIT)
Copyright (c) 2016-2017 Sebastian Ritterbusch ospac@ritterbusch.de
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.