- Who owns VCA?
Christian Doppler Laboratory ATHENA is the primary developer of VCA. Christian Doppler Laboratory ATHENA owns the copyright to VCA. All portions of VCA are either works of original authorship of Christian Doppler Laboratory ATHENA, contributions from developers who have signed a Contributor Agreement or were otherwise fully licensed with all necessary rights by Christian Doppler Laboratory ATHENA.
- How is VCA licensed?
VCA is made available under the open-source GNU GPL v3 license, to anyone who is willing to comply with the terms of this license.
- Can I use VCA in my open-source product?
If your open-source product is offered under and compliant with the GPL v3, the answer is yes: you can incorporate and distribute the combined work in full compliance with VCA’s GPL v3 license. You can build and distribute products under even more permissive open-source licenses like the BSD modified or Apache license, but you must keep the VCA library as a separate library, distributed under the GPL v3. You cannot cause VCA to become available under another open source license.
- Can I use VCA in my commercial product?
Yes, if your commercial product is distributed under the GPL v3 license.
- If I use VCA in my product, will I be required to disclose my source code?
When you incorporate VCA offered under the GPL v3 license into your product, your product will be subject to the terms of the GPL v3 license. Thus, you must make the source code to your product available to any user upon request.
- If I use VCA, obtained under the GNU GPL v3, am I allowed to modify the original code into a new program, then distribute and sell that new program commercially?
If you use VCA under the GPL v3 license, you are allowed to sell copies of the modified program commercially, but only under the terms of the GNU GPL v3. You must make the source code available to the users of the program as described in the GPL, and they must be allowed to redistribute and modify it as described in the GPL. These requirements are the condition for including the GPL-covered code you received in a program of your own.
- Instead of using VCA (GPL v3), can I use FFMPEG or VLC (LGPL) with VCA in my commercial product?
Although FFMPEG and VLC are offered under the LGPL license, when compiled with VCA they are subject to the GPL v3 license. If you use FFMPEG or VLC compiled with VCA in your commercial product it will be subject to the terms of the GPL v3.
- To avoid causing my commercial product to be subject to the terms of the GPL v3, can I create or use a “wrapper” application or API, where the wrapper is offered under the LGPL?
An LGPL API or application cannot use GPL v3 software and still comply with the LGPL. Doing this causes the wrapper application or API to be subject to the terms of the GPL v3. If you would like to add VCA to your commercial application, your product will be subject to the terms of the GPL v3 open source license.
- Aren’t there exceptions that would allow me to use VCA GPL v3 in my commercial application if I don’t do “deep integration” (for example, if I only pass a command-line to libvca, feeding frames in through pipes)?
Given the nature of what VCA does when used with any video related product, we don’t believe that this is possible. “You cannot incorporate GPL-covered software in a proprietary system. A system incorporating a GPL-covered program is an extended version of that program. The GPL says that any extended version of the program must be released under the GPL if it is released at all.”
- Are there exceptions for dynamic linking instead of static linking VCA?
No. Linking a GPL covered work statically or dynamically with other modules is making a combined work based on the GPL covered work. Thus, the terms and conditions of the GNU General Public License cover the whole combination. See https://www.gnu.org/licenses/gpl-faq.html#GPLStaticVsDynamic
- Isn’t Christian Doppler Laboratory ATHENA subject to the terms of the GNU GPL v3?
No. Christian Doppler Laboratory ATHENA owns VCA. Christian Doppler Laboratory ATHENA is the licensor, not the licensee. However, VCA will always be available under the GPL v3, and there will be no private forks of VCA.