Limitations and Changes
- Presently, upstream changes have to be manually merged into the
- Binary builds for Linux are run as Flatpak builds, but are not published to any repository.
- Builds are signed with an untrusted certificate.
The licensing situation of the FDK library is complicated. The source of the library is open and has a copyleft license for copyright purposes, but Fraunhofer grants no patent license.
Copyright: The FFmpeg developers have deemed FDK to be GPL incompatible. In deference to that determination, HandBrake's developers no longer distribute binaries of HandBrake with FDK compiled in. The position of both the FFmpeg and HandBrake projects is that binaries with FDK built in cannot be distributed by reason of the GPL incompatibility, even though end-users may compile FDK for their own use. The incremental difficulty of compiling HandBrake with FDK is trivial — adding the
--enable-fdk-aac flag is the developers' recommended solution.
Patents: A separate issue concerns the patents necessary to use the FDK library, because it supports not only "simple" AAC (initially specified in MPEG-2) but also features of AAC introduced in MPEG-4, as well as HE-AAC. MPEG-4 and HE-AAC are still covered by patents today. A stripped version of the FDK library exists and has been submitted for inclusion in Fedora; that version of the library pares down FDK to the features in MPEG-2 that are no longer patent-encumbered. I am looking into integrating that stripped version of FDK into HandBrake.
Above, builds without FDK are public. Builds with FDK are compiled on private servers and are not currently being redistributed; the above links presently require authentication.