* Handle MP3 files with special logic, since they typically only have 1 frame of video
* Better support for missing frames (handling of missing audio and missing video data separated), and fixed a missing audio regression.
* Integration of libresvg SVG library (optional during build)
* Major refactor of max_width and max_height for preview optimization
* Fixed many bugs related to preview resizing, with regards to cached frames
* Updating gitlab CI to find RESVGDIR correctly for windows, and adding svgz support
* Updating cmake findresvg module to search for windows locations first, to prevent an issue on our windows builders and updating some CMake output.
* Removing folder path from resvg header, since it could be installed in different named folders. This is an attempt to fix Windows include issues.
* Making call to AV_FREE_FRAME conditional for non windows systems (because it crashes on Windows for seemingly no reason). Needs more investigation.
* FFmpeg4 support. Compile warnings fixes. Credit goes to many people, including ferdnyc, peterM, and other awesome folks!
* Adding environment checking to enable/disable omp taskwait after each video/audio frame is processed. This is experimental for some users with crashes.
* Moving `omp taskwait` to after the ProcessVideoPacket() method, since that is the only place it is useful.
* Fixing crashes on missing Clip source file, and changing FFmpeg scaling algorthm from SWS_BILINEAR to SWS_LANCZOS (for higher quality scaling)
* Update FindFFmpeg.cmake module, and updating build script. Also enabling debug builds.
* Updating experimental travis build script
* Fixed unit test for newer version of FFmpeg (audio resampling)
* Experimental travis multiple jobs
* Adding OMP schedule hint (thanks PeterM), which prevents crashes in some circumstances.
* Adding strict experimental to FFmpegReader and Writer (hopefully allowing all the encoders to be used)
(cherry picked from commit 1bcd1e5)
* init all formats and codecs before checking if valid
(cherry picked from commit 7250226)
