Avidemux 2.7.2

What's new in this version:

- Win64 version are now compiled with Visual C++, it should help stability wise  
- New Demuxer:Native AviSynth demuxer (MSVC++ 64 bits Windows builds only), 64bits avisynth only !
- New Demuxer:VapourSynth demuxer to directly load .vpy scripts (MSVC++, macOS with Homebrew, custom Linux builds), 64bits vapoursynth only on win64!
- New Installer:Replace NSIS installer with Qt Installer Framework for native MSVC++ 64 bits Windows builds
- New Encoder:Add FFmpeg-based VA-API HW accelerated H.264 encoder (Intel/Linux)
- New Encoder:Add FFmpeg-based VA-API HW accelerated HEVC encoder (Intel/Linux)
- FFmpeg:Migrate to the 4.x branch
- Decoder:As a result of the FFmpeg upgrade, HW accelerated HEVC decoding on macOS is now available when supported by the hardware
- Encoder:Fix issues with image quality and skipped frames in the MJPEG encoder
- Demuxer:Fix audio delay calculation in the Mp4 demuxer
- Demuxer:Fix crash loading large MP4 files with LPCM audio
- Demuxer:Fix multiple issues in the ASF demuxer, allow to cancel indexing
- Demuxer:Allow to cancel indexing of MKV files
- Demuxer:Re-enable multiloading for MPEG-TS streams cut in chunks of 256, 512 MiB, 1, 2 and 4 GiB in size only
- Demuxer:Fix MPEG-TS indexer to start a H.264 or HEVC frame with the Access Unit Delimiter
- Muxer:Add Annex B to Annex B video stream filter to deal with misplaced frame boundaries
- Muxer:Add support for setting rotation flag to the MP4 muxer
- Filter:Add rubber band selector to the "Blacken Borders" filter
- Filter:Add option to deal with anamorphic display to the subtitle filter, fix issues in SRT to SSA converter
- UI:Autosave session on video close, add session restore feature
- UI:Add file name extension when saving audio for some audio types
- Audio:Make maximum level in the "Normalize" filter customizable
- Audio:Improve AAC sampling frequency detection
- Audio:Add decoding support for multichannel Opus audio
- Miscellaneous:Fix regression playback stuck after going to the previous picture
- Miscellaneous:Fix regression "Fade to black" reset when starting filtered playback close to the end of video
- Miscellaneous:Fix regression stopping playback rewinds to the start of video if seek back to the last displayed picture fails