New Features

New HiDPI compatible button set
Fast method to add partial filters via CTRL+F shortcut
Audio department improvements
    custom frame rate change (audio stretch with pitch control)
    configurable compressor (DRC)
    3-band equalizer
    independent channel gain options
    independent channel delay options
    channel remap options
    new downmix options: stereo headphone and headphone virtual surround
    audio track configuration up to 32 tracks
    volume setting is saved upon exit
Light and dark theme options in View menu
Option to remember selected resize method in "Resize", "Fit to size" and "Zoom" filters
New filter: 3D LUT
New filter: Decimate
New filter: Arbitrary Rotate
New video encoder: VideoToolbox HEVC ("ffVTEncHEVC", macOS only)

Other Enhancements

HDR tonemapping performance and quality improvements
Extended file info
Rotating mouse wheel over buttons to seek by 60 seconds cycles through 1/2/4/60 seconds seek modes
Support for decoding 8-bit VP9 in hardware via DXVA2 on Windows and via VDPAU on Linux with graphics cards featuring a VP9 decoder
Buttons to seek to selection start (A) and end (B) in on-the-fly video filter preview
Logo image in "Add logo" video filter configuration dialog is now scalable, can be repositioned by dragging
By default, on-the-fly preview in video filter configuration dialogs is now rendered using OpenGL to improve performance in HiDPI conditions

Bugfixes

Crash on copy to clipboard if selection extends to the end of video, a regression introduced in v2.8.0
Crashes in "Resample FPS" video filter with motion interpolation enabled
Crash on finishing encoding with the vp9 encoder
Avidemux falling victim to a crash in VA-API driver triggered by probing on application startup on Linux with some recent hardware
Crash loading MPEG-TS or MPEG-PS file with MPEG-1 video track and HW decoder via VDPAU enabled
Wrong number of channels or wrong channel layout with some E-AC3 streams
Reduced contrast and desaturated colors in loaded BMP images
Selection starting at zero and ending at the last picture of video cannot be deleted
Disabling B-frames breaks VideoToolbox HW encoder (macOS only)

Miscellaneous

Bundled FFmpeg libraries have been updated to 4.4.2 release.