As you may notice this is quite a "big release" if you look at the changelog.

Features added:

• Render: Audio buffer size is now tunable in Options > Preferences.
• Render: Blitters are now cached for additional speed.
• Render: Performance sub-panel of status window now shows more appropriate stats.
• Render: Navigation keyboard shortcuts now work during preview.
• Filters: IVTC is now a video filter.
• Filters: Convert format filter now has options for UYVY and YUY2.
• Filters: Field swap now supports YCbCr formats.
• Filters: The filter system now automatically prerolls forward to compensate for filters with a lag (delay from input to output).
• Filters: New interlace filter to generate interlaced video.
• Filters: New interpolate filter to resample to different frame rates with blending.
• Filters: Added ELA, Yadif, and frame rate doubling modes to deinterlace filter.
• Filters: The filter system is now better at detecting and reporting errors in filters.
• Filters: Fixed overrun crash in box blur filter if radius exceeds size of image.
• PluginAPI: Video filters can request multiple source frames per output frame.
• PluginAPI: Video filters can request aligned scanlines.
• PluginAPI: Video filters can initiate direct bypass for frames during smart rendering.
• Capture: Fixed wrong area captured by screen capture driver with OpenGL acceleration enabled, rescale on, and mouse pointer capture enabled.
• Display: Added options for zooming to 12%.
• UI: Added Ctrl+Shift+F7 as a shortcut for batching Save AVI.
• UI: Preview no longer sticks if you seek to the end of the timeline.
• UI: Curve editor position now updates at end of timeline.
• AVI: Added DVSD to list of video formats that only have key frames.

Bugs fixed:

• Audio duration in File Information was incorrect for VBR audio streams.
• Fixed crashes with test videos when input color format was set to 4:4:4 YCbCr (YV24).
• Audio display now updates after preview stops.
• Decoders: MJPEG decoder was decoding blocks in the wrong order for 4:2:0 mode.
• Decoders: MJPEG decoder didn't safely handle corrupt data having skip-16 codes overruning the coefficient matrix.
• Filters: Fixed cases where resize filter was not using fast paths for 1:1 resampling along an axis.
• Filters: Fixed crash in warpsharp filter due to out of bounds displacement vectors.
• Filters: Fixed script error when loading configurations with warpsharp filters.
• Filters: The filter system no longer tries Y8 before other YCbCr formats if the filter cannot support a RGB32 source.
• Filters: The resize filter was using incorrect border fill colors for 4:4:4 YCbCr (YV24) input.
• Capture: Frame rate changes in filters are now respected.
• Display: Panes could get stuck in GDI mode if auto-fallback mode was disabled.
• Display: Reduced CPU usage when GPU queue becomes full in Direct3D mode with vsync off.
• Display: You can no longer resize panes below 1x1.
• Render: "Show decompressed output" no longer misses the very first frame if activated at the start of a render.
• Render: "Show decompressed output" wasn't using internal video decoders.

Regressions fixed:

• Filters: Sampling with levels filter didn't work when the input format was YCbCr (since 1.9.0).
• Filters: Filter preview broke when toggling luma mode on levels filter with YCbCr input (since 1.9.0).
• Filters: Fixed cropping bug where tall, narrow videos didn't crop properly.
• Filters: Brightness/contrast filter was broken for RGB32 input (since 1.9.0).
• Render: Fixed smart rendering issue that could cause broken frames at the start of a new processed section (since 1.8.1).
• Fixed a rare crash when doing YUV to RGB conversion on SSE2 capable systems (since 1.9.0).
• Settings saving in the Save Segmented AVI... dialog was scrambled (since 1.9.0).
• Fixed an off-by-one error in the frame count limit for segmented saving.

You can download VirtualDub 1.9.1 build 31536 here.