VirtualDub help - Capture: Pipeline
Processing: Main UI Editing Filtering Rendering/saving Artifacts The pipeline Direct mode Display panes Frameserver Video filter reference Video shader reference Video capture Hardware setup Driver selection Audio setup Pipeline Filtering Info panel Multi-segment mode Timing dialog Performance Troubleshooting Dialogs: Video filters Video frame rate control Video color depth Video range Video compression Audio filters Audio interleaving Audio compression Audio conversion Audio volume Capture settings Preferences On a crash... | Like during a render-to-disk, captured audio and video flows through a series of processing stages before written to disk. This is what VirtualDub's capture pipeline looks like:
Video path | Audio path
--- | ---
Video callback | Audio callback
Statistics layer
Resynchronizer
Capture filters | Audio compression
Video filters
Video display
Video compression
Spill synchronizer
Disk write
Video/audio callback This is the entry point at which the capture API (VFW/DirectShow) notifies VirtualDub that audio or video data has been captured. Statistics layer Most of the statistics in the information sidebar are collected at this point. Additional information not available from the capture layer, such as the timestamp of audio capture, is added at this point. Resynchronizer Audio/video resynchronization occurs at this point, both adjusting the video timing and resampling audio. The exact operations performed here are controlled by the settings in the Timing dialog. Capture video filters Capture-specific video filters such as field swap, 2:1 vertical reduction, and level compression occur here. Unlike the regular video filters, capture filters run directly in the capture format, either YCbCr or RGB — if the capture filter can't run in the current format, an error is displayed instead of a conversion being performed. Video filters Any standard video filters execute now; the video is converted to 32-bit RGB before entering the video filter chain. If the video filter chain is not enabled, the conversion to 32-bit RGB is skipped. Video display If the display mode is set to Preview, the video stream is tapped off at this point for display purposes. Video/audio compression The selected video and audio compression codecs now apply data compression. Spill synchronizer If spill mode is enabled for multi-file capture, the spill synchronization code now determines which file the audio and video streams write into, to ensure that each file is cleanly cut with the same audio and video durations. Video/audio write, disk write Audio and video data is buffered and eventually written to disk.