Refine v2.0.0 changelog structure

Reworked the v2.0.0 release notes for clearer organization and wording across trigger sync, timestamps, recording, monochrome support, processor workflows, lifecycle handling, GUI updates, and diagnostics.

Author: C-Achard

changelog/v2_0_0.md

@@ -1,159 +1,187 @@
 # DeepLabCut-Live-GUI v2.0.0
 
-This release expands hardware synchronization, high-throughput multi-camera recording, frame timestamp reporting, monochrome capture performance, and custom processor integration.
-It also improves data safety, camera lifecycle handling, diagnostics, and general GUI usability.
+This release expands hardware synchronization, high-throughput multi-camera recording, frame timestamp reporting, monochrome capture, and custom processor integration.
+It also improves data safety, lifecycle management, diagnostics, and general usability.
 
 ## Camera triggering and synchronization
 
 ### Added
 
-- Added hardware trigger configuration for compatible **GenTL** and **Basler** cameras
-- Added trigger roles for common synchronization setups:
+- Hardware trigger configuration for compatible **GenTL** and **Basler** cameras
+- Trigger roles for common synchronization setups:
   - **Off / Free-run** for continuous acquisition
   - **External trigger** for cameras driven by an external hardware signal
   - **Follower** for cameras synchronized to a master camera or shared trigger source
   - **Master output** for free-running cameras that emit a synchronization signal
-- Added configuration fields for trigger selector, input source, signal activation, and frame read timeout
-- Includes a **Strict mode** to reject unsupported trigger configurations instead of applying them best-effort
+- Configuration for trigger selector, input source, activation condition, and frame read timeout
+- **Strict mode** to reject unsupported trigger configurations instead of applying them best-effort
 
 ### Changed
 
-- Updated the camera configuration dialog with a dedicated trigger settings GUI section
-- Updated active camera labels to show trigger roles
-- Changed multi-camera startup ordering so external and follower cameras begin opening before free-running cameras and trigger-generating masters
-
-## Multi-camera performance and recording
-
-### Added
-
-- Added a dedicated recording path for each active camera
-  - Rather than being coupled upstream of inference and UI display, recording is now a fully independent, prioritized pipeline
-  - This helps ensure that recording is not affected by inference or display slowdowns, and that each camera can be recorded at its full frame rate
-- Added additional recorder throughput, write latency, and buffer diagnostics.
-- Added an optional **Use faster encoding parameters** setting for supported FFmpeg software codecs.
-  - At the cost of file size, this can help support very high frame rates and resolutions on multi-camera setups
-
-### Changed
-
-- Decoupled the GUI display rate from camera capture, pose inference, and recording rates
-  - The GUI is now capped at 30 FPS for display, while cameras can run at their full frame rate for inference and recording.
-  - Inference still ignores any stale frames.
-- Added support for better using each camera’s reported runtime frame rate when configuring its recorder
-- Moved recording dispatch and frame transformations closer to the camera worker to reduce the impact on GUI responsiveness
+- Added a dedicated trigger settings dialog to the camera configuration workflow
+- Active camera labels now show configured trigger roles
+- Multi-camera startup now prioritizes external and follower cameras before free-running cameras and trigger-generating masters
 
 ### Fixed
 
-- Several logic and lifecycle fixes, which should help improve overall error handling and stability
+- Improved handling of unsupported or incomplete trigger configurations
+- Improved expected timeout handling while cameras wait for hardware trigger pulses
+- Improved trigger cleanup when cameras stop or close
+
 
 ## Frame timestamps and synchronization data
 
 ### Added
 
-- Added optional hardware frame timestamp reporting for supported cameras
-- Added Basler camera timestamp-counter reporting with raw tick values and tick-frequency metadata when available
-- Added updated timestamp JSON schema with:
+- Optional hardware frame timestamp reporting for supported cameras
+- Basler camera timestamp-counter reporting with raw tick values and tick-frequency metadata when available
+- An updated timestamp JSON schema containing:
   - Per-frame software timestamps
-  - Optional per-frame hardware timestamp values, supplied by cameras and SDK
+  - Optional per-frame hardware timestamp values supplied by cameras or SDKs
   - Timestamp source, timebase, unit, and conversion metadata
-  - Explicit frame indexes for written frames
+  - Explicit indexes for written frames
 
 ### Changed
 
-- Changed timestamp sidecars to describe software and hardware timestamp sources separately
-- Clarified the distinction between Unix wall-clock timestamps and device-specific camera-clock values
-- Changed timestamp recording so entries are added only for frames successfully written by the encoder
-  - This should help the reliability of timestamp data for downstream analysis
+- Software and hardware timestamp sources are now described separately
+- Timestamp entries are added only after frames are successfully written by the encoder
+- Documentation now distinguishes Unix wall-clock timestamps from device-specific camera clock values
 
 ### Fixed
 
 - Improved timestamp consistency when frames are dropped before encoding
+- Preserved raw hardware timestamp values alongside converted values
+- Improved fallback behavior when hardware timestamps or conversion metadata are unavailable
 
-## Monochrome camera performance improvements
+## Multi-camera performance and recording
 
 ### Added
 
-- Added a **Preserve mono frames** option for supported backends.
-  - This avoids performance bottlenecks from unnecessary conversion of mono frames to color
-- Added camera output format settings and runtime format reporting
-- Added native monochrome frame support for compatible GenTL & Basler cameras
-- Added camera probing for detected pixel format, emitted frame format, and recommended mono handling.
+- An optional **Use faster encoding parameters** setting for supported FFmpeg software codecs
+  - This can improve encoding throughput for high-resolution or high-frame-rate recordings, at the cost of larger files
+- A dedicated full-rate recording path for each active camera
+  - Recording is independent of the inference and display pipelines
+  - Display or inference slowdowns no longer directly limit recording throughput
+- Recorder diagnostics for throughput, write latency, queue depth, and dropped frames
 
 ### Changed
 
-- Updated camera labels and diagnostics to indicate preserved mono output
-- Additional reporting when the camera’s pixel format differs from the frame format emitted to the application
+- Decoupled GUI display from camera capture, pose inference, and recording rates
+  - The GUI display is capped at 30 FPS while cameras can continue running at their full rate
+  - Inference continues to discard stale frames
+- Improved use of each camera's reported runtime frame rate when configuring its recorder
+- Moved recording dispatch and frame transformations closer to camera workers to reduce work on the GUI thread
+- Reorganized recording logic into dedicated services
 
-## GUI and usability
+### Fixed
+
+- Prevented asynchronously queued frames from being modified through reused camera buffers or NumPy views
+- Improved frame-size mismatch and encoder error handling
+- Improved recording shutdown, retry, cleanup, and UI recovery behavior
+- Prevented recording controls from remaining disabled after a failed stop operation
+
+## Monochrome camera performance improvements
 
 ### Added
 
-- Added detected camera resolution, frame rate, pixel format, and output format to the camera configuration dialog
-- Added better recording path previews with session and run folder placeholders.
-- Added additional persistent preferences for recording names, processor selection, inference camera, and encoding options
-- Added **Help → View documentation** to open the DeepLabCut-Live-GUI documentation
+- A **Preserve mono frames** option for supported backends
+  - This avoids unnecessary conversion of monochrome frames to three-channel color
+- Native monochrome frame support for compatible GenTL and Basler cameras
+- Camera output-format settings and runtime format reporting
+- Camera probing for detected pixel format, emitted frame format, and recommended mono handling
 
 ### Changed
 
-- Improved camera configuration, reset, discovery, and preview workflows
-- Improved camera and recorder status summaries
-- Improved recording session naming and container-aware filename handling
+- Camera labels and diagnostics now indicate preserved mono output
+- Improved reporting when the camera pixel format differs from the frame format emitted to the application
+- Grayscale conversion remains available in the recorder when required by the selected encoding path
 
 ### Fixed
 
-- Prevented recording and preview controls from becoming permanently disabled after failed stop operations
-- Improved cleanup when closing camera dialogs or the main application window
-- Improved handling of unavailable cameras loaded from a saved configuration
-- Improved configuration persistence and restoration across application sessions
+- Improved handling of monochrome and higher-bit-depth frames before display and encoding
 
 ## Custom processor workflows
 
 ### Added
 
-- Added processor hooks for recording start and recording stop events
-  - This allows custom data processing, saving, or cleanup to be performed in sync with the recording
-  - NOTE: Stopping inference while recording is active may leave processor data unsaved or unpaired with the recording, depending on the processor implementation.
-- Added recording context communication with session, run folder, filename, and output file information
-- Added support for processor plugins that must be constructed in the inference worker
-- Added clearer processor status and recording state information in the GUI
+- Processor hooks for recording start and stop events
+  - These allow custom processing, saving, and cleanup to remain synchronized with recording
+- Recording context containing session, run folder, filename, and output file information
+- Support for processor plugins that must be constructed in the inference worker
+- Clearer processor status and recording state information in the GUI
 
 ### Changed
 
-- Improved custom processor discovery, selection and settings persistence
+- Improved custom processor discovery, selection, enablement, and settings persistence
+- Processor-controlled recording now uses the standard recording lifecycle
+- Stopping inference while recording now provides a clearer warning that processor data may remain unsaved or unpaired, depending on the processor implementation
 
 ### Fixed
 
-- Improved processor cleanup and finalization when recording stop
+- Improved processor cleanup and finalization when recording stops
+- Prevented duplicate recording start notifications
+- Improved handling of processors that do not implement optional saving methods
 
 ## Camera and preview lifecycle
 
 ### Added
 
-- Added better checks for cameras that are starting, running, or stopping to avoid unresponsive GUI states
-- Improved cancelling preview while cameras are still opening
+- Explicit handling for cameras that are starting, running, or stopping
+- Support for cancelling preview while cameras are still opening
+- Runtime reporting of actual camera frame rate, resolution, pixel format, and output format
 
 ### Changed
 
-- Updated preview controls so **Stop Preview** remains available during camera startup
-- Preserved user-configured camera order for the tiled display
+- **Stop Preview** remains available during camera startup
+- User-configured camera order is preserved in the tiled display while trigger startup ordering is handled separately
+- Stable internal camera identities are now separated from human-readable display labels
 
 ### Fixed
 
-- Improved partial multi-camera startup behavior when some cameras open successfully and others fail
-- Separated stable internal camera identity from human-readable display labels
-- Prevented a camera from reporting a successful start after startup was cancelled
+- Improved partial multi-camera startup when some cameras open successfully and others fail
+- Prevented cameras from reporting a successful start after startup was cancelled
 - Improved cleanup of partially initialized backends and worker threads
 - Improved detection and rejection of duplicate camera configurations
-- Improved recovery when cameras disconnect, repeatedly return empty frames, or fail during startup
+- Improved recovery from camera disconnections, repeated empty frames, and startup failures
 - Improved controller shutdown finalization
 
+## GUI and usability
+
+### Added
+
+- **Help → View documentation** action for opening the DeepLabCut-Live-GUI documentation
+- Detected camera resolution, frame rate, pixel format, and output format in the camera configuration dialog
+- Improved recording path previews with session and run-folder placeholders
+- Persistent preferences for recording names, processor selection, inference camera, and encoding options
+
+### Changed
+
+- Improved camera discovery, configuration, reset, and preview workflows
+- Improved camera and recorder status summaries
+- Improved recording session naming and container-aware filename handling
+- Improved control availability during camera startup, inference, recording, and shutdown
+
+### Fixed
+
+- Improved asynchronous error reporting so background failures are visible in the GUI
+- Improved cleanup when closing camera dialogs or the main application window
+- Improved handling of unavailable cameras restored from saved configurations
+- Improved configuration persistence and restoration across application sessions
+
 ## Reliability and diagnostics
 
 ### Added
 
-- Added focused timing diagnostics for camera workers, controller dispatch, inference, and recording
+- Timing diagnostics for camera workers, controller dispatch, inference, and recording
+- Expanded automated coverage for camera backends, trigger modes, recording, timestamps, processor hooks, and GUI lifecycle behavior
+
+### Changed
+
+- Improved logging for camera discovery, runtime information, recording state, and processor lifecycle events
+- Expanded backend contract tests for camera reads, trigger waits, timestamp propagation, and cleanup
 
 ### Fixed
 
 - Improved handling of stale camera identities and GenTL producer paths
-- Improved best-effort cleanup without allowing cleanup errors to hide the original failure
-- Improved consistency between camera backend return values and downstream capture, inference, and recording code
+- Improved best-effort cleanup without hiding the original failure
+- Improved consistency between camera backend results and downstream capture, inference, and recording code