knowledge

Knowledge Base

Protocol documentation, research notes, and technical findings for Anycubic RV1106 printers.

Contents

knowledge/
├── TIMELAPSE_PROTOCOL.md      # Timelapse RPC/MQTT protocol
├── TIMELAPSE_IMPLEMENTATION_PLAN.md  # Implementation design
├── USB_CAMERA_BANDWIDTH.md    # USB bandwidth analysis
├── USB_CAMERA_CONTROLS.md     # V4L2 camera controls reference
├── MJPEG_CPU_OPTIMIZATION.md  # CPU optimization techniques
└── DISPLAY_STANDBY.md         # Display wake/sleep control

Document Summaries

TIMELAPSE_PROTOCOL.md

Complete protocol documentation for timelapse recording based on gkcam packet captures.

Topics covered:

• RPC message format (ETX-delimited JSON on port 18086)
• Video stream request/reply patterns
• MQTT topics and commands (port 9883 TLS)
• Frame capture triggers (startLanCapture)
• Print completion detection
• Output file naming conventions

TIMELAPSE_IMPLEMENTATION_PLAN.md

Design document for implementing timelapse in rkmpi_enc.

Topics covered:

• Architecture decision (encoder vs Python vs hybrid)
• RPC handler extensions
• Frame capture logic
• MP4 assembly with ffmpeg
• Phase-by-phase implementation plan

USB_CAMERA_BANDWIDTH.md

Investigation into USB bandwidth constraints for camera capture.

Key findings:

• USB 2.0 isochronous limit: 24 MB/s
• YUYV 720p limited to ~4 fps (1.8 MB/frame)
• MJPEG 720p can achieve 30+ fps (50-150 KB/frame)
• MMAP is optimal V4L2 access method
• USERPTR not supported on ARM dma_contig allocator

MJPEG_CPU_OPTIMIZATION.md

CPU optimization techniques for MJPEG streaming.

Topics covered:

• Architecture overview (decode path vs passthrough)
• Camera frame rate detection (advertised vs actual)
• Auto-skip based on CPU usage
• TurboJPEG optimization flags
• Target: <5% CPU for MJPEG passthrough

DISPLAY_STANDBY.md

Research into display standby detection and wake control.

Key findings:

• Display wake via sysfs brightness: Confirmed working
• Touch injection via /dev/input/event0: Confirmed working
• Touch device: hyn_ts (Hynitron), I2C bus 0018
• Resolution: 800x480, Multi-touch Protocol B
• Backlight: PWM-controlled

USB_CAMERA_CONTROLS.md

V4L2 camera controls reference for USB cameras on Anycubic printers.

Topics covered:

• Available V4L2 controls (brightness, contrast, exposure, etc.)
• Control IDs and ranges for UVC cameras
• Control dependencies (auto vs manual modes)
• Implementation in rkmpi_enc and control_server
• Control file format (/tmp/h264_ctrl)
• API endpoints for real-time adjustment

Related Resources

• Packet captures: /shared/dev/Rinkhals/docs/timelapse-captures/
• Firmware analysis: See Rinkhals project documentation