USBTrace : Class Decoding : Video

USB devices which belong to the Video class can be monitored using the Video class decoder (Plug-in dll). The devices which fall in to this category include WebCams, digital camcoders, analog video convertors, analog and digital television tuners and still image cameras that support video streaming. The decoder will capture, decode and display USB Video class specific requests, descriptors and data. Both Video Control (VC) & Video Streaming (VS) interfaces are supported. The decoder is up to date with version 1.5 of USB Video class (UVC 1.5) specification.

The type of requests captured are:

• Video Control (VC) Requests
• Interface Control Requests
• Power Mode Control
• Request Error Code Control
• Unit and Terminal Control Requests
• Camera Terminal Control Requests
• Selector Unit Control Requests
• Processing Unit Control Requests
• Extension Unit Control Requests
• Video Streaming (VS) Requests
• Interface Control Requests
• Video Probe and Commit Control
• Video Still Probe and Still Commit Control
• Synch Delay Control
• Still Image Trigger Control
• Generate Key Frame Control
• Update Frame Segment Control
• Stream Error Code Control

The following types of video class descriptors are displayed:

• Video Control (VC) Interface Descriptors
• Input Terminal
• Output Terminal
• Camera Terminal
• Selector Unit
• Processing Unit
• Extension Unit
• Video Control (VC) Interrupt Endpoint Descriptor
• Video Streaming (VS) Interface Descriptors
• Input Header
• Output Header
• Payload Format
• Video Frame
• Still Image Frame
• Color Matching

The Video Decoder also captures video and still image payload data (both bulk and isochronous).

Image below shows a video request packet, decoded and displayed by USBTrace.