Uvc camera code parsing 1

I. FAQ1. determine whether your camera supports uvc standard input lsusb // list usb devices [cpp] Bus 001 Device 001: ID 1d6b: 0002 Linux Foundation 2.0 root hub Bus 001 Device 003: ID 0c45: 62f1 Microdia // camera Bus 002 Device 001: ID 1d6b: 0002 Linux Foundation 2.0 root hub Bus 002 Device 002: ID 1a40: 0101 terminus technology inc. bus 002 Device 003: ID 17ef: 6025 Lenovo more detailed tree structure lsusb-t [cpp]/: Bus 02. port 1: Dev 1, Class = root_hub, Driver = musb-hdrc/1 p, 480 M |__ Port 1: Dev 2, If 0, Class = hub, driver = hub/4 p, 480 M/: Bus 01. port 1: Dev 1, Class = root_hub, Driver = musb-hdrc/1 p, 480 M |__ Port 1: Dev 4, If 0, class = 'binterfaceclass 0x0e not yet handled ', Driver =, 480 M |__ Port 1: Dev 4, If 1, Class = 'binterfaceclass 0x0e not yet handled', Driver =, 480 M |__ Port 1: Dev 4, If 2, Class = audio, Driver = snd-usb-audio, 480 M |__ Port 1: Dev 4, If 3, class = audio, Driver = snd-usb-audio, 480 M lsusb-d 0c45: 62f1-v | grep "14 Video" detection device attributes [cpp] bFunctionClasss 14 Video bInterfaceClass 14 Video bInterfaceClass 14 Video bInterfaceClass 14 Video audio 14 Video audio 14 Video audio 14 Video audio 14 Video audio 14 Video audio 14 Video display similar to the above information indicates that the camera supports the uvc Standard 2. enable/disable debug trace printing information [cpp] echo 0 xffff>/sys/module/uvcvideo/parameters/trace echo 0>/sys/module/uvcvideo/parameters/trace 3. playback test [cpp] view plaincopymplayer TV: //-TV fps = 25 II. uvc Standard 1. download Standard Protocol address [cpp] http://www.usb.org/developers/devclass_docs 2. features (translation) Each video function has a single VideoControl (VC) interface and can have several VideoStreaming (VS) interfaces Each video has only one VideoControl (VC) the VideoControl (VC) interface is used to access the device controls of the function whereasthe VideoStreaming () interfaces are used to transport data streams into and out of the function. the VC Interface is used for device function control, and the VS Interface is used to transmit data streams in and out of the Video Interface Class Code (A.1 P171) the video Interface class code is the macro-defined USB_CLASS_VIDEO. There are a total of three sub-classes: subclass1.VideoControl Interface video control Interface sub-class 2. videoStreaming Interface: video data stream Interface subclass 3. video Interface Collection Subclass macro definition [cpp] v/* A.2. Video Interface Subclass Codes */# define UVC_ SC _UNDEFINED 0x00 # define UVC_ SC _VIDEOCONTROL 0x01 # define UVC_ SC _VIDEOSTREAMING 0x02 # define UVC_ SC _VIDEO_INTERFACE_COLLECTION 0x03 Units provide the basic building blocks to fully describe most video functions, A Unit has one or more Input Pins and a single Output Pin, Unit provides basic modules to fully describe most of the video functions, A Unit can be composed of one or more input pins and only one output pin (each pin here represents a logical data stream)