video using webcamd on Raspberry Pi 3

[Curtis Villamizar]

On 09/30/17 14:11, Hans Petter Selasky wrote:
> lsusb -v 

The output is 740 lines long.  Here are the bDescriptorSubtype lines:

         bDescriptorSubtype      1 (HEADER)
         bDescriptorSubtype      3 (OUTPUT_TERMINAL)
         bDescriptorSubtype      6 (EXTENSION_UNIT)
         bDescriptorSubtype      2 (INPUT_TERMINAL)
         bDescriptorSubtype      5 (PROCESSING_UNIT)
         bDescriptorSubtype                  1 (INPUT_HEADER)
         bDescriptorSubtype                  6 (FORMAT_MJPEG)
         bDescriptorSubtype                  7 (FRAME_MJPEG)
         bDescriptorSubtype                  7 (FRAME_MJPEG)
         bDescriptorSubtype                  7 (FRAME_MJPEG)
         bDescriptorSubtype                  7 (FRAME_MJPEG)
         bDescriptorSubtype                  7 (FRAME_MJPEG)
         bDescriptorSubtype                  7 (FRAME_MJPEG)
         bDescriptorSubtype                  7 (FRAME_MJPEG)
         bDescriptorSubtype                  7 (FRAME_MJPEG)
         bDescriptorSubtype                  3 (STILL_IMAGE_FRAME)
         bDescriptorSubtype                  4 (FORMAT_UNCOMPRESSED)
         bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
         bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
         bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
         bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
         bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
         bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
         bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
         bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
         bDescriptorSubtype                  3 (STILL_IMAGE_FRAME)
         bDescriptorSubtype                 13 (COLORFORMAT)
         bDescriptorSubtype      1 (HEADER)
         bDescriptorSubtype      2 (INPUT_TERMINAL)
         bDescriptorSubtype      6 (FEATURE_UNIT)
         bDescriptorSubtype      3 (OUTPUT_TERMINAL)
         bDescriptorSubtype      1 (AS_GENERAL)
         bDescriptorSubtype      2 (FORMAT_TYPE)
           bDescriptorSubtype      1 (EP_GENERAL)

The format is MJPEG or raw.

For the resolution of 320x240 we have:

       VideoStreaming Interface Descriptor:
         bLength                            30
         bDescriptorType                    36
         bDescriptorSubtype                  7 (FRAME_MJPEG)
         bFrameIndex                         4
         bmCapabilities                   0x00
           Still image unsupported
         wWidth                            320
         wHeight                           240
         dwMinBitRate                 37005360
         dwMaxBitRate                 37005360
         dwMaxVideoFrameBufferSize      154189
         dwDefaultFrameInterval         333333
         bFrameIntervalType                  1
         dwFrameInterval( 0)            333333

       VideoStreaming Interface Descriptor:
         bLength                            30
         bDescriptorType                    36
         bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
         bFrameIndex                         4
         bmCapabilities                   0x00
           Still image unsupported
         wWidth                            320
         wHeight                           240
         dwMinBitRate                 36864000
         dwMaxBitRate                 36864000
         dwMaxVideoFrameBufferSize      153600
         dwDefaultFrameInterval         333333
         bFrameIntervalType                  1
         dwFrameInterval( 0)            333333

This still doesn't work with 160x120 and 5 fps so probably not a CPU 
issue, but I could be wrong.  OTOH I just got a kernel panic while 
running 160x120.  It doesn't seem related based on where it was. I'm 
running that again and no panic so far but also nothing on the screen 
even after quite a few minutes.

Curtis