Laurent and all,

I just got one of those new Minoru stereo webcams.  At 90 bucks from
Amazon, the Minoru is several times cheaper than any alternative, and
there are lots of cool things you could do with a stereo camera under
Linux (see http://www.minoru3d.com/ ).

The good news is that uvcvideo recognizes the stereo camera as two
separate cameras (which appear as /dev/video0 and /dev/video1 in my
laptop with Ubuntu 8.10). I can grab video from the left and right
camera separately with no problem.  I'm using the standard uvcvideo
driver that comes with Ubuntu 8.10 Intrepid.

The problem is that I cannot seem to be able to grab from both cameras
simultaneously.  If I turn on streaming on one camera, the second
camera refuses to turn on streaming. In other words "
ioctl(fd, VIDIOC_STREAMON, &type)" with 
"type = V4L2_BUF_TYPE_VIDEO_CAPTURE" fails (it returns -2).

dmesg says:
uvcvideo: Failed to submit URB 0 (-28).

Similarly, if I have luvcview running on one camera and I try to start
luvcview on the other camera, I get the error message: 
"Unable to start capture: No space left on device"

I suspect this is a problem with the USB bus bandwidth.

The problem with luvcview occurs even if I reduce the 
resolution to 160x120 with "luvcview -d /dev/video0 -s 160x120"

Is there an easy fix? A difficult fix?

Thanks,

  -- Yann

________________________________________________________________
Trace of luvcview:

$ luvcview -d /dev/video0 &
[1] 6266
$ luvcview 0.2.4

SDL information:
  Video driver: x11
  A window manager is available
Device information:
  Device path:  /dev/video0
Stream settings:
  Frame format: YUYV (MJPG is not supported by device)
  Frame size:   640x480
  Frame rate:   30 fps

$ luvcview -d /dev/video1 &
[2] 6296
$ luvcview 0.2.4

SDL information:
  Video driver: x11
  A window manager is available
Device information:
  Device path:  /dev/video1
Stream settings:
  Frame format: YUYV (MJPG is not supported by device)
  Frame size:   640x480
  Frame rate:   30 fps
Unable to start capture: No space left on device
Error grabbing
Cleanup done. Exiting ...
$ 

________________________________________________________________
Here is the output of "sudo lsusb -v" for one of the cameras
(the other is deleted to stay below the 40KB limit).

Bus 005 Device 020: ID 0ac8:3410 Z-Star Microelectronics Corp. 
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2 ?
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0        64
  idVendor           0x0ac8 Z-Star Microelectronics Corp.
  idProduct          0x3410 
  bcdDevice            1.00
  iManufacturer           1 Vimicro Corp.
  iProduct                2 Vimicro USB2.0 PC Camera
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength          481
    bNumInterfaces          2
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0x80
      (Bus Powered)
    MaxPower              128mA
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         0
      bInterfaceCount         2
      bFunctionClass         14 Video
      bFunctionSubClass       3 Video Interface Collection
      bFunctionProtocol       0 
      iFunction               2 Vimicro USB2.0 PC Camera
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      1 Video Control
      bInterfaceProtocol      0 
      iInterface              2 Vimicro USB2.0 PC Camera
      VideoControl Interface Descriptor:
        bLength                13
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdUVC               1.00
        wTotalLength           79
        dwClockFrequency       30.000000MHz
        bInCollection           1
        baInterfaceNr( 0)       1
      VideoControl Interface Descriptor:
        bLength                18
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             1
        wTerminalType      0x0201 Camera Sensor
        bAssocTerminal          0
        iTerminal               0 
        wObjectiveFocalLengthMin      0
        wObjectiveFocalLengthMax      0
        wOcularFocalLength            0
        bControlSize                  3
        bmControls           0x0000000a
          Auto-Exposure Mode
          Exposure Time (Absolute)
      VideoControl Interface Descriptor:
        bLength                11
        bDescriptorType        36
        bDescriptorSubtype      5 (PROCESSING_UNIT)
      Warning: Descriptor too short
        bUnitID                 2
        bSourceID               1
        wMaxMultiplier          0
        bControlSize            2
        bmControls     0x0000177b
          Brightness
          Contrast
          Saturation
          Sharpness
          Gamma
          White Balance Temperature
          Backlight Compensation
          Gain
          Power Line Frequency
          White Balance Temperature, Auto
        iProcessing             0 
        bmVideoStandards     0x 9
          None
          SECAM - 625/50
      VideoControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID             3
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          0
        bSourceID               2
        iTerminal               0 
      VideoControl Interface Descriptor:
        bLength                28
        bDescriptorType        36
        bDescriptorSubtype      6 (EXTENSION_UNIT)
        bUnitID                 4
        guidExtensionCode         {5dc717a9-1941-da11-ae0e-000d56ac7b4c}
        bNumControl             8
        bNrPins                 1
        baSourceID( 0)          1
        bControlSize            3
        bmControls( 0)       0x59
        bmControls( 1)       0x80
        bmControls( 2)       0x80
        iExtension              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x000a  1x 10 bytes
        bInterval               5
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      VideoStreaming Interface Descriptor:
        bLength                            14
        bDescriptorType                    36
        bDescriptorSubtype                  1 (INPUT_HEADER)
        bNumFormats                        1
        wTotalLength                      243
        bEndPointAddress                  130
        bmInfo                              0
        bTerminalLink                       3
        bStillCaptureMethod                 2
        bTriggerSupport                     1
        bTriggerUsage                       1
        bControlSize                        1
        bmaControls( 0)                    27
      VideoStreaming Interface Descriptor:
        bLength                            27
        bDescriptorType                    36
        bDescriptorSubtype                  4 (FORMAT_UNCOMPRESSED)
        bFormatIndex                        1
        bNumFrameDescriptors                5
        guidFormat                            
{59555932-0000-1000-8000-00aa00389b71}
        bBitsPerPixel                      16
        bDefaultFrameIndex                  1
        bAspectRatioX                       0
        bAspectRatioY                       0
        bmInterlaceFlags                 0x00
          Interlaced stream or variable: No
          Fields per frame: 1 fields
          Field 1 first: No
          Field pattern: Field 1 only
          bCopyProtect                      0
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         1
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                            640
        wHeight                           480
        dwMinBitRate                   768000
        dwMaxBitRate                196608000
        dwMaxVideoFrameBufferSize      614400
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666667
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         2
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                            352
        wHeight                           288
        dwMinBitRate                   768000
        dwMaxBitRate                196608000
        dwMaxVideoFrameBufferSize      202752
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666667
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         3
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                            320
        wHeight                           240
        dwMinBitRate                   768000
        dwMaxBitRate                196608000
        dwMaxVideoFrameBufferSize      153600
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666667
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         4
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                            176
        wHeight                           144
        dwMinBitRate                   768000
        dwMaxBitRate                196608000
        dwMaxVideoFrameBufferSize       50688
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666667
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         5
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                            160
        wHeight                           120
        dwMinBitRate                   768000
        dwMaxBitRate                196608000
        dwMaxVideoFrameBufferSize       38400
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666667
      VideoStreaming Interface Descriptor:
        bLength                            26
        bDescriptorType                    36
        bDescriptorSubtype                  3 (STILL_IMAGE_FRAME)
        bEndpointAddress                    0
        bNumImageSizePatterns               5
        wWidth( 0)                        640
        wHeight( 0)                       480
        wWidth( 1)                        352
        wHeight( 1)                       288
        wWidth( 2)                        320
        wHeight( 2)                       240
        wWidth( 3)                        176
        wHeight( 3)                       144
        wWidth( 4)                        160
        wHeight( 4)                       120
        bNumCompressionPatterns             5
      VideoStreaming Interface Descriptor:
        bLength                             6
        bDescriptorType                    36
        bDescriptorSubtype                 13 (COLORFORMAT)
        bColorPrimaries                     0 (Unspecified)
        bTransferCharacteristics            0 (Unspecified)
        bMatrixCoefficients                 0 (Unspecified)
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       1
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0080  1x 128 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       2
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       3
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0400  1x 1024 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       4
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0b00  2x 768 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       5
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0c00  2x 1024 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       6
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x1380  3x 896 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       7
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x1400  3x 1024 bytes
        bInterval               1
Device Qualifier (for other device speed):
  bLength                10
  bDescriptorType         6
  bcdUSB               2.00
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2 ?
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0        64
  bNumConfigurations      1
Device Status:     0x0000
  (Bus Powered)



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