Hi Paulo,
On Wednesday 05 May 2010 10:59:26 Paulo Assis wrote:
> Hi,
> Are you sure the camera supports MJPG ?
That's indeed the problem.
> It seems to report only a uncompressed format (YUYV ?).
> You can check the supported formats with luvcview, guvcview or
> uvcdynctrl (libwebcam)
It can also be checked from the USB descriptors:
[snip]
> > Interface Descriptor:
> > bLength 9
> > bDescriptorType 4
> > bInterfaceNumber 1
> > bAlternateSetting 0
> > bNumEndpoints 0
> > bInterfaceClass 14 Video
> > bInterfaceSubClass 2 Video Streaming
> > bInterfaceProtocol 0
> > iInterface 0
in the Video Streaming interface,
> > VideoStreaming Interface Descriptor:
> > bLength 27
> > bDescriptorType 36
> > bDescriptorSubtype 4 (FORMAT_UNCOMPRESSED)
> > bFormatIndex 1
> > bNumFrameDescriptors 2
> > 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
descriptors of type 36 (class-specific) report, among other information, the
formats supported by the device. In this case there's a single format
descriptor, of subtype 4 (FORMAT_UNCOMPRESSED). Devices supporting MJPEG have
a subtype 6 descriptor (in addition to the FORMAT_UNCOMPRESSED descriptor if
they support uncompressed formats).
There's no need to verify this with luvcview.
Alternatively, setting the trace level to 3 when loading the uvcvideo driver
will print the formats supported by the device.
--
Regards,
Laurent Pinchart
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