Cédric Hi,
Could you pleaser try the following function, you will have to make the
necessary adaptations to your code.
int set_format(int fd, int formatIn, int width, int height, int fps)
{
struct v4l2_format fmt;
struct v4l2_streamparm streamparm;
int ret=0;
// set format
fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
fmt.fmt.pix.width = width;
fmt.fmt.pix.height = height;
fmt.fmt.pix.pixelformat = formatIn;
fmt.fmt.pix.field = V4L2_FIELD_ANY;
ret = ioctl(fd, VIDIOC_S_FMT, &fmt);
if (ret < 0)
{
fprintf(stderr, "VIDIOC_S_FORMAT - Unable to set format\n");
return (-1);
}
if ((fmt.fmt.pix.width != width) ||
(fmt.fmt.pix.height != height))
{
fprintf(stderr, "Requested Format unavailable: get width %d
height %d \n",
fmt.fmt.pix.width, fmt.fmt.pix.height);
return(-2);
}
streamparm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
streamparm.parm.capture.timeperframe.numerator = 1;
streamparm.parm.capture.timeperframe.denominator = fps;
ret = ioctl(fd,VIDIOC_S_PARM, &streamparm);
if (ret < 0)
{
fprintf(stderr, "VIDIOC_S_PARM error\n");
return (-3);
}
return (0);
}
Best regards,
Paulo
lesc...@esiee.fr escreveu:
> Hi,
>
> This is my problem, I don't have any errors. V4L2 API says that when you
> ask for a Width and Heigth, the driver will give you the max ones below
> the values you asked for. Meaning if you ask for 817x616, it will set
> 800x600 without returning any errors.
>
>
> My DMESG (no pb, I have got my "/dev/video0"):
>
> usb 1-2: new full speed USB device using ohci_hcd and address 3
> usb 1-2: configuration #1 chosen from 1 choice
> uvcvideo: Found UVC 1.00 device <unnamed> (046d:0991)
> input: UVC Camera (046d:0991) as
> /devices/pci0000:00/0000:00:02.2/usb1/1-2/1-2:1.0/input/input9
>
>
> An extract of my code, taken from the web (Capture.c):
>
> CLEAR (fmt);
>
> fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> if (-1 == xioctl (fd, VIDIOC_G_FMT, &fmt))
> errno_exit ("VIDIOC_G_FMT");
>
> fmt.fmt.pix.width = WB_FRAME_WIDTH; // 800
> fmt.fmt.pix.height = WB_FRAME_HEIGHT; // 600
> fmt.fmt.pix.pixelformat = WB_COLOR_FORMAT; // YUYV which is perfect for me
> fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;
>
> // Note VIDIOC_S_FMT may change width and height
> // So I check the *new* values
>
> fprintf (stderr,
> "width: %d\n"
> "height: %d\n",
> fmt.fmt.pix.width,
> fmt.fmt.pix.height);
>
>
> It prints 176 by 144! What am I doing wrong?
> (later, I check the buffer size allocated via MMAP: 50688 => 176 x 144 x 2)
>
> Any ideas? Where could be the problem?
>
> Regards,
>
>
> Cédric Lescop
>
>
>
> On Wed, March 18, 2009 13:52, Laurent Pinchart wrote:
>
>> Hi,
>>
>>
>> On Monday 16 March 2009 14:43:35 lesc...@esiee.fr wrote:
>>
>>
>>> Hello everyone,
>>>
>>>
>>> I'm using this webcam to do some streaming and image analysis.
>>> When using Logitech's driver under MS Window, it works fine. I've access
>>> to all resolutions with the RGB24 format.
>>>
>> The camera doesn't support the RGB24 format natively. Transcoding has to
>> be done in software. libv4l2 can help you there.
>>
>>
>>> The problem is when running under Linux. I'm using uvcvideo driver via
>>> V4L2 but I can't make it work properly.
>>> The resolution gets stuck to 176x144
>>> and the format is YUYV.
>>>
>>> Normally, the webcam is supposed to support a 1600x1200 resolution, how
>>> can I set it up correctly?
>>>
>> You should be able to use higher resolutions. Can you describe your
>> problem in details, including the steps performed and the error messages
>> being printed ?
>>
>>
>>> Thank you in advance,
>>>
>>>
>>> xioctl (fd, VIDIOC_ENUM_FMT, &fdq)
>>>
>>> returns me 2 formats only: MJPEG and YUYV. YUYV is fine for me but I
>>> can't reach 1600x1200, or 800x600 or even not 320x240!!!!
>>>
>> Best regards,
>>
>>
>> Laurent Pinchart
>>
>>
>>
>>
>
>
> _______________________________________________
> Linux-uvc-devel mailing list
> Linux-uvc-devel@lists.berlios.de
> https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
>
>
_______________________________________________
Linux-uvc-devel mailing list
Linux-uvc-devel@lists.berlios.de
https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
