bttv 0.8.xx and V4L2

[Andrea Oddera <oddera@xxxxxxxx>]

Hi,
I'm trying to use the bttv 0.8.x driver in order to acquire frames from a bt878 framegrabber.
Before I was using the bttv2 driver from bttv-v4l2.sourceforge.net and the videodevX module.
I'm aquiring images using the mmap function, in this way (this is an exaple.... my code is similar)

....................

struct v4l2_requestbuffers req;
struct v4l2_buffer vidbuf[4];
unsigned char *data[4];

    req.count = 4;
    req.type = V4L2_BUF_TYPE_CAPTURE;
    err = ioctl(grab_fd, VIDIOC_REQBUFS, &req);
    if (err < 0 || req.count < 1) {
        printf("REQBUFS returned error %s, count %d\n",
               strerror(errno), req.count);
        return -1;
    }

    for (i = 0; i < req.count; ++i) {
        vidbuf[i].index = i;
        vidbuf[i].type = V4L2_BUF_TYPE_CAPTURE;
        err = ioctl(grab_fd, VIDIOC_QUERYBUF,
                    &vidbuf[i]);
        if (err < 0) {
            printf("QUERYBUF returned error %s\n", strerror(errno));
            return -1;
        }
        data[i] = mmap(0,
                              vidbuf[i].length, PROT_READ,
                              MAP_SHARED, grab_fd,
                              vidbuf[i].offset);
    }

then I'll use VIDIOC_QBUF and VIDIOC_DQBUF  to acquire the images... There is a similar example in the v4l2 examples from thedirks.

The problem is that when I make the mmap function it returns "Invalid argument". What can I do? Can you please help me?!

Thanks,
    Andrea Oddera

-- 
Andrea Oddera oddera@xxxxxxxx  http://www.aitek.it
Aitek S.p.A. - Via della Crocetta 15 - 16122 Genova