The following program shows hangs at random between typically 60 and 500
frames captured. Nothing is logged when the camera hangs. A ^C and
restart normally recovers the situation but not always.
It also occasionally causes machine crashes here
(OHCI, K7)
/*
* I/O routines: Taken from mp1e. Why rewrite it when these guys already
* did the work well.
*
* Removed V4L2 stuff to unclutter the code for now (its easy to paste back
* once this app works)
*
* From:
*
* MPEG-1 Real Time Encoder
*
* Copyright (C) 1999-2000 Michael H. Schimek
* Ported back to v4l/bttv by Justin Schoeman
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/* $Id: io.c,v 1.7 2000/01/21 15:45:19 michael Exp $ */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <errno.h>
#include <linux/videodev.h>
static int cap_fd;
static unsigned char * cap_buffer[256];
static int cap_buffers;
static struct video_capability vcap;
static struct video_channel chan;
static struct video_mbuf buf;
static struct video_mmap vmmap;
static struct video_audio vaud;
static int cframe;
static struct timeval tv;
static char *cap_dev = "/dev/video1";
static char *my_name = "gvp";
static int y_offs, v_offs, u_offs;
static int stride;
static char *le4cc2str(int n)
{
static char buf[4 * 4 + 1];
int i, c;
buf[0] = '\0';
for (i = 0; i < 4; i++) {
c = (n >> (8 * i)) & 0xFF;
if (isprint(c))
sprintf(buf + strlen(buf), "%c", c);
else
sprintf(buf + strlen(buf), "\\%o", c);
}
return buf;
}
void cap_init(int width, int height)
{
int aligned_width = (width + 15) & -16;
int aligned_height = (height + 15) & -16;
int uv_size;
unsigned long buf_base;
cap_fd = open(cap_dev, O_RDONLY);
if(cap_fd == -1)
{
perror(cap_dev);
exit(EXIT_FAILURE);
}
if(ioctl(cap_fd, VIDIOCGCAP, &vcap)<0)
{
fprintf(stderr, "%s: %s is not a capture device.\n",
my_name, cap_dev);
exit(EXIT_FAILURE);
}
if (!(vcap.type&VID_TYPE_CAPTURE))
{
fprintf(stderr, "%s: %s ('%s') is not a capture device\n",
my_name, cap_dev, vcap.name);
exit(EXIT_FAILURE);
}
if(ioctl(cap_fd, VIDIOCGAUDIO, &vaud)==-1)
{
fprintf(stderr, "%s: %s is not audio capable.\n", my_name, cap_dev);
}
else
{
vaud.flags&=~VIDEO_AUDIO_MUTE;
vaud.volume=60000;
if(ioctl(cap_fd, VIDIOCSAUDIO, &vaud)<0)
fprintf(stderr, "%s: unable to configure audio.\n",
my_name, cap_dev);
}
if(ioctl(cap_fd, VIDIOCGCHAN, &chan)<0)
{
fprintf(stderr, "%s: %s is not video capable ??\n",
my_name, cap_dev);
exit(EXIT_FAILURE);
}
fprintf(stderr, "Video standard is '%s'\n", chan.norm == 0 ? "PAL" : "NTSC");
vmmap.width = aligned_width;
vmmap.height = aligned_height;
vmmap.format = VIDEO_PALETTE_RGB24;
stride = vmmap.width;
if(ioctl(cap_fd, VIDIOCGMBUF, &buf)<0)
{
fprintf(stderr, "%s: %s does not support mmap capture.\n",
my_name, cap_dev);
/* FIXME - should handle this eg quickcam */
exit(EXIT_FAILURE);
}
if (buf.frames == 0)
{
fprintf(stderr, "%s: No capture buffers granted\n", my_name);
exit(EXIT_FAILURE);
}
buf_base=(unsigned long)mmap(NULL, buf.size, PROT_READ,
MAP_SHARED, cap_fd, 0);
if(buf_base == -1)
{
fprintf(stderr, "%s: unable to map buffers\n", my_name);
exit(EXIT_FAILURE);
}
cap_buffer[0] = (unsigned char *)(buf_base + buf.offsets[0]);
for (cap_buffers = 1; cap_buffers < buf.frames; cap_buffers++)
{
cap_buffer[cap_buffers] = (unsigned char *)(buf_base +
buf.offsets[cap_buffers]);
}
}
void cap_capture_on(void)
{
for (cframe = 0; cframe < cap_buffers; cframe++)
{
vmmap.frame = cframe;
if(ioctl(cap_fd, VIDIOCMCAPTURE, &vmmap)<0)
fprintf(stderr, "%s: capture request refused.\n",
my_name);
}
cframe = 0;
}
void cap_wait_frame(double *time, int *buf_index, void **ptr)
{
int r = -1;
while (r <= 0)
{
r = ioctl(cap_fd, VIDIOCSYNC, &cframe);
gettimeofday(&tv, NULL);
if (r < 0 && errno == EINTR)
continue;
if(r>0)
fprintf(stderr, "%s: execute video sync failed.\n",
my_name);
*time = tv.tv_sec + tv.tv_usec / 1e6;
*buf_index = cframe;
*ptr = cap_buffer[cframe];
break;
}
}
void cap_frame_done(int buf_index)
{
vmmap.frame = buf_index;
if(ioctl(cap_fd, VIDIOCMCAPTURE, &vmmap)<0)
{
fprintf(stderr, "%s: requeue buffer failed.\n",
my_name);
exit(EXIT_FAILURE);
}
cframe++;
if (cframe == cap_buffers)
cframe = 0;
}
int main(int argc, char *argv[])
{
void *p;
int idx;
int fr=0;
double t;
cap_init(320,200);
cap_capture_on();
while(1)
{
cap_wait_frame(&t, &idx, &p);
cap_frame_done(idx);
printf("Done %d\n",++fr);
}
}
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