void VideoCaptureV4L2::update() {
if(!is_opened) {
printf("WARNING: calling update() but not device opened.\n");
return;
}
struct v4l2_buffer buf;
switch(io_method) {
case LINCAP_IO_METHOD_MMAP: {
memset(&buf, 0, sizeof(buf));
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
if(ioctl(fd, VIDIOC_DQBUF, &buf) == -1) {
if(errno == EAGAIN) {
//printf("VERBOSE: non-blocking, and no new frame in buffer (EAGAIN). \n");
return;
}
else if(errno == EINVAL) {
printf("ERROR: The buffer type is not supported, or the index is out of bound. no buffer allocated. (EINVAL)\n");
return;
}
else if(EIO) {
printf("ERROR: VIDIOC_DQBUF failed due to an internal error. VIDIOC_QBUF.(EIO)\n");
return ;
}
else {
printf("ERROR: cannot get buffer; unhandled..\n");
return;
}
}
if(frame_cb) {
//printf("buf.index: %d, buf.bytes_used: %d, buffers[buf.index].length: %zu\n", buf.index, buf.bytesused, buffers[buf.index]->length);
frame_cb(buffers[buf.index]->start, buffers[buf.index]->length, frame_user);
}
if(ioctl(fd, VIDIOC_QBUF, &buf) == -1) {
printf("ERROR: cannot enqueue buf again.\n");
return;
}
break;
}
default: {
printf("ERROR: unhandled io_method for update().\n");
break;
}
}
}
static void parse_string(sd_stringparser *parser,
void(*frame_cb)(sd_stringparser*, void*, char,int),
void(*tag_cb)(sd_stringparser*, void*, tag_attribute*, int param),
void *data) {
if(parser->string) {
int pos = 0;
while(1) {
const char *start = parser->string + pos;
const char *str = parser->string + pos;
int type = next_tag(&str);
pos += (str-start);
start = parser->string + pos;
if(type == TAG_TAG) {
// a tag
tag_attribute attrib;
if(rn_tag_attribute(static_taglist, &str, &attrib) == 0) {
// read the numeric param and call the callback function
// if a param is not present, 0 is assumed
int pos = 0;
int param = rn_int(&pos, str);
str += pos;
if(tag_cb) tag_cb(parser, data, &attrib, param);
}
} else if(type == TAG_FRAME) {
// a frame
int duration=0;
char frame_letter=0;
rn_frame(&str, &frame_letter, &duration);
if(frame_cb) frame_cb(parser, data, frame_letter, duration);
} else if(type == TAG_MARKER) {
// an end of frame descriptor marker (a dash, '-')
rn_descriptor_marker(&str);
} else {
// the end of stream
break;
}
pos += (str-start);
}
}
}
