diff options
Diffstat (limited to 'v4l2-apps/lib/libv4l/include')
-rw-r--r-- | v4l2-apps/lib/libv4l/include/libv4l2.h | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/v4l2-apps/lib/libv4l/include/libv4l2.h b/v4l2-apps/lib/libv4l/include/libv4l2.h new file mode 100644 index 000000000..0e88039b8 --- /dev/null +++ b/v4l2-apps/lib/libv4l/include/libv4l2.h @@ -0,0 +1,104 @@ +/* +# (C) 2008 Hans de Goede <j.w.r.degoede@hhs.nl> + +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU Lesser General Public License as published by +# the Free Software Foundation; either version 2.1 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 Lesser General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA +*/ + +#ifndef __LIBV4L2_H +#define __LIBV4L2_H + +#include <stdio.h> +#include <unistd.h> + +#ifdef __cplusplus +extern "C" { +#endif /* __cplusplus */ + +/* Point this to a FILE opened for writing when you want to log error and + status messages to a file, when NULL errors will get send to stderr */ +extern FILE *v4l2_log_file; + +/* Just like your regular open/close/etc, except that format conversion is + done if necessary when capturing. That is if you (try to) set a capture + format which is not supported by the cam, but is supported by libv4lconvert, + then the try_fmt / set_fmt will succeed as if the cam supports the format + and on dqbuf / read the data will be converted for you and returned in + the request format. + + Another difference is that you can make v4l2_read() calls even on devices + which do not support the regular read() method. + + Note that libv4l2 normally does not interfere with enum_fmt, so enum_fmt + will still return the actual formats the hardware supports, and not any + formats which may be emulated on top of that. If you pass the + V4L2_ENABLE_ENUM_FMT_EMULATION flag to v4l2_fd_open (as the v4l2convert.so + wrapper does) then enum_fmt will also report support for the formats to + which conversion is possible. + + Note the device name passed to v4l2_open must be of a video4linux2 device, + if it is anything else (including a video4linux1 device), v4l2_open will + fail. +*/ + +int v4l2_open (const char *file, int oflag, ...); +int v4l2_close(int fd); +int v4l2_dup(int fd); +int v4l2_ioctl (int fd, unsigned long int request, ...); +ssize_t v4l2_read (int fd, void* buffer, size_t n); +void *v4l2_mmap(void *start, size_t length, int prot, int flags, int fd, + off_t offset); +int v4l2_munmap(void *_start, size_t length); + + +/* Misc utility functions */ + +/* This function takes a value of 0 - 65535, and then scales that range to + the actual range of the given v4l control id, and then if the cid exists + and is not locked sets the cid to the scaled value. + + Normally returns 0, even if the cid did not exist or was locked, returns + non 0 when an other error occured. */ +int v4l2_set_control(int fd, int cid, int value); + +/* This function returns a value of 0 - 65535, scaled to from the actual range + of the given v4l control id. when the cid does not exist, could not be + accessed for some reason, or some error occured 0 is returned. */ +int v4l2_get_control(int fd, int cid); + + +/* "low level" access functions, these functions allow somewhat lower level + access to libv4l2 (currently there only is v4l2_fd_open here) */ + +/* Flags for v4l2_fd_open's v4l2_flags argument */ + +/* Disable all format conversion done by libv4l2 (reduces libv4l2 functionality + to offering v4l2_read() even on devices which don't implement read()) */ +#define V4L2_DISABLE_CONVERSION 0x01 +/* Report not only real but also emulated formats with the ENUM_FMT ioctl */ +#define V4L2_ENABLE_ENUM_FMT_EMULATION 02 + +/* v4l2_fd_open: open an already opened fd for further use through + v4l2lib and possibly modify libv4l2's default behavior through the + v4l2_flags argument. + + Returns fd on success, -1 if the fd is not suitable for use through libv4l2 + (note the fd is left open in this case). */ +int v4l2_fd_open(int fd, int v4l2_flags); + +#ifdef __cplusplus +} +#endif /* __cplusplus */ + +#endif |