device_property.c

unicap provides an uniform access to video capture devices. Currently you can access v4l, v4l2, IIDC

/*
    unicap
    Copyright (C) 2004  Arne Caspari

    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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

/**
   device_property
   
     Print a list of supported properties and let the user edit the value of a specific property

 **/


#include <stdlib.h>
#include <stdio.h>
#include <getopt.h>
#include <unicap.h>
#include <unicap_status.h>


static char *property_type_strings[] =
{
	"RANGE", 
	"VALUE_LIST", 
	"MENU", 
	"DATA", 
	"FLAGS"
};

static char *property_flag_strings[] =
{
	"MANUAL", 
	"AUTO", 
	"ONE_PUSH" 
};


void print_usage( char *progname )
{
	printf( "Usage: \n" );
	printf( "%s PropertyId [-M Model] [-v Value] [-m MenuItem] [-l]\n", progname );
	printf( "\n" );
}


int main( int argc, char **argv )
{
	unicap_handle_t handle;
	unicap_device_t device;
	unicap_device_t device_spec;
	unicap_property_t property;
	unicap_property_t property_spec;
	double new_value;

	int list_only = 0;
	
	int i;
	int c = 0;

	unicap_void_device( &device_spec );
	
	while( c != -1 )
	{
		c = getopt( argc, argv, "M:v:m:l" );
		switch( c )
		{
			case 'M':
				if( optarg )
				{
					printf( "Model: %s\n", optarg );
					strcpy( device_spec.model_name, optarg );
				}
				else
				{
					print_usage( argv[0] );
					exit( 1 );
				}
				break;
				
			case 'v':
				if( optarg )
				{
					sscanf( optarg, "%f", &property.value );
				}
				else
				{
					print_usage( argv[0] );
					exit( 1 );	
				}
				break;
				
			case 'm':
				if( optarg )
				{
					strcpy( property.menu_item, optarg );
				}
				else
				{
					print_usage( argv[0] );
					exit( 1 );
				}
				break;
				
			case 'l':
				list_only = 1;
				break;
				
			case -1:
				printf( "optind: %d\n", optind );
				break;
				
			default:
				print_usage( argv[0] );
				exit( 1 );
				break;
		}
	}
	
	

	//
	// Enumerate all video capture devices; if more than 1 device present, ask for which device to open
	//
	for( i = 0; SUCCESS( unicap_enumerate_devices( &device_spec, &device, i ) ); i++ )
	{
		printf( "%i: %s\n", i, device.identifier );
	}
	if( --i > 0 )
	{
		printf( "Select video capture device: " );
		scanf( "%d", &i );
	}

	if( !SUCCESS( unicap_enumerate_devices( NULL, &device, i ) ) )
	{
		fprintf( stderr, "Failed to get info for device '%s'\n", device.identifier );
		exit( 1 );
	}

	/*
	  Acquire a handle to this device
	 */
	if( !SUCCESS( unicap_open( &handle, &device ) ) )
	{
		fprintf( stderr, "Failed to open device: %s\n", device.identifier );
		exit( 1 );
	}

	printf( "Opened video capture device: %s\n", device.identifier );

	
	// Initialize a property specifier structure
	unicap_void_property( &property_spec );

	printf( "Supported properties: \n" );
	printf( "\tName\t\tValue\n" );

	//
	// Print a list of all properties matching the specifier. For a "void" specifier, this matches all 
	//   properties supported by the device
	// If more than 1 property is supported, ask for which property to modify
	for( i = 0; SUCCESS( unicap_enumerate_properties( handle, &property_spec, &property, i ) ); i++ )
	{
		unicap_get_property( handle, &property );

		printf( "%i: \t%s\t\t%f\n", i, property.identifier, property.value );
	}
	if( --i > 0 )
	{
		printf( "Select a property to edit: " );
		scanf( "%d", &i );
	}

	// Now get the description of the requested property. unicap_enumerate_property gives the 
	// property structure initialized to the default values. So just change the value of the 
	// returned property to the new one and set it using 'unicap_set_property'
	if( !SUCCESS( unicap_enumerate_properties( handle, &property_spec, &property, i ) ) )
	{
		printf( "Failed to enumerate property\n" );
		exit( -1 );
	}
	printf( "Enter new value for property '%s': ", property.identifier );
	scanf( "%lf", &new_value );

	property.value = new_value;
	if( !SUCCESS( unicap_set_property( handle, &property ) ) )
	{
		printf( "Failed to set property!\n" );
	}

	unicap_close( handle );
	
	
	return 0;
}