v4l.c

来自「Video4Linux_test.rar 接視訊的範例程式」· C语言 代码 · 共 248 行

#include <stdio.h>
#include <unistd.h>
#include <error.h>
#include <assert.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <linux/videodev.h>
#include "v4l.h"

#define DEFAULT_DEVICE "/dev/v4l/video0"
#define DEFAULT_PALETTE VIDEO_PALETTE_YUV420P
#define FALSE           0
#define TRUE            1

int v4l_open(char *dev,v4l_device *vd)
{
	if(!dev)
	{
		dev = DEFAULT_DEVICE;
	}

	if( (vd->fd = open(dev,O_RDWR)) < 0 )
	{
		perror("v4l_open:");
		return -1;
	}

	if(v4l_get_capability(vd)) return -1;

	if(v4l_get_picture(vd)) return -1;

	return 0;
}

int v4l_get_capability(v4l_device *vd)
{
	if(ioctl(vd->fd,VIDIOCGCAP,&(vd->capability)) < 0)
	{
		perror("v4l_get_capability:");
		return -1;
	}

	return 0;
}

int v4l_get_channels(v4l_device *vd)
{
	int i;

	for(i=0;i<vd->capability.channels;i++)
	{
		vd->channel[i].channel = i;
		if(ioctl(vd->fd,VIDIOCGCHAN,&(vd->channel[i])) < 0)
		{
			perror("v4l_get_channel:");
			return -1;
		}
	}
	return 0;
}

int v4l_get_audios(v4l_device *vd)
{
	int i;

	for(i=0;i<vd->capability.audios;i++)
	{
		if(ioctl(vd->fd,VIDIOCGAUDIO,&(vd->audio[i])) < 0)
		{
			perror("v4l_get_audio:");
			return -1;
		}
	}
	return 0;
}

int v4l_get_picture(v4l_device *vd)
{
	if(ioctl(vd->fd,VIDIOCGPICT,&(vd->picture)) < 0)
	{
		perror("v4l_get_picture");
		return -1;
	}

	//printf("vd->picture.depth:%d\n",vd->picture.depth);

	return 0;
}

int v4l_close(v4l_device *vd)
{
	close(vd->fd);
	return 0;
}


int v4l_mmap_init(v4l_device *vd)
{
	if(v4l_get_mbuf(vd) < 0) return -1;

	if((vd->map = mmap(0,vd->mbuf.size,PROT_READ|PROT_WRITE,MAP_SHARED,vd->fd,0)) < 0)
	{
		perror("v4l_mmap_init:mmap");
		return -1;
	}

	return 0;
}

int v4l_get_buffer(v4l_device *vd)
{
	if(ioctl(vd->fd,VIDIOCSFBUF,&(vd->buffer)) < 0)
	{
		perror("v4l_get_buffer:");
		return -1;
	}

	return 0;
}

int v4l_set_buffer(v4l_device *vd)
{
	if(ioctl(vd->fd,VIDIOCGFBUF,&(vd->buffer)) < 0)
	{
		perror("v4l_set_buff:");
		return -1;
	}

	return 0;
}

int v4l_get_mbuf(v4l_device *vd)
{
	if(ioctl(vd->fd,VIDIOCGMBUF,&(vd->mbuf)) < 0)
	{
		perror("v4l_get_mbuf");
		return -1;
	}

	return 0;
}

int v4l_switch_channel(v4l_device *vd,int c)
{
	if(ioctl(vd->fd,VIDIOCSCHAN,&(vd->channel[c])) < 0)
	{
		perror("v4l_switch_channel:");
		return -1;
	}

	return 0;
}

int v4l_set_norm(v4l_device *vd, int norm)
{
	int i;

	for(i=0;i<vd->capability.channels;i++)
	{
		vd->channel[i].norm = norm;
	}

	if(v4l_get_capability(vd))
	{
		perror("v4l_set_norm");
		return -1;
	}

	if(v4l_get_picture(vd))
	{
		perror("v4l_set_norm");
	}

	return 0;
}

int v4l_grab_init(v4l_device *vd , int width,int height)
{
	vd->mmap.width = width;
	vd->mmap.height = height;
	vd->mmap.format = vd->picture.palette;
	//printf("vd->picture.palette: %d\n",vd->picture.palette);
	vd->frame_current = 0;
	vd->frame_using[0] = FALSE;
	vd->frame_using[1] = FALSE;
	return v4l_grab_frame(vd,0);
}

int v4l_grab_frame(v4l_device *vd,int frame)
{
	if(vd->frame_using[frame])
	{
		fprintf(stderr,"v4l_grab_frame:frame %d is already used. \n",frame);
		return -1;
	}
	vd->mmap.frame = frame;
	if(ioctl(vd->fd,VIDIOCMCAPTURE,&(vd->mmap))<0)
	{
		perror("v4l_grab_frame");
		return -1;
	}
	
	//printf("vd->mmap.frame: %d\n",vd->mmap.frame);
	//printf("vd->mmap.height: %d\n",vd->mmap.height);
	//printf("vd->mmap.width: %d\n",vd->mmap.width);
	//printf("vd->mmap.format: %d\n",vd->mmap.format);

	vd->frame_using[frame] = TRUE;
	vd->frame_current = frame;
	
	return 0;
}

int v4l_set_palette(v4l_device *vd,int palette)
{
	vd->picture.palette = palette;
	if(ioctl(vd->fd,VIDIOCSPICT,&(vd->picture)))
	{
		perror("v4l_set_palette");
		return -1;
	}

	if(v4l_get_picture(vd))
	{
		perror("v4l_set_palette");
		return -1;
	}
	return 0;
}

unsigned char *device_get_address(v4l_device *vd)
{
	return vd->map + vd->mbuf.offsets[0];
}

int v4l_grab_sync(v4l_device *vd)
{
	if(ioctl(vd->fd,VIDIOCSYNC,&(vd->frame_current))<0)
	{
		perror("v4l_grab_sync");
	}
	vd->frame_using[vd->frame_current] = FALSE;
	return 0;
}