FFmpeg/libav/grab.c
Fabrice Bellard de6d9b6404 Initial revision
Originally committed as revision 5 to svn://svn.ffmpeg.org/ffmpeg/trunk
2001-07-22 14:18:56 +00:00

322 lines
8.0 KiB
C

/*
* Linux video grab interface
* Copyright (c) 2000,2001 Gerard Lantau.
*
* 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.
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <linux/videodev.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <errno.h>
#include <sys/time.h>
#include "avformat.h"
typedef struct {
int fd;
int frame_format; /* see VIDEO_PALETTE_xxx */
int use_mmap;
int width, height;
float rate;
INT64 time_frame;
} VideoData;
const char *v4l_device = "/dev/video";
/* XXX: move all that to the context */
static struct video_capability video_cap;
static UINT8 *video_buf;
static struct video_mbuf gb_buffers;
static struct video_mmap gb_buf;
static struct video_audio audio;
static int gb_frame = 0;
static int v4l_init(URLContext *h)
{
VideoData *s = h->priv_data;
int width, height;
int ret;
int video_fd, frame_size;
width = s->width;
height = s->height;
video_fd = open(v4l_device, O_RDWR);
if (video_fd < 0) {
perror(v4l_device);
return -EIO;
}
if (ioctl(video_fd,VIDIOCGCAP,&video_cap) < 0) {
perror("VIDIOCGCAP");
goto fail;
}
if (!(video_cap.type & VID_TYPE_CAPTURE)) {
fprintf(stderr, "Fatal: grab device does not handle capture\n");
goto fail;
}
/* unmute audio */
ioctl(video_fd, VIDIOCGAUDIO, &audio);
audio.flags &= ~VIDEO_AUDIO_MUTE;
ioctl(video_fd, VIDIOCSAUDIO, &audio);
ret = ioctl(video_fd,VIDIOCGMBUF,&gb_buffers);
if (ret < 0) {
/* try to use read based access */
struct video_window win;
struct video_picture pict;
int val;
win.x = 0;
win.y = 0;
win.width = width;
win.height = height;
win.chromakey = -1;
win.flags = 0;
ioctl(video_fd, VIDIOCSWIN, &win);
ioctl(video_fd, VIDIOCGPICT, &pict);
#if 0
printf("v4l: colour=%d hue=%d brightness=%d constrast=%d whiteness=%d\n",
pict.colour,
pict.hue,
pict.brightness,
pict.contrast,
pict.whiteness);
#endif
/* try to choose a suitable video format */
pict.palette=VIDEO_PALETTE_YUV420P;
ret = ioctl(video_fd, VIDIOCSPICT, &pict);
if (ret < 0) {
pict.palette=VIDEO_PALETTE_YUV422;
ret = ioctl(video_fd, VIDIOCSPICT, &pict);
if (ret < 0) {
pict.palette=VIDEO_PALETTE_RGB24;
ret = ioctl(video_fd, VIDIOCSPICT, &pict);
if (ret < 0)
goto fail1;
}
}
s->frame_format = pict.palette;
val = 1;
ioctl(video_fd, VIDIOCCAPTURE, &val);
s->time_frame = gettime();
s->use_mmap = 0;
} else {
video_buf = mmap(0,gb_buffers.size,PROT_READ|PROT_WRITE,MAP_SHARED,video_fd,0);
if ((unsigned char*)-1 == video_buf) {
perror("mmap");
goto fail;
}
gb_frame = 0;
s->time_frame = gettime();
/* start to grab the first frame */
gb_buf.frame = 1 - gb_frame;
gb_buf.height = height;
gb_buf.width = width;
gb_buf.format = VIDEO_PALETTE_YUV420P;
ret = ioctl(video_fd, VIDIOCMCAPTURE, &gb_buf);
if (ret < 0 && errno != EAGAIN) {
/* try YUV422 */
gb_buf.format = VIDEO_PALETTE_YUV422;
ret = ioctl(video_fd, VIDIOCMCAPTURE, &gb_buf);
if (ret < 0 && errno != EAGAIN) {
/* try RGB24 */
gb_buf.format = VIDEO_PALETTE_RGB24;
ret = ioctl(video_fd, VIDIOCMCAPTURE, &gb_buf);
}
}
if (ret < 0) {
if (errno != EAGAIN) {
fail1:
fprintf(stderr, "Fatal: grab device does not support suitable format\n");
} else {
fprintf(stderr,"Fatal: grab device does not receive any video signal\n");
}
goto fail;
}
s->frame_format = gb_buf.format;
s->use_mmap = 1;
}
switch(s->frame_format) {
case VIDEO_PALETTE_YUV420P:
frame_size = (width * height * 3) / 2;
break;
case VIDEO_PALETTE_YUV422:
frame_size = width * height * 2;
break;
case VIDEO_PALETTE_RGB24:
frame_size = width * height * 3;
break;
default:
goto fail;
}
s->fd = video_fd;
h->packet_size = frame_size;
return 0;
fail:
close(video_fd);
return -EIO;
}
static int v4l_mm_read_picture(URLContext *h, UINT8 *buf)
{
VideoData *s = h->priv_data;
UINT8 *ptr;
gb_buf.frame = gb_frame;
if (ioctl(s->fd, VIDIOCMCAPTURE, &gb_buf) < 0) {
if (errno == EAGAIN)
fprintf(stderr,"Cannot Sync\n");
else
perror("VIDIOCMCAPTURE");
return -EIO;
}
gb_frame = 1 - gb_frame;
while (ioctl(s->fd, VIDIOCSYNC, &gb_frame) < 0 &&
(errno == EAGAIN || errno == EINTR));
ptr = video_buf + gb_buffers.offsets[gb_frame];
memcpy(buf, ptr, h->packet_size);
return h->packet_size;
}
/* note: we support only one picture read at a time */
static int video_read(URLContext *h, UINT8 *buf, int size)
{
VideoData *s = h->priv_data;
INT64 curtime;
if (size != h->packet_size)
return -EINVAL;
/* wait based on the frame rate */
s->time_frame += (int)(1000000 / s->rate);
do {
curtime = gettime();
} while (curtime < s->time_frame);
/* read one frame */
if (s->use_mmap) {
return v4l_mm_read_picture(h, buf);
} else {
if (read(s->fd, buf, size) != size)
return -EIO;
return h->packet_size;
}
}
static int video_get_format(URLContext *h, URLFormat *f)
{
VideoData *s = h->priv_data;
f->width = s->width;
f->height = s->height;
f->frame_rate = (int)(s->rate * FRAME_RATE_BASE);
strcpy(f->format_name, "rawvideo");
switch(s->frame_format) {
case VIDEO_PALETTE_YUV420P:
f->pix_fmt = PIX_FMT_YUV420P;
break;
case VIDEO_PALETTE_YUV422:
f->pix_fmt = PIX_FMT_YUV422;
break;
case VIDEO_PALETTE_RGB24:
f->pix_fmt = PIX_FMT_BGR24; /* NOTE: v4l uses BGR24, not RGB24 ! */
break;
default:
abort();
}
return 0;
}
/* URI syntax: 'video:width,height,rate'
*/
static int video_open(URLContext *h, const char *uri, int flags)
{
VideoData *s;
const char *p;
int width, height;
int ret;
float rate;
/* extract parameters */
p = uri;
strstart(p, "video:", &p);
width = strtol(p, (char **)&p, 0);
if (width <= 0)
return -EINVAL;
if (*p == ',')
p++;
height = strtol(p, (char **)&p, 0);
if (height <= 0)
return -EINVAL;
if (*p == ',')
p++;
rate = strtod(p, (char **)&p);
if (rate <= 0)
return -EINVAL;
s = malloc(sizeof(VideoData));
if (!s)
return -ENOMEM;
h->priv_data = s;
h->is_streamed = 1;
s->width = width;
s->height = height;
s->rate = rate;
ret = v4l_init(h);
if (ret)
free(s);
return ret;
}
static int video_close(URLContext *h)
{
VideoData *s = h->priv_data;
close(s->fd);
free(s);
return 0;
}
URLProtocol video_protocol = {
"video",
video_open,
video_read,
NULL,
NULL, /* seek */
video_close,
video_get_format,
};