/* * Linux video grab interface * Copyright (c) 2000,2001 Fabrice Bellard. * * This library 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 of the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include "avformat.h" #include <linux/videodev.h> #include <unistd.h> #include <fcntl.h> #include <sys/ioctl.h> #include <sys/mman.h> #include <sys/time.h> #include <time.h> typedef struct { int fd; int frame_format; /* see VIDEO_PALETTE_xxx */ int use_mmap; int width, height; int frame_rate; INT64 time_frame; int frame_size; } 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, audio_saved; static int gb_frame = 0; static int grab_read_header(AVFormatContext *s1, AVFormatParameters *ap) { VideoData *s = s1->priv_data; AVStream *st; int width, height; int video_fd, frame_size; int ret, frame_rate; int desired_palette; if (!ap || ap->width <= 0 || ap->height <= 0 || ap->frame_rate <= 0) return -1; width = ap->width; height = ap->height; frame_rate = ap->frame_rate; st = av_new_stream(s1, 0); if (!st) return -ENOMEM; s->width = width; s->height = height; s->frame_rate = frame_rate; video_fd = open(v4l_device, O_RDWR); if (video_fd < 0) { perror(v4l_device); goto fail; } 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; } desired_palette = -1; if (st->codec.pix_fmt == PIX_FMT_YUV420P) { desired_palette = VIDEO_PALETTE_YUV420P; } else if (st->codec.pix_fmt == PIX_FMT_YUV422) { desired_palette = VIDEO_PALETTE_YUV422; } else if (st->codec.pix_fmt == PIX_FMT_BGR24) { desired_palette = VIDEO_PALETTE_RGB24; } /* unmute audio */ ioctl(video_fd, VIDIOCGAUDIO, &audio); memcpy(&audio_saved, &audio, sizeof(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 = desired_palette; if (desired_palette == -1 || (ret = ioctl(video_fd, VIDIOCSPICT, &pict)) < 0) { 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 = gb_frame % gb_buffers.frames; gb_buf.height = height; gb_buf.width = width; gb_buf.format = desired_palette; if (desired_palette == -1 || (ret = ioctl(video_fd, VIDIOCMCAPTURE, &gb_buf)) < 0) { 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; st->codec.pix_fmt = PIX_FMT_YUV420P; break; case VIDEO_PALETTE_YUV422: frame_size = width * height * 2; st->codec.pix_fmt = PIX_FMT_YUV422; break; case VIDEO_PALETTE_RGB24: frame_size = width * height * 3; st->codec.pix_fmt = PIX_FMT_BGR24; /* NOTE: v4l uses BGR24, not RGB24 ! */ break; default: goto fail; } s->fd = video_fd; s->frame_size = frame_size; st->codec.codec_type = CODEC_TYPE_VIDEO; st->codec.codec_id = CODEC_ID_RAWVIDEO; st->codec.width = width; st->codec.height = height; st->codec.frame_rate = frame_rate; return 0; fail: if (video_fd >= 0) close(video_fd); av_free(st); return -EIO; } static int v4l_mm_read_picture(VideoData *s, UINT8 *buf) { UINT8 *ptr; struct timeval tv_s; //struct timeval tv_e; //int delay; /* Setup to capture the next frame */ gb_buf.frame = (gb_frame + 1) % gb_buffers.frames; if (ioctl(s->fd, VIDIOCMCAPTURE, &gb_buf) < 0) { if (errno == EAGAIN) fprintf(stderr,"Cannot Sync\n"); else perror("VIDIOCMCAPTURE"); return -EIO; } gettimeofday(&tv_s, 0); while (ioctl(s->fd, VIDIOCSYNC, &gb_frame) < 0 && (errno == EAGAIN || errno == EINTR)); /* gettimeofday(&tv_e, 0); delay = (tv_e.tv_sec - tv_s.tv_sec) * 1000000 + tv_e.tv_usec - tv_s.tv_usec; if (delay > 10000) printf("VIDIOCSYNC took %d us\n", delay); */ ptr = video_buf + gb_buffers.offsets[gb_frame]; memcpy(buf, ptr, s->frame_size); /* This is now the grabbing frame */ gb_frame = gb_buf.frame; return s->frame_size; } static int grab_read_packet(AVFormatContext *s1, AVPacket *pkt) { VideoData *s = s1->priv_data; INT64 curtime, delay; struct timespec ts; int first; INT64 per_frame = (INT64_C(1000000) * FRAME_RATE_BASE) / s->frame_rate; int dropped = 0; /* Calculate the time of the next frame */ s->time_frame += per_frame; /* wait based on the frame rate */ for(first = 1;; first = 0) { curtime = gettime(); delay = s->time_frame - curtime; if (delay <= 0) { if (delay < -per_frame) { /* printf("grabbing is %d frames late (dropping)\n", (int) -(delay / 16666)); */ dropped = 1; s->time_frame += per_frame; } break; } ts.tv_sec = delay / 1000000; ts.tv_nsec = (delay % 1000000) * 1000; nanosleep(&ts, NULL); } if (av_new_packet(pkt, s->frame_size) < 0) return -EIO; if (dropped) pkt->flags |= PKT_FLAG_DROPPED_FRAME; /* read one frame */ if (s->use_mmap) { return v4l_mm_read_picture(s, pkt->data); } else { if (read(s->fd, pkt->data, pkt->size) != pkt->size) return -EIO; return s->frame_size; } } static int grab_read_close(AVFormatContext *s1) { VideoData *s = s1->priv_data; /* restore audio settings */ ioctl(s->fd, VIDIOCSAUDIO, &audio_saved); close(s->fd); return 0; } AVInputFormat video_grab_device_format = { "video_grab_device", "video grab", sizeof(VideoData), NULL, grab_read_header, grab_read_packet, grab_read_close, flags: AVFMT_NOFILE, }; int video_grab_init(void) { av_register_input_format(&video_grab_device_format); return 0; }