libavdevice/v4l.c

   1 /*
   2  * Linux video grab interface
   3  * Copyright (c) 2000,2001 Fabrice Bellard
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #undef __STRICT_ANSI__ //workaround due to broken kernel headers
  23 #include "config.h"
  24 #include "libavutil/rational.h"
  25 #include "libavformat/avformat.h"
  26 #include "libavcodec/dsputil.h"
  27 #include <unistd.h>
  28 #include <fcntl.h>
  29 #include <sys/ioctl.h>
  30 #include <sys/mman.h>
  31 #include <sys/time.h>
  32 #define _LINUX_TIME_H 1
  33 #include <linux/videodev.h>
  34 #include <time.h>
  35 #include <strings.h>
  36
  37 typedef struct {
  38     int fd;
  39     int frame_format; /* see VIDEO_PALETTE_xxx */
  40     int use_mmap;
  41     AVRational time_base;
  42     int64_t time_frame;
  43     int frame_size;
  44     struct video_capability video_cap;
  45     struct video_audio audio_saved;
  46     struct video_window video_win;
  47     uint8_t *video_buf;
  48     struct video_mbuf gb_buffers;
  49     struct video_mmap gb_buf;
  50     int gb_frame;
  51 } VideoData;
  52
  53 static const struct {
  54     int palette;
  55     int depth;
  56     enum PixelFormat pix_fmt;
  57 } video_formats [] = {
  58     {.palette = VIDEO_PALETTE_YUV420P, .depth = 12, .pix_fmt = PIX_FMT_YUV420P },
  59     {.palette = VIDEO_PALETTE_YUV422,  .depth = 16, .pix_fmt = PIX_FMT_YUYV422 },
  60     {.palette = VIDEO_PALETTE_UYVY,    .depth = 16, .pix_fmt = PIX_FMT_UYVY422 },
  61     {.palette = VIDEO_PALETTE_YUYV,    .depth = 16, .pix_fmt = PIX_FMT_YUYV422 },
  62     /* NOTE: v4l uses BGR24, not RGB24 */
  63     {.palette = VIDEO_PALETTE_RGB24,   .depth = 24, .pix_fmt = PIX_FMT_BGR24   },
  64     {.palette = VIDEO_PALETTE_RGB565,  .depth = 16, .pix_fmt = PIX_FMT_BGR565  },
  65     {.palette = VIDEO_PALETTE_GREY,    .depth = 8,  .pix_fmt = PIX_FMT_GRAY8   },
  66 };
  67
  68
  69 static int grab_read_header(AVFormatContext *s1, AVFormatParameters *ap)
  70 {
  71     VideoData *s = s1->priv_data;
  72     AVStream *st;
  73     int video_fd;
  74     int desired_palette, desired_depth;
  75     struct video_tuner tuner;
  76     struct video_audio audio;
  77     struct video_picture pict;
  78     int j;
  79     int vformat_num = FF_ARRAY_ELEMS(video_formats);
  80
  81     if (ap->time_base.den <= 0) {
  82         av_log(s1, AV_LOG_ERROR, "Wrong time base (%d)\n", ap->time_base.den);
  83         return -1;
  84     }
  85     s->time_base = ap->time_base;
  86
  87     s->video_win.width = ap->width;
  88     s->video_win.height = ap->height;
  89
  90     st = av_new_stream(s1, 0);
  91     if (!st)
  92         return AVERROR(ENOMEM);
  93     av_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
  94
  95     video_fd = open(s1->filename, O_RDWR);
  96     if (video_fd < 0) {
  97         av_log(s1, AV_LOG_ERROR, "%s: %s\n", s1->filename, strerror(errno));
  98         goto fail;
  99     }
 100
 101     if (ioctl(video_fd, VIDIOCGCAP, &s->video_cap) < 0) {
 102         av_log(s1, AV_LOG_ERROR, "VIDIOCGCAP: %s\n", strerror(errno));
 103         goto fail;
 104     }
 105
 106     if (!(s->video_cap.type & VID_TYPE_CAPTURE)) {
 107         av_log(s1, AV_LOG_ERROR, "Fatal: grab device does not handle capture\n");
 108         goto fail;
 109     }
 110
 111     /* no values set, autodetect them */
 112     if (s->video_win.width <= 0 || s->video_win.height <= 0) {
 113         if (ioctl(video_fd, VIDIOCGWIN, &s->video_win, sizeof(s->video_win)) < 0) {
 114             av_log(s1, AV_LOG_ERROR, "VIDIOCGWIN: %s\n", strerror(errno));
 115             goto fail;
 116         }
 117     }
 118
 119     if(avcodec_check_dimensions(s1, s->video_win.width, s->video_win.height) < 0)
 120         return -1;
 121
 122     desired_palette = -1;
 123     desired_depth = -1;
 124     for (j = 0; j < vformat_num; j++) {
 125         if (ap->pix_fmt == video_formats[j].pix_fmt) {
 126             desired_palette = video_formats[j].palette;
 127             desired_depth = video_formats[j].depth;
 128             break;
 129         }
 130     }
 131
 132     /* set tv standard */
 133     if (ap->standard && !ioctl(video_fd, VIDIOCGTUNER, &tuner)) {
 134         if (!strcasecmp(ap->standard, "pal"))
 135             tuner.mode = VIDEO_MODE_PAL;
 136         else if (!strcasecmp(ap->standard, "secam"))
 137             tuner.mode = VIDEO_MODE_SECAM;
 138         else
 139             tuner.mode = VIDEO_MODE_NTSC;
 140         ioctl(video_fd, VIDIOCSTUNER, &tuner);
 141     }
 142
 143     /* unmute audio */
 144     audio.audio = 0;
 145     ioctl(video_fd, VIDIOCGAUDIO, &audio);
 146     memcpy(&s->audio_saved, &audio, sizeof(audio));
 147     audio.flags &= ~VIDEO_AUDIO_MUTE;
 148     ioctl(video_fd, VIDIOCSAUDIO, &audio);
 149
 150     ioctl(video_fd, VIDIOCGPICT, &pict);
 151 #if 0
 152     printf("v4l: colour=%d hue=%d brightness=%d constrast=%d whiteness=%d\n",
 153            pict.colour,
 154            pict.hue,
 155            pict.brightness,
 156            pict.contrast,
 157            pict.whiteness);
 158 #endif
 159     /* try to choose a suitable video format */
 160     pict.palette = desired_palette;
 161     pict.depth= desired_depth;
 162     if (desired_palette == -1 || ioctl(video_fd, VIDIOCSPICT, &pict) < 0) {
 163         for (j = 0; j < vformat_num; j++) {
 164             pict.palette = video_formats[j].palette;
 165             pict.depth = video_formats[j].depth;
 166             if (-1 != ioctl(video_fd, VIDIOCSPICT, &pict))
 167                 break;
 168         }
 169         if (j >= vformat_num)
 170             goto fail1;
 171     }
 172
 173     if (ioctl(video_fd, VIDIOCGMBUF, &s->gb_buffers) < 0) {
 174         /* try to use read based access */
 175         int val;
 176
 177         s->video_win.x = 0;
 178         s->video_win.y = 0;
 179         s->video_win.chromakey = -1;
 180         s->video_win.flags = 0;
 181
 182         if (ioctl(video_fd, VIDIOCSWIN, s->video_win) < 0) {
 183             av_log(s1, AV_LOG_ERROR, "VIDIOCSWIN: %s\n", strerror(errno));
 184             goto fail;
 185         }
 186
 187         s->frame_format = pict.palette;
 188
 189         val = 1;
 190         if (ioctl(video_fd, VIDIOCCAPTURE, &val) < 0) {
 191             av_log(s1, AV_LOG_ERROR, "VIDIOCCAPTURE: %s\n", strerror(errno));
 192             goto fail;
 193         }
 194
 195         s->time_frame = av_gettime() * s->time_base.den / s->time_base.num;
 196         s->use_mmap = 0;
 197     } else {
 198         s->video_buf = mmap(0, s->gb_buffers.size, PROT_READ|PROT_WRITE, MAP_SHARED, video_fd, 0);
 199         if ((unsigned char*)-1 == s->video_buf) {
 200             s->video_buf = mmap(0, s->gb_buffers.size, PROT_READ|PROT_WRITE, MAP_PRIVATE, video_fd, 0);
 201             if ((unsigned char*)-1 == s->video_buf) {
 202                 av_log(s1, AV_LOG_ERROR, "mmap: %s\n", strerror(errno));
 203                 goto fail;
 204             }
 205         }
 206         s->gb_frame = 0;
 207         s->time_frame = av_gettime() * s->time_base.den / s->time_base.num;
 208
 209         /* start to grab the first frame */
 210         s->gb_buf.frame = s->gb_frame % s->gb_buffers.frames;
 211         s->gb_buf.height = s->video_win.height;
 212         s->gb_buf.width = s->video_win.width;
 213         s->gb_buf.format = pict.palette;
 214
 215         if (ioctl(video_fd, VIDIOCMCAPTURE, &s->gb_buf) < 0) {
 216             if (errno != EAGAIN) {
 217             fail1:
 218                 av_log(s1, AV_LOG_ERROR, "VIDIOCMCAPTURE: %s\n", strerror(errno));
 219             } else {
 220                 av_log(s1, AV_LOG_ERROR, "Fatal: grab device does not receive any video signal\n");
 221             }
 222             goto fail;
 223         }
 224         for (j = 1; j < s->gb_buffers.frames; j++) {
 225           s->gb_buf.frame = j;
 226           ioctl(video_fd, VIDIOCMCAPTURE, &s->gb_buf);
 227         }
 228         s->frame_format = s->gb_buf.format;
 229         s->use_mmap = 1;
 230     }
 231
 232     for (j = 0; j < vformat_num; j++) {
 233         if (s->frame_format == video_formats[j].palette) {
 234             s->frame_size = s->video_win.width * s->video_win.height * video_formats[j].depth / 8;
 235             st->codec->pix_fmt = video_formats[j].pix_fmt;
 236             break;
 237         }
 238     }
 239
 240     if (j >= vformat_num)
 241         goto fail;
 242
 243     s->fd = video_fd;
 244
 245     st->codec->codec_type = CODEC_TYPE_VIDEO;
 246     st->codec->codec_id = CODEC_ID_RAWVIDEO;
 247     st->codec->width = s->video_win.width;
 248     st->codec->height = s->video_win.height;
 249     st->codec->time_base = s->time_base;
 250     st->codec->bit_rate = s->frame_size * 1/av_q2d(st->codec->time_base) * 8;
 251
 252     return 0;
 253  fail:
 254     if (video_fd >= 0)
 255         close(video_fd);
 256     return AVERROR(EIO);
 257 }
 258
 259 static int v4l_mm_read_picture(VideoData *s, uint8_t *buf)
 260 {
 261     uint8_t *ptr;
 262
 263     while (ioctl(s->fd, VIDIOCSYNC, &s->gb_frame) < 0 &&
 264            (errno == EAGAIN || errno == EINTR));
 265
 266     ptr = s->video_buf + s->gb_buffers.offsets[s->gb_frame];
 267     memcpy(buf, ptr, s->frame_size);
 268
 269     /* Setup to capture the next frame */
 270     s->gb_buf.frame = s->gb_frame;
 271     if (ioctl(s->fd, VIDIOCMCAPTURE, &s->gb_buf) < 0) {
 272         if (errno == EAGAIN)
 273             av_log(NULL, AV_LOG_ERROR, "Cannot Sync\n");
 274         else
 275             av_log(NULL, AV_LOG_ERROR, "VIDIOCMCAPTURE: %s\n", strerror(errno));
 276         return AVERROR(EIO);
 277     }
 278
 279     /* This is now the grabbing frame */
 280     s->gb_frame = (s->gb_frame + 1) % s->gb_buffers.frames;
 281
 282     return s->frame_size;
 283 }
 284
 285 static int grab_read_packet(AVFormatContext *s1, AVPacket *pkt)
 286 {
 287     VideoData *s = s1->priv_data;
 288     int64_t curtime, delay;
 289     struct timespec ts;
 290
 291     /* Calculate the time of the next frame */
 292     s->time_frame += INT64_C(1000000);
 293
 294     /* wait based on the frame rate */
 295     for(;;) {
 296         curtime = av_gettime();
 297         delay = s->time_frame * s->time_base.num / s->time_base.den - curtime;
 298         if (delay <= 0) {
 299             if (delay < INT64_C(-1000000) * s->time_base.num / s->time_base.den) {
 300                 /* printf("grabbing is %d frames late (dropping)\n", (int) -(delay / 16666)); */
 301                 s->time_frame += INT64_C(1000000);
 302             }
 303             break;
 304         }
 305         ts.tv_sec = delay / 1000000;
 306         ts.tv_nsec = (delay % 1000000) * 1000;
 307         nanosleep(&ts, NULL);
 308     }
 309
 310     if (av_new_packet(pkt, s->frame_size) < 0)
 311         return AVERROR(EIO);
 312
 313     pkt->pts = curtime;
 314
 315     /* read one frame */
 316     if (s->use_mmap) {
 317         return v4l_mm_read_picture(s, pkt->data);
 318     } else {
 319         if (read(s->fd, pkt->data, pkt->size) != pkt->size)
 320             return AVERROR(EIO);
 321         return s->frame_size;
 322     }
 323 }
 324
 325 static int grab_read_close(AVFormatContext *s1)
 326 {
 327     VideoData *s = s1->priv_data;
 328
 329     if (s->use_mmap)
 330         munmap(s->video_buf, s->gb_buffers.size);
 331
 332     /* mute audio. we must force it because the BTTV driver does not
 333        return its state correctly */
 334     s->audio_saved.flags |= VIDEO_AUDIO_MUTE;
 335     ioctl(s->fd, VIDIOCSAUDIO, &s->audio_saved);
 336
 337     close(s->fd);
 338     return 0;
 339 }
 340
 341 AVInputFormat v4l_demuxer = {
 342     "video4linux",
 343     NULL_IF_CONFIG_SMALL("Video4Linux device grab"),
 344     sizeof(VideoData),
 345     NULL,
 346     grab_read_header,
 347     grab_read_packet,
 348     grab_read_close,
 349     .flags = AVFMT_NOFILE,
 350 };