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libavdevice/v4l.c

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00001 /*
00002  * Linux video grab interface
00003  * Copyright (c) 2000,2001 Fabrice Bellard
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #undef __STRICT_ANSI__ //workaround due to broken kernel headers
00023 #include "config.h"
00024 #include "libavutil/rational.h"
00025 #include "libavformat/avformat.h"
00026 #include "libavcodec/dsputil.h"
00027 #include <unistd.h>
00028 #include <fcntl.h>
00029 #include <sys/ioctl.h>
00030 #include <sys/mman.h>
00031 #include <sys/time.h>
00032 #define _LINUX_TIME_H 1
00033 #include <linux/videodev.h>
00034 #include <time.h>
00035 #include <strings.h>
00036 
00037 typedef struct {
00038     int fd;
00039     int frame_format; /* see VIDEO_PALETTE_xxx */
00040     int use_mmap;
00041     AVRational time_base;
00042     int64_t time_frame;
00043     int frame_size;
00044     struct video_capability video_cap;
00045     struct video_audio audio_saved;
00046     struct video_window video_win;
00047     uint8_t *video_buf;
00048     struct video_mbuf gb_buffers;
00049     struct video_mmap gb_buf;
00050     int gb_frame;
00051 } VideoData;
00052 
00053 static const struct {
00054     int palette;
00055     int depth;
00056     enum PixelFormat pix_fmt;
00057 } video_formats [] = {
00058     {.palette = VIDEO_PALETTE_YUV420P, .depth = 12, .pix_fmt = PIX_FMT_YUV420P },
00059     {.palette = VIDEO_PALETTE_YUV422,  .depth = 16, .pix_fmt = PIX_FMT_YUYV422 },
00060     {.palette = VIDEO_PALETTE_UYVY,    .depth = 16, .pix_fmt = PIX_FMT_UYVY422 },
00061     {.palette = VIDEO_PALETTE_YUYV,    .depth = 16, .pix_fmt = PIX_FMT_YUYV422 },
00062     /* NOTE: v4l uses BGR24, not RGB24 */
00063     {.palette = VIDEO_PALETTE_RGB24,   .depth = 24, .pix_fmt = PIX_FMT_BGR24   },
00064     {.palette = VIDEO_PALETTE_RGB565,  .depth = 16, .pix_fmt = PIX_FMT_BGR565  },
00065     {.palette = VIDEO_PALETTE_GREY,    .depth = 8,  .pix_fmt = PIX_FMT_GRAY8   },
00066 };
00067 
00068 
00069 static int grab_read_header(AVFormatContext *s1, AVFormatParameters *ap)
00070 {
00071     VideoData *s = s1->priv_data;
00072     AVStream *st;
00073     int video_fd;
00074     int desired_palette, desired_depth;
00075     struct video_tuner tuner;
00076     struct video_audio audio;
00077     struct video_picture pict;
00078     int j;
00079     int vformat_num = FF_ARRAY_ELEMS(video_formats);
00080 
00081     if (ap->time_base.den <= 0) {
00082         av_log(s1, AV_LOG_ERROR, "Wrong time base (%d)\n", ap->time_base.den);
00083         return -1;
00084     }
00085     s->time_base = ap->time_base;
00086 
00087     s->video_win.width = ap->width;
00088     s->video_win.height = ap->height;
00089 
00090     st = av_new_stream(s1, 0);
00091     if (!st)
00092         return AVERROR(ENOMEM);
00093     av_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
00094 
00095     video_fd = open(s1->filename, O_RDWR);
00096     if (video_fd < 0) {
00097         av_log(s1, AV_LOG_ERROR, "%s: %s\n", s1->filename, strerror(errno));
00098         goto fail;
00099     }
00100 
00101     if (ioctl(video_fd, VIDIOCGCAP, &s->video_cap) < 0) {
00102         av_log(s1, AV_LOG_ERROR, "VIDIOCGCAP: %s\n", strerror(errno));
00103         goto fail;
00104     }
00105 
00106     if (!(s->video_cap.type & VID_TYPE_CAPTURE)) {
00107         av_log(s1, AV_LOG_ERROR, "Fatal: grab device does not handle capture\n");
00108         goto fail;
00109     }
00110 
00111     /* no values set, autodetect them */
00112     if (s->video_win.width <= 0 || s->video_win.height <= 0) {
00113         if (ioctl(video_fd, VIDIOCGWIN, &s->video_win, sizeof(s->video_win)) < 0) {
00114             av_log(s1, AV_LOG_ERROR, "VIDIOCGWIN: %s\n", strerror(errno));
00115             goto fail;
00116         }
00117     }
00118 
00119     if(avcodec_check_dimensions(s1, s->video_win.width, s->video_win.height) < 0)
00120         return -1;
00121 
00122     desired_palette = -1;
00123     desired_depth = -1;
00124     for (j = 0; j < vformat_num; j++) {
00125         if (ap->pix_fmt == video_formats[j].pix_fmt) {
00126             desired_palette = video_formats[j].palette;
00127             desired_depth = video_formats[j].depth;
00128             break;
00129         }
00130     }
00131 
00132     /* set tv standard */
00133     if (ap->standard && !ioctl(video_fd, VIDIOCGTUNER, &tuner)) {
00134         if (!strcasecmp(ap->standard, "pal"))
00135             tuner.mode = VIDEO_MODE_PAL;
00136         else if (!strcasecmp(ap->standard, "secam"))
00137             tuner.mode = VIDEO_MODE_SECAM;
00138         else
00139             tuner.mode = VIDEO_MODE_NTSC;
00140         ioctl(video_fd, VIDIOCSTUNER, &tuner);
00141     }
00142 
00143     /* unmute audio */
00144     audio.audio = 0;
00145     ioctl(video_fd, VIDIOCGAUDIO, &audio);
00146     memcpy(&s->audio_saved, &audio, sizeof(audio));
00147     audio.flags &= ~VIDEO_AUDIO_MUTE;
00148     ioctl(video_fd, VIDIOCSAUDIO, &audio);
00149 
00150     ioctl(video_fd, VIDIOCGPICT, &pict);
00151 #if 0
00152     printf("v4l: colour=%d hue=%d brightness=%d constrast=%d whiteness=%d\n",
00153            pict.colour,
00154            pict.hue,
00155            pict.brightness,
00156            pict.contrast,
00157            pict.whiteness);
00158 #endif
00159     /* try to choose a suitable video format */
00160     pict.palette = desired_palette;
00161     pict.depth= desired_depth;
00162     if (desired_palette == -1 || ioctl(video_fd, VIDIOCSPICT, &pict) < 0) {
00163         for (j = 0; j < vformat_num; j++) {
00164             pict.palette = video_formats[j].palette;
00165             pict.depth = video_formats[j].depth;
00166             if (-1 != ioctl(video_fd, VIDIOCSPICT, &pict))
00167                 break;
00168         }
00169         if (j >= vformat_num)
00170             goto fail1;
00171     }
00172 
00173     if (ioctl(video_fd, VIDIOCGMBUF, &s->gb_buffers) < 0) {
00174         /* try to use read based access */
00175         int val;
00176 
00177         s->video_win.x = 0;
00178         s->video_win.y = 0;
00179         s->video_win.chromakey = -1;
00180         s->video_win.flags = 0;
00181 
00182         if (ioctl(video_fd, VIDIOCSWIN, s->video_win) < 0) {
00183             av_log(s1, AV_LOG_ERROR, "VIDIOCSWIN: %s\n", strerror(errno));
00184             goto fail;
00185         }
00186 
00187         s->frame_format = pict.palette;
00188 
00189         val = 1;
00190         if (ioctl(video_fd, VIDIOCCAPTURE, &val) < 0) {
00191             av_log(s1, AV_LOG_ERROR, "VIDIOCCAPTURE: %s\n", strerror(errno));
00192             goto fail;
00193         }
00194 
00195         s->time_frame = av_gettime() * s->time_base.den / s->time_base.num;
00196         s->use_mmap = 0;
00197     } else {
00198         s->video_buf = mmap(0, s->gb_buffers.size, PROT_READ|PROT_WRITE, MAP_SHARED, video_fd, 0);
00199         if ((unsigned char*)-1 == s->video_buf) {
00200             s->video_buf = mmap(0, s->gb_buffers.size, PROT_READ|PROT_WRITE, MAP_PRIVATE, video_fd, 0);
00201             if ((unsigned char*)-1 == s->video_buf) {
00202                 av_log(s1, AV_LOG_ERROR, "mmap: %s\n", strerror(errno));
00203                 goto fail;
00204             }
00205         }
00206         s->gb_frame = 0;
00207         s->time_frame = av_gettime() * s->time_base.den / s->time_base.num;
00208 
00209         /* start to grab the first frame */
00210         s->gb_buf.frame = s->gb_frame % s->gb_buffers.frames;
00211         s->gb_buf.height = s->video_win.height;
00212         s->gb_buf.width = s->video_win.width;
00213         s->gb_buf.format = pict.palette;
00214 
00215         if (ioctl(video_fd, VIDIOCMCAPTURE, &s->gb_buf) < 0) {
00216             if (errno != EAGAIN) {
00217             fail1:
00218                 av_log(s1, AV_LOG_ERROR, "VIDIOCMCAPTURE: %s\n", strerror(errno));
00219             } else {
00220                 av_log(s1, AV_LOG_ERROR, "Fatal: grab device does not receive any video signal\n");
00221             }
00222             goto fail;
00223         }
00224         for (j = 1; j < s->gb_buffers.frames; j++) {
00225           s->gb_buf.frame = j;
00226           ioctl(video_fd, VIDIOCMCAPTURE, &s->gb_buf);
00227         }
00228         s->frame_format = s->gb_buf.format;
00229         s->use_mmap = 1;
00230     }
00231 
00232     for (j = 0; j < vformat_num; j++) {
00233         if (s->frame_format == video_formats[j].palette) {
00234             s->frame_size = s->video_win.width * s->video_win.height * video_formats[j].depth / 8;
00235             st->codec->pix_fmt = video_formats[j].pix_fmt;
00236             break;
00237         }
00238     }
00239 
00240     if (j >= vformat_num)
00241         goto fail;
00242 
00243     s->fd = video_fd;
00244 
00245     st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
00246     st->codec->codec_id = CODEC_ID_RAWVIDEO;
00247     st->codec->width = s->video_win.width;
00248     st->codec->height = s->video_win.height;
00249     st->codec->time_base = s->time_base;
00250     st->codec->bit_rate = s->frame_size * 1/av_q2d(st->codec->time_base) * 8;
00251 
00252     return 0;
00253  fail:
00254     if (video_fd >= 0)
00255         close(video_fd);
00256     return AVERROR(EIO);
00257 }
00258 
00259 static int v4l_mm_read_picture(VideoData *s, uint8_t *buf)
00260 {
00261     uint8_t *ptr;
00262 
00263     while (ioctl(s->fd, VIDIOCSYNC, &s->gb_frame) < 0 &&
00264            (errno == EAGAIN || errno == EINTR));
00265 
00266     ptr = s->video_buf + s->gb_buffers.offsets[s->gb_frame];
00267     memcpy(buf, ptr, s->frame_size);
00268 
00269     /* Setup to capture the next frame */
00270     s->gb_buf.frame = s->gb_frame;
00271     if (ioctl(s->fd, VIDIOCMCAPTURE, &s->gb_buf) < 0) {
00272         if (errno == EAGAIN)
00273             av_log(NULL, AV_LOG_ERROR, "Cannot Sync\n");
00274         else
00275             av_log(NULL, AV_LOG_ERROR, "VIDIOCMCAPTURE: %s\n", strerror(errno));
00276         return AVERROR(EIO);
00277     }
00278 
00279     /* This is now the grabbing frame */
00280     s->gb_frame = (s->gb_frame + 1) % s->gb_buffers.frames;
00281 
00282     return s->frame_size;
00283 }
00284 
00285 static int grab_read_packet(AVFormatContext *s1, AVPacket *pkt)
00286 {
00287     VideoData *s = s1->priv_data;
00288     int64_t curtime, delay;
00289     struct timespec ts;
00290 
00291     /* Calculate the time of the next frame */
00292     s->time_frame += INT64_C(1000000);
00293 
00294     /* wait based on the frame rate */
00295     for(;;) {
00296         curtime = av_gettime();
00297         delay = s->time_frame * s->time_base.num / s->time_base.den - curtime;
00298         if (delay <= 0) {
00299             if (delay < INT64_C(-1000000) * s->time_base.num / s->time_base.den) {
00300                 /* printf("grabbing is %d frames late (dropping)\n", (int) -(delay / 16666)); */
00301                 s->time_frame += INT64_C(1000000);
00302             }
00303             break;
00304         }
00305         ts.tv_sec = delay / 1000000;
00306         ts.tv_nsec = (delay % 1000000) * 1000;
00307         nanosleep(&ts, NULL);
00308     }
00309 
00310     if (av_new_packet(pkt, s->frame_size) < 0)
00311         return AVERROR(EIO);
00312 
00313     pkt->pts = curtime;
00314 
00315     /* read one frame */
00316     if (s->use_mmap) {
00317         return v4l_mm_read_picture(s, pkt->data);
00318     } else {
00319         if (read(s->fd, pkt->data, pkt->size) != pkt->size)
00320             return AVERROR(EIO);
00321         return s->frame_size;
00322     }
00323 }
00324 
00325 static int grab_read_close(AVFormatContext *s1)
00326 {
00327     VideoData *s = s1->priv_data;
00328 
00329     if (s->use_mmap)
00330         munmap(s->video_buf, s->gb_buffers.size);
00331 
00332     /* mute audio. we must force it because the BTTV driver does not
00333        return its state correctly */
00334     s->audio_saved.flags |= VIDEO_AUDIO_MUTE;
00335     ioctl(s->fd, VIDIOCSAUDIO, &s->audio_saved);
00336 
00337     close(s->fd);
00338     return 0;
00339 }
00340 
00341 AVInputFormat v4l_demuxer = {
00342     "video4linux",
00343     NULL_IF_CONFIG_SMALL("Video4Linux device grab"),
00344     sizeof(VideoData),
00345     NULL,
00346     grab_read_header,
00347     grab_read_packet,
00348     grab_read_close,
00349     .flags = AVFMT_NOFILE,
00350 };

Generated on Fri Sep 16 2011 17:17:47 for FFmpeg by  doxygen 1.7.1