FFmpeg: libavdevice/v4l.c Source File

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libavdevice

v4l.c

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1 /*

2 * Linux video grab interface

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 */

22 #include "avdevice.h"

24 #undef __STRICT_ANSI__ //workaround due to broken kernel headers

25 #include "config.h"

26 #include "libavutil/rational.h"

27 #include "libavutil/imgutils.h"

28 #include "libavutil/log.h"

29 #include "libavutil/opt.h"

30 #include "libavformat/internal.h"

31 #include "libavcodec/dsputil.h"

32 #include <unistd.h>

33 #include <fcntl.h>

34 #include <sys/ioctl.h>

35 #include <sys/mman.h>

36 #include <sys/time.h>

37 #define _LINUX_TIME_H 1

38 #include <linux/videodev.h>

39 #include <time.h>

41 typedef struct {

42 AVClass *class;

43 int fd;

44 int frame_format; /* see VIDEO_PALETTE_xxx */

45 int use_mmap;

46 AVRational time_base;

47 int64_t time_frame;

48 int frame_size;

49 struct video_capability video_cap;

50 struct video_audio audio_saved;

51 struct video_window video_win;

52 uint8_t *video_buf;

53 struct video_mbuf gb_buffers;

54 struct video_mmap gb_buf;

55 int gb_frame;

56 int standard;

57 } VideoData;

59 static const struct {

60 int palette;

61 int depth;

62 enum AVPixelFormat pix_fmt;

63 } video_formats [] = {

64 {.palette = VIDEO_PALETTE_YUV420P, .depth = 12, .pix_fmt = AV_PIX_FMT_YUV420P },

65 {.palette = VIDEO_PALETTE_YUV422, .depth = 16, .pix_fmt = AV_PIX_FMT_YUYV422 },

66 {.palette = VIDEO_PALETTE_UYVY, .depth = 16, .pix_fmt = AV_PIX_FMT_UYVY422 },

67 {.palette = VIDEO_PALETTE_YUYV, .depth = 16, .pix_fmt = AV_PIX_FMT_YUYV422 },

68 /* NOTE: v4l uses BGR24, not RGB24 */

69 {.palette = VIDEO_PALETTE_RGB24, .depth = 24, .pix_fmt = AV_PIX_FMT_BGR24 },

70 {.palette = VIDEO_PALETTE_RGB565, .depth = 16, .pix_fmt = AV_PIX_FMT_BGR565 },

71 {.palette = VIDEO_PALETTE_GREY, .depth = 8, .pix_fmt = AV_PIX_FMT_GRAY8 },

72 };

75 static int grab_read_header(AVFormatContext *s1, AVFormatParameters *ap)

76 {

77 VideoData *s = s1->priv_data;

78 AVStream *st;

79 int video_fd;

80 int desired_palette, desired_depth;

81 struct video_tuner tuner;

82 struct video_audio audio;

83 struct video_picture pict;

84 int j;

85 int vformat_num = FF_ARRAY_ELEMS(video_formats);

87 av_log(s1, AV_LOG_WARNING, "V4L input device is deprecated and will be removed in the next release.");

89 if (ap->time_base.den <= 0) {

90 av_log(s1, AV_LOG_ERROR, "Wrong time base (%d)\n", ap->time_base.den);

91 return -1;

92 }

93 s->time_base = ap->time_base;

95 s->video_win.width = ap->width;

96 s->video_win.height = ap->height;

98 st = avformat_new_stream(s1, NULL);

99 if (!st)

100 return AVERROR(ENOMEM);

101 avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */

102

103 video_fd = open(s1->filename, O_RDWR);

104 if (video_fd < 0) {

105 av_log(s1, AV_LOG_ERROR, "%s: %s\n", s1->filename, strerror(errno));

106 goto fail;

107 }

108

109 if (ioctl(video_fd, VIDIOCGCAP, &s->video_cap) < 0) {

110 av_log(s1, AV_LOG_ERROR, "VIDIOCGCAP: %s\n", strerror(errno));

111 goto fail;

112 }

113

114 if (!(s->video_cap.type & VID_TYPE_CAPTURE)) {

115 av_log(s1, AV_LOG_ERROR, "Fatal: grab device does not handle capture\n");

116 goto fail;

117 }

118

119 /* no values set, autodetect them */

120 if (s->video_win.width <= 0 || s->video_win.height <= 0) {

121 if (ioctl(video_fd, VIDIOCGWIN, &s->video_win, sizeof(s->video_win)) < 0) {

122 av_log(s1, AV_LOG_ERROR, "VIDIOCGWIN: %s\n", strerror(errno));

123 goto fail;

124 }

125 }

126

127 if(av_image_check_size(s->video_win.width, s->video_win.height, 0, s1) < 0)

128 return -1;

129

130 desired_palette = -1;

131 desired_depth = -1;

132 for (j = 0; j < vformat_num; j++) {

133 if (ap->pix_fmt == video_formats[j].pix_fmt) {

134 desired_palette = video_formats[j].palette;

135 desired_depth = video_formats[j].depth;

136 break;

137 }

138 }

139

140 /* set tv standard */

141 if (!ioctl(video_fd, VIDIOCGTUNER, &tuner)) {

142 tuner.mode = s->standard;

143 ioctl(video_fd, VIDIOCSTUNER, &tuner);

144 }

145

146 /* unmute audio */

147 audio.audio = 0;

148 ioctl(video_fd, VIDIOCGAUDIO, &audio);

149 memcpy(&s->audio_saved, &audio, sizeof(audio));

150 audio.flags &= ~VIDEO_AUDIO_MUTE;

151 ioctl(video_fd, VIDIOCSAUDIO, &audio);

152

153 ioctl(video_fd, VIDIOCGPICT, &pict);

154 av_dlog(s1, "v4l: colour=%d hue=%d brightness=%d constrast=%d whiteness=%d\n",

155 pict.colour, pict.hue, pict.brightness, pict.contrast, pict.whiteness);

156 /* try to choose a suitable video format */

157 pict.palette = desired_palette;

158 pict.depth= desired_depth;

159 if (desired_palette == -1 || ioctl(video_fd, VIDIOCSPICT, &pict) < 0) {

160 for (j = 0; j < vformat_num; j++) {

161 pict.palette = video_formats[j].palette;

162 pict.depth = video_formats[j].depth;

163 if (-1 != ioctl(video_fd, VIDIOCSPICT, &pict))

164 break;

165 }

166 if (j >= vformat_num)

167 goto fail1;

168 }

169

170 if (ioctl(video_fd, VIDIOCGMBUF, &s->gb_buffers) < 0) {

171 /* try to use read based access */

172 int val;

173

174 s->video_win.x = 0;

175 s->video_win.y = 0;

176 s->video_win.chromakey = -1;

177 s->video_win.flags = 0;

178

179 if (ioctl(video_fd, VIDIOCSWIN, s->video_win) < 0) {

180 av_log(s1, AV_LOG_ERROR, "VIDIOCSWIN: %s\n", strerror(errno));

181 goto fail;

182 }

183

184 s->frame_format = pict.palette;

185

186 val = 1;

187 if (ioctl(video_fd, VIDIOCCAPTURE, &val) < 0) {

188 av_log(s1, AV_LOG_ERROR, "VIDIOCCAPTURE: %s\n", strerror(errno));

189 goto fail;

190 }

191

192 s->time_frame = av_gettime() * s->time_base.den / s->time_base.num;

193 s->use_mmap = 0;

194 } else {

195 s->video_buf = mmap(0, s->gb_buffers.size, PROT_READ|PROT_WRITE, MAP_SHARED, video_fd, 0);

196 if ((unsigned char*)-1 == s->video_buf) {

197 s->video_buf = mmap(0, s->gb_buffers.size, PROT_READ|PROT_WRITE, MAP_PRIVATE, video_fd, 0);

198 if ((unsigned char*)-1 == s->video_buf) {

199 av_log(s1, AV_LOG_ERROR, "mmap: %s\n", strerror(errno));

200 goto fail;

201 }

202 }

203 s->gb_frame = 0;

204 s->time_frame = av_gettime() * s->time_base.den / s->time_base.num;

205

206 /* start to grab the first frame */

207 s->gb_buf.frame = s->gb_frame % s->gb_buffers.frames;

208 s->gb_buf.height = s->video_win.height;

209 s->gb_buf.width = s->video_win.width;

210 s->gb_buf.format = pict.palette;

211

212 if (ioctl(video_fd, VIDIOCMCAPTURE, &s->gb_buf) < 0) {

213 if (errno != EAGAIN) {

214 fail1:

215 av_log(s1, AV_LOG_ERROR, "VIDIOCMCAPTURE: %s\n", strerror(errno));

216 } else {

217 av_log(s1, AV_LOG_ERROR, "Fatal: grab device does not receive any video signal\n");

218 }

219 goto fail;

220 }

221 for (j = 1; j < s->gb_buffers.frames; j++) {

222 s->gb_buf.frame = j;

223 ioctl(video_fd, VIDIOCMCAPTURE, &s->gb_buf);

224 }

225 s->frame_format = s->gb_buf.format;

226 s->use_mmap = 1;

227 }

228

229 for (j = 0; j < vformat_num; j++) {

230 if (s->frame_format == video_formats[j].palette) {

231 s->frame_size = s->video_win.width * s->video_win.height * video_formats[j].depth / 8;

232 st->codec->pix_fmt = video_formats[j].pix_fmt;

233 break;

234 }

235 }

236

237 if (j >= vformat_num)

238 goto fail;

239

240 s->fd = video_fd;

241

242 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

243 st->codec->codec_id = AV_CODEC_ID_RAWVIDEO;

244 st->codec->width = s->video_win.width;

245 st->codec->height = s->video_win.height;

246 st->codec->time_base = s->time_base;

247 st->codec->bit_rate = s->frame_size * 1/av_q2d(st->codec->time_base) * 8;

248

249 return 0;

250 fail:

251 if (video_fd >= 0)

252 close(video_fd);

253 return AVERROR(EIO);

254 }

255

256 static int v4l_mm_read_picture(VideoData *s, uint8_t *buf)

257 {

258 uint8_t *ptr;

259

260 while (ioctl(s->fd, VIDIOCSYNC, &s->gb_frame) < 0 &&

261 (errno == EAGAIN || errno == EINTR));

262

263 ptr = s->video_buf + s->gb_buffers.offsets[s->gb_frame];

264 memcpy(buf, ptr, s->frame_size);

265

266 /* Setup to capture the next frame */

267 s->gb_buf.frame = s->gb_frame;

268 if (ioctl(s->fd, VIDIOCMCAPTURE, &s->gb_buf) < 0) {

269 if (errno == EAGAIN)

270 av_log(NULL, AV_LOG_ERROR, "Cannot Sync\n");

271 else

272 av_log(NULL, AV_LOG_ERROR, "VIDIOCMCAPTURE: %s\n", strerror(errno));

273 return AVERROR(EIO);

274 }

275

276 /* This is now the grabbing frame */

277 s->gb_frame = (s->gb_frame + 1) % s->gb_buffers.frames;

278

279 return s->frame_size;

280 }

281

282 static int grab_read_packet(AVFormatContext *s1, AVPacket *pkt)

283 {

284 VideoData *s = s1->priv_data;

285 int64_t curtime, delay;

286 struct timespec ts;

287

288 /* Calculate the time of the next frame */

289 s->time_frame += INT64_C(1000000);

290

291 /* wait based on the frame rate */

292 for(;;) {

293 curtime = av_gettime();

294 delay = s->time_frame * s->time_base.num / s->time_base.den - curtime;

295 if (delay <= 0) {

296 if (delay < INT64_C(-1000000) * s->time_base.num / s->time_base.den) {

297 /* printf("grabbing is %d frames late (dropping)\n", (int) -(delay / 16666)); */

298 s->time_frame += INT64_C(1000000);

299 }

300 break;

301 }

302 ts.tv_sec = delay / 1000000;

303 ts.tv_nsec = (delay % 1000000) * 1000;

304 nanosleep(&ts, NULL);

305 }

306

307 if (av_new_packet(pkt, s->frame_size) < 0)

308 return AVERROR(EIO);

309

310 pkt->pts = curtime;

311

312 /* read one frame */

313 if (s->use_mmap) {

314 return v4l_mm_read_picture(s, pkt->data);

315 } else {

316 if (read(s->fd, pkt->data, pkt->size) != pkt->size)

317 return AVERROR(EIO);

318 return s->frame_size;

319 }

320 }

321

322 static int grab_read_close(AVFormatContext *s1)

323 {

324 VideoData *s = s1->priv_data;

325

326 if (s->use_mmap)

327 munmap(s->video_buf, s->gb_buffers.size);

328

329 /* mute audio. we must force it because the BTTV driver does not

330 return its state correctly */

331 s->audio_saved.flags |= VIDEO_AUDIO_MUTE;

332 ioctl(s->fd, VIDIOCSAUDIO, &s->audio_saved);

333

334 close(s->fd);

335 return 0;

336 }

337

338 static const AVOption options[] = {

339 { "standard", "", offsetof(VideoData, standard), AV_OPT_TYPE_INT, {.i64 = VIDEO_MODE_NTSC}, VIDEO_MODE_PAL, VIDEO_MODE_NTSC, AV_OPT_FLAG_DECODING_PARAM, "standard" },

340 { "PAL", "", 0, AV_OPT_TYPE_CONST, {.i64 = VIDEO_MODE_PAL}, 0, 0, AV_OPT_FLAG_DECODING_PARAM, "standard" },

341 { "SECAM", "", 0, AV_OPT_TYPE_CONST, {.i64 = VIDEO_MODE_SECAM}, 0, 0, AV_OPT_FLAG_DECODING_PARAM, "standard" },

342 { "NTSC", "", 0, AV_OPT_TYPE_CONST, {.i64 = VIDEO_MODE_NTSC}, 0, 0, AV_OPT_FLAG_DECODING_PARAM, "standard" },

343 { NULL },

344 };

345

346 static const AVClass v4l_class = {

347 .class_name = "V4L indev",

348 .item_name = av_default_item_name,

349 .option = options,

350 .version = LIBAVUTIL_VERSION_INT,

351 .category = AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT,

352 };

353

354 AVInputFormat ff_v4l_demuxer = {

355 .name = "video4linux,v4l",

356 .long_name = NULL_IF_CONFIG_SMALL("Video4Linux device grab"),

357 .priv_data_size = sizeof(VideoData),

358 .read_header = grab_read_header,

359 .read_packet = grab_read_packet,

360 .read_close = grab_read_close,

361 .flags = AVFMT_NOFILE,

362 .priv_class = &v4l_class,

363 };

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