FFmpeg: libavdevice/v4l2.c Source File

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libavdevice

v4l2.c

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1 /*

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 /**

23 * @file

24 * Video4Linux2 grab interface

25 *

26 * Part of this file is based on the V4L2 video capture example

27 * (http://linuxtv.org/downloads/v4l-dvb-apis/capture-example.html)

28 *

29 * Thanks to Michael Niedermayer for providing the mapping between

30 * V4L2_PIX_FMT_* and AV_PIX_FMT_*

31 */

33 #include "v4l2-common.h"

35 #if CONFIG_LIBV4L2

36 #include <libv4l2.h>

37 #endif

39 static const int desired_video_buffers = 256;

41 #define V4L_ALLFORMATS 3

42 #define V4L_RAWFORMATS 1

43 #define V4L_COMPFORMATS 2

45 /**

46 * Return timestamps to the user exactly as returned by the kernel

47 */

48 #define V4L_TS_DEFAULT 0

49 /**

50 * Autodetect the kind of timestamps returned by the kernel and convert to

51 * absolute (wall clock) timestamps.

52 */

53 #define V4L_TS_ABS 1

54 /**

55 * Assume kernel timestamps are from the monotonic clock and convert to

56 * absolute timestamps.

57 */

58 #define V4L_TS_MONO2ABS 2

60 /**

61 * Once the kind of timestamps returned by the kernel have been detected,

62 * the value of the timefilter (NULL or not) determines whether a conversion

63 * takes place.

64 */

65 #define V4L_TS_CONVERT_READY V4L_TS_DEFAULT

67 struct video_data {

68 AVClass *class;

69 int fd;

70 int frame_format; /* V4L2_PIX_FMT_* */

71 int width, height;

72 int frame_size;

73 int interlaced;

74 int top_field_first;

75 int ts_mode;

76 TimeFilter *timefilter;

77 int64_t last_time_m;

79 int buffers;

80 volatile int buffers_queued;

81 void **buf_start;

82 unsigned int *buf_len;

83 char *standard;

84 v4l2_std_id std_id;

85 int channel;

86 char *pixel_format; /**< Set by a private option. */

87 int list_format; /**< Set by a private option. */

88 int list_standard; /**< Set by a private option. */

89 char *framerate; /**< Set by a private option. */

91 int use_libv4l2;

92 int (*open_f)(const char *file, int oflag, ...);

93 int (*close_f)(int fd);

94 int (*dup_f)(int fd);

95 int (*ioctl_f)(int fd, unsigned long int request, ...);

96 ssize_t (*read_f)(int fd, void *buffer, size_t n);

97 void *(*mmap_f)(void *start, size_t length, int prot, int flags, int fd, int64_t offset);

98 int (*munmap_f)(void *_start, size_t length);

99 };

100

101 struct buff_data {

102 struct video_data *s;

103 int index;

104 };

105

106 static int device_open(AVFormatContext *ctx)

107 {

108 struct video_data *s = ctx->priv_data;

109 struct v4l2_capability cap;

110 int fd;

111 int ret;

112 int flags = O_RDWR;

113

114 #define SET_WRAPPERS(prefix) do { \

115 s->open_f = prefix ## open; \

116 s->close_f = prefix ## close; \

117 s->dup_f = prefix ## dup; \

118 s->ioctl_f = prefix ## ioctl; \

119 s->read_f = prefix ## read; \

120 s->mmap_f = prefix ## mmap; \

121 s->munmap_f = prefix ## munmap; \

122 } while (0)

123

124 if (s->use_libv4l2) {

125 #if CONFIG_LIBV4L2

126 SET_WRAPPERS(v4l2_);

127 #else

128 av_log(ctx, AV_LOG_ERROR, "libavdevice is not build with libv4l2 support.\n");

129 return AVERROR(EINVAL);

130 #endif

131 } else {

132 SET_WRAPPERS();

133 }

134

135 #define v4l2_open s->open_f

136 #define v4l2_close s->close_f

137 #define v4l2_dup s->dup_f

138 #define v4l2_ioctl s->ioctl_f

139 #define v4l2_read s->read_f

140 #define v4l2_mmap s->mmap_f

141 #define v4l2_munmap s->munmap_f

142

143 if (ctx->flags & AVFMT_FLAG_NONBLOCK) {

144 flags |= O_NONBLOCK;

145 }

146

147 fd = v4l2_open(ctx->filename, flags, 0);

148 if (fd < 0) {

149 ret = AVERROR(errno);

150 av_log(ctx, AV_LOG_ERROR, "Cannot open video device %s: %s\n",

151 ctx->filename, av_err2str(ret));

152 return ret;

153 }

154

155 if (v4l2_ioctl(fd, VIDIOC_QUERYCAP, &cap) < 0) {

156 ret = AVERROR(errno);

157 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYCAP): %s\n",

158 av_err2str(ret));

159 goto fail;

160 }

161

162 av_log(ctx, AV_LOG_VERBOSE, "fd:%d capabilities:%x\n",

163 fd, cap.capabilities);

164

165 if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {

166 av_log(ctx, AV_LOG_ERROR, "Not a video capture device.\n");

167 ret = AVERROR(ENODEV);

168 goto fail;

169 }

170

171 if (!(cap.capabilities & V4L2_CAP_STREAMING)) {

172 av_log(ctx, AV_LOG_ERROR,

173 "The device does not support the streaming I/O method.\n");

174 ret = AVERROR(ENOSYS);

175 goto fail;

176 }

177

178 return fd;

179

180 fail:

181 v4l2_close(fd);

182 return ret;

183 }

184

185 static int device_init(AVFormatContext *ctx, int *width, int *height,

186 uint32_t pix_fmt)

187 {

188 struct video_data *s = ctx->priv_data;

189 int fd = s->fd;

190 struct v4l2_format fmt = { .type = V4L2_BUF_TYPE_VIDEO_CAPTURE };

191 struct v4l2_pix_format *pix = &fmt.fmt.pix;

192

193 int res = 0;

194

195 pix->width = *width;

196 pix->height = *height;

197 pix->pixelformat = pix_fmt;

198 pix->field = V4L2_FIELD_ANY;

199

200 if (v4l2_ioctl(fd, VIDIOC_S_FMT, &fmt) < 0)

201 res = AVERROR(errno);

202

203 if ((*width != fmt.fmt.pix.width) || (*height != fmt.fmt.pix.height)) {

204 av_log(ctx, AV_LOG_INFO,

205 "The V4L2 driver changed the video from %dx%d to %dx%d\n",

206 *width, *height, fmt.fmt.pix.width, fmt.fmt.pix.height);

207 *width = fmt.fmt.pix.width;

208 *height = fmt.fmt.pix.height;

209 }

210

211 if (pix_fmt != fmt.fmt.pix.pixelformat) {

212 av_log(ctx, AV_LOG_DEBUG,

213 "The V4L2 driver changed the pixel format "

214 "from 0x%08X to 0x%08X\n",

215 pix_fmt, fmt.fmt.pix.pixelformat);

216 res = AVERROR(EINVAL);

217 }

218

219 if (fmt.fmt.pix.field == V4L2_FIELD_INTERLACED) {

220 av_log(ctx, AV_LOG_DEBUG,

221 "The V4L2 driver is using the interlaced mode\n");

222 s->interlaced = 1;

223 }

224

225 return res;

226 }

227

228 static int first_field(const struct video_data *s, int fd)

229 {

230 int res;

231 v4l2_std_id std;

232

233 res = v4l2_ioctl(fd, VIDIOC_G_STD, &std);

234 if (res < 0) {

235 return 0;

236 }

237 if (std & V4L2_STD_NTSC) {

238 return 0;

239 }

240

241 return 1;

242 }

243

244 #if HAVE_STRUCT_V4L2_FRMIVALENUM_DISCRETE

245 static void list_framesizes(AVFormatContext *ctx, int fd, uint32_t pixelformat)

246 {

247 const struct video_data *s = ctx->priv_data;

248 struct v4l2_frmsizeenum vfse = { .pixel_format = pixelformat };

249

250 while(!v4l2_ioctl(fd, VIDIOC_ENUM_FRAMESIZES, &vfse)) {

251 switch (vfse.type) {

252 case V4L2_FRMSIZE_TYPE_DISCRETE:

253 av_log(ctx, AV_LOG_INFO, " %ux%u",

254 vfse.discrete.width, vfse.discrete.height);

255 break;

256 case V4L2_FRMSIZE_TYPE_CONTINUOUS:

257 case V4L2_FRMSIZE_TYPE_STEPWISE:

258 av_log(ctx, AV_LOG_INFO, " {%u-%u, %u}x{%u-%u, %u}",

259 vfse.stepwise.min_width,

260 vfse.stepwise.max_width,

261 vfse.stepwise.step_width,

262 vfse.stepwise.min_height,

263 vfse.stepwise.max_height,

264 vfse.stepwise.step_height);

265 }

266 vfse.index++;

267 }

268 }

269 #endif

270

271 static void list_formats(AVFormatContext *ctx, int fd, int type)

272 {

273 const struct video_data *s = ctx->priv_data;

274 struct v4l2_fmtdesc vfd = { .type = V4L2_BUF_TYPE_VIDEO_CAPTURE };

275

276 while(!v4l2_ioctl(fd, VIDIOC_ENUM_FMT, &vfd)) {

277 enum AVCodecID codec_id = avpriv_fmt_v4l2codec(vfd.pixelformat);

278 enum AVPixelFormat pix_fmt = avpriv_fmt_v4l2ff(vfd.pixelformat, codec_id);

279

280 vfd.index++;

281

282 if (!(vfd.flags & V4L2_FMT_FLAG_COMPRESSED) &&

283 type & V4L_RAWFORMATS) {

284 const char *fmt_name = av_get_pix_fmt_name(pix_fmt);

285 av_log(ctx, AV_LOG_INFO, "Raw : %9s : %20s :",

286 fmt_name ? fmt_name : "Unsupported",

287 vfd.description);

288 } else if (vfd.flags & V4L2_FMT_FLAG_COMPRESSED &&

289 type & V4L_COMPFORMATS) {

290 AVCodec *codec = avcodec_find_decoder(codec_id);

291 av_log(ctx, AV_LOG_INFO, "Compressed: %9s : %20s :",

292 codec ? codec->name : "Unsupported",

293 vfd.description);

294 } else {

295 continue;

296 }

297

298 #ifdef V4L2_FMT_FLAG_EMULATED

299 if (vfd.flags & V4L2_FMT_FLAG_EMULATED)

300 av_log(ctx, AV_LOG_INFO, " Emulated :");

301 #endif

302 #if HAVE_STRUCT_V4L2_FRMIVALENUM_DISCRETE

303 list_framesizes(ctx, fd, vfd.pixelformat);

304 #endif

305 av_log(ctx, AV_LOG_INFO, "\n");

306 }

307 }

308

309 static void list_standards(AVFormatContext *ctx)

310 {

311 int ret;

312 struct video_data *s = ctx->priv_data;

313 struct v4l2_standard standard;

314

315 if (s->std_id == 0)

316 return;

317

318 for (standard.index = 0; ; standard.index++) {

319 if (v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {

320 ret = AVERROR(errno);

321 if (ret == AVERROR(EINVAL)) {

322 break;

323 } else {

324 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_ENUMSTD): %s\n", av_err2str(ret));

325 return;

326 }

327 }

328 av_log(ctx, AV_LOG_INFO, "%2d, %16"PRIx64", %s\n",

329 standard.index, (uint64_t)standard.id, standard.name);

330 }

331 }

332

333 static int mmap_init(AVFormatContext *ctx)

334 {

335 int i, res;

336 struct video_data *s = ctx->priv_data;

337 struct v4l2_requestbuffers req = {

338 .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,

339 .count = desired_video_buffers,

340 .memory = V4L2_MEMORY_MMAP

341 };

342

343 if (v4l2_ioctl(s->fd, VIDIOC_REQBUFS, &req) < 0) {

344 res = AVERROR(errno);

345 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_REQBUFS): %s\n", av_err2str(res));

346 return res;

347 }

348

349 if (req.count < 2) {

350 av_log(ctx, AV_LOG_ERROR, "Insufficient buffer memory\n");

351 return AVERROR(ENOMEM);

352 }

353 s->buffers = req.count;

354 s->buf_start = av_malloc(sizeof(void *) * s->buffers);

355 if (s->buf_start == NULL) {

356 av_log(ctx, AV_LOG_ERROR, "Cannot allocate buffer pointers\n");

357 return AVERROR(ENOMEM);

358 }

359 s->buf_len = av_malloc(sizeof(unsigned int) * s->buffers);

360 if (s->buf_len == NULL) {

361 av_log(ctx, AV_LOG_ERROR, "Cannot allocate buffer sizes\n");

362 av_free(s->buf_start);

363 return AVERROR(ENOMEM);

364 }

365

366 for (i = 0; i < req.count; i++) {

367 struct v4l2_buffer buf = {

368 .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,

369 .index = i,

370 .memory = V4L2_MEMORY_MMAP

371 };

372 if (v4l2_ioctl(s->fd, VIDIOC_QUERYBUF, &buf) < 0) {

373 res = AVERROR(errno);

374 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYBUF): %s\n", av_err2str(res));

375 return res;

376 }

377

378 s->buf_len[i] = buf.length;

379 if (s->frame_size > 0 && s->buf_len[i] < s->frame_size) {

380 av_log(ctx, AV_LOG_ERROR,

381 "buf_len[%d] = %d < expected frame size %d\n",

382 i, s->buf_len[i], s->frame_size);

383 return AVERROR(ENOMEM);

384 }

385 s->buf_start[i] = v4l2_mmap(NULL, buf.length,

386 PROT_READ | PROT_WRITE, MAP_SHARED,

387 s->fd, buf.m.offset);

388

389 if (s->buf_start[i] == MAP_FAILED) {

390 res = AVERROR(errno);

391 av_log(ctx, AV_LOG_ERROR, "mmap: %s\n", av_err2str(res));

392 return res;

393 }

394 }

395

396 return 0;

397 }

398

399 #if FF_API_DESTRUCT_PACKET

400 static void dummy_release_buffer(AVPacket *pkt)

401 {

402 av_assert0(0);

403 }

404 #endif

405

406 static void mmap_release_buffer(void *opaque, uint8_t *data)

407 {

408 struct v4l2_buffer buf = { 0 };

409 int res;

410 struct buff_data *buf_descriptor = opaque;

411 struct video_data *s = buf_descriptor->s;

412

413 buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

414 buf.memory = V4L2_MEMORY_MMAP;

415 buf.index = buf_descriptor->index;

416 av_free(buf_descriptor);

417

418 if (v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf) < 0) {

419 res = AVERROR(errno);

420 av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n",

421 av_err2str(res));

422 }

423

424 avpriv_atomic_int_add_and_fetch(&s->buffers_queued, 1);

425 }

426

427 #if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)

428 static int64_t av_gettime_monotonic(void)

429 {

430 struct timespec tv;

431

432 clock_gettime(CLOCK_MONOTONIC, &tv);

433 return (int64_t)tv.tv_sec * 1000000 + tv.tv_nsec / 1000;

434 }

435 #endif

436

437 static int init_convert_timestamp(AVFormatContext *ctx, int64_t ts)

438 {

439 struct video_data *s = ctx->priv_data;

440 int64_t now;

441

442 now = av_gettime();

443 if (s->ts_mode == V4L_TS_ABS &&

444 ts <= now + 1 * AV_TIME_BASE && ts >= now - 10 * AV_TIME_BASE) {

445 av_log(ctx, AV_LOG_INFO, "Detected absolute timestamps\n");

446 s->ts_mode = V4L_TS_CONVERT_READY;

447 return 0;

448 }

449 #if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)

450 if (ctx->streams[0]->avg_frame_rate.num) {

451 now = av_gettime_monotonic();

452 if (s->ts_mode == V4L_TS_MONO2ABS ||

453 (ts <= now + 1 * AV_TIME_BASE && ts >= now - 10 * AV_TIME_BASE)) {

454 AVRational tb = {AV_TIME_BASE, 1};

455 int64_t period = av_rescale_q(1, tb, ctx->streams[0]->avg_frame_rate);

456 av_log(ctx, AV_LOG_INFO, "Detected monotonic timestamps, converting\n");

457 /* microseconds instead of seconds, MHz instead of Hz */

458 s->timefilter = ff_timefilter_new(1, period, 1.0E-6);

459 if (!s->timefilter)

460 return AVERROR(ENOMEM);

461 s->ts_mode = V4L_TS_CONVERT_READY;

462 return 0;

463 }

464 }

465 #endif

466 av_log(ctx, AV_LOG_ERROR, "Unknown timestamps\n");

467 return AVERROR(EIO);

468 }

469

470 static int convert_timestamp(AVFormatContext *ctx, int64_t *ts)

471 {

472 struct video_data *s = ctx->priv_data;

473

474 if (s->ts_mode) {

475 int r = init_convert_timestamp(ctx, *ts);

476 if (r < 0)

477 return r;

478 }

479 #if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)

480 if (s->timefilter) {

481 int64_t nowa = av_gettime();

482 int64_t nowm = av_gettime_monotonic();

483 ff_timefilter_update(s->timefilter, nowa, nowm - s->last_time_m);

484 s->last_time_m = nowm;

485 *ts = ff_timefilter_eval(s->timefilter, *ts - nowm);

486 }

487 #endif

488 return 0;

489 }

490

491 static int mmap_read_frame(AVFormatContext *ctx, AVPacket *pkt)

492 {

493 struct video_data *s = ctx->priv_data;

494 struct v4l2_buffer buf = {

495 .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,

496 .memory = V4L2_MEMORY_MMAP

497 };

498 int res;

499

500 /* FIXME: Some special treatment might be needed in case of loss of signal... */

501 while ((res = v4l2_ioctl(s->fd, VIDIOC_DQBUF, &buf)) < 0 && (errno == EINTR));

502 if (res < 0) {

503 if (errno == EAGAIN) {

504 pkt->size = 0;

505 return AVERROR(EAGAIN);

506 }

507 res = AVERROR(errno);

508 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_DQBUF): %s\n", av_err2str(res));

509 return res;

510 }

511

512 if (buf.index >= s->buffers) {

513 av_log(ctx, AV_LOG_ERROR, "Invalid buffer index received.\n");

514 return AVERROR(EINVAL);

515 }

516 avpriv_atomic_int_add_and_fetch(&s->buffers_queued, -1);

517 // always keep at least one buffer queued

518 av_assert0(avpriv_atomic_int_get(&s->buffers_queued) >= 1);

519

520 /* CPIA is a compressed format and we don't know the exact number of bytes

521 * used by a frame, so set it here as the driver announces it.

522 */

523 if (ctx->video_codec_id == AV_CODEC_ID_CPIA)

524 s->frame_size = buf.bytesused;

525

526 if (s->frame_size > 0 && buf.bytesused != s->frame_size) {

527 av_log(ctx, AV_LOG_ERROR,

528 "The v4l2 frame is %d bytes, but %d bytes are expected\n",

529 buf.bytesused, s->frame_size);

530 return AVERROR_INVALIDDATA;

531 }

532

533 /* Image is at s->buff_start[buf.index] */

534 if (avpriv_atomic_int_get(&s->buffers_queued) == FFMAX(s->buffers / 8, 1)) {

535 /* when we start getting low on queued buffers, fall back on copying data */

536 res = av_new_packet(pkt, buf.bytesused);

537 if (res < 0) {

538 av_log(ctx, AV_LOG_ERROR, "Error allocating a packet.\n");

539 if (v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf) == 0)

540 avpriv_atomic_int_add_and_fetch(&s->buffers_queued, 1);

541 return res;

542 }

543 memcpy(pkt->data, s->buf_start[buf.index], buf.bytesused);

544

545 if (v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf) < 0) {

546 res = AVERROR(errno);

547 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", av_err2str(res));

548 av_free_packet(pkt);

549 return res;

550 }

551 avpriv_atomic_int_add_and_fetch(&s->buffers_queued, 1);

552 } else {

553 struct buff_data *buf_descriptor;

554

555 pkt->data = s->buf_start[buf.index];

556 pkt->size = buf.bytesused;

557 #if FF_API_DESTRUCT_PACKET

558 FF_DISABLE_DEPRECATION_WARNINGS

559 pkt->destruct = dummy_release_buffer;

560 FF_ENABLE_DEPRECATION_WARNINGS

561 #endif

562

563 buf_descriptor = av_malloc(sizeof(struct buff_data));

564 if (buf_descriptor == NULL) {

565 /* Something went wrong... Since av_malloc() failed, we cannot even

566 * allocate a buffer for memcpying into it

567 */

568 av_log(ctx, AV_LOG_ERROR, "Failed to allocate a buffer descriptor\n");

569 if (v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf) == 0)

570 avpriv_atomic_int_add_and_fetch(&s->buffers_queued, 1);

571

572 return AVERROR(ENOMEM);

573 }

574 buf_descriptor->index = buf.index;

575 buf_descriptor->s = s;

576

577 pkt->buf = av_buffer_create(pkt->data, pkt->size, mmap_release_buffer,

578 buf_descriptor, 0);

579 if (!pkt->buf) {

580 av_log(ctx, AV_LOG_ERROR, "Failed to create a buffer\n");

581 if (v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf) == 0)

582 avpriv_atomic_int_add_and_fetch(&s->buffers_queued, 1);

583 av_freep(&buf_descriptor);

584 return AVERROR(ENOMEM);

585 }

586 }

587 pkt->pts = buf.timestamp.tv_sec * INT64_C(1000000) + buf.timestamp.tv_usec;

588 convert_timestamp(ctx, &pkt->pts);

589

590 return s->buf_len[buf.index];

591 }

592

593 static int mmap_start(AVFormatContext *ctx)

594 {

595 struct video_data *s = ctx->priv_data;

596 enum v4l2_buf_type type;

597 int i, res;

598

599 for (i = 0; i < s->buffers; i++) {

600 struct v4l2_buffer buf = {

601 .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,

602 .index = i,

603 .memory = V4L2_MEMORY_MMAP

604 };

605

606 if (v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf) < 0) {

607 res = AVERROR(errno);

608 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", av_err2str(res));

609 return res;

610 }

611 }

612 s->buffers_queued = s->buffers;

613

614 type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

615 if (v4l2_ioctl(s->fd, VIDIOC_STREAMON, &type) < 0) {

616 res = AVERROR(errno);

617 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_STREAMON): %s\n", av_err2str(res));

618 return res;

619 }

620

621 return 0;

622 }

623

624 static void mmap_close(struct video_data *s)

625 {

626 enum v4l2_buf_type type;

627 int i;

628

629 type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

630 /* We do not check for the result, because we could

631 * not do anything about it anyway...

632 */

633 v4l2_ioctl(s->fd, VIDIOC_STREAMOFF, &type);

634 for (i = 0; i < s->buffers; i++) {

635 v4l2_munmap(s->buf_start[i], s->buf_len[i]);

636 }

637 av_free(s->buf_start);

638 av_free(s->buf_len);

639 }

640

641 static int v4l2_set_parameters(AVFormatContext *s1)

642 {

643 struct video_data *s = s1->priv_data;

644 struct v4l2_standard standard = { 0 };

645 struct v4l2_streamparm streamparm = { 0 };

646 struct v4l2_fract *tpf;

647 AVRational framerate_q = { 0 };

648 int i, ret;

649

650 if (s->framerate &&

651 (ret = av_parse_video_rate(&framerate_q, s->framerate)) < 0) {

652 av_log(s1, AV_LOG_ERROR, "Could not parse framerate '%s'.\n",

653 s->framerate);

654 return ret;

655 }

656

657 if (s->standard) {

658 if (s->std_id) {

659 ret = 0;

660 av_log(s1, AV_LOG_DEBUG, "Setting standard: %s\n", s->standard);

661 /* set tv standard */

662 for (i = 0; ; i++) {

663 standard.index = i;

664 if (v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {

665 ret = AVERROR(errno);

666 break;

667 }

668 if (!av_strcasecmp(standard.name, s->standard))

669 break;

670 }

671 if (ret < 0) {

672 av_log(s1, AV_LOG_ERROR, "Unknown or unsupported standard '%s'\n", s->standard);

673 return ret;

674 }

675

676 if (v4l2_ioctl(s->fd, VIDIOC_S_STD, &standard.id) < 0) {

677 ret = AVERROR(errno);

678 av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_S_STD): %s\n", av_err2str(ret));

679 return ret;

680 }

681 } else {

682 av_log(s1, AV_LOG_WARNING,

683 "This device does not support any standard\n");

684 }

685 }

686

687 /* get standard */

688 if (v4l2_ioctl(s->fd, VIDIOC_G_STD, &s->std_id) == 0) {

689 tpf = &standard.frameperiod;

690 for (i = 0; ; i++) {

691 standard.index = i;

692 if (v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {

693 ret = AVERROR(errno);

694 if (ret == AVERROR(EINVAL)) {

695 tpf = &streamparm.parm.capture.timeperframe;

696 break;

697 }

698 av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_ENUMSTD): %s\n", av_err2str(ret));

699 return ret;

700 }

701 if (standard.id == s->std_id) {

702 av_log(s1, AV_LOG_DEBUG,

703 "Current standard: %s, id: %"PRIx64", frameperiod: %d/%d\n",

704 standard.name, (uint64_t)standard.id, tpf->numerator, tpf->denominator);

705 break;

706 }

707 }

708 } else {

709 tpf = &streamparm.parm.capture.timeperframe;

710 }

711

712 streamparm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

713 if (v4l2_ioctl(s->fd, VIDIOC_G_PARM, &streamparm) < 0) {

714 ret = AVERROR(errno);

715 av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_PARM): %s\n", av_err2str(ret));

716 return ret;

717 }

718

719 if (framerate_q.num && framerate_q.den) {

720 if (streamparm.parm.capture.capability & V4L2_CAP_TIMEPERFRAME) {

721 tpf = &streamparm.parm.capture.timeperframe;

722

723 av_log(s1, AV_LOG_DEBUG, "Setting time per frame to %d/%d\n",

724 framerate_q.den, framerate_q.num);

725 tpf->numerator = framerate_q.den;

726 tpf->denominator = framerate_q.num;

727

728 if (v4l2_ioctl(s->fd, VIDIOC_S_PARM, &streamparm) < 0) {

729 ret = AVERROR(errno);

730 av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_S_PARM): %s\n", av_err2str(ret));

731 return ret;

732 }

733

734 if (framerate_q.num != tpf->denominator ||

735 framerate_q.den != tpf->numerator) {

736 av_log(s1, AV_LOG_INFO,

737 "The driver changed the time per frame from "

738 "%d/%d to %d/%d\n",

739 framerate_q.den, framerate_q.num,

740 tpf->numerator, tpf->denominator);

741 }

742 } else {

743 av_log(s1, AV_LOG_WARNING,

744 "The driver does not allow to change time per frame\n");

745 }

746 }

747 if (tpf->denominator > 0 && tpf->numerator > 0) {

748 s1->streams[0]->avg_frame_rate.num = tpf->denominator;

749 s1->streams[0]->avg_frame_rate.den = tpf->numerator;

750 s1->streams[0]->r_frame_rate = s1->streams[0]->avg_frame_rate;

751 } else

752 av_log(s1, AV_LOG_WARNING, "Time per frame unknown\n");

753

754 return 0;

755 }

756

757 static int device_try_init(AVFormatContext *s1,

758 enum AVPixelFormat pix_fmt,

759 int *width,

760 int *height,

761 uint32_t *desired_format,

762 enum AVCodecID *codec_id)

763 {

764 int ret, i;

765

766 *desired_format = avpriv_fmt_ff2v4l(pix_fmt, s1->video_codec_id);

767

768 if (*desired_format) {

769 ret = device_init(s1, width, height, *desired_format);

770 if (ret < 0) {

771 *desired_format = 0;

772 if (ret != AVERROR(EINVAL))

773 return ret;

774 }

775 }

776

777 if (!*desired_format) {

778 for (i = 0; avpriv_fmt_conversion_table[i].codec_id != AV_CODEC_ID_NONE; i++) {

779 if (s1->video_codec_id == AV_CODEC_ID_NONE ||

780 avpriv_fmt_conversion_table[i].codec_id == s1->video_codec_id) {

781 av_log(s1, AV_LOG_DEBUG, "Trying to set codec:%s pix_fmt:%s\n",

782 avcodec_get_name(avpriv_fmt_conversion_table[i].codec_id),

783 (char *)av_x_if_null(av_get_pix_fmt_name(avpriv_fmt_conversion_table[i].ff_fmt), "none"));

784

785 *desired_format = avpriv_fmt_conversion_table[i].v4l2_fmt;

786 ret = device_init(s1, width, height, *desired_format);

787 if (ret >= 0)

788 break;

789 else if (ret != AVERROR(EINVAL))

790 return ret;

791 *desired_format = 0;

792 }

793 }

794

795 if (*desired_format == 0) {

796 av_log(s1, AV_LOG_ERROR, "Cannot find a proper format for "

797 "codec '%s' (id %d), pixel format '%s' (id %d)\n",

798 avcodec_get_name(s1->video_codec_id), s1->video_codec_id,

799 (char *)av_x_if_null(av_get_pix_fmt_name(pix_fmt), "none"), pix_fmt);

800 ret = AVERROR(EINVAL);

801 }

802 }

803

804 *codec_id = avpriv_fmt_v4l2codec(*desired_format);

805 av_assert0(*codec_id != AV_CODEC_ID_NONE);

806 return ret;

807 }

808

809 static int v4l2_read_header(AVFormatContext *s1)

810 {

811 struct video_data *s = s1->priv_data;

812 AVStream *st;

813 int res = 0;

814 uint32_t desired_format;

815 enum AVCodecID codec_id = AV_CODEC_ID_NONE;

816 enum AVPixelFormat pix_fmt = AV_PIX_FMT_NONE;

817 struct v4l2_input input = { 0 };

818

819 st = avformat_new_stream(s1, NULL);

820 if (!st)

821 return AVERROR(ENOMEM);

822

823 #if CONFIG_LIBV4L2

824 /* silence libv4l2 logging. if fopen() fails v4l2_log_file will be NULL

825 and errors will get sent to stderr */

826 if (s->use_libv4l2)

827 v4l2_log_file = fopen("/dev/null", "w");

828 #endif

829

830 s->fd = device_open(s1);

831 if (s->fd < 0)

832 return s->fd;

833

834 if (s->channel != -1) {

835 /* set video input */

836 av_log(s1, AV_LOG_DEBUG, "Selecting input_channel: %d\n", s->channel);

837 if (v4l2_ioctl(s->fd, VIDIOC_S_INPUT, &s->channel) < 0) {

838 res = AVERROR(errno);

839 av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_S_INPUT): %s\n", av_err2str(res));

840 return res;

841 }

842 } else {

843 /* get current video input */

844 if (v4l2_ioctl(s->fd, VIDIOC_G_INPUT, &s->channel) < 0) {

845 res = AVERROR(errno);

846 av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_INPUT): %s\n", av_err2str(res));

847 return res;

848 }

849 }

850

851 /* enum input */

852 input.index = s->channel;

853 if (v4l2_ioctl(s->fd, VIDIOC_ENUMINPUT, &input) < 0) {

854 res = AVERROR(errno);

855 av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_ENUMINPUT): %s\n", av_err2str(res));

856 return res;

857 }

858 s->std_id = input.std;

859 av_log(s1, AV_LOG_DEBUG, "Current input_channel: %d, input_name: %s, input_std: %"PRIx64"\n",

860 s->channel, input.name, (uint64_t)input.std);

861

862 if (s->list_format) {

863 list_formats(s1, s->fd, s->list_format);

864 return AVERROR_EXIT;

865 }

866

867 if (s->list_standard) {

868 list_standards(s1);

869 return AVERROR_EXIT;

870 }

871

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

873

874 if ((res = v4l2_set_parameters(s1)) < 0)

875 return res;

876

877 if (s->pixel_format) {

878 AVCodec *codec = avcodec_find_decoder_by_name(s->pixel_format);

879

880 if (codec)

881 s1->video_codec_id = codec->id;

882

883 pix_fmt = av_get_pix_fmt(s->pixel_format);

884

885 if (pix_fmt == AV_PIX_FMT_NONE && !codec) {

886 av_log(s1, AV_LOG_ERROR, "No such input format: %s.\n",

887 s->pixel_format);

888

889 return AVERROR(EINVAL);

890 }

891 }

892

893 if (!s->width && !s->height) {

894 struct v4l2_format fmt = { .type = V4L2_BUF_TYPE_VIDEO_CAPTURE };

895

896 av_log(s1, AV_LOG_VERBOSE,

897 "Querying the device for the current frame size\n");

898 if (v4l2_ioctl(s->fd, VIDIOC_G_FMT, &fmt) < 0) {

899 res = AVERROR(errno);

900 av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_FMT): %s\n", av_err2str(res));

901 return res;

902 }

903

904 s->width = fmt.fmt.pix.width;

905 s->height = fmt.fmt.pix.height;

906 av_log(s1, AV_LOG_VERBOSE,

907 "Setting frame size to %dx%d\n", s->width, s->height);

908 }

909

910 res = device_try_init(s1, pix_fmt, &s->width, &s->height, &desired_format, &codec_id);

911 if (res < 0) {

912 v4l2_close(s->fd);

913 return res;

914 }

915

916 /* If no pixel_format was specified, the codec_id was not known up

917 * until now. Set video_codec_id in the context, as codec_id will

918 * not be available outside this function

919 */

920 if (codec_id != AV_CODEC_ID_NONE && s1->video_codec_id == AV_CODEC_ID_NONE)

921 s1->video_codec_id = codec_id;

922

923 if ((res = av_image_check_size(s->width, s->height, 0, s1)) < 0)

924 return res;

925

926 s->frame_format = desired_format;

927

928 st->codec->pix_fmt = avpriv_fmt_v4l2ff(desired_format, codec_id);

929 s->frame_size =

930 avpicture_get_size(st->codec->pix_fmt, s->width, s->height);

931

932 if ((res = mmap_init(s1)) ||

933 (res = mmap_start(s1)) < 0) {

934 v4l2_close(s->fd);

935 return res;

936 }

937

938 s->top_field_first = first_field(s, s->fd);

939

940 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

941 st->codec->codec_id = codec_id;

942 if (codec_id == AV_CODEC_ID_RAWVIDEO)

943 st->codec->codec_tag =

944 avcodec_pix_fmt_to_codec_tag(st->codec->pix_fmt);

945 else if (codec_id == AV_CODEC_ID_H264) {

946 st->need_parsing = AVSTREAM_PARSE_HEADERS;

947 }

948 if (desired_format == V4L2_PIX_FMT_YVU420)

949 st->codec->codec_tag = MKTAG('Y', 'V', '1', '2');

950 else if (desired_format == V4L2_PIX_FMT_YVU410)

951 st->codec->codec_tag = MKTAG('Y', 'V', 'U', '9');

952 st->codec->width = s->width;

953 st->codec->height = s->height;

954 if (st->avg_frame_rate.den)

955 st->codec->bit_rate = s->frame_size * av_q2d(st->avg_frame_rate) * 8;

956

957 return 0;

958 }

959

960 static int v4l2_read_packet(AVFormatContext *s1, AVPacket *pkt)

961 {

962 struct video_data *s = s1->priv_data;

963 AVFrame *frame = s1->streams[0]->codec->coded_frame;

964 int res;

965

966 av_init_packet(pkt);

967 if ((res = mmap_read_frame(s1, pkt)) < 0) {

968 return res;

969 }

970

971 if (frame && s->interlaced) {

972 frame->interlaced_frame = 1;

973 frame->top_field_first = s->top_field_first;

974 }

975

976 return pkt->size;

977 }

978

979 static int v4l2_read_close(AVFormatContext *s1)

980 {

981 struct video_data *s = s1->priv_data;

982

983 if (avpriv_atomic_int_get(&s->buffers_queued) != s->buffers)

984 av_log(s1, AV_LOG_WARNING, "Some buffers are still owned by the caller on "

985 "close.\n");

986

987 mmap_close(s);

988

989 v4l2_close(s->fd);

990 return 0;

991 }

992

993 #define OFFSET(x) offsetof(struct video_data, x)

994 #define DEC AV_OPT_FLAG_DECODING_PARAM

995

996 static const AVOption options[] = {

997 { "standard", "set TV standard, used only by analog frame grabber", OFFSET(standard), AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, DEC },

998 { "channel", "set TV channel, used only by frame grabber", OFFSET(channel), AV_OPT_TYPE_INT, {.i64 = -1 }, -1, INT_MAX, DEC },

999 { "video_size", "set frame size", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC },

1000 { "pixel_format", "set preferred pixel format", OFFSET(pixel_format), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },

1001 { "input_format", "set preferred pixel format (for raw video) or codec name", OFFSET(pixel_format), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },

1002 { "framerate", "set frame rate", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },

1003

1004 { "list_formats", "list available formats and exit", OFFSET(list_format), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, INT_MAX, DEC, "list_formats" },

1005 { "all", "show all available formats", OFFSET(list_format), AV_OPT_TYPE_CONST, {.i64 = V4L_ALLFORMATS }, 0, INT_MAX, DEC, "list_formats" },

1006 { "raw", "show only non-compressed formats", OFFSET(list_format), AV_OPT_TYPE_CONST, {.i64 = V4L_RAWFORMATS }, 0, INT_MAX, DEC, "list_formats" },

1007 { "compressed", "show only compressed formats", OFFSET(list_format), AV_OPT_TYPE_CONST, {.i64 = V4L_COMPFORMATS }, 0, INT_MAX, DEC, "list_formats" },

1008

1009 { "list_standards", "list supported standards and exit", OFFSET(list_standard), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 1, DEC, "list_standards" },

1010 { "all", "show all supported standards", OFFSET(list_standard), AV_OPT_TYPE_CONST, {.i64 = 1 }, 0, 0, DEC, "list_standards" },

1011

1012 { "timestamps", "set type of timestamps for grabbed frames", OFFSET(ts_mode), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 2, DEC, "timestamps" },

1013 { "ts", "set type of timestamps for grabbed frames", OFFSET(ts_mode), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 2, DEC, "timestamps" },

1014 { "default", "use timestamps from the kernel", OFFSET(ts_mode), AV_OPT_TYPE_CONST, {.i64 = V4L_TS_DEFAULT }, 0, 2, DEC, "timestamps" },

1015 { "abs", "use absolute timestamps (wall clock)", OFFSET(ts_mode), AV_OPT_TYPE_CONST, {.i64 = V4L_TS_ABS }, 0, 2, DEC, "timestamps" },

1016 { "mono2abs", "force conversion from monotonic to absolute timestamps", OFFSET(ts_mode), AV_OPT_TYPE_CONST, {.i64 = V4L_TS_MONO2ABS }, 0, 2, DEC, "timestamps" },

1017 { "use_libv4l2", "use libv4l2 (v4l-utils) convertion functions", OFFSET(use_libv4l2), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, DEC },

1018 { NULL },

1019 };

1020

1021 static const AVClass v4l2_class = {

1022 .class_name = "V4L2 indev",

1023 .item_name = av_default_item_name,

1024 .option = options,

1025 .version = LIBAVUTIL_VERSION_INT,

1026 };

1027

1028 AVInputFormat ff_v4l2_demuxer = {

1029 .name = "video4linux2,v4l2",

1030 .long_name = NULL_IF_CONFIG_SMALL("Video4Linux2 device grab"),

1031 .priv_data_size = sizeof(struct video_data),

1032 .read_header = v4l2_read_header,

1033 .read_packet = v4l2_read_packet,

1034 .read_close = v4l2_read_close,

1035 .flags = AVFMT_NOFILE,

1036 .priv_class = &v4l2_class,

1037 };

Generated on Sun Mar 23 2014 23:50:07 for FFmpeg by doxygen 1.8.2