libavformat/async.c

   1 /*
   2  * Input async protocol.
   3  * Copyright (c) 2015 Zhang Rui <bbcallen@gmail.com>
   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  * Based on libavformat/cache.c by Michael Niedermayer
  22  */
  23
  24  /**
  25  * @TODO
  26  *      support timeout
  27  *      support work with concatdec, hls
  28  */
  29
  30 #include "libavutil/avassert.h"
  31 #include "libavutil/avstring.h"
  32 #include "libavutil/error.h"
  33 #include "libavutil/fifo.h"
  34 #include "libavutil/log.h"
  35 #include "libavutil/opt.h"
  36 #include "libavutil/thread.h"
  37 #include "url.h"
  38 #include <stdint.h>
  39
  40 #if HAVE_UNISTD_H
  41 #include <unistd.h>
  42 #endif
  43
  44 #define BUFFER_CAPACITY         (4 * 1024 * 1024)
  45 #define READ_BACK_CAPACITY      (4 * 1024 * 1024)
  46 #define SHORT_SEEK_THRESHOLD    (256 * 1024)
  47
  48 typedef struct RingBuffer
  49 {
  50     AVFifo       *fifo;
  51     int           read_back_capacity;
  52
  53     int           read_pos;
  54 } RingBuffer;
  55
  56 typedef struct AsyncContext {
  57     AVClass        *class;
  58     URLContext     *inner;
  59
  60     int             seek_request;
  61     int64_t         seek_pos;
  62     int             seek_whence;
  63     int             seek_completed;
  64     int64_t         seek_ret;
  65
  66     int             inner_io_error;
  67     int             io_error;
  68     int             io_eof_reached;
  69
  70     int64_t         logical_pos;
  71     int64_t         logical_size;
  72     RingBuffer      ring;
  73
  74     pthread_cond_t  cond_wakeup_main;
  75     pthread_cond_t  cond_wakeup_background;
  76     pthread_mutex_t mutex;
  77     pthread_t       async_buffer_thread;
  78
  79     int             abort_request;
  80     AVIOInterruptCB interrupt_callback;
  81 } AsyncContext;
  82
  83 static int ring_init(RingBuffer *ring, unsigned int capacity, int read_back_capacity)
  84 {
  85     memset(ring, 0, sizeof(RingBuffer));
  86     ring->fifo = av_fifo_alloc2(capacity + read_back_capacity, 1, 0);
  87     if (!ring->fifo)
  88         return AVERROR(ENOMEM);
  89
  90     ring->read_back_capacity = read_back_capacity;
  91     return 0;
  92 }
  93
  94 static void ring_destroy(RingBuffer *ring)
  95 {
  96     av_fifo_freep2(&ring->fifo);
  97 }
  98
  99 static void ring_reset(RingBuffer *ring)
 100 {
 101     av_fifo_reset2(ring->fifo);
 102     ring->read_pos = 0;
 103 }
 104
 105 static int ring_size(RingBuffer *ring)
 106 {
 107     return av_fifo_can_read(ring->fifo) - ring->read_pos;
 108 }
 109
 110 static int ring_space(RingBuffer *ring)
 111 {
 112     return av_fifo_can_write(ring->fifo);
 113 }
 114
 115 static int ring_read(RingBuffer *ring, void *dest, int buf_size)
 116 {
 117     int ret = 0;
 118
 119     av_assert2(buf_size <= ring_size(ring));
 120     if (dest)
 121         ret = av_fifo_peek(ring->fifo, dest, buf_size, ring->read_pos);
 122     ring->read_pos += buf_size;
 123
 124     if (ring->read_pos > ring->read_back_capacity) {
 125         av_fifo_drain2(ring->fifo, ring->read_pos - ring->read_back_capacity);
 126         ring->read_pos = ring->read_back_capacity;
 127     }
 128
 129     return ret;
 130 }
 131
 132 static int wrapped_url_read(void *src, void *dst, size_t *size)
 133 {
 134     URLContext *h   = src;
 135     AsyncContext *c = h->priv_data;
 136     int         ret;
 137
 138     ret = ffurl_read(c->inner, dst, *size);
 139     *size             = ret > 0 ? ret : 0;
 140     c->inner_io_error = ret < 0 ? ret : 0;
 141
 142     return c->inner_io_error;
 143 }
 144
 145 static int ring_write(RingBuffer *ring, URLContext *h, size_t size)
 146 {
 147     int ret;
 148
 149     av_assert2(size <= ring_space(ring));
 150     ret = av_fifo_write_from_cb(ring->fifo, wrapped_url_read, h, &size);
 151     if (ret < 0)
 152         return ret;
 153
 154     return size;
 155 }
 156
 157 static int ring_size_of_read_back(RingBuffer *ring)
 158 {
 159     return ring->read_pos;
 160 }
 161
 162 static int ring_drain(RingBuffer *ring, int offset)
 163 {
 164     av_assert2(offset >= -ring_size_of_read_back(ring));
 165     av_assert2(offset <= ring_size(ring));
 166     ring->read_pos += offset;
 167     return 0;
 168 }
 169
 170 static int async_check_interrupt(void *arg)
 171 {
 172     URLContext *h   = arg;
 173     AsyncContext *c = h->priv_data;
 174
 175     if (c->abort_request)
 176         return 1;
 177
 178     if (ff_check_interrupt(&c->interrupt_callback))
 179         c->abort_request = 1;
 180
 181     return c->abort_request;
 182 }
 183
 184 static void *async_buffer_task(void *arg)
 185 {
 186     URLContext   *h    = arg;
 187     AsyncContext *c    = h->priv_data;
 188     RingBuffer   *ring = &c->ring;
 189     int           ret  = 0;
 190     int64_t       seek_ret;
 191
 192     ff_thread_setname("async");
 193
 194     while (1) {
 195         int fifo_space, to_copy;
 196
 197         pthread_mutex_lock(&c->mutex);
 198         if (async_check_interrupt(h)) {
 199             c->io_eof_reached = 1;
 200             c->io_error       = AVERROR_EXIT;
 201             pthread_cond_signal(&c->cond_wakeup_main);
 202             pthread_mutex_unlock(&c->mutex);
 203             break;
 204         }
 205
 206         if (c->seek_request) {
 207             seek_ret = ffurl_seek(c->inner, c->seek_pos, c->seek_whence);
 208             if (seek_ret >= 0) {
 209                 c->io_eof_reached = 0;
 210                 c->io_error       = 0;
 211                 ring_reset(ring);
 212             }
 213
 214             c->seek_completed = 1;
 215             c->seek_ret       = seek_ret;
 216             c->seek_request   = 0;
 217
 218
 219             pthread_cond_signal(&c->cond_wakeup_main);
 220             pthread_mutex_unlock(&c->mutex);
 221             continue;
 222         }
 223
 224         fifo_space = ring_space(ring);
 225         if (c->io_eof_reached || fifo_space <= 0) {
 226             pthread_cond_signal(&c->cond_wakeup_main);
 227             pthread_cond_wait(&c->cond_wakeup_background, &c->mutex);
 228             pthread_mutex_unlock(&c->mutex);
 229             continue;
 230         }
 231         pthread_mutex_unlock(&c->mutex);
 232
 233         to_copy = FFMIN(4096, fifo_space);
 234         ret = ring_write(ring, h, to_copy);
 235
 236         pthread_mutex_lock(&c->mutex);
 237         if (ret <= 0) {
 238             c->io_eof_reached = 1;
 239             if (c->inner_io_error < 0)
 240                 c->io_error = c->inner_io_error;
 241         }
 242
 243         pthread_cond_signal(&c->cond_wakeup_main);
 244         pthread_mutex_unlock(&c->mutex);
 245     }
 246
 247     return NULL;
 248 }
 249
 250 static int async_open(URLContext *h, const char *arg, int flags, AVDictionary **options)
 251 {
 252     AsyncContext *c = h->priv_data;
 253     int              ret;
 254     AVIOInterruptCB  interrupt_callback = {.callback = async_check_interrupt, .opaque = h};
 255
 256     av_strstart(arg, "async:", &arg);
 257
 258     ret = ring_init(&c->ring, BUFFER_CAPACITY, READ_BACK_CAPACITY);
 259     if (ret < 0)
 260         goto fifo_fail;
 261
 262     /* wrap interrupt callback */
 263     c->interrupt_callback = h->interrupt_callback;
 264     ret = ffurl_open_whitelist(&c->inner, arg, flags, &interrupt_callback, options, h->protocol_whitelist, h->protocol_blacklist, h);
 265     if (ret != 0) {
 266         av_log(h, AV_LOG_ERROR, "ffurl_open failed : %s, %s\n", av_err2str(ret), arg);
 267         goto url_fail;
 268     }
 269
 270     c->logical_size = ffurl_size(c->inner);
 271     h->is_streamed  = c->inner->is_streamed;
 272
 273     ret = pthread_mutex_init(&c->mutex, NULL);
 274     if (ret != 0) {
 275         ret = AVERROR(ret);
 276         av_log(h, AV_LOG_ERROR, "pthread_mutex_init failed : %s\n", av_err2str(ret));
 277         goto mutex_fail;
 278     }
 279
 280     ret = pthread_cond_init(&c->cond_wakeup_main, NULL);
 281     if (ret != 0) {
 282         ret = AVERROR(ret);
 283         av_log(h, AV_LOG_ERROR, "pthread_cond_init failed : %s\n", av_err2str(ret));
 284         goto cond_wakeup_main_fail;
 285     }
 286
 287     ret = pthread_cond_init(&c->cond_wakeup_background, NULL);
 288     if (ret != 0) {
 289         ret = AVERROR(ret);
 290         av_log(h, AV_LOG_ERROR, "pthread_cond_init failed : %s\n", av_err2str(ret));
 291         goto cond_wakeup_background_fail;
 292     }
 293
 294     ret = pthread_create(&c->async_buffer_thread, NULL, async_buffer_task, h);
 295     if (ret) {
 296         ret = AVERROR(ret);
 297         av_log(h, AV_LOG_ERROR, "pthread_create failed : %s\n", av_err2str(ret));
 298         goto thread_fail;
 299     }
 300
 301     return 0;
 302
 303 thread_fail:
 304     pthread_cond_destroy(&c->cond_wakeup_background);
 305 cond_wakeup_background_fail:
 306     pthread_cond_destroy(&c->cond_wakeup_main);
 307 cond_wakeup_main_fail:
 308     pthread_mutex_destroy(&c->mutex);
 309 mutex_fail:
 310     ffurl_closep(&c->inner);
 311 url_fail:
 312     ring_destroy(&c->ring);
 313 fifo_fail:
 314     return ret;
 315 }
 316
 317 static int async_close(URLContext *h)
 318 {
 319     AsyncContext *c = h->priv_data;
 320     int      ret;
 321
 322     pthread_mutex_lock(&c->mutex);
 323     c->abort_request = 1;
 324     pthread_cond_signal(&c->cond_wakeup_background);
 325     pthread_mutex_unlock(&c->mutex);
 326
 327     ret = pthread_join(c->async_buffer_thread, NULL);
 328     if (ret != 0)
 329         av_log(h, AV_LOG_ERROR, "pthread_join(): %s\n", av_err2str(ret));
 330
 331     pthread_cond_destroy(&c->cond_wakeup_background);
 332     pthread_cond_destroy(&c->cond_wakeup_main);
 333     pthread_mutex_destroy(&c->mutex);
 334     ffurl_closep(&c->inner);
 335     ring_destroy(&c->ring);
 336
 337     return 0;
 338 }
 339
 340 static int async_read_internal(URLContext *h, void *dest, int size)
 341 {
 342     AsyncContext *c       = h->priv_data;
 343     RingBuffer   *ring    = &c->ring;
 344     int     read_complete = !dest;
 345     int           to_read = size;
 346     int           ret     = 0;
 347
 348     pthread_mutex_lock(&c->mutex);
 349
 350     while (to_read > 0) {
 351         int fifo_size, to_copy;
 352         if (async_check_interrupt(h)) {
 353             ret = AVERROR_EXIT;
 354             break;
 355         }
 356         fifo_size = ring_size(ring);
 357         to_copy   = FFMIN(to_read, fifo_size);
 358         if (to_copy > 0) {
 359             ring_read(ring, dest, to_copy);
 360             if (dest)
 361                 dest = (uint8_t *)dest + to_copy;
 362             c->logical_pos += to_copy;
 363             to_read        -= to_copy;
 364             ret             = size - to_read;
 365
 366             if (to_read <= 0 || !read_complete)
 367                 break;
 368         } else if (c->io_eof_reached) {
 369             if (ret <= 0) {
 370                 if (c->io_error)
 371                     ret = c->io_error;
 372                 else
 373                     ret = AVERROR_EOF;
 374             }
 375             break;
 376         }
 377         pthread_cond_signal(&c->cond_wakeup_background);
 378         pthread_cond_wait(&c->cond_wakeup_main, &c->mutex);
 379     }
 380
 381     pthread_cond_signal(&c->cond_wakeup_background);
 382     pthread_mutex_unlock(&c->mutex);
 383
 384     return ret;
 385 }
 386
 387 static int async_read(URLContext *h, unsigned char *buf, int size)
 388 {
 389     return async_read_internal(h, buf, size);
 390 }
 391
 392 static int64_t async_seek(URLContext *h, int64_t pos, int whence)
 393 {
 394     AsyncContext *c    = h->priv_data;
 395     RingBuffer   *ring = &c->ring;
 396     int64_t       ret;
 397     int64_t       new_logical_pos;
 398     int fifo_size;
 399     int fifo_size_of_read_back;
 400
 401     if (whence == AVSEEK_SIZE) {
 402         av_log(h, AV_LOG_TRACE, "async_seek: AVSEEK_SIZE: %"PRId64"\n", (int64_t)c->logical_size);
 403         return c->logical_size;
 404     } else if (whence == SEEK_CUR) {
 405         av_log(h, AV_LOG_TRACE, "async_seek: %"PRId64"\n", pos);
 406         new_logical_pos = pos + c->logical_pos;
 407     } else if (whence == SEEK_SET){
 408         av_log(h, AV_LOG_TRACE, "async_seek: %"PRId64"\n", pos);
 409         new_logical_pos = pos;
 410     } else {
 411         return AVERROR(EINVAL);
 412     }
 413     if (new_logical_pos < 0)
 414         return AVERROR(EINVAL);
 415
 416     fifo_size = ring_size(ring);
 417     fifo_size_of_read_back = ring_size_of_read_back(ring);
 418     if (new_logical_pos == c->logical_pos) {
 419         /* current position */
 420         return c->logical_pos;
 421     } else if ((new_logical_pos >= (c->logical_pos - fifo_size_of_read_back)) &&
 422                (new_logical_pos < (c->logical_pos + fifo_size + SHORT_SEEK_THRESHOLD))) {
 423         int pos_delta = (int)(new_logical_pos - c->logical_pos);
 424         /* fast seek */
 425         av_log(h, AV_LOG_TRACE, "async_seek: fask_seek %"PRId64" from %d dist:%d/%d\n",
 426                 new_logical_pos, (int)c->logical_pos,
 427                 (int)(new_logical_pos - c->logical_pos), fifo_size);
 428
 429         if (pos_delta > 0) {
 430             // fast seek forwards
 431             async_read_internal(h, NULL, pos_delta);
 432         } else {
 433             // fast seek backwards
 434             ring_drain(ring, pos_delta);
 435             c->logical_pos = new_logical_pos;
 436         }
 437
 438         return c->logical_pos;
 439     } else if (c->logical_size <= 0) {
 440         /* can not seek */
 441         return AVERROR(EINVAL);
 442     } else if (new_logical_pos > c->logical_size) {
 443         /* beyond end */
 444         return AVERROR(EINVAL);
 445     }
 446
 447     pthread_mutex_lock(&c->mutex);
 448
 449     c->seek_request   = 1;
 450     c->seek_pos       = new_logical_pos;
 451     c->seek_whence    = SEEK_SET;
 452     c->seek_completed = 0;
 453     c->seek_ret       = 0;
 454
 455     while (1) {
 456         if (async_check_interrupt(h)) {
 457             ret = AVERROR_EXIT;
 458             break;
 459         }
 460         if (c->seek_completed) {
 461             if (c->seek_ret >= 0)
 462                 c->logical_pos  = c->seek_ret;
 463             ret = c->seek_ret;
 464             break;
 465         }
 466         pthread_cond_signal(&c->cond_wakeup_background);
 467         pthread_cond_wait(&c->cond_wakeup_main, &c->mutex);
 468     }
 469
 470     pthread_mutex_unlock(&c->mutex);
 471
 472     return ret;
 473 }
 474
 475 #define OFFSET(x) offsetof(AsyncContext, x)
 476 #define D AV_OPT_FLAG_DECODING_PARAM
 477
 478 static const AVOption options[] = {
 479     {NULL},
 480 };
 481
 482 #undef D
 483 #undef OFFSET
 484
 485 static const AVClass async_context_class = {
 486     .class_name = "Async",
 487     .item_name  = av_default_item_name,
 488     .option     = options,
 489     .version    = LIBAVUTIL_VERSION_INT,
 490 };
 491
 492 const URLProtocol ff_async_protocol = {
 493     .name                = "async",
 494     .url_open2           = async_open,
 495     .url_read            = async_read,
 496     .url_seek            = async_seek,
 497     .url_close           = async_close,
 498     .priv_data_size      = sizeof(AsyncContext),
 499     .priv_data_class     = &async_context_class,
 500 };
 501
 502 #if 0
 503
 504 #define TEST_SEEK_POS    (1536)
 505 #define TEST_STREAM_SIZE (2048)
 506
 507 typedef struct TestContext {
 508     AVClass        *class;
 509     int64_t         logical_pos;
 510     int64_t         logical_size;
 511
 512     /* options */
 513     int             opt_read_error;
 514 } TestContext;
 515
 516 static int async_test_open(URLContext *h, const char *arg, int flags, AVDictionary **options)
 517 {
 518     TestContext *c = h->priv_data;
 519     c->logical_pos  = 0;
 520     c->logical_size = TEST_STREAM_SIZE;
 521     return 0;
 522 }
 523
 524 static int async_test_close(URLContext *h)
 525 {
 526     return 0;
 527 }
 528
 529 static int async_test_read(URLContext *h, unsigned char *buf, int size)
 530 {
 531     TestContext *c = h->priv_data;
 532     int          i;
 533     int          read_len = 0;
 534
 535     if (c->opt_read_error)
 536         return c->opt_read_error;
 537
 538     if (c->logical_pos >= c->logical_size)
 539         return AVERROR_EOF;
 540
 541     for (i = 0; i < size; ++i) {
 542         buf[i] = c->logical_pos & 0xFF;
 543
 544         c->logical_pos++;
 545         read_len++;
 546
 547         if (c->logical_pos >= c->logical_size)
 548             break;
 549     }
 550
 551     return read_len;
 552 }
 553
 554 static int64_t async_test_seek(URLContext *h, int64_t pos, int whence)
 555 {
 556     TestContext *c = h->priv_data;
 557     int64_t      new_logical_pos;
 558
 559     if (whence == AVSEEK_SIZE) {
 560         return c->logical_size;
 561     } else if (whence == SEEK_CUR) {
 562         new_logical_pos = pos + c->logical_pos;
 563     } else if (whence == SEEK_SET){
 564         new_logical_pos = pos;
 565     } else {
 566         return AVERROR(EINVAL);
 567     }
 568     if (new_logical_pos < 0)
 569         return AVERROR(EINVAL);
 570
 571     c->logical_pos = new_logical_pos;
 572     return new_logical_pos;
 573 }
 574
 575 #define OFFSET(x) offsetof(TestContext, x)
 576 #define D AV_OPT_FLAG_DECODING_PARAM
 577
 578 static const AVOption async_test_options[] = {
 579     { "async-test-read-error",      "cause read fail",
 580         OFFSET(opt_read_error),     AV_OPT_TYPE_INT, { .i64 = 0 }, INT_MIN, INT_MAX, .flags = D },
 581     {NULL},
 582 };
 583
 584 #undef D
 585 #undef OFFSET
 586
 587 static const AVClass async_test_context_class = {
 588     .class_name = "Async-Test",
 589     .item_name  = av_default_item_name,
 590     .option     = async_test_options,
 591     .version    = LIBAVUTIL_VERSION_INT,
 592 };
 593
 594 const URLProtocol ff_async_test_protocol = {
 595     .name                = "async-test",
 596     .url_open2           = async_test_open,
 597     .url_read            = async_test_read,
 598     .url_seek            = async_test_seek,
 599     .url_close           = async_test_close,
 600     .priv_data_size      = sizeof(TestContext),
 601     .priv_data_class     = &async_test_context_class,
 602 };
 603
 604 int main(void)
 605 {
 606     URLContext   *h = NULL;
 607     int           i;
 608     int           ret;
 609     int64_t       size;
 610     int64_t       pos;
 611     int64_t       read_len;
 612     unsigned char buf[4096];
 613     AVDictionary *opts = NULL;
 614
 615     ffurl_register_protocol(&ff_async_protocol);
 616     ffurl_register_protocol(&ff_async_test_protocol);
 617
 618     /*
 619      * test normal read
 620      */
 621     ret = ffurl_open_whitelist(&h, "async:async-test:", AVIO_FLAG_READ,
 622                                NULL, NULL, NULL, NULL, NULL);
 623     printf("open: %d\n", ret);
 624
 625     size = ffurl_size(h);
 626     printf("size: %"PRId64"\n", size);
 627
 628     pos = ffurl_seek(h, 0, SEEK_CUR);
 629     read_len = 0;
 630     while (1) {
 631         ret = ffurl_read(h, buf, sizeof(buf));
 632         if (ret == AVERROR_EOF) {
 633             printf("read-error: AVERROR_EOF at %"PRId64"\n", ffurl_seek(h, 0, SEEK_CUR));
 634             break;
 635         }
 636         else if (ret == 0)
 637             break;
 638         else if (ret < 0) {
 639             printf("read-error: %d at %"PRId64"\n", ret, ffurl_seek(h, 0, SEEK_CUR));
 640             goto fail;
 641         } else {
 642             for (i = 0; i < ret; ++i) {
 643                 if (buf[i] != (pos & 0xFF)) {
 644                     printf("read-mismatch: actual %d, expecting %d, at %"PRId64"\n",
 645                            (int)buf[i], (int)(pos & 0xFF), pos);
 646                     break;
 647                 }
 648                 pos++;
 649             }
 650         }
 651
 652         read_len += ret;
 653     }
 654     printf("read: %"PRId64"\n", read_len);
 655
 656     /*
 657      * test normal seek
 658      */
 659     ret = ffurl_read(h, buf, 1);
 660     printf("read: %d\n", ret);
 661
 662     pos = ffurl_seek(h, TEST_SEEK_POS, SEEK_SET);
 663     printf("seek: %"PRId64"\n", pos);
 664
 665     read_len = 0;
 666     while (1) {
 667         ret = ffurl_read(h, buf, sizeof(buf));
 668         if (ret == AVERROR_EOF)
 669             break;
 670         else if (ret == 0)
 671             break;
 672         else if (ret < 0) {
 673             printf("read-error: %d at %"PRId64"\n", ret, ffurl_seek(h, 0, SEEK_CUR));
 674             goto fail;
 675         } else {
 676             for (i = 0; i < ret; ++i) {
 677                 if (buf[i] != (pos & 0xFF)) {
 678                     printf("read-mismatch: actual %d, expecting %d, at %"PRId64"\n",
 679                            (int)buf[i], (int)(pos & 0xFF), pos);
 680                     break;
 681                 }
 682                 pos++;
 683             }
 684         }
 685
 686         read_len += ret;
 687     }
 688     printf("read: %"PRId64"\n", read_len);
 689
 690     ret = ffurl_read(h, buf, 1);
 691     printf("read: %d\n", ret);
 692
 693     /*
 694      * test read error
 695      */
 696     ffurl_close(h);
 697     av_dict_set_int(&opts, "async-test-read-error", -10000, 0);
 698     ret = ffurl_open_whitelist(&h, "async:async-test:", AVIO_FLAG_READ,
 699                                NULL, &opts, NULL, NULL, NULL);
 700     printf("open: %d\n", ret);
 701
 702     ret = ffurl_read(h, buf, 1);
 703     printf("read: %d\n", ret);
 704
 705 fail:
 706     av_dict_free(&opts);
 707     ffurl_close(h);
 708     return 0;
 709 }
 710
 711 #endif