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 Context {
  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 } Context;
  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     Context    *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     Context    *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     Context      *c    = h->priv_data;
 188     RingBuffer   *ring = &c->ring;
 189     int           ret  = 0;
 190     int64_t       seek_ret;
 191
 192     while (1) {
 193         int fifo_space, to_copy;
 194
 195         pthread_mutex_lock(&c->mutex);
 196         if (async_check_interrupt(h)) {
 197             c->io_eof_reached = 1;
 198             c->io_error       = AVERROR_EXIT;
 199             pthread_cond_signal(&c->cond_wakeup_main);
 200             pthread_mutex_unlock(&c->mutex);
 201             break;
 202         }
 203
 204         if (c->seek_request) {
 205             seek_ret = ffurl_seek(c->inner, c->seek_pos, c->seek_whence);
 206             if (seek_ret >= 0) {
 207                 c->io_eof_reached = 0;
 208                 c->io_error       = 0;
 209                 ring_reset(ring);
 210             }
 211
 212             c->seek_completed = 1;
 213             c->seek_ret       = seek_ret;
 214             c->seek_request   = 0;
 215
 216
 217             pthread_cond_signal(&c->cond_wakeup_main);
 218             pthread_mutex_unlock(&c->mutex);
 219             continue;
 220         }
 221
 222         fifo_space = ring_space(ring);
 223         if (c->io_eof_reached || fifo_space <= 0) {
 224             pthread_cond_signal(&c->cond_wakeup_main);
 225             pthread_cond_wait(&c->cond_wakeup_background, &c->mutex);
 226             pthread_mutex_unlock(&c->mutex);
 227             continue;
 228         }
 229         pthread_mutex_unlock(&c->mutex);
 230
 231         to_copy = FFMIN(4096, fifo_space);
 232         ret = ring_write(ring, h, to_copy);
 233
 234         pthread_mutex_lock(&c->mutex);
 235         if (ret <= 0) {
 236             c->io_eof_reached = 1;
 237             if (c->inner_io_error < 0)
 238                 c->io_error = c->inner_io_error;
 239         }
 240
 241         pthread_cond_signal(&c->cond_wakeup_main);
 242         pthread_mutex_unlock(&c->mutex);
 243     }
 244
 245     return NULL;
 246 }
 247
 248 static int async_open(URLContext *h, const char *arg, int flags, AVDictionary **options)
 249 {
 250     Context         *c = h->priv_data;
 251     int              ret;
 252     AVIOInterruptCB  interrupt_callback = {.callback = async_check_interrupt, .opaque = h};
 253
 254     av_strstart(arg, "async:", &arg);
 255
 256     ret = ring_init(&c->ring, BUFFER_CAPACITY, READ_BACK_CAPACITY);
 257     if (ret < 0)
 258         goto fifo_fail;
 259
 260     /* wrap interrupt callback */
 261     c->interrupt_callback = h->interrupt_callback;
 262     ret = ffurl_open_whitelist(&c->inner, arg, flags, &interrupt_callback, options, h->protocol_whitelist, h->protocol_blacklist, h);
 263     if (ret != 0) {
 264         av_log(h, AV_LOG_ERROR, "ffurl_open failed : %s, %s\n", av_err2str(ret), arg);
 265         goto url_fail;
 266     }
 267
 268     c->logical_size = ffurl_size(c->inner);
 269     h->is_streamed  = c->inner->is_streamed;
 270
 271     ret = pthread_mutex_init(&c->mutex, NULL);
 272     if (ret != 0) {
 273         ret = AVERROR(ret);
 274         av_log(h, AV_LOG_ERROR, "pthread_mutex_init failed : %s\n", av_err2str(ret));
 275         goto mutex_fail;
 276     }
 277
 278     ret = pthread_cond_init(&c->cond_wakeup_main, NULL);
 279     if (ret != 0) {
 280         ret = AVERROR(ret);
 281         av_log(h, AV_LOG_ERROR, "pthread_cond_init failed : %s\n", av_err2str(ret));
 282         goto cond_wakeup_main_fail;
 283     }
 284
 285     ret = pthread_cond_init(&c->cond_wakeup_background, NULL);
 286     if (ret != 0) {
 287         ret = AVERROR(ret);
 288         av_log(h, AV_LOG_ERROR, "pthread_cond_init failed : %s\n", av_err2str(ret));
 289         goto cond_wakeup_background_fail;
 290     }
 291
 292     ret = pthread_create(&c->async_buffer_thread, NULL, async_buffer_task, h);
 293     if (ret) {
 294         ret = AVERROR(ret);
 295         av_log(h, AV_LOG_ERROR, "pthread_create failed : %s\n", av_err2str(ret));
 296         goto thread_fail;
 297     }
 298
 299     return 0;
 300
 301 thread_fail:
 302     pthread_cond_destroy(&c->cond_wakeup_background);
 303 cond_wakeup_background_fail:
 304     pthread_cond_destroy(&c->cond_wakeup_main);
 305 cond_wakeup_main_fail:
 306     pthread_mutex_destroy(&c->mutex);
 307 mutex_fail:
 308     ffurl_closep(&c->inner);
 309 url_fail:
 310     ring_destroy(&c->ring);
 311 fifo_fail:
 312     return ret;
 313 }
 314
 315 static int async_close(URLContext *h)
 316 {
 317     Context *c = h->priv_data;
 318     int      ret;
 319
 320     pthread_mutex_lock(&c->mutex);
 321     c->abort_request = 1;
 322     pthread_cond_signal(&c->cond_wakeup_background);
 323     pthread_mutex_unlock(&c->mutex);
 324
 325     ret = pthread_join(c->async_buffer_thread, NULL);
 326     if (ret != 0)
 327         av_log(h, AV_LOG_ERROR, "pthread_join(): %s\n", av_err2str(ret));
 328
 329     pthread_cond_destroy(&c->cond_wakeup_background);
 330     pthread_cond_destroy(&c->cond_wakeup_main);
 331     pthread_mutex_destroy(&c->mutex);
 332     ffurl_closep(&c->inner);
 333     ring_destroy(&c->ring);
 334
 335     return 0;
 336 }
 337
 338 static int async_read_internal(URLContext *h, void *dest, int size)
 339 {
 340     Context      *c       = h->priv_data;
 341     RingBuffer   *ring    = &c->ring;
 342     int     read_complete = !dest;
 343     int           to_read = size;
 344     int           ret     = 0;
 345
 346     pthread_mutex_lock(&c->mutex);
 347
 348     while (to_read > 0) {
 349         int fifo_size, to_copy;
 350         if (async_check_interrupt(h)) {
 351             ret = AVERROR_EXIT;
 352             break;
 353         }
 354         fifo_size = ring_size(ring);
 355         to_copy   = FFMIN(to_read, fifo_size);
 356         if (to_copy > 0) {
 357             ring_read(ring, dest, to_copy);
 358             if (dest)
 359                 dest = (uint8_t *)dest + to_copy;
 360             c->logical_pos += to_copy;
 361             to_read        -= to_copy;
 362             ret             = size - to_read;
 363
 364             if (to_read <= 0 || !read_complete)
 365                 break;
 366         } else if (c->io_eof_reached) {
 367             if (ret <= 0) {
 368                 if (c->io_error)
 369                     ret = c->io_error;
 370                 else
 371                     ret = AVERROR_EOF;
 372             }
 373             break;
 374         }
 375         pthread_cond_signal(&c->cond_wakeup_background);
 376         pthread_cond_wait(&c->cond_wakeup_main, &c->mutex);
 377     }
 378
 379     pthread_cond_signal(&c->cond_wakeup_background);
 380     pthread_mutex_unlock(&c->mutex);
 381
 382     return ret;
 383 }
 384
 385 static int async_read(URLContext *h, unsigned char *buf, int size)
 386 {
 387     return async_read_internal(h, buf, size);
 388 }
 389
 390 static int64_t async_seek(URLContext *h, int64_t pos, int whence)
 391 {
 392     Context      *c    = h->priv_data;
 393     RingBuffer   *ring = &c->ring;
 394     int64_t       ret;
 395     int64_t       new_logical_pos;
 396     int fifo_size;
 397     int fifo_size_of_read_back;
 398
 399     if (whence == AVSEEK_SIZE) {
 400         av_log(h, AV_LOG_TRACE, "async_seek: AVSEEK_SIZE: %"PRId64"\n", (int64_t)c->logical_size);
 401         return c->logical_size;
 402     } else if (whence == SEEK_CUR) {
 403         av_log(h, AV_LOG_TRACE, "async_seek: %"PRId64"\n", pos);
 404         new_logical_pos = pos + c->logical_pos;
 405     } else if (whence == SEEK_SET){
 406         av_log(h, AV_LOG_TRACE, "async_seek: %"PRId64"\n", pos);
 407         new_logical_pos = pos;
 408     } else {
 409         return AVERROR(EINVAL);
 410     }
 411     if (new_logical_pos < 0)
 412         return AVERROR(EINVAL);
 413
 414     fifo_size = ring_size(ring);
 415     fifo_size_of_read_back = ring_size_of_read_back(ring);
 416     if (new_logical_pos == c->logical_pos) {
 417         /* current position */
 418         return c->logical_pos;
 419     } else if ((new_logical_pos >= (c->logical_pos - fifo_size_of_read_back)) &&
 420                (new_logical_pos < (c->logical_pos + fifo_size + SHORT_SEEK_THRESHOLD))) {
 421         int pos_delta = (int)(new_logical_pos - c->logical_pos);
 422         /* fast seek */
 423         av_log(h, AV_LOG_TRACE, "async_seek: fask_seek %"PRId64" from %d dist:%d/%d\n",
 424                 new_logical_pos, (int)c->logical_pos,
 425                 (int)(new_logical_pos - c->logical_pos), fifo_size);
 426
 427         if (pos_delta > 0) {
 428             // fast seek forwards
 429             async_read_internal(h, NULL, pos_delta);
 430         } else {
 431             // fast seek backwards
 432             ring_drain(ring, pos_delta);
 433             c->logical_pos = new_logical_pos;
 434         }
 435
 436         return c->logical_pos;
 437     } else if (c->logical_size <= 0) {
 438         /* can not seek */
 439         return AVERROR(EINVAL);
 440     } else if (new_logical_pos > c->logical_size) {
 441         /* beyond end */
 442         return AVERROR(EINVAL);
 443     }
 444
 445     pthread_mutex_lock(&c->mutex);
 446
 447     c->seek_request   = 1;
 448     c->seek_pos       = new_logical_pos;
 449     c->seek_whence    = SEEK_SET;
 450     c->seek_completed = 0;
 451     c->seek_ret       = 0;
 452
 453     while (1) {
 454         if (async_check_interrupt(h)) {
 455             ret = AVERROR_EXIT;
 456             break;
 457         }
 458         if (c->seek_completed) {
 459             if (c->seek_ret >= 0)
 460                 c->logical_pos  = c->seek_ret;
 461             ret = c->seek_ret;
 462             break;
 463         }
 464         pthread_cond_signal(&c->cond_wakeup_background);
 465         pthread_cond_wait(&c->cond_wakeup_main, &c->mutex);
 466     }
 467
 468     pthread_mutex_unlock(&c->mutex);
 469
 470     return ret;
 471 }
 472
 473 #define OFFSET(x) offsetof(Context, x)
 474 #define D AV_OPT_FLAG_DECODING_PARAM
 475
 476 static const AVOption options[] = {
 477     {NULL},
 478 };
 479
 480 #undef D
 481 #undef OFFSET
 482
 483 static const AVClass async_context_class = {
 484     .class_name = "Async",
 485     .item_name  = av_default_item_name,
 486     .option     = options,
 487     .version    = LIBAVUTIL_VERSION_INT,
 488 };
 489
 490 const URLProtocol ff_async_protocol = {
 491     .name                = "async",
 492     .url_open2           = async_open,
 493     .url_read            = async_read,
 494     .url_seek            = async_seek,
 495     .url_close           = async_close,
 496     .priv_data_size      = sizeof(Context),
 497     .priv_data_class     = &async_context_class,
 498 };
 499
 500 #if 0
 501
 502 #define TEST_SEEK_POS    (1536)
 503 #define TEST_STREAM_SIZE (2048)
 504
 505 typedef struct TestContext {
 506     AVClass        *class;
 507     int64_t         logical_pos;
 508     int64_t         logical_size;
 509
 510     /* options */
 511     int             opt_read_error;
 512 } TestContext;
 513
 514 static int async_test_open(URLContext *h, const char *arg, int flags, AVDictionary **options)
 515 {
 516     TestContext *c = h->priv_data;
 517     c->logical_pos  = 0;
 518     c->logical_size = TEST_STREAM_SIZE;
 519     return 0;
 520 }
 521
 522 static int async_test_close(URLContext *h)
 523 {
 524     return 0;
 525 }
 526
 527 static int async_test_read(URLContext *h, unsigned char *buf, int size)
 528 {
 529     TestContext *c = h->priv_data;
 530     int          i;
 531     int          read_len = 0;
 532
 533     if (c->opt_read_error)
 534         return c->opt_read_error;
 535
 536     if (c->logical_pos >= c->logical_size)
 537         return AVERROR_EOF;
 538
 539     for (i = 0; i < size; ++i) {
 540         buf[i] = c->logical_pos & 0xFF;
 541
 542         c->logical_pos++;
 543         read_len++;
 544
 545         if (c->logical_pos >= c->logical_size)
 546             break;
 547     }
 548
 549     return read_len;
 550 }
 551
 552 static int64_t async_test_seek(URLContext *h, int64_t pos, int whence)
 553 {
 554     TestContext *c = h->priv_data;
 555     int64_t      new_logical_pos;
 556
 557     if (whence == AVSEEK_SIZE) {
 558         return c->logical_size;
 559     } else if (whence == SEEK_CUR) {
 560         new_logical_pos = pos + c->logical_pos;
 561     } else if (whence == SEEK_SET){
 562         new_logical_pos = pos;
 563     } else {
 564         return AVERROR(EINVAL);
 565     }
 566     if (new_logical_pos < 0)
 567         return AVERROR(EINVAL);
 568
 569     c->logical_pos = new_logical_pos;
 570     return new_logical_pos;
 571 }
 572
 573 #define OFFSET(x) offsetof(TestContext, x)
 574 #define D AV_OPT_FLAG_DECODING_PARAM
 575
 576 static const AVOption async_test_options[] = {
 577     { "async-test-read-error",      "cause read fail",
 578         OFFSET(opt_read_error),     AV_OPT_TYPE_INT, { .i64 = 0 }, INT_MIN, INT_MAX, .flags = D },
 579     {NULL},
 580 };
 581
 582 #undef D
 583 #undef OFFSET
 584
 585 static const AVClass async_test_context_class = {
 586     .class_name = "Async-Test",
 587     .item_name  = av_default_item_name,
 588     .option     = async_test_options,
 589     .version    = LIBAVUTIL_VERSION_INT,
 590 };
 591
 592 const URLProtocol ff_async_test_protocol = {
 593     .name                = "async-test",
 594     .url_open2           = async_test_open,
 595     .url_read            = async_test_read,
 596     .url_seek            = async_test_seek,
 597     .url_close           = async_test_close,
 598     .priv_data_size      = sizeof(TestContext),
 599     .priv_data_class     = &async_test_context_class,
 600 };
 601
 602 int main(void)
 603 {
 604     URLContext   *h = NULL;
 605     int           i;
 606     int           ret;
 607     int64_t       size;
 608     int64_t       pos;
 609     int64_t       read_len;
 610     unsigned char buf[4096];
 611     AVDictionary *opts = NULL;
 612
 613     ffurl_register_protocol(&ff_async_protocol);
 614     ffurl_register_protocol(&ff_async_test_protocol);
 615
 616     /*
 617      * test normal read
 618      */
 619     ret = ffurl_open_whitelist(&h, "async:async-test:", AVIO_FLAG_READ,
 620                                NULL, NULL, NULL, NULL, NULL);
 621     printf("open: %d\n", ret);
 622
 623     size = ffurl_size(h);
 624     printf("size: %"PRId64"\n", size);
 625
 626     pos = ffurl_seek(h, 0, SEEK_CUR);
 627     read_len = 0;
 628     while (1) {
 629         ret = ffurl_read(h, buf, sizeof(buf));
 630         if (ret == AVERROR_EOF) {
 631             printf("read-error: AVERROR_EOF at %"PRId64"\n", ffurl_seek(h, 0, SEEK_CUR));
 632             break;
 633         }
 634         else if (ret == 0)
 635             break;
 636         else if (ret < 0) {
 637             printf("read-error: %d at %"PRId64"\n", ret, ffurl_seek(h, 0, SEEK_CUR));
 638             goto fail;
 639         } else {
 640             for (i = 0; i < ret; ++i) {
 641                 if (buf[i] != (pos & 0xFF)) {
 642                     printf("read-mismatch: actual %d, expecting %d, at %"PRId64"\n",
 643                            (int)buf[i], (int)(pos & 0xFF), pos);
 644                     break;
 645                 }
 646                 pos++;
 647             }
 648         }
 649
 650         read_len += ret;
 651     }
 652     printf("read: %"PRId64"\n", read_len);
 653
 654     /*
 655      * test normal seek
 656      */
 657     ret = ffurl_read(h, buf, 1);
 658     printf("read: %d\n", ret);
 659
 660     pos = ffurl_seek(h, TEST_SEEK_POS, SEEK_SET);
 661     printf("seek: %"PRId64"\n", pos);
 662
 663     read_len = 0;
 664     while (1) {
 665         ret = ffurl_read(h, buf, sizeof(buf));
 666         if (ret == AVERROR_EOF)
 667             break;
 668         else if (ret == 0)
 669             break;
 670         else if (ret < 0) {
 671             printf("read-error: %d at %"PRId64"\n", ret, ffurl_seek(h, 0, SEEK_CUR));
 672             goto fail;
 673         } else {
 674             for (i = 0; i < ret; ++i) {
 675                 if (buf[i] != (pos & 0xFF)) {
 676                     printf("read-mismatch: actual %d, expecting %d, at %"PRId64"\n",
 677                            (int)buf[i], (int)(pos & 0xFF), pos);
 678                     break;
 679                 }
 680                 pos++;
 681             }
 682         }
 683
 684         read_len += ret;
 685     }
 686     printf("read: %"PRId64"\n", read_len);
 687
 688     ret = ffurl_read(h, buf, 1);
 689     printf("read: %d\n", ret);
 690
 691     /*
 692      * test read error
 693      */
 694     ffurl_close(h);
 695     av_dict_set_int(&opts, "async-test-read-error", -10000, 0);
 696     ret = ffurl_open_whitelist(&h, "async:async-test:", AVIO_FLAG_READ,
 697                                NULL, &opts, NULL, NULL, NULL);
 698     printf("open: %d\n", ret);
 699
 700     ret = ffurl_read(h, buf, 1);
 701     printf("read: %d\n", ret);
 702
 703 fail:
 704     av_dict_free(&opts);
 705     ffurl_close(h);
 706     return 0;
 707 }
 708
 709 #endif