git.sesse.net Git - nageru/blob - nageru/video_encoder.cpp

   1 #include <algorithm>
   2 #include <assert.h>
   3 #include <chrono>
   4 #include <epoxy/gl.h>
   5 #include <memory>
   6 #include <movit/image_format.h>
   7 #include <mutex>
   8 #include <netdb.h>
   9 #include <stdint.h>
  10 #include <stdio.h>
  11 #include <string.h>
  12 #include <string>
  13 #include <sys/socket.h>
  14 #include <thread>
  15 #include <time.h>
  16 #include <unistd.h>
  17 #include <vector>
  18
  19 extern "C" {
  20 #include <libavutil/mem.h>
  21 #include <libavformat/avformat.h>
  22 #include <libavformat/avio.h>
  23 #include <libavutil/avutil.h>
  24 #include <libavutil/rational.h>
  25 }
  26
  27 #include "audio_encoder.h"
  28 #ifdef HAVE_AV1
  29 #include "av1_encoder.h"
  30 #endif
  31 #include "defs.h"
  32 #include "shared/ffmpeg_raii.h"
  33 #include "flags.h"
  34 #include "shared/httpd.h"
  35 #include "shared/mux.h"
  36 #include "quicksync_encoder.h"
  37 #include "shared/timebase.h"
  38 #include "x264_encoder.h"
  39 #include "video_encoder.h"
  40 #include "shared/metrics.h"
  41 #include "shared/ref_counted_gl_sync.h"
  42 #include "shared/shared_defs.h"
  43
  44 class RefCountedFrame;
  45
  46 using namespace std;
  47 using namespace std::chrono;
  48 using namespace movit;
  49
  50 namespace {
  51
  52 string generate_local_dump_filename(int frame)
  53 {
  54         time_t now = time(NULL);
  55         tm now_tm;
  56         localtime_r(&now, &now_tm);
  57
  58         char timestamp[64];
  59         strftime(timestamp, sizeof(timestamp), "%F-%H%M%S%z", &now_tm);
  60
  61         // Use the frame number to disambiguate between two cuts starting
  62         // on the same second.
  63         char filename[256];
  64         snprintf(filename, sizeof(filename), "%s/%s%s-f%02d%s",
  65                 global_flags.recording_dir.c_str(),
  66                 LOCAL_DUMP_PREFIX, timestamp, frame % 100, LOCAL_DUMP_SUFFIX);
  67         return filename;
  68 }
  69
  70 }  // namespace
  71
  72 VideoEncoder::VideoEncoder(ResourcePool *resource_pool, QSurface *surface, const std::string &va_display, int width, int height, HTTPD *httpd, DiskSpaceEstimator *disk_space_estimator)
  73         : resource_pool(resource_pool), surface(surface), va_display(va_display), width(width), height(height), httpd(httpd), disk_space_estimator(disk_space_estimator)
  74 {
  75         // TODO: If we're outputting AV1, we can't use MPEG-TS currently.
  76         srt_oformat = av_guess_format("mpegts", nullptr, nullptr);
  77         assert(srt_oformat != nullptr);
  78
  79         oformat = av_guess_format(global_flags.stream_mux_name.c_str(), nullptr, nullptr);
  80         assert(oformat != nullptr);
  81         if (global_flags.stream_audio_codec_name.empty()) {
  82                 stream_audio_encoder.reset(new AudioEncoder(AUDIO_OUTPUT_CODEC_NAME, DEFAULT_AUDIO_OUTPUT_BIT_RATE, oformat));
  83         } else {
  84                 stream_audio_encoder.reset(new AudioEncoder(global_flags.stream_audio_codec_name, global_flags.stream_audio_codec_bitrate, oformat));
  85         }
  86         if (global_flags.x264_video_to_http || global_flags.x264_video_to_disk) {
  87                 x264_encoder.reset(new X264Encoder(oformat, /*use_separate_disk_params=*/false));
  88         }
  89         VideoCodecInterface *http_encoder = x264_encoder.get();
  90         VideoCodecInterface *disk_encoder = x264_encoder.get();
  91 #ifdef HAVE_AV1
  92         if (global_flags.av1_video_to_http) {
  93                 av1_encoder.reset(new AV1Encoder(oformat));
  94                 http_encoder = av1_encoder.get();
  95         }
  96 #endif
  97         if (global_flags.x264_separate_disk_encode) {
  98                 x264_disk_encoder.reset(new X264Encoder(oformat, /*use_separate_disk_params=*/true));
  99                 disk_encoder = x264_disk_encoder.get();
 100         }
 101
 102         string filename = generate_local_dump_filename(/*frame=*/0);
 103         quicksync_encoder.reset(new QuickSyncEncoder(filename, resource_pool, surface, va_display, width, height, oformat, http_encoder, disk_encoder, disk_space_estimator));
 104
 105         open_output_streams();
 106         stream_audio_encoder->add_mux(http_mux.get());
 107         if (srt_mux != nullptr) {
 108                 stream_audio_encoder->add_mux(srt_mux.get());
 109         }
 110         quicksync_encoder->set_http_mux(http_mux.get());
 111         if (srt_mux != nullptr) {
 112                 quicksync_encoder->set_srt_mux(srt_mux.get());
 113         }
 114         if (global_flags.x264_video_to_http) {
 115                 x264_encoder->add_mux(http_mux.get());
 116                 if (srt_mux != nullptr) {
 117                         x264_encoder->add_mux(srt_mux.get());
 118                 }
 119         }
 120 #ifdef HAVE_AV1
 121         if (global_flags.av1_video_to_http) {
 122                 av1_encoder->add_mux(http_mux.get());
 123                 if (srt_mux != nullptr) {
 124                         av1_encoder->add_mux(srt_mux.get());
 125                 }
 126         }
 127 #endif
 128 }
 129
 130 VideoEncoder::~VideoEncoder()
 131 {
 132         should_quit = true;
 133         quicksync_encoder->shutdown();
 134         x264_encoder.reset(nullptr);
 135         x264_disk_encoder.reset(nullptr);
 136         quicksync_encoder->close_file();
 137         quicksync_encoder.reset(nullptr);
 138         while (quicksync_encoders_in_shutdown.load() > 0) {
 139                 usleep(10000);
 140         }
 141 }
 142
 143 void VideoEncoder::do_cut(int frame)
 144 {
 145         string filename = generate_local_dump_filename(frame);
 146         printf("Starting new recording: %s\n", filename.c_str());
 147
 148         // Do the shutdown of the old encoder in a separate thread, since it can
 149         // take some time (it needs to wait for all the frames in the queue to be
 150         // done encoding, for one) and we are running on the main mixer thread.
 151         // However, since this means both encoders could be sending packets at
 152         // the same time, it means pts could come out of order to the stream mux,
 153         // and we need to plug it until the shutdown is complete.
 154         http_mux->plug();
 155         lock(qs_mu, qs_audio_mu);
 156         lock_guard<mutex> lock1(qs_mu, adopt_lock), lock2(qs_audio_mu, adopt_lock);
 157         QuickSyncEncoder *old_encoder = quicksync_encoder.release();  // When we go C++14, we can use move capture instead.
 158         X264Encoder *old_x264_encoder = nullptr;
 159         X264Encoder *old_x264_disk_encoder = nullptr;
 160         if (global_flags.x264_video_to_disk) {
 161                 old_x264_encoder = x264_encoder.release();
 162         }
 163         if (global_flags.x264_separate_disk_encode) {
 164                 old_x264_disk_encoder = x264_disk_encoder.release();
 165         }
 166         thread([old_encoder, old_x264_encoder, old_x264_disk_encoder, this]{
 167                 old_encoder->shutdown();
 168                 delete old_x264_encoder;
 169                 delete old_x264_disk_encoder;
 170                 old_encoder->close_file();
 171                 http_mux->unplug();
 172
 173                 // We cannot delete the encoder here, as this thread has no OpenGL context.
 174                 // We'll deal with it in begin_frame().
 175                 lock_guard<mutex> lock(qs_mu);
 176                 qs_needing_cleanup.emplace_back(old_encoder);
 177         }).detach();
 178
 179         if (global_flags.x264_video_to_disk) {
 180                 x264_encoder.reset(new X264Encoder(oformat, /*use_separate_disk_params=*/false));
 181                 assert(global_flags.x264_video_to_http);
 182                 if (global_flags.x264_video_to_http) {
 183                         x264_encoder->add_mux(http_mux.get());
 184                 }
 185                 if (overriding_bitrate != 0) {
 186                         x264_encoder->change_bitrate(overriding_bitrate);
 187                 }
 188         }
 189         X264Encoder *http_encoder = x264_encoder.get();
 190         X264Encoder *disk_encoder = x264_encoder.get();
 191         if (global_flags.x264_separate_disk_encode) {
 192                 x264_disk_encoder.reset(new X264Encoder(oformat, /*use_separate_disk_params=*/true));
 193                 disk_encoder = x264_disk_encoder.get();
 194         }
 195
 196         quicksync_encoder.reset(new QuickSyncEncoder(filename, resource_pool, surface, va_display, width, height, oformat, http_encoder, disk_encoder, disk_space_estimator));
 197         quicksync_encoder->set_http_mux(http_mux.get());
 198 }
 199
 200 void VideoEncoder::change_x264_bitrate(unsigned rate_kbit)
 201 {
 202         overriding_bitrate = rate_kbit;
 203         x264_encoder->change_bitrate(rate_kbit);
 204 }
 205
 206 void VideoEncoder::add_audio(int64_t pts, std::vector<float> audio)
 207 {
 208         // Take only qs_audio_mu, since add_audio() is thread safe
 209         // (we can only conflict with do_cut(), which takes qs_audio_mu)
 210         // and we don't want to contend with begin_frame().
 211         {
 212                 lock_guard<mutex> lock(qs_audio_mu);
 213                 quicksync_encoder->add_audio(pts, audio);
 214         }
 215         stream_audio_encoder->encode_audio(audio, pts + quicksync_encoder->global_delay());
 216 }
 217
 218 bool VideoEncoder::is_zerocopy() const
 219 {
 220         // Explicitly do _not_ take qs_mu; this is called from the mixer,
 221         // and qs_mu might be contended. is_zerocopy() is thread safe
 222         // and never called in parallel with do_cut() (both happen only
 223         // from the mixer thread).
 224         return quicksync_encoder->is_zerocopy();
 225 }
 226
 227 bool VideoEncoder::begin_frame(int64_t pts, int64_t duration, movit::YCbCrLumaCoefficients ycbcr_coefficients, const std::vector<RefCountedFrame> &input_frames, GLuint *y_tex, GLuint *cbcr_tex)
 228 {
 229         lock_guard<mutex> lock(qs_mu);
 230         qs_needing_cleanup.clear();  // Since we have an OpenGL context here, and are called regularly.
 231         return quicksync_encoder->begin_frame(pts, duration, ycbcr_coefficients, input_frames, y_tex, cbcr_tex);
 232 }
 233
 234 RefCountedGLsync VideoEncoder::end_frame()
 235 {
 236         want_srt_metric_update = true;
 237         lock_guard<mutex> lock(qs_mu);
 238         return quicksync_encoder->end_frame();
 239 }
 240
 241 void VideoEncoder::open_output_streams()
 242 {
 243         for (bool is_srt : {false, true}) {
 244                 if (is_srt && global_flags.srt_destination_host.empty()) {
 245                         continue;
 246                 }
 247
 248                 AVFormatContext *avctx = avformat_alloc_context();
 249                 avctx->oformat = is_srt ? srt_oformat : oformat;
 250
 251                 uint8_t *buf = (uint8_t *)av_malloc(MUX_BUFFER_SIZE);
 252                 avctx->pb = avio_alloc_context(buf, MUX_BUFFER_SIZE, 1, this, nullptr, nullptr, nullptr);
 253                 if (is_srt) {
 254                         avctx->pb->write_packet = &VideoEncoder::write_srt_packet_thunk;
 255                 } else {
 256                         avctx->pb->write_data_type = &VideoEncoder::write_packet2_thunk;
 257                         avctx->pb->ignore_boundary_point = 1;
 258                 }
 259
 260                 Mux::Codec video_codec;
 261                 if (global_flags.av1_video_to_http) {
 262                         video_codec = Mux::CODEC_AV1;
 263                 } else {
 264                         video_codec = Mux::CODEC_H264;
 265                 }
 266
 267                 avctx->flags = AVFMT_FLAG_CUSTOM_IO;
 268
 269                 string video_extradata;
 270                 if (global_flags.x264_video_to_http) {
 271                         video_extradata = x264_encoder->get_global_headers();
 272 #ifdef HAVE_AV1
 273                 } else if (global_flags.av1_video_to_http) {
 274                         video_extradata = av1_encoder->get_global_headers();
 275 #endif
 276                 }
 277
 278                 Mux *mux = new Mux(avctx, width, height, video_codec, video_extradata, stream_audio_encoder->get_codec_parameters().get(),
 279                         get_color_space(global_flags.ycbcr_rec709_coefficients), COARSE_TIMEBASE,
 280                         /*write_callback=*/nullptr, is_srt ? Mux::WRITE_BACKGROUND : Mux::WRITE_FOREGROUND, { is_srt ? &srt_mux_metrics : &http_mux_metrics });
 281                 if (is_srt) {
 282                         srt_mux.reset(mux);
 283                         srt_mux_metrics.init({{ "destination", "srt" }});
 284                         srt_metrics.init({{ "cardtype", "output" }});
 285                         global_metrics.add("srt_num_connection_attempts", {{ "cardtype", "output" }}, &metric_srt_num_connection_attempts);
 286                 } else {
 287                         http_mux.reset(mux);
 288                         http_mux_metrics.init({{ "destination", "http" }});
 289                 }
 290         }
 291 }
 292
 293 int VideoEncoder::write_packet2_thunk(void *opaque, uint8_t *buf, int buf_size, AVIODataMarkerType type, int64_t time)
 294 {
 295         VideoEncoder *video_encoder = (VideoEncoder *)opaque;
 296         return video_encoder->write_packet2(buf, buf_size, type, time);
 297 }
 298
 299 int VideoEncoder::write_packet2(uint8_t *buf, int buf_size, AVIODataMarkerType type, int64_t time)
 300 {
 301         if (type == AVIO_DATA_MARKER_SYNC_POINT || type == AVIO_DATA_MARKER_BOUNDARY_POINT) {
 302                 seen_sync_markers = true;
 303         } else if (type == AVIO_DATA_MARKER_UNKNOWN && !seen_sync_markers) {
 304                 // We don't know if this is a keyframe or not (the muxer could
 305                 // avoid marking it), so we just have to make the best of it.
 306                 type = AVIO_DATA_MARKER_SYNC_POINT;
 307         }
 308
 309         if (type == AVIO_DATA_MARKER_HEADER) {
 310                 http_mux_header.append((char *)buf, buf_size);
 311                 httpd->set_header(HTTPD::StreamID{ HTTPD::MAIN_STREAM, 0 }, http_mux_header);
 312         } else {
 313                 httpd->add_data(HTTPD::StreamID{ HTTPD::MAIN_STREAM, 0 }, (char *)buf, buf_size, type == AVIO_DATA_MARKER_SYNC_POINT, time, AVRational{ AV_TIME_BASE, 1 });
 314         }
 315         return buf_size;
 316 }
 317
 318 int VideoEncoder::write_srt_packet_thunk(void *opaque, uint8_t *buf, int buf_size)
 319 {
 320         VideoEncoder *video_encoder = (VideoEncoder *)opaque;
 321         return video_encoder->write_srt_packet(buf, buf_size);
 322 }
 323
 324 static string print_addrinfo(const addrinfo *ai)
 325 {
 326         char hoststr[NI_MAXHOST], portstr[NI_MAXSERV];
 327         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, hoststr, sizeof(hoststr), portstr, sizeof(portstr), NI_DGRAM | NI_NUMERICHOST | NI_NUMERICSERV) != 0) {
 328                 return "<unknown address>";  // Should basically never happen, since we're not doing DNS lookups.
 329         }
 330
 331         if (ai->ai_family == AF_INET6) {
 332                 return string("[") + hoststr + "]:" + portstr;
 333         } else {
 334                 return string(hoststr) + ":" + portstr;
 335         }
 336 }
 337
 338 int VideoEncoder::open_srt_socket()
 339 {
 340         int sock = srt_create_socket();
 341         if (sock == -1) {
 342                 fprintf(stderr, "srt_create_socket(): %s\n", srt_getlasterror_str());
 343                 return -1;
 344         }
 345
 346         SRT_TRANSTYPE live = SRTT_LIVE;
 347         if (srt_setsockopt(sock, 0, SRTO_TRANSTYPE, &live, sizeof(live)) < 0) {
 348                 fprintf(stderr, "srt_setsockopt(SRTO_TRANSTYPE): %s\n", srt_getlasterror_str());
 349                 srt_close(sock);
 350                 return -1;
 351         }
 352
 353         if (srt_setsockopt(sock, 0, SRTO_LATENCY, &global_flags.srt_output_latency_ms, sizeof(global_flags.srt_output_latency_ms)) < 0) {
 354                 fprintf(stderr, "srt_setsockopt(SRTO_LATENCY): %s\n", srt_getlasterror_str());
 355                 srt_close(sock);
 356                 return -1;
 357         }
 358
 359         if (!global_flags.srt_streamid.empty()) {
 360                 if (srt_setsockopt(sock, 0, SRTO_STREAMID, global_flags.srt_streamid.data(), global_flags.srt_streamid.size()) < 0) {
 361                         fprintf(stderr, "srt_setsockopt(SRTO_STREAMID): %s\n", srt_getlasterror_str());
 362                         srt_close(sock);
 363                         return -1;
 364                 }
 365         }
 366
 367         if (!global_flags.srt_passphrase.empty()) {
 368                 if (srt_setsockopt(sock, 0, SRTO_PASSPHRASE, global_flags.srt_passphrase.data(), global_flags.srt_passphrase.size()) < 0) {
 369                         fprintf(stderr, "srt_setsockopt(SRTO_PASSPHRASE): %s\n", srt_getlasterror_str());
 370                         srt_close(sock);
 371                         return -1;
 372                 }
 373         }
 374
 375         return sock;
 376 }
 377
 378 int VideoEncoder::connect_to_srt()
 379 {
 380         // We need to specify SOCK_DGRAM as a hint, or we'll get all addresses
 381         // three times (for each of TCP, UDP, raw).
 382         addrinfo hints;
 383         memset(&hints, 0, sizeof(hints));
 384         hints.ai_flags = AI_ADDRCONFIG;
 385         hints.ai_socktype = SOCK_DGRAM;
 386
 387         addrinfo *ai;
 388         int ret = getaddrinfo(global_flags.srt_destination_host.c_str(), global_flags.srt_destination_port.c_str(), &hints, &ai);
 389         if (ret != 0) {
 390                 fprintf(stderr, "getaddrinfo(%s:%s): %s\n", global_flags.srt_destination_host.c_str(), global_flags.srt_destination_port.c_str(), gai_strerror(ret));
 391                 return -1;
 392         }
 393
 394         unique_ptr<addrinfo, decltype(freeaddrinfo) *> ai_cleanup(ai, &freeaddrinfo);
 395
 396         for (const addrinfo *cur = ai; cur != nullptr; cur = cur->ai_next) {
 397                 // Seemingly, srt_create_socket() isn't universal; once we try to connect,
 398                 // it gets locked to either IPv4 or IPv6. So we need to create a new one
 399                 // for every address we try.
 400                 int sock = open_srt_socket();
 401                 if (sock == -1) {
 402                         // Die immediately.
 403                         return sock;
 404                 }
 405                 ++metric_srt_num_connection_attempts;
 406
 407                 // We do a non-blocking connect, so that we can check should_quit
 408                 // every now and then.
 409                 int blocking = 0;
 410                 if (srt_setsockopt(sock, 0, SRTO_RCVSYN, &blocking, sizeof(blocking)) < 0) {
 411                         fprintf(stderr, "srt_setsockopt(SRTO_SNDSYN=0): %s\n", srt_getlasterror_str());
 412                         srt_close(sock);
 413                         continue;
 414                 }
 415                 if (srt_connect(sock, cur->ai_addr, cur->ai_addrlen) < 0) {
 416                         fprintf(stderr, "srt_connect(%s): %s\n", print_addrinfo(cur).c_str(), srt_getlasterror_str());
 417                         srt_close(sock);
 418                         continue;
 419                 }
 420                 int eid = srt_epoll_create();
 421                 if (eid < 0) {
 422                         fprintf(stderr, "srt_epoll_create(): %s\n", srt_getlasterror_str());
 423                         srt_close(sock);
 424                         continue;
 425                 }
 426                 int modes = SRT_EPOLL_ERR | SRT_EPOLL_OUT;
 427                 if (srt_epoll_add_usock(eid, sock, &modes) < 0) {
 428                         fprintf(stderr, "srt_epoll_usock(): %s\n", srt_getlasterror_str());
 429                         srt_close(sock);
 430                         srt_epoll_release(eid);
 431                         continue;
 432                 }
 433                 bool ok;
 434                 while (!should_quit.load()) {
 435                         SRTSOCKET errfds[1], writefds[1];
 436                         int num_errfds = 1, num_writefds = 1;
 437                         int poll_time_ms = 100;
 438                         int ret = srt_epoll_wait(eid, errfds, &num_errfds, writefds, &num_writefds, poll_time_ms, 0, 0, 0, 0);
 439                         if (ret < 0) {
 440                                 if (srt_getlasterror(nullptr) == SRT_ETIMEOUT) {
 441                                         continue;
 442                                 } else {
 443                                         fprintf(stderr, "srt_epoll_wait(): %s\n", srt_getlasterror_str());
 444                                         srt_close(sock);
 445                                         srt_epoll_release(eid);
 446                                         return -1;
 447                                 }
 448                         } else if (ret > 0) {
 449                                 // The SRT epoll framework is pretty odd, but seemingly,
 450                                 // this is the way. Getting the same error code as srt_connect()
 451                                 // would normally return seems to be impossible, though.
 452                                 ok = (num_errfds == 0);
 453                                 break;
 454                                 fprintf(stderr, "num_errfds=%d num_writefds=%d last_err=%s\n", num_errfds, num_writefds, srt_getlasterror_str());
 455                                 break;
 456                         }
 457                 }
 458                 srt_epoll_release(eid);
 459                 if (should_quit.load()) {
 460                         srt_close(sock);
 461                         return -1;
 462                 }
 463                 if (ok) {
 464                         fprintf(stderr, "Connected to destination SRT endpoint at %s.\n", print_addrinfo(cur).c_str());
 465                         return sock;
 466                 } else {
 467                         fprintf(stderr, "srt_connect(%s): %s\n", print_addrinfo(cur).c_str(), srt_getlasterror_str());
 468                         srt_close(sock);
 469                 }
 470         }
 471
 472         // Out of candidates, so give up.
 473         return -1;
 474 }
 475
 476 int VideoEncoder::write_srt_packet(uint8_t *buf, int buf_size)
 477 {
 478         if (want_srt_metric_update.exchange(false) && srt_sock != -1) {
 479                 srt_metrics.update_srt_stats(srt_sock);
 480         }
 481
 482         bool has_drained = false;
 483         bool trying_reconnect = false;
 484         steady_clock::time_point first_connect_start;
 485
 486         while (buf_size > 0 && !should_quit.load()) {
 487                 if (srt_sock == -1) {
 488                         if (!trying_reconnect) {
 489                                 first_connect_start = steady_clock::now();
 490                                 trying_reconnect = true;
 491                         }
 492                         srt_sock = connect_to_srt();
 493                         if (srt_sock == -1) {
 494                                 usleep(100000);
 495                                 if (!has_drained && duration<double>(steady_clock::now() - first_connect_start).count() >= global_flags.srt_output_latency_ms * 1e-3) {
 496                                         // The entire concept for SRT is to have fixed, low latency.
 497                                         // If we've been out for more than a latency period, we shouldn't
 498                                         // try to send the entire backlog. (But we should be tolerant
 499                                         // of a quick disconnect and reconnect.) Maybe it would be better
 500                                         // to have a sliding window of how much we remove, but it quickly
 501                                         // starts getting esoteric, so juts drop it all.
 502                                         fprintf(stderr, "WARNING: No SRT connection for more than %d ms, dropping data.\n",
 503                                                 global_flags.srt_output_latency_ms);
 504                                         srt_mux->drain();
 505                                         has_drained = true;
 506                                 }
 507                                 continue;
 508                         }
 509                         srt_metrics.update_srt_stats(srt_sock);
 510                 }
 511                 if (has_drained) {
 512                         // Now that we're reconnected, we can start accepting data again,
 513                         // but discard the rest of this write (it is very old by now).
 514                         srt_mux->undrain();
 515                         break;
 516                 }
 517                 int to_send = min(buf_size, SRT_LIVE_DEF_PLSIZE);
 518                 int ret = srt_send(srt_sock, (char *)buf, to_send);
 519                 if (ret < 0)  {
 520                         fprintf(stderr, "srt_send(): %s\n", srt_getlasterror_str());
 521                         srt_close(srt_sock);
 522                         srt_metrics.metric_srt_uptime_seconds = 0.0 / 0.0;
 523                         if (!trying_reconnect) {
 524                                 first_connect_start = steady_clock::now();
 525                                 trying_reconnect = true;
 526                         }
 527                         srt_sock = connect_to_srt();
 528                         continue;
 529                 }
 530                 buf += ret;
 531                 buf_size -= ret;
 532         }
 533         return buf_size;
 534 }
 535